// The MIT License(MIT)
//
// Copyright(c) 2016 Cedric Guillemet
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files(the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions :
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

#define IMGUI_DEFINE_MATH_OPERATORS

// includes patches for multiview from
// https://github.com/CedricGuillemet/ImGuizmo/issues/15

namespace ImGuizmo
{
   static const float ZPI = 3.14159265358979323846f;
   static const float RAD2DEG = (180.f / ZPI);
   static const float DEG2RAD = (ZPI / 180.f);
   static const float gGizmoSizeClipSpace = 0.1f;
   const float screenRotateSize = 0.06f;

   ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
   // utility and math

   void FPU_MatrixF_x_MatrixF(const float *a, const float *b, float *r)
   {
      r[0] = a[0] * b[0] + a[1] * b[4] + a[2] * b[8] + a[3] * b[12];
      r[1] = a[0] * b[1] + a[1] * b[5] + a[2] * b[9] + a[3] * b[13];
      r[2] = a[0] * b[2] + a[1] * b[6] + a[2] * b[10] + a[3] * b[14];
      r[3] = a[0] * b[3] + a[1] * b[7] + a[2] * b[11] + a[3] * b[15];

      r[4] = a[4] * b[0] + a[5] * b[4] + a[6] * b[8] + a[7] * b[12];
      r[5] = a[4] * b[1] + a[5] * b[5] + a[6] * b[9] + a[7] * b[13];
      r[6] = a[4] * b[2] + a[5] * b[6] + a[6] * b[10] + a[7] * b[14];
      r[7] = a[4] * b[3] + a[5] * b[7] + a[6] * b[11] + a[7] * b[15];

      r[8] = a[8] * b[0] + a[9] * b[4] + a[10] * b[8] + a[11] * b[12];
      r[9] = a[8] * b[1] + a[9] * b[5] + a[10] * b[9] + a[11] * b[13];
      r[10] = a[8] * b[2] + a[9] * b[6] + a[10] * b[10] + a[11] * b[14];
      r[11] = a[8] * b[3] + a[9] * b[7] + a[10] * b[11] + a[11] * b[15];

      r[12] = a[12] * b[0] + a[13] * b[4] + a[14] * b[8] + a[15] * b[12];
      r[13] = a[12] * b[1] + a[13] * b[5] + a[14] * b[9] + a[15] * b[13];
      r[14] = a[12] * b[2] + a[13] * b[6] + a[14] * b[10] + a[15] * b[14];
      r[15] = a[12] * b[3] + a[13] * b[7] + a[14] * b[11] + a[15] * b[15];
   }

   //template <typename T> T LERP(T x, T y, float z) { return (x + (y - x)*z); }
   template <typename T> T Clamp(T x, T y, T z) { return ((x<y) ? y : ((x>z) ? z : x)); }
   template <typename T> T max(T x, T y) { return (x > y) ? x : y; }
   template <typename T> T min(T x, T y) { return (x < y) ? x : y; }
   template <typename T> bool IsWithin(T x, T y, T z) { return (x>=y) && (x<=z); }

   struct matrix_t;
   struct vec_t
   {
   public:
      float x, y, z, w;

      void Lerp(const vec_t& v, float t)
      {
         x += (v.x - x) * t;
         y += (v.y - y) * t;
         z += (v.z - z) * t;
         w += (v.w - w) * t;
      }

      void Set(float v) { x = y = z = w = v; }
      void Set(float _x, float _y, float _z = 0.f, float _w = 0.f) { x = _x; y = _y; z = _z; w = _w; }

      vec_t& operator -= (const vec_t& v) { x -= v.x; y -= v.y; z -= v.z; w -= v.w; return *this; }
      vec_t& operator += (const vec_t& v) { x += v.x; y += v.y; z += v.z; w += v.w; return *this; }
      vec_t& operator *= (const vec_t& v) { x *= v.x; y *= v.y; z *= v.z; w *= v.w; return *this; }
      vec_t& operator *= (float v) { x *= v;    y *= v;    z *= v;    w *= v;    return *this; }

      vec_t operator * (float f) const;
      vec_t operator - () const;
      vec_t operator - (const vec_t& v) const;
      vec_t operator + (const vec_t& v) const;
      vec_t operator * (const vec_t& v) const;

      const vec_t& operator + () const { return (*this); }
      float Length() const { return sqrtf(x*x + y*y + z*z); };
      float LengthSq() const { return (x*x + y*y + z*z); };
      vec_t Normalize() { (*this) *= (1.f / Length()); return (*this); }
      vec_t Normalize(const vec_t& v) { this->Set(v.x, v.y, v.z, v.w); this->Normalize(); return (*this); }
      vec_t Abs() const;
      void Cross(const vec_t& v)
      {
         vec_t res;
         res.x = y * v.z - z * v.y;
         res.y = z * v.x - x * v.z;
         res.z = x * v.y - y * v.x;

         x = res.x;
         y = res.y;
         z = res.z;
         w = 0.f;
      }
      void Cross(const vec_t& v1, const vec_t& v2)
      {
         x = v1.y * v2.z - v1.z * v2.y;
         y = v1.z * v2.x - v1.x * v2.z;
         z = v1.x * v2.y - v1.y * v2.x;
         w = 0.f;
      }
      float Dot(const vec_t &v) const
      {
         return (x * v.x) + (y * v.y) + (z * v.z) + (w * v.w);
      }
      float Dot3(const vec_t &v) const
      {
         return (x * v.x) + (y * v.y) + (z * v.z);
      }

      void Transform(const matrix_t& matrix);
      void Transform(const vec_t & s, const matrix_t& matrix);

      void TransformVector(const matrix_t& matrix);
      void TransformPoint(const matrix_t& matrix);
      void TransformVector(const vec_t& v, const matrix_t& matrix) { (*this) = v; this->TransformVector(matrix); }
      void TransformPoint(const vec_t& v, const matrix_t& matrix) { (*this) = v; this->TransformPoint(matrix); }

      float& operator [] (size_t index) { return ((float*)&x)[index]; }
      const float& operator [] (size_t index) const { return ((float*)&x)[index]; }
   };

   vec_t makeVect(float _x, float _y, float _z = 0.f, float _w = 0.f) { vec_t res; res.x = _x; res.y = _y; res.z = _z; res.w = _w; return res; }
   vec_t makeVect(ImVec2 v) { vec_t res; res.x = v.x; res.y = v.y; res.z = 0.f; res.w = 0.f; return res; }
   vec_t vec_t::operator * (float f) const { return makeVect(x * f, y * f, z * f, w *f); }
   vec_t vec_t::operator - () const { return makeVect(-x, -y, -z, -w); }
   vec_t vec_t::operator - (const vec_t& v) const { return makeVect(x - v.x, y - v.y, z - v.z, w - v.w); }
   vec_t vec_t::operator + (const vec_t& v) const { return makeVect(x + v.x, y + v.y, z + v.z, w + v.w); }
   vec_t vec_t::operator * (const vec_t& v) const { return makeVect(x * v.x, y * v.y, z * v.z, w * v.w); }
   vec_t vec_t::Abs() const { return makeVect(fabsf(x), fabsf(y), fabsf(z)); }

   vec_t Normalized(const vec_t& v) { vec_t res; res = v; res.Normalize(); return res; }
   vec_t Cross(const vec_t& v1, const vec_t& v2)
   {
      vec_t res;
      res.x = v1.y * v2.z - v1.z * v2.y;
      res.y = v1.z * v2.x - v1.x * v2.z;
      res.z = v1.x * v2.y - v1.y * v2.x;
      res.w = 0.f;
      return res;
   }

   float Dot(const vec_t &v1, const vec_t &v2)
   {
      return (v1.x * v2.x) + (v1.y * v2.y) + (v1.z * v2.z);
   }

   vec_t BuildPlan(const vec_t & p_point1, const vec_t & p_normal)
   {
      vec_t normal, res;
      normal.Normalize(p_normal);
      res.w = normal.Dot(p_point1);
      res.x = normal.x;
      res.y = normal.y;
      res.z = normal.z;
      return res;
   }

   struct matrix_t
   {
   public:

      union
      {
         float m[4][4];
         float m16[16];
         struct
         {
            vec_t right, up, dir, position;
         } v;
         vec_t component[4];
      };

      matrix_t(const matrix_t& other) { memcpy(&m16[0], &other.m16[0], sizeof(float) * 16); }
      matrix_t() {}

      operator float * () { return m16; }
      operator const float* () const { return m16; }
      void Translation(float _x, float _y, float _z) { this->Translation(makeVect(_x, _y, _z)); }

      void Translation(const vec_t& vt)
      {
         v.right.Set(1.f, 0.f, 0.f, 0.f);
         v.up.Set(0.f, 1.f, 0.f, 0.f);
         v.dir.Set(0.f, 0.f, 1.f, 0.f);
         v.position.Set(vt.x, vt.y, vt.z, 1.f);
      }

      void Scale(float _x, float _y, float _z)
      {
         v.right.Set(_x, 0.f, 0.f, 0.f);
         v.up.Set(0.f, _y, 0.f, 0.f);
         v.dir.Set(0.f, 0.f, _z, 0.f);
         v.position.Set(0.f, 0.f, 0.f, 1.f);
      }
      void Scale(const vec_t& s) { Scale(s.x, s.y, s.z); }

      matrix_t& operator *= (const matrix_t& mat)
      {
         matrix_t tmpMat;
         tmpMat = *this;
         tmpMat.Multiply(mat);
         *this = tmpMat;
         return *this;
      }
      matrix_t operator * (const matrix_t& mat) const
      {
         matrix_t matT;
         matT.Multiply(*this, mat);
         return matT;
      }

      void Multiply(const matrix_t &matrix)
      {
         matrix_t tmp;
         tmp = *this;

         FPU_MatrixF_x_MatrixF((float*)&tmp, (float*)&matrix, (float*)this);
      }

      void Multiply(const matrix_t &m1, const matrix_t &m2)
      {
         FPU_MatrixF_x_MatrixF((float*)&m1, (float*)&m2, (float*)this);
      }

      float GetDeterminant() const
      {
         return m[0][0] * m[1][1] * m[2][2] + m[0][1] * m[1][2] * m[2][0] + m[0][2] * m[1][0] * m[2][1] -
            m[0][2] * m[1][1] * m[2][0] - m[0][1] * m[1][0] * m[2][2] - m[0][0] * m[1][2] * m[2][1];
      }

      float Inverse(const matrix_t &srcMatrix, bool affine = false);
      void SetToIdentity()
      {
         v.right.Set(1.f, 0.f, 0.f, 0.f);
         v.up.Set(0.f, 1.f, 0.f, 0.f);
         v.dir.Set(0.f, 0.f, 1.f, 0.f);
         v.position.Set(0.f, 0.f, 0.f, 1.f);
      }
      void Transpose()
      {
         matrix_t tmpm;
         for (int l = 0; l < 4; l++)
         {
            for (int c = 0; c < 4; c++)
            {
               tmpm.m[l][c] = m[c][l];
            }
         }
         (*this) = tmpm;
      }

      void RotationAxis(const vec_t & axis, float angle);

      void OrthoNormalize()
      {
         v.right.Normalize();
         v.up.Normalize();
         v.dir.Normalize();
      }
   };

   void vec_t::Transform(const matrix_t& matrix)
   {
      vec_t out;

      out.x = x * matrix.m[0][0] + y * matrix.m[1][0] + z * matrix.m[2][0] + w * matrix.m[3][0];
      out.y = x * matrix.m[0][1] + y * matrix.m[1][1] + z * matrix.m[2][1] + w * matrix.m[3][1];
      out.z = x * matrix.m[0][2] + y * matrix.m[1][2] + z * matrix.m[2][2] + w * matrix.m[3][2];
      out.w = x * matrix.m[0][3] + y * matrix.m[1][3] + z * matrix.m[2][3] + w * matrix.m[3][3];

      x = out.x;
      y = out.y;
      z = out.z;
      w = out.w;
   }

   void vec_t::Transform(const vec_t & s, const matrix_t& matrix)
   {
      *this = s;
      Transform(matrix);
   }

   void vec_t::TransformPoint(const matrix_t& matrix)
   {
      vec_t out;

      out.x = x * matrix.m[0][0] + y * matrix.m[1][0] + z * matrix.m[2][0] + matrix.m[3][0];
      out.y = x * matrix.m[0][1] + y * matrix.m[1][1] + z * matrix.m[2][1] + matrix.m[3][1];
      out.z = x * matrix.m[0][2] + y * matrix.m[1][2] + z * matrix.m[2][2] + matrix.m[3][2];
      out.w = x * matrix.m[0][3] + y * matrix.m[1][3] + z * matrix.m[2][3] + matrix.m[3][3];

      x = out.x;
      y = out.y;
      z = out.z;
      w = out.w;
   }


   void vec_t::TransformVector(const matrix_t& matrix)
   {
      vec_t out;

      out.x = x * matrix.m[0][0] + y * matrix.m[1][0] + z * matrix.m[2][0];
      out.y = x * matrix.m[0][1] + y * matrix.m[1][1] + z * matrix.m[2][1];
      out.z = x * matrix.m[0][2] + y * matrix.m[1][2] + z * matrix.m[2][2];
      out.w = x * matrix.m[0][3] + y * matrix.m[1][3] + z * matrix.m[2][3];

      x = out.x;
      y = out.y;
      z = out.z;
      w = out.w;
   }

   float matrix_t::Inverse(const matrix_t &srcMatrix, bool affine)
   {
      float det = 0;

      if (affine)
      {
         det = GetDeterminant();
         float s = 1 / det;
         m[0][0] = (srcMatrix.m[1][1] * srcMatrix.m[2][2] - srcMatrix.m[1][2] * srcMatrix.m[2][1]) * s;
         m[0][1] = (srcMatrix.m[2][1] * srcMatrix.m[0][2] - srcMatrix.m[2][2] * srcMatrix.m[0][1]) * s;
         m[0][2] = (srcMatrix.m[0][1] * srcMatrix.m[1][2] - srcMatrix.m[0][2] * srcMatrix.m[1][1]) * s;
         m[1][0] = (srcMatrix.m[1][2] * srcMatrix.m[2][0] - srcMatrix.m[1][0] * srcMatrix.m[2][2]) * s;
         m[1][1] = (srcMatrix.m[2][2] * srcMatrix.m[0][0] - srcMatrix.m[2][0] * srcMatrix.m[0][2]) * s;
         m[1][2] = (srcMatrix.m[0][2] * srcMatrix.m[1][0] - srcMatrix.m[0][0] * srcMatrix.m[1][2]) * s;
         m[2][0] = (srcMatrix.m[1][0] * srcMatrix.m[2][1] - srcMatrix.m[1][1] * srcMatrix.m[2][0]) * s;
         m[2][1] = (srcMatrix.m[2][0] * srcMatrix.m[0][1] - srcMatrix.m[2][1] * srcMatrix.m[0][0]) * s;
         m[2][2] = (srcMatrix.m[0][0] * srcMatrix.m[1][1] - srcMatrix.m[0][1] * srcMatrix.m[1][0]) * s;
         m[3][0] = -(m[0][0] * srcMatrix.m[3][0] + m[1][0] * srcMatrix.m[3][1] + m[2][0] * srcMatrix.m[3][2]);
         m[3][1] = -(m[0][1] * srcMatrix.m[3][0] + m[1][1] * srcMatrix.m[3][1] + m[2][1] * srcMatrix.m[3][2]);
         m[3][2] = -(m[0][2] * srcMatrix.m[3][0] + m[1][2] * srcMatrix.m[3][1] + m[2][2] * srcMatrix.m[3][2]);
      }
      else
      {
         // transpose matrix
         float src[16];
         for (int i = 0; i < 4; ++i)
         {
            src[i] = srcMatrix.m16[i * 4];
            src[i + 4] = srcMatrix.m16[i * 4 + 1];
            src[i + 8] = srcMatrix.m16[i * 4 + 2];
            src[i + 12] = srcMatrix.m16[i * 4 + 3];
         }

         // calculate pairs for first 8 elements (cofactors)
         float tmp[12]; // temp array for pairs
         tmp[0] = src[10] * src[15];
         tmp[1] = src[11] * src[14];
         tmp[2] = src[9] * src[15];
         tmp[3] = src[11] * src[13];
         tmp[4] = src[9] * src[14];
         tmp[5] = src[10] * src[13];
         tmp[6] = src[8] * src[15];
         tmp[7] = src[11] * src[12];
         tmp[8] = src[8] * src[14];
         tmp[9] = src[10] * src[12];
         tmp[10] = src[8] * src[13];
         tmp[11] = src[9] * src[12];

         // calculate first 8 elements (cofactors)
         m16[0] = (tmp[0] * src[5] + tmp[3] * src[6] + tmp[4] * src[7]) - (tmp[1] * src[5] + tmp[2] * src[6] + tmp[5] * src[7]);
         m16[1] = (tmp[1] * src[4] + tmp[6] * src[6] + tmp[9] * src[7]) - (tmp[0] * src[4] + tmp[7] * src[6] + tmp[8] * src[7]);
         m16[2] = (tmp[2] * src[4] + tmp[7] * src[5] + tmp[10] * src[7]) - (tmp[3] * src[4] + tmp[6] * src[5] + tmp[11] * src[7]);
         m16[3] = (tmp[5] * src[4] + tmp[8] * src[5] + tmp[11] * src[6]) - (tmp[4] * src[4] + tmp[9] * src[5] + tmp[10] * src[6]);
         m16[4] = (tmp[1] * src[1] + tmp[2] * src[2] + tmp[5] * src[3]) - (tmp[0] * src[1] + tmp[3] * src[2] + tmp[4] * src[3]);
         m16[5] = (tmp[0] * src[0] + tmp[7] * src[2] + tmp[8] * src[3]) - (tmp[1] * src[0] + tmp[6] * src[2] + tmp[9] * src[3]);
         m16[6] = (tmp[3] * src[0] + tmp[6] * src[1] + tmp[11] * src[3]) - (tmp[2] * src[0] + tmp[7] * src[1] + tmp[10] * src[3]);
         m16[7] = (tmp[4] * src[0] + tmp[9] * src[1] + tmp[10] * src[2]) - (tmp[5] * src[0] + tmp[8] * src[1] + tmp[11] * src[2]);

         // calculate pairs for second 8 elements (cofactors)
         tmp[0] = src[2] * src[7];
         tmp[1] = src[3] * src[6];
         tmp[2] = src[1] * src[7];
         tmp[3] = src[3] * src[5];
         tmp[4] = src[1] * src[6];
         tmp[5] = src[2] * src[5];
         tmp[6] = src[0] * src[7];
         tmp[7] = src[3] * src[4];
         tmp[8] = src[0] * src[6];
         tmp[9] = src[2] * src[4];
         tmp[10] = src[0] * src[5];
         tmp[11] = src[1] * src[4];

         // calculate second 8 elements (cofactors)
         m16[8] = (tmp[0] * src[13] + tmp[3] * src[14] + tmp[4] * src[15]) - (tmp[1] * src[13] + tmp[2] * src[14] + tmp[5] * src[15]);
         m16[9] = (tmp[1] * src[12] + tmp[6] * src[14] + tmp[9] * src[15]) - (tmp[0] * src[12] + tmp[7] * src[14] + tmp[8] * src[15]);
         m16[10] = (tmp[2] * src[12] + tmp[7] * src[13] + tmp[10] * src[15]) - (tmp[3] * src[12] + tmp[6] * src[13] + tmp[11] * src[15]);
         m16[11] = (tmp[5] * src[12] + tmp[8] * src[13] + tmp[11] * src[14]) - (tmp[4] * src[12] + tmp[9] * src[13] + tmp[10] * src[14]);
         m16[12] = (tmp[2] * src[10] + tmp[5] * src[11] + tmp[1] * src[9]) - (tmp[4] * src[11] + tmp[0] * src[9] + tmp[3] * src[10]);
         m16[13] = (tmp[8] * src[11] + tmp[0] * src[8] + tmp[7] * src[10]) - (tmp[6] * src[10] + tmp[9] * src[11] + tmp[1] * src[8]);
         m16[14] = (tmp[6] * src[9] + tmp[11] * src[11] + tmp[3] * src[8]) - (tmp[10] * src[11] + tmp[2] * src[8] + tmp[7] * src[9]);
         m16[15] = (tmp[10] * src[10] + tmp[4] * src[8] + tmp[9] * src[9]) - (tmp[8] * src[9] + tmp[11] * src[10] + tmp[5] * src[8]);

         // calculate determinant
         det = src[0] * m16[0] + src[1] * m16[1] + src[2] * m16[2] + src[3] * m16[3];

         // calculate matrix inverse
         float invdet = 1 / det;
         for (int j = 0; j < 16; ++j)
         {
            m16[j] *= invdet;
         }
      }

      return det;
   }

   void matrix_t::RotationAxis(const vec_t & axis, float angle)
   {
      float length2 = axis.LengthSq();
      if (length2 < FLT_EPSILON)
      {
         SetToIdentity();
         return;
      }

      vec_t n = axis * (1.f / sqrtf(length2));
      float s = sinf(angle);
      float c = cosf(angle);
      float k = 1.f - c;

      float xx = n.x * n.x * k + c;
      float yy = n.y * n.y * k + c;
      float zz = n.z * n.z * k + c;
      float xy = n.x * n.y * k;
      float yz = n.y * n.z * k;
      float zx = n.z * n.x * k;
      float xs = n.x * s;
      float ys = n.y * s;
      float zs = n.z * s;

      m[0][0] = xx;
      m[0][1] = xy + zs;
      m[0][2] = zx - ys;
      m[0][3] = 0.f;
      m[1][0] = xy - zs;
      m[1][1] = yy;
      m[1][2] = yz + xs;
      m[1][3] = 0.f;
      m[2][0] = zx + ys;
      m[2][1] = yz - xs;
      m[2][2] = zz;
      m[2][3] = 0.f;
      m[3][0] = 0.f;
      m[3][1] = 0.f;
      m[3][2] = 0.f;
      m[3][3] = 1.f;
   }

   ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
   //

   enum MOVETYPE
   {
      NONE,
      MOVE_X,
      MOVE_Y,
      MOVE_Z,
      MOVE_YZ,
      MOVE_ZX,
      MOVE_XY,
      MOVE_SCREEN,
      ROTATE_X,
      ROTATE_Y,
      ROTATE_Z,
      ROTATE_SCREEN,
      SCALE_X,
      SCALE_Y,
      SCALE_Z,
      SCALE_XYZ
   };

   struct Context
   {
      Context() : mbUsing(false), mbEnable(true), mbUsingBounds(false)
      {
      }

      ImDrawList* mDrawList;

      MODE mMode;
      matrix_t mViewMat;
      matrix_t mProjectionMat;
      matrix_t mModel;
      matrix_t mModelInverse;
      matrix_t mModelSource;
      matrix_t mModelSourceInverse;
      matrix_t mMVP;
      matrix_t mViewProjection;

      vec_t mModelScaleOrigin;
      vec_t mCameraEye;
      vec_t mCameraRight;
      vec_t mCameraDir;
      vec_t mCameraUp;
      vec_t mRayOrigin;
      vec_t mRayVector;

      float  mRadiusSquareCenter;
      ImVec2 mScreenSquareCenter;
      ImVec2 mScreenSquareMin;
      ImVec2 mScreenSquareMax;

      float mScreenFactor;
      vec_t mRelativeOrigin;

      bool mbUsing;
      bool mbEnable;

      // translation
      vec_t mTranslationPlan;
      vec_t mTranslationPlanOrigin;
      vec_t mMatrixOrigin;

      // rotation
      vec_t mRotationVectorSource;
      float mRotationAngle;
      float mRotationAngleOrigin;
      //vec_t mWorldToLocalAxis;

      // scale
      vec_t mScale;
      vec_t mScaleValueOrigin;
      float mSaveMousePosx;

      // save axis factor when using gizmo
      bool mBelowAxisLimit[3];
      bool mBelowPlaneLimit[3];
      float mAxisFactor[3];

      // bounds stretching
      vec_t mBoundsPivot;
      vec_t mBoundsAnchor;
      vec_t mBoundsPlan;
      vec_t mBoundsLocalPivot;
      int mBoundsBestAxis;
      int mBoundsAxis[2];
      bool mbUsingBounds;
      matrix_t mBoundsMatrix;

      //
      int mCurrentOperation;

      float mX = 0.f;
      float mY = 0.f;
      float mWidth = 0.f;
      float mHeight = 0.f;
      float mXMax = 0.f;
      float mYMax = 0.f;
     float mDisplayRatio = 1.f;

     bool mIsOrthographic = false;
   };

   static Context gContext;

   static const float angleLimit = 0.96f;
   static const float planeLimit = 0.2f;

   static const vec_t directionUnary[3] = { makeVect(1.f, 0.f, 0.f), makeVect(0.f, 1.f, 0.f), makeVect(0.f, 0.f, 1.f) };
   static const ImU32 directionColor[3] = { 0xFF0000AA, 0xFF00AA00, 0xFFAA0000 };

   // Alpha: 100%: FF, 87%: DE, 70%: B3, 54%: 8A, 50%: 80, 38%: 61, 12%: 1F
   static const ImU32 planeColor[3] = { 0x610000AA, 0x6100AA00, 0x61AA0000 };
   static const ImU32 selectionColor = 0x8A1080FF;
   static const ImU32 inactiveColor = 0x99999999;
   static const ImU32 translationLineColor = 0xAAAAAAAA;
   static const char *translationInfoMask[] = { "X : %5.3f", "Y : %5.3f", "Z : %5.3f",
      "Y : %5.3f Z : %5.3f", "X : %5.3f Z : %5.3f", "X : %5.3f Y : %5.3f",
      "X : %5.3f Y : %5.3f Z : %5.3f" };
   static const char *scaleInfoMask[] = { "X : %5.2f", "Y : %5.2f", "Z : %5.2f", "XYZ : %5.2f" };
   static const char *rotationInfoMask[] = { "X : %5.2f deg %5.2f rad", "Y : %5.2f deg %5.2f rad", "Z : %5.2f deg %5.2f rad", "Screen : %5.2f deg %5.2f rad" };
   static const int translationInfoIndex[] = { 0,0,0, 1,0,0, 2,0,0, 1,2,0, 0,2,0, 0,1,0, 0,1,2 };
   static const float quadMin = 0.5f;
   static const float quadMax = 0.8f;
   static const float quadUV[8] = { quadMin, quadMin, quadMin, quadMax, quadMax, quadMax, quadMax, quadMin };
   static const int halfCircleSegmentCount = 64;
   static const float snapTension = 0.5f;

   ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
   //
   static int GetMoveType(vec_t *gizmoHitProportion);
   static int GetRotateType();
   static int GetScaleType();

   static ImVec2 worldToPos(const vec_t& worldPos, const matrix_t& mat)
   {
      vec_t trans;
      trans.TransformPoint(worldPos, mat);
      trans *= 0.5f / trans.w;
      trans += makeVect(0.5f, 0.5f);
      trans.y = 1.f - trans.y;
      trans.x *= gContext.mWidth;
      trans.y *= gContext.mHeight;
      trans.x += gContext.mX;
      trans.y += gContext.mY;
      return ImVec2(trans.x, trans.y);
   }

   static void ComputeCameraRay(vec_t &rayOrigin, vec_t &rayDir)
   {
      ImGuiIO& io = ImGui::GetIO();

      matrix_t mViewProjInverse;
      mViewProjInverse.Inverse(gContext.mViewMat * gContext.mProjectionMat);

      float mox = ((io.MousePos.x - gContext.mX) / gContext.mWidth) * 2.f - 1.f;
      float moy = (1.f - ((io.MousePos.y - gContext.mY) / gContext.mHeight)) * 2.f - 1.f;

      rayOrigin.Transform(makeVect(mox, moy, 0.f, 1.f), mViewProjInverse);
      rayOrigin *= 1.f / rayOrigin.w;
      vec_t rayEnd;
      rayEnd.Transform(makeVect(mox, moy, 1.f, 1.f), mViewProjInverse);
      rayEnd *= 1.f / rayEnd.w;
      rayDir = Normalized(rayEnd - rayOrigin);
   }

   static float GetSegmentLengthClipSpace(const vec_t& start, const vec_t& end)
   {
      vec_t startOfSegment = start;
      startOfSegment.TransformPoint(gContext.mMVP);
      if (fabsf(startOfSegment.w)> FLT_EPSILON) // check for axis aligned with camera direction
         startOfSegment *= 1.f / startOfSegment.w;

      vec_t endOfSegment = end;
      endOfSegment.TransformPoint(gContext.mMVP);
      if (fabsf(endOfSegment.w)> FLT_EPSILON) // check for axis aligned with camera direction
         endOfSegment *= 1.f / endOfSegment.w;

      vec_t clipSpaceAxis = endOfSegment - startOfSegment;
      clipSpaceAxis.y /= gContext.mDisplayRatio;
      float segmentLengthInClipSpace = sqrtf(clipSpaceAxis.x*clipSpaceAxis.x + clipSpaceAxis.y*clipSpaceAxis.y);
      return segmentLengthInClipSpace;
   }

   static float GetParallelogram(const vec_t& ptO, const vec_t& ptA, const vec_t& ptB)
   {
      vec_t pts[] = { ptO, ptA, ptB };
      for (unsigned int i = 0; i < 3; i++)
      {
         pts[i].TransformPoint(gContext.mMVP);
         if (fabsf(pts[i].w)> FLT_EPSILON) // check for axis aligned with camera direction
            pts[i] *= 1.f / pts[i].w;
      }
      vec_t segA = pts[1] - pts[0];
      vec_t segB = pts[2] - pts[0];
      segA.y /= gContext.mDisplayRatio;
      segB.y /= gContext.mDisplayRatio;
      vec_t segAOrtho = makeVect(-segA.y, segA.x);
      segAOrtho.Normalize();
      float dt = segAOrtho.Dot3(segB);
      float surface = sqrtf(segA.x*segA.x + segA.y*segA.y) * fabsf(dt);
      return surface;
   }

   inline vec_t PointOnSegment(const vec_t & point, const vec_t & vertPos1, const vec_t & vertPos2)
   {
      vec_t c = point - vertPos1;
      vec_t V;

      V.Normalize(vertPos2 - vertPos1);
      float d = (vertPos2 - vertPos1).Length();
      float t = V.Dot3(c);

      if (t < 0.f)
         return vertPos1;

      if (t > d)
         return vertPos2;

      return vertPos1 + V * t;
   }

   static float IntersectRayPlane(const vec_t & rOrigin, const vec_t& rVector, const vec_t& plan)
   {
      float numer = plan.Dot3(rOrigin) - plan.w;
      float denom = plan.Dot3(rVector);

      if (fabsf(denom) < FLT_EPSILON)  // normal is orthogonal to vector, cant intersect
         return -1.0f;

      return -(numer / denom);
   }

   static bool IsInContextRect( ImVec2 p )
   {
       return IsWithin( p.x, gContext.mX, gContext.mXMax ) && IsWithin(p.y, gContext.mY, gContext.mYMax );
   }

   void SetRect(float x, float y, float width, float height)
   {
       gContext.mX = x;
       gContext.mY = y;
       gContext.mWidth = width;
       gContext.mHeight = height;
       gContext.mXMax = gContext.mX + gContext.mWidth;
       gContext.mYMax = gContext.mY + gContext.mXMax;
      gContext.mDisplayRatio = width / height;
   }

   IMGUI_API void SetOrthographic(bool isOrthographic)
   {
      gContext.mIsOrthographic = isOrthographic;
   }

   void SetDrawlist()
   {
      gContext.mDrawList = ImGui::GetWindowDrawList();
   }

   void BeginFrame()
   {
      ImGuiIO& io = ImGui::GetIO();

      const ImU32 flags = ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoInputs | ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_NoFocusOnAppearing | ImGuiWindowFlags_NoBringToFrontOnFocus;
      ImGui::SetNextWindowSize(io.DisplaySize);
      ImGui::SetNextWindowPos(ImVec2(0, 0));
      
      ImGui::PushStyleColor(ImGuiCol_WindowBg, 0);
      ImGui::PushStyleColor(ImGuiCol_Border, 0);
      ImGui::PushStyleVar(ImGuiStyleVar_WindowRounding, 0.0f);
     
      ImGui::Begin("gizmo", NULL, flags);
      gContext.mDrawList = ImGui::GetWindowDrawList();
      ImGui::End();
      ImGui::PopStyleVar();
      ImGui::PopStyleColor(2);
   }

   bool IsUsing()
   {
      return gContext.mbUsing||gContext.mbUsingBounds;
   }

   bool IsOver()
   {
      return (GetMoveType(NULL) != NONE) || GetRotateType() != NONE || GetScaleType() != NONE || IsUsing();
   }

   void Enable(bool enable)
   {
      gContext.mbEnable = enable;
      if (!enable)
      {
          gContext.mbUsing = false;
          gContext.mbUsingBounds = false;
      }
   }

   static void ComputeContext(const float *view, const float *projection, float *matrix, MODE mode)
   {
      gContext.mMode = mode;
      gContext.mViewMat = *(matrix_t*)view;
      gContext.mProjectionMat = *(matrix_t*)projection;

      if (mode == LOCAL)
      {
         gContext.mModel = *(matrix_t*)matrix;
         gContext.mModel.OrthoNormalize();
      }
      else
      {
         gContext.mModel.Translation(((matrix_t*)matrix)->v.position);
      }
      gContext.mModelSource = *(matrix_t*)matrix;
      gContext.mModelScaleOrigin.Set(gContext.mModelSource.v.right.Length(), gContext.mModelSource.v.up.Length(), gContext.mModelSource.v.dir.Length());

      gContext.mModelInverse.Inverse(gContext.mModel);
      gContext.mModelSourceInverse.Inverse(gContext.mModelSource);
      gContext.mViewProjection = gContext.mViewMat * gContext.mProjectionMat;
      gContext.mMVP = gContext.mModel * gContext.mViewProjection;

      matrix_t viewInverse;
      viewInverse.Inverse(gContext.mViewMat);
      gContext.mCameraDir = viewInverse.v.dir;
      gContext.mCameraEye = viewInverse.v.position;
      gContext.mCameraRight = viewInverse.v.right;
      gContext.mCameraUp = viewInverse.v.up;

     // compute scale from the size of camera right vector projected on screen at the matrix position
     vec_t pointRight = viewInverse.v.right;
     pointRight.TransformPoint(gContext.mViewProjection);
     gContext.mScreenFactor = gGizmoSizeClipSpace / (pointRight.x / pointRight.w - gContext.mMVP.v.position.x / gContext.mMVP.v.position.w);

     vec_t rightViewInverse = viewInverse.v.right;
     rightViewInverse.TransformVector(gContext.mModelInverse);
     float rightLength = GetSegmentLengthClipSpace(makeVect(0.f, 0.f), rightViewInverse);
     gContext.mScreenFactor = gGizmoSizeClipSpace / rightLength;

      ImVec2 centerSSpace = worldToPos(makeVect(0.f, 0.f), gContext.mMVP);
      gContext.mScreenSquareCenter = centerSSpace;
      gContext.mScreenSquareMin = ImVec2(centerSSpace.x - 10.f, centerSSpace.y - 10.f);
      gContext.mScreenSquareMax = ImVec2(centerSSpace.x + 10.f, centerSSpace.y + 10.f);

      ComputeCameraRay(gContext.mRayOrigin, gContext.mRayVector);
   }

   static void ComputeColors(ImU32 *colors, int type, OPERATION operation)
   {
      if (gContext.mbEnable)
      {
         switch (operation)
         {
         case TRANSLATE:
            colors[0] = (type == MOVE_SCREEN) ? selectionColor : 0xFFFFFFFF;
            for (int i = 0; i < 3; i++)
            {
               colors[i + 1] = (type == (int)(MOVE_X + i)) ? selectionColor : directionColor[i];
               colors[i + 4] = (type == (int)(MOVE_YZ + i)) ? selectionColor : planeColor[i];
               colors[i + 4] = (type == MOVE_SCREEN) ? selectionColor : colors[i + 4];
            }
            break;
         case ROTATE:
            colors[0] = (type == ROTATE_SCREEN) ? selectionColor : 0xFFFFFFFF;
            for (int i = 0; i < 3; i++)
               colors[i + 1] = (type == (int)(ROTATE_X + i)) ? selectionColor : directionColor[i];
            break;
         case SCALE:
            colors[0] = (type == SCALE_XYZ) ? selectionColor : 0xFFFFFFFF;
            for (int i = 0; i < 3; i++)
               colors[i + 1] = (type == (int)(SCALE_X + i)) ? selectionColor : directionColor[i];
            break;
         case BOUNDS:
            break;
         }
      }
      else
      {
         for (int i = 0; i < 7; i++)
            colors[i] = inactiveColor;
      }
   }

   static void ComputeTripodAxisAndVisibility(int axisIndex, vec_t& dirAxis, vec_t& dirPlaneX, vec_t& dirPlaneY, bool& belowAxisLimit, bool& belowPlaneLimit)
   {
      dirAxis = directionUnary[axisIndex];
      dirPlaneX = directionUnary[(axisIndex + 1) % 3];
      dirPlaneY = directionUnary[(axisIndex + 2) % 3];

      if (gContext.mbUsing)
      {
         // when using, use stored factors so the gizmo doesn't flip when we translate
         belowAxisLimit = gContext.mBelowAxisLimit[axisIndex];
         belowPlaneLimit = gContext.mBelowPlaneLimit[axisIndex];

         dirAxis *= gContext.mAxisFactor[axisIndex];
         dirPlaneX *= gContext.mAxisFactor[(axisIndex + 1) % 3];
         dirPlaneY *= gContext.mAxisFactor[(axisIndex + 2) % 3];
      }
      else
      {
         // new method
         float lenDir = GetSegmentLengthClipSpace(makeVect(0.f, 0.f, 0.f), dirAxis);
         float lenDirMinus = GetSegmentLengthClipSpace(makeVect(0.f, 0.f, 0.f), -dirAxis);

         float lenDirPlaneX = GetSegmentLengthClipSpace(makeVect(0.f, 0.f, 0.f), dirPlaneX);
         float lenDirMinusPlaneX = GetSegmentLengthClipSpace(makeVect(0.f, 0.f, 0.f), -dirPlaneX);

         float lenDirPlaneY = GetSegmentLengthClipSpace(makeVect(0.f, 0.f, 0.f), dirPlaneY);
         float lenDirMinusPlaneY = GetSegmentLengthClipSpace(makeVect(0.f, 0.f, 0.f), -dirPlaneY);

         float mulAxis = (lenDir < lenDirMinus && fabsf(lenDir - lenDirMinus) > FLT_EPSILON) ? -1.f : 1.f;
         float mulAxisX = (lenDirPlaneX < lenDirMinusPlaneX && fabsf(lenDirPlaneX - lenDirMinusPlaneX) > FLT_EPSILON) ? -1.f : 1.f;
         float mulAxisY = (lenDirPlaneY < lenDirMinusPlaneY && fabsf(lenDirPlaneY - lenDirMinusPlaneY) > FLT_EPSILON) ? -1.f : 1.f;
         dirAxis *= mulAxis;
         dirPlaneX *= mulAxisX;
         dirPlaneY *= mulAxisY;

         // for axis
         float axisLengthInClipSpace = GetSegmentLengthClipSpace(makeVect(0.f, 0.f, 0.f), dirAxis * gContext.mScreenFactor);

         float paraSurf = GetParallelogram(makeVect(0.f, 0.f, 0.f), dirPlaneX * gContext.mScreenFactor, dirPlaneY * gContext.mScreenFactor);
         belowPlaneLimit = (paraSurf > 0.0025f);
         belowAxisLimit = (axisLengthInClipSpace > 0.02f);

         // and store values
         gContext.mAxisFactor[axisIndex] = mulAxis;
         gContext.mAxisFactor[(axisIndex + 1) % 3] = mulAxisX;
         gContext.mAxisFactor[(axisIndex + 2) % 3] = mulAxisY;
         gContext.mBelowAxisLimit[axisIndex] = belowAxisLimit;
         gContext.mBelowPlaneLimit[axisIndex] = belowPlaneLimit;
      }
   }

   static void ComputeSnap(float*value, float snap)
   {
      if (snap <= FLT_EPSILON)
         return;
      float modulo = fmodf(*value, snap);
      float moduloRatio = fabsf(modulo) / snap;
      if (moduloRatio < snapTension)
         *value -= modulo;
      else if (moduloRatio >(1.f - snapTension))
         *value = *value - modulo + snap * ((*value<0.f) ? -1.f : 1.f);
   }
   static void ComputeSnap(vec_t& value, float *snap)
   {
      for (int i = 0; i < 3; i++)
      {
         ComputeSnap(&value[i], snap[i]);
      }
   }

   static float ComputeAngleOnPlan()
   {
      const float len = IntersectRayPlane(gContext.mRayOrigin, gContext.mRayVector, gContext.mTranslationPlan);
      vec_t localPos = Normalized(gContext.mRayOrigin + gContext.mRayVector * len - gContext.mModel.v.position);

      vec_t perpendicularVector;
      perpendicularVector.Cross(gContext.mRotationVectorSource, gContext.mTranslationPlan);
      perpendicularVector.Normalize();
      float acosAngle = Clamp(Dot(localPos, gContext.mRotationVectorSource), -0.9999f, 0.9999f);
      float angle = acosf(acosAngle);
      angle *= (Dot(localPos, perpendicularVector) < 0.f) ? 1.f : -1.f;
      return angle;
   }

   static void DrawRotationGizmo(int type)
   {
      ImDrawList* drawList = gContext.mDrawList;

      // colors
      ImU32 colors[7];
      ComputeColors(colors, type, ROTATE);

     vec_t cameraToModelNormalized;
     if (gContext.mIsOrthographic)
     {
        matrix_t viewInverse;
        viewInverse.Inverse(*(matrix_t*)&gContext.mViewMat);
        cameraToModelNormalized = viewInverse.v.dir;
     }
     else
     {
        cameraToModelNormalized = Normalized(gContext.mModel.v.position - gContext.mCameraEye);
     }

      cameraToModelNormalized.TransformVector(gContext.mModelInverse);

      gContext.mRadiusSquareCenter = screenRotateSize * gContext.mHeight;

     for (int axis = 0; axis < 3; axis++)
      {
         ImVec2 circlePos[halfCircleSegmentCount];

         float angleStart = atan2f(cameraToModelNormalized[(4-axis)%3], cameraToModelNormalized[(3 - axis) % 3]) + ZPI * 0.5f;

         for (unsigned int i = 0; i < halfCircleSegmentCount; i++)
         {
            float ng = angleStart + ZPI * ((float)i / (float)halfCircleSegmentCount);
            vec_t axisPos = makeVect(cosf(ng), sinf(ng), 0.f);
            vec_t pos = makeVect(axisPos[axis], axisPos[(axis+1)%3], axisPos[(axis+2)%3]) * gContext.mScreenFactor;
            circlePos[i] = worldToPos(pos, gContext.mMVP);
         }

         float radiusAxis = sqrtf( (ImLengthSqr(worldToPos(gContext.mModel.v.position, gContext.mViewProjection) - circlePos[0]) ));
         if(radiusAxis > gContext.mRadiusSquareCenter)
           gContext.mRadiusSquareCenter = radiusAxis;

         drawList->AddPolyline(circlePos, halfCircleSegmentCount, colors[3 - axis], false, 2);
      }
      drawList->AddCircle(worldToPos(gContext.mModel.v.position, gContext.mViewProjection), gContext.mRadiusSquareCenter, colors[0], 64, 3.f);

      if (gContext.mbUsing)
      {
         ImVec2 circlePos[halfCircleSegmentCount +1];

         circlePos[0] = worldToPos(gContext.mModel.v.position, gContext.mViewProjection);
         for (unsigned int i = 1; i < halfCircleSegmentCount; i++)
         {
            float ng = gContext.mRotationAngle * ((float)(i-1) / (float)(halfCircleSegmentCount -1));
            matrix_t rotateVectorMatrix;
            rotateVectorMatrix.RotationAxis(gContext.mTranslationPlan, ng);
            vec_t pos;
            pos.TransformPoint(gContext.mRotationVectorSource, rotateVectorMatrix);
            pos *= gContext.mScreenFactor;
            circlePos[i] = worldToPos(pos + gContext.mModel.v.position, gContext.mViewProjection);
         }
         drawList->AddConvexPolyFilled(circlePos, halfCircleSegmentCount, 0x801080FF);
         drawList->AddPolyline(circlePos, halfCircleSegmentCount, 0xFF1080FF, true, 2);

         ImVec2 destinationPosOnScreen = circlePos[1];
         char tmps[512];
         ImFormatString(tmps, sizeof(tmps), rotationInfoMask[type - ROTATE_X], (gContext.mRotationAngle/ZPI)*180.f, gContext.mRotationAngle);
         drawList->AddText(ImVec2(destinationPosOnScreen.x + 15, destinationPosOnScreen.y + 15), 0xFF000000, tmps);
         drawList->AddText(ImVec2(destinationPosOnScreen.x + 14, destinationPosOnScreen.y + 14), 0xFFFFFFFF, tmps);
      }
   }

   static void DrawHatchedAxis(const vec_t& axis)
   {
      for (int j = 1; j < 10; j++)
      {
         ImVec2 baseSSpace2 = worldToPos(axis * 0.05f * (float)(j * 2) * gContext.mScreenFactor, gContext.mMVP);
         ImVec2 worldDirSSpace2 = worldToPos(axis * 0.05f * (float)(j * 2 + 1) * gContext.mScreenFactor, gContext.mMVP);
         gContext.mDrawList->AddLine(baseSSpace2, worldDirSSpace2, 0x80000000, 6.f);
      }
   }

   static void DrawScaleGizmo(int type)
   {
      ImDrawList* drawList = gContext.mDrawList;

      // colors
      ImU32 colors[7];
      ComputeColors(colors, type, SCALE);

      // draw
      vec_t scaleDisplay = { 1.f, 1.f, 1.f, 1.f };

      if (gContext.mbUsing)
         scaleDisplay = gContext.mScale;

      for (unsigned int i = 0; i < 3; i++)
      {
        vec_t dirPlaneX, dirPlaneY, dirAxis;
         bool belowAxisLimit, belowPlaneLimit;
         ComputeTripodAxisAndVisibility(i, dirAxis, dirPlaneX, dirPlaneY, belowAxisLimit, belowPlaneLimit);

         // draw axis
         if (belowAxisLimit)
         {
            ImVec2 baseSSpace = worldToPos(dirAxis * 0.1f * gContext.mScreenFactor, gContext.mMVP);
            ImVec2 worldDirSSpaceNoScale = worldToPos(dirAxis * gContext.mScreenFactor, gContext.mMVP);
            ImVec2 worldDirSSpace = worldToPos((dirAxis * scaleDisplay[i]) * gContext.mScreenFactor, gContext.mMVP);

            if (gContext.mbUsing)
            {
               drawList->AddLine(baseSSpace, worldDirSSpaceNoScale, 0xFF404040, 3.f);
               drawList->AddCircleFilled(worldDirSSpaceNoScale, 6.f, 0xFF404040);
            }

            drawList->AddLine(baseSSpace, worldDirSSpace, colors[i + 1], 3.f);
            drawList->AddCircleFilled(worldDirSSpace, 6.f, colors[i + 1]);

            if (gContext.mAxisFactor[i] < 0.f)
               DrawHatchedAxis(dirAxis * scaleDisplay[i]);
         }
      }

      // draw screen cirle
      drawList->AddCircleFilled(gContext.mScreenSquareCenter, 6.f, colors[0], 32);

      if (gContext.mbUsing)
      {
         //ImVec2 sourcePosOnScreen = worldToPos(gContext.mMatrixOrigin, gContext.mViewProjection);
         ImVec2 destinationPosOnScreen = worldToPos(gContext.mModel.v.position, gContext.mViewProjection);
         /*vec_t dif(destinationPosOnScreen.x - sourcePosOnScreen.x, destinationPosOnScreen.y - sourcePosOnScreen.y);
         dif.Normalize();
         dif *= 5.f;
         drawList->AddCircle(sourcePosOnScreen, 6.f, translationLineColor);
         drawList->AddCircle(destinationPosOnScreen, 6.f, translationLineColor);
         drawList->AddLine(ImVec2(sourcePosOnScreen.x + dif.x, sourcePosOnScreen.y + dif.y), ImVec2(destinationPosOnScreen.x - dif.x, destinationPosOnScreen.y - dif.y), translationLineColor, 2.f);
         */
         char tmps[512];
         //vec_t deltaInfo = gContext.mModel.v.position - gContext.mMatrixOrigin;
         int componentInfoIndex = (type - SCALE_X) * 3;
         ImFormatString(tmps, sizeof(tmps), scaleInfoMask[type - SCALE_X], scaleDisplay[translationInfoIndex[componentInfoIndex]]);
         drawList->AddText(ImVec2(destinationPosOnScreen.x + 15, destinationPosOnScreen.y + 15), 0xFF000000, tmps);
         drawList->AddText(ImVec2(destinationPosOnScreen.x + 14, destinationPosOnScreen.y + 14), 0xFFFFFFFF, tmps);
      }
   }


   static void DrawTranslationGizmo(int type)
   {
      ImDrawList* drawList = gContext.mDrawList;
      if (!drawList)
          return;

      // colors
      ImU32 colors[7];
      ComputeColors(colors, type, TRANSLATE);

      const ImVec2 origin = worldToPos(gContext.mModel.v.position, gContext.mViewProjection);

      // draw
      bool belowAxisLimit = false;
      bool belowPlaneLimit = false;
      for (unsigned int i = 0; i < 3; ++i)
      {
         vec_t dirPlaneX, dirPlaneY, dirAxis;
         ComputeTripodAxisAndVisibility(i, dirAxis, dirPlaneX, dirPlaneY, belowAxisLimit, belowPlaneLimit);

         // draw axis
         if (belowAxisLimit)
         {
            ImVec2 baseSSpace = worldToPos(dirAxis * 0.1f * gContext.mScreenFactor, gContext.mMVP);
            ImVec2 worldDirSSpace = worldToPos(dirAxis * gContext.mScreenFactor, gContext.mMVP);

            drawList->AddLine(baseSSpace, worldDirSSpace, colors[i + 1], 3.f);

            // Arrow head begin
            ImVec2 dir(origin - worldDirSSpace);

            float d = sqrtf(ImLengthSqr(dir));
            dir /= d; // Normalize
            dir *= 6.0f;

            ImVec2 ortogonalDir(dir.y, -dir.x); // Perpendicular vector
            ImVec2 a(worldDirSSpace + dir);
            drawList->AddTriangleFilled(worldDirSSpace - dir, a + ortogonalDir, a - ortogonalDir, colors[i + 1]);
            // Arrow head end

            if (gContext.mAxisFactor[i] < 0.f)
               DrawHatchedAxis(dirAxis);
         }

         // draw plane
         if (belowPlaneLimit)
         {
            ImVec2 screenQuadPts[4];
            for (int j = 0; j < 4; ++j)
            {
               vec_t cornerWorldPos = (dirPlaneX * quadUV[j * 2] + dirPlaneY  * quadUV[j * 2 + 1]) * gContext.mScreenFactor;
               screenQuadPts[j] = worldToPos(cornerWorldPos, gContext.mMVP);
            }
            drawList->AddPolyline(screenQuadPts, 4, directionColor[i], true, 1.0f);
            drawList->AddConvexPolyFilled(screenQuadPts, 4, colors[i + 4]);
         }
      }

      drawList->AddCircleFilled(gContext.mScreenSquareCenter, 6.f, colors[0], 32);

      if (gContext.mbUsing)
      {
         ImVec2 sourcePosOnScreen = worldToPos(gContext.mMatrixOrigin, gContext.mViewProjection);
         ImVec2 destinationPosOnScreen = worldToPos(gContext.mModel.v.position, gContext.mViewProjection);
         vec_t dif = { destinationPosOnScreen.x - sourcePosOnScreen.x, destinationPosOnScreen.y - sourcePosOnScreen.y, 0.f, 0.f };
         dif.Normalize();
         dif *= 5.f;
         drawList->AddCircle(sourcePosOnScreen, 6.f, translationLineColor);
         drawList->AddCircle(destinationPosOnScreen, 6.f, translationLineColor);
         drawList->AddLine(ImVec2(sourcePosOnScreen.x + dif.x, sourcePosOnScreen.y + dif.y), ImVec2(destinationPosOnScreen.x - dif.x, destinationPosOnScreen.y - dif.y), translationLineColor, 2.f);

         char tmps[512];
         vec_t deltaInfo = gContext.mModel.v.position - gContext.mMatrixOrigin;
         int componentInfoIndex = (type - MOVE_X) * 3;
         ImFormatString(tmps, sizeof(tmps), translationInfoMask[type - MOVE_X], deltaInfo[translationInfoIndex[componentInfoIndex]], deltaInfo[translationInfoIndex[componentInfoIndex + 1]], deltaInfo[translationInfoIndex[componentInfoIndex + 2]]);
         drawList->AddText(ImVec2(destinationPosOnScreen.x + 15, destinationPosOnScreen.y + 15), 0xFF000000, tmps);
         drawList->AddText(ImVec2(destinationPosOnScreen.x + 14, destinationPosOnScreen.y + 14), 0xFFFFFFFF, tmps);
      }
   }

   static bool CanActivate()
   {
      if (ImGui::IsMouseClicked(0) && !ImGui::IsAnyItemHovered() && !ImGui::IsAnyItemActive())
         return true;
      return false;
   }

   static void HandleAndDrawLocalBounds(float *bounds, matrix_t *matrix, float *snapValues, OPERATION operation)
   {
       ImGuiIO& io = ImGui::GetIO();
       ImDrawList* drawList = gContext.mDrawList;

       // compute best projection axis
       vec_t axesWorldDirections[3];
       vec_t bestAxisWorldDirection = { 0.0f, 0.0f, 0.0f, 0.0f };
       int axes[3];
       unsigned int numAxes = 1;
       axes[0] = gContext.mBoundsBestAxis;
       int bestAxis = axes[0];
       if (!gContext.mbUsingBounds)
       {
           numAxes = 0;
           float bestDot = 0.f;
           for (unsigned int i = 0; i < 3; i++)
           {
               vec_t dirPlaneNormalWorld;
               dirPlaneNormalWorld.TransformVector(directionUnary[i], gContext.mModelSource);
               dirPlaneNormalWorld.Normalize();

               float dt = fabsf( Dot(Normalized(gContext.mCameraEye - gContext.mModelSource.v.position), dirPlaneNormalWorld) );
               if ( dt >= bestDot )
               {
                   bestDot = dt;
                   bestAxis = i;
                   bestAxisWorldDirection = dirPlaneNormalWorld;
               }

               if( dt >= 0.1f )
               {
                   axes[numAxes] = i;
                   axesWorldDirections[numAxes] = dirPlaneNormalWorld;
                   ++numAxes;
               }
           }
       }

       if( numAxes == 0 )
       {
            axes[0] = bestAxis;
            axesWorldDirections[0] = bestAxisWorldDirection;
            numAxes = 1;
       }
       else if( bestAxis != axes[0] )
       {
          unsigned int bestIndex = 0;
          for (unsigned int i = 0; i < numAxes; i++)
          {
              if( axes[i] == bestAxis )
              {
                  bestIndex = i;
                  break;
              }
          }
          int tempAxis = axes[0];
          axes[0] = axes[bestIndex];
          axes[bestIndex] = tempAxis;
          vec_t tempDirection = axesWorldDirections[0];
          axesWorldDirections[0] = axesWorldDirections[bestIndex];
          axesWorldDirections[bestIndex] = tempDirection;
       }

       for (unsigned int axisIndex = 0; axisIndex < numAxes; ++axisIndex)
       {
           bestAxis = axes[axisIndex];
           bestAxisWorldDirection = axesWorldDirections[axisIndex];

           // corners
           vec_t aabb[4];

           int secondAxis = (bestAxis + 1) % 3;
           int thirdAxis = (bestAxis + 2) % 3;

           for (int i = 0; i < 4; i++)
           {
               aabb[i][3] = aabb[i][bestAxis] = 0.f;
               aabb[i][secondAxis] = bounds[secondAxis + 3 * (i >> 1)];
               aabb[i][thirdAxis] = bounds[thirdAxis + 3 * ((i >> 1) ^ (i & 1))];
           }

           // draw bounds
           unsigned int anchorAlpha = gContext.mbEnable ? 0xFF000000 : 0x80000000;

           matrix_t boundsMVP = gContext.mModelSource * gContext.mViewProjection;
           for (int i = 0; i < 4;i++)
           {
               ImVec2 worldBound1 = worldToPos(aabb[i], boundsMVP);
               ImVec2 worldBound2 = worldToPos(aabb[(i+1)%4], boundsMVP);
               if( !IsInContextRect( worldBound1 ) || !IsInContextRect( worldBound2 ) )
               {
                   continue;
               }
               float boundDistance = sqrtf(ImLengthSqr(worldBound1 - worldBound2));
               int stepCount = (int)(boundDistance / 10.f);
               stepCount = min( stepCount, 1000 );
               float stepLength = 1.f / (float)stepCount;
               for (int j = 0; j < stepCount; j++)
               {
                   float t1 = (float)j * stepLength;
                   float t2 = (float)j * stepLength + stepLength * 0.5f;
                   ImVec2 worldBoundSS1 = ImLerp(worldBound1, worldBound2, ImVec2(t1, t1));
                   ImVec2 worldBoundSS2 = ImLerp(worldBound1, worldBound2, ImVec2(t2, t2));
                   //drawList->AddLine(worldBoundSS1, worldBoundSS2, 0x000000 + anchorAlpha, 3.f);
               drawList->AddLine(worldBoundSS1, worldBoundSS2, 0xAAAAAA + anchorAlpha, 2.f);
               }
               vec_t midPoint = (aabb[i] + aabb[(i + 1) % 4] ) * 0.5f;
               ImVec2 midBound = worldToPos(midPoint, boundsMVP);
               static const float AnchorBigRadius = 8.f;
               static const float AnchorSmallRadius = 6.f;
               bool overBigAnchor = ImLengthSqr(worldBound1 - io.MousePos) <= (AnchorBigRadius*AnchorBigRadius);
               bool overSmallAnchor = ImLengthSqr(midBound - io.MousePos) <= (AnchorBigRadius*AnchorBigRadius);

            int type = NONE;
            vec_t gizmoHitProportion;

            switch (operation)
            {
            case TRANSLATE: type = GetMoveType(&gizmoHitProportion); break;
            case ROTATE: type = GetRotateType(); break;
            case SCALE: type = GetScaleType(); break;
            case BOUNDS: break;
            }
            if (type != NONE)
            {
               overBigAnchor = false;
               overSmallAnchor = false;
            }


               unsigned int bigAnchorColor = overBigAnchor ? selectionColor : (0xAAAAAA + anchorAlpha);
               unsigned int smallAnchorColor = overSmallAnchor ? selectionColor : (0xAAAAAA + anchorAlpha);

               drawList->AddCircleFilled(worldBound1, AnchorBigRadius, 0xFF000000);
            drawList->AddCircleFilled(worldBound1, AnchorBigRadius-1.2f, bigAnchorColor);

               drawList->AddCircleFilled(midBound, AnchorSmallRadius, 0xFF000000);
            drawList->AddCircleFilled(midBound, AnchorSmallRadius-1.2f, smallAnchorColor);
               int oppositeIndex = (i + 2) % 4;
               // big anchor on corners
               if (!gContext.mbUsingBounds && gContext.mbEnable && overBigAnchor && CanActivate())
               {
                   gContext.mBoundsPivot.TransformPoint(aabb[(i + 2) % 4], gContext.mModelSource);
                   gContext.mBoundsAnchor.TransformPoint(aabb[i], gContext.mModelSource);
                   gContext.mBoundsPlan = BuildPlan(gContext.mBoundsAnchor, bestAxisWorldDirection);
                   gContext.mBoundsBestAxis = bestAxis;
                   gContext.mBoundsAxis[0] = secondAxis;
                   gContext.mBoundsAxis[1] = thirdAxis;

                   gContext.mBoundsLocalPivot.Set(0.f);
                   gContext.mBoundsLocalPivot[secondAxis] = aabb[oppositeIndex][secondAxis];
                   gContext.mBoundsLocalPivot[thirdAxis] = aabb[oppositeIndex][thirdAxis];

                   gContext.mbUsingBounds = true;
                   gContext.mBoundsMatrix = gContext.mModelSource;
               }
               // small anchor on middle of segment
               if (!gContext.mbUsingBounds && gContext.mbEnable && overSmallAnchor && CanActivate())
               {
                   vec_t midPointOpposite = (aabb[(i + 2) % 4] + aabb[(i + 3) % 4]) * 0.5f;
                   gContext.mBoundsPivot.TransformPoint(midPointOpposite, gContext.mModelSource);
                   gContext.mBoundsAnchor.TransformPoint(midPoint, gContext.mModelSource);
                   gContext.mBoundsPlan = BuildPlan(gContext.mBoundsAnchor, bestAxisWorldDirection);
                   gContext.mBoundsBestAxis = bestAxis;
                   int indices[] = { secondAxis , thirdAxis };
                   gContext.mBoundsAxis[0] = indices[i%2];
                   gContext.mBoundsAxis[1] = -1;

                   gContext.mBoundsLocalPivot.Set(0.f);
                   gContext.mBoundsLocalPivot[gContext.mBoundsAxis[0]] = aabb[oppositeIndex][indices[i % 2]];// bounds[gContext.mBoundsAxis[0]] * (((i + 1) & 2) ? 1.f : -1.f);

                   gContext.mbUsingBounds = true;
                   gContext.mBoundsMatrix = gContext.mModelSource;
               }
           }

           if (gContext.mbUsingBounds)
           {
               matrix_t scale;
               scale.SetToIdentity();

               // compute projected mouse position on plan
               const float len = IntersectRayPlane(gContext.mRayOrigin, gContext.mRayVector, gContext.mBoundsPlan);
               vec_t newPos = gContext.mRayOrigin + gContext.mRayVector * len;

               // compute a reference and delta vectors base on mouse move
               vec_t deltaVector = (newPos - gContext.mBoundsPivot).Abs();
               vec_t referenceVector = (gContext.mBoundsAnchor - gContext.mBoundsPivot).Abs();

               // for 1 or 2 axes, compute a ratio that's used for scale and snap it based on resulting length
               for (int i = 0; i < 2; i++)
               {
                   int axisIndex1 = gContext.mBoundsAxis[i];
                   if (axisIndex1 == -1)
                       continue;

                   float ratioAxis = 1.f;
                   vec_t axisDir = gContext.mBoundsMatrix.component[axisIndex1].Abs();

                   float dtAxis = axisDir.Dot(referenceVector);
                   float boundSize = bounds[axisIndex1 + 3] - bounds[axisIndex1];
                   if (dtAxis > FLT_EPSILON)
                       ratioAxis = axisDir.Dot(deltaVector) / dtAxis;

                   if (snapValues)
                   {
                       float length = boundSize * ratioAxis;
                       ComputeSnap(&length, snapValues[axisIndex1]);
                       if (boundSize > FLT_EPSILON)
                           ratioAxis = length / boundSize;
                   }
                   scale.component[axisIndex1] *= ratioAxis;
               }

               // transform matrix
               matrix_t preScale, postScale;
               preScale.Translation(-gContext.mBoundsLocalPivot);
               postScale.Translation(gContext.mBoundsLocalPivot);
               matrix_t res = preScale * scale * postScale * gContext.mBoundsMatrix;
               *matrix = res;

               // info text
               char tmps[512];
               ImVec2 destinationPosOnScreen = worldToPos(gContext.mModel.v.position, gContext.mViewProjection);
               ImFormatString(tmps, sizeof(tmps), "X: %.2f Y: %.2f Z:%.2f"
                   , (bounds[3] - bounds[0]) * gContext.mBoundsMatrix.component[0].Length() * scale.component[0].Length()
                   , (bounds[4] - bounds[1]) * gContext.mBoundsMatrix.component[1].Length() * scale.component[1].Length()
                   , (bounds[5] - bounds[2]) * gContext.mBoundsMatrix.component[2].Length() * scale.component[2].Length()
               );
               drawList->AddText(ImVec2(destinationPosOnScreen.x + 15, destinationPosOnScreen.y + 15), 0xFF000000, tmps);
               drawList->AddText(ImVec2(destinationPosOnScreen.x + 14, destinationPosOnScreen.y + 14), 0xFFFFFFFF, tmps);
            }

           if (!io.MouseDown[0])
               gContext.mbUsingBounds = false;

           if( gContext.mbUsingBounds )
               break;
       }
   }

   ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
   //

   static int GetScaleType()
   {
      ImGuiIO& io = ImGui::GetIO();
      int type = NONE;

      // screen
      if (io.MousePos.x >= gContext.mScreenSquareMin.x && io.MousePos.x <= gContext.mScreenSquareMax.x &&
         io.MousePos.y >= gContext.mScreenSquareMin.y && io.MousePos.y <= gContext.mScreenSquareMax.y)
         type = SCALE_XYZ;

      // compute
      for (unsigned int i = 0; i < 3 && type == NONE; i++)
      {
         vec_t dirPlaneX, dirPlaneY, dirAxis;
         bool belowAxisLimit, belowPlaneLimit;
         ComputeTripodAxisAndVisibility(i, dirAxis, dirPlaneX, dirPlaneY, belowAxisLimit, belowPlaneLimit);

         dirAxis.TransformVector(gContext.mModel);
       const float len = IntersectRayPlane(gContext.mRayOrigin, gContext.mRayVector, BuildPlan(gContext.mModel.v.position, dirAxis));
       vec_t posOnPlan = gContext.mRayOrigin + gContext.mRayVector * len;

       const ImVec2 posOnPlanScreen = worldToPos(posOnPlan, gContext.mViewProjection);
       const ImVec2 axisStartOnScreen = worldToPos(gContext.mModel.v.position + dirAxis * gContext.mScreenFactor * 0.1f, gContext.mViewProjection);
       const ImVec2 axisEndOnScreen = worldToPos(gContext.mModel.v.position + dirAxis * gContext.mScreenFactor, gContext.mViewProjection);

       vec_t closestPointOnAxis = PointOnSegment(makeVect(posOnPlanScreen), makeVect(axisStartOnScreen), makeVect(axisEndOnScreen));

       if ((closestPointOnAxis - makeVect(posOnPlanScreen)).Length() < 12.f) // pixel size
          type = SCALE_X + i;
      }
      return type;
   }

   static int GetRotateType()
   {
      ImGuiIO& io = ImGui::GetIO();
      int type = NONE;

      vec_t deltaScreen = { io.MousePos.x - gContext.mScreenSquareCenter.x, io.MousePos.y - gContext.mScreenSquareCenter.y, 0.f, 0.f };
      float dist = deltaScreen.Length();
      if (dist >= (gContext.mRadiusSquareCenter - 1.0f) && dist < (gContext.mRadiusSquareCenter + 1.0f))
         type = ROTATE_SCREEN;

      const vec_t planNormals[] = { gContext.mModel.v.right, gContext.mModel.v.up, gContext.mModel.v.dir};

      for (unsigned int i = 0; i < 3 && type == NONE; i++)
      {
         // pickup plan
         vec_t pickupPlan = BuildPlan(gContext.mModel.v.position, planNormals[i]);

         const float len = IntersectRayPlane(gContext.mRayOrigin, gContext.mRayVector, pickupPlan);
         vec_t localPos = gContext.mRayOrigin + gContext.mRayVector * len - gContext.mModel.v.position;

         if (Dot(Normalized(localPos), gContext.mRayVector) > FLT_EPSILON)
            continue;
       vec_t idealPosOnCircle = Normalized(localPos);
       idealPosOnCircle.TransformVector(gContext.mModelInverse);
       ImVec2 idealPosOnCircleScreen = worldToPos(idealPosOnCircle * gContext.mScreenFactor, gContext.mMVP);

       //gContext.mDrawList->AddCircle(idealPosOnCircleScreen, 5.f, 0xFFFFFFFF);
       ImVec2 distanceOnScreen = idealPosOnCircleScreen - io.MousePos;

         float distance = makeVect(distanceOnScreen).Length();
         if (distance < 8.f) // pixel size
            type = ROTATE_X + i;
      }

      return type;
   }

   static int GetMoveType(vec_t *gizmoHitProportion)
   {
      ImGuiIO& io = ImGui::GetIO();
      int type = NONE;

      // screen
      if (io.MousePos.x >= gContext.mScreenSquareMin.x && io.MousePos.x <= gContext.mScreenSquareMax.x &&
         io.MousePos.y >= gContext.mScreenSquareMin.y && io.MousePos.y <= gContext.mScreenSquareMax.y)
         type = MOVE_SCREEN;

      // compute
      for (unsigned int i = 0; i < 3 && type == NONE; i++)
      {
         vec_t dirPlaneX, dirPlaneY, dirAxis;
         bool belowAxisLimit, belowPlaneLimit;
         ComputeTripodAxisAndVisibility(i, dirAxis, dirPlaneX, dirPlaneY, belowAxisLimit, belowPlaneLimit);
       dirAxis.TransformVector(gContext.mModel);
         dirPlaneX.TransformVector(gContext.mModel);
         dirPlaneY.TransformVector(gContext.mModel);

         const float len = IntersectRayPlane(gContext.mRayOrigin, gContext.mRayVector, BuildPlan(gContext.mModel.v.position, dirAxis));
         vec_t posOnPlan = gContext.mRayOrigin + gContext.mRayVector * len;

       const ImVec2 posOnPlanScreen = worldToPos(posOnPlan, gContext.mViewProjection);
       const ImVec2 axisStartOnScreen = worldToPos(gContext.mModel.v.position + dirAxis * gContext.mScreenFactor * 0.1f, gContext.mViewProjection);
       const ImVec2 axisEndOnScreen = worldToPos(gContext.mModel.v.position + dirAxis * gContext.mScreenFactor, gContext.mViewProjection);

       vec_t closestPointOnAxis = PointOnSegment(makeVect(posOnPlanScreen), makeVect(axisStartOnScreen), makeVect(axisEndOnScreen));

       if ((closestPointOnAxis - makeVect(posOnPlanScreen)).Length() < 12.f) // pixel size
            type = MOVE_X + i;

       const float dx = dirPlaneX.Dot3((posOnPlan - gContext.mModel.v.position) * (1.f / gContext.mScreenFactor));
       const float dy = dirPlaneY.Dot3((posOnPlan - gContext.mModel.v.position) * (1.f / gContext.mScreenFactor));
         if (belowPlaneLimit && dx >= quadUV[0] && dx <= quadUV[4] && dy >= quadUV[1] && dy <= quadUV[3])
            type = MOVE_YZ + i;

         if (gizmoHitProportion)
            *gizmoHitProportion = makeVect(dx, dy, 0.f);
      }
      return type;
   }

   static void HandleTranslation(float *matrix, float *deltaMatrix, int& type, float *snap)
   {
      ImGuiIO& io = ImGui::GetIO();
      bool applyRotationLocaly = gContext.mMode == LOCAL || type == MOVE_SCREEN;

      // move
      if (gContext.mbUsing)
      {
         ImGui::CaptureMouseFromApp();
         const float len = fabsf(IntersectRayPlane(gContext.mRayOrigin, gContext.mRayVector, gContext.mTranslationPlan)); // near plan
         vec_t newPos = gContext.mRayOrigin + gContext.mRayVector * len;



         // compute delta
         vec_t newOrigin = newPos - gContext.mRelativeOrigin * gContext.mScreenFactor;
         vec_t delta = newOrigin - gContext.mModel.v.position;

         // 1 axis constraint
         if (gContext.mCurrentOperation >= MOVE_X && gContext.mCurrentOperation <= MOVE_Z)
         {
            int axisIndex = gContext.mCurrentOperation - MOVE_X;
            const vec_t& axisValue = *(vec_t*)&gContext.mModel.m[axisIndex];
            float lengthOnAxis = Dot(axisValue, delta);
            delta = axisValue * lengthOnAxis;
         }

         // snap
         if (snap)
         {
            vec_t cumulativeDelta = gContext.mModel.v.position + delta - gContext.mMatrixOrigin;
            if (applyRotationLocaly)
            {
               matrix_t modelSourceNormalized = gContext.mModelSource;
               modelSourceNormalized.OrthoNormalize();
               matrix_t modelSourceNormalizedInverse;
               modelSourceNormalizedInverse.Inverse(modelSourceNormalized);
               cumulativeDelta.TransformVector(modelSourceNormalizedInverse);
               ComputeSnap(cumulativeDelta, snap);
               cumulativeDelta.TransformVector(modelSourceNormalized);
            }
            else
            {
               ComputeSnap(cumulativeDelta, snap);
            }
            delta = gContext.mMatrixOrigin + cumulativeDelta - gContext.mModel.v.position;

         }

         // compute matrix & delta
         matrix_t deltaMatrixTranslation;
         deltaMatrixTranslation.Translation(delta);
         if (deltaMatrix)
            memcpy(deltaMatrix, deltaMatrixTranslation.m16, sizeof(float) * 16);


         matrix_t res = gContext.mModelSource * deltaMatrixTranslation;
         *(matrix_t*)matrix = res;

         if (!io.MouseDown[0])
            gContext.mbUsing = false;

         type = gContext.mCurrentOperation;
      }
      else
      {
         // find new possible way to move
         vec_t gizmoHitProportion;
         type = GetMoveType(&gizmoHitProportion);
         if(type != NONE)
         {
            ImGui::CaptureMouseFromApp();
         }
       if (CanActivate() && type != NONE)
       {
          gContext.mbUsing = true;
          gContext.mCurrentOperation = type;
          vec_t movePlanNormal[] = { gContext.mModel.v.right, gContext.mModel.v.up, gContext.mModel.v.dir,
             gContext.mModel.v.right, gContext.mModel.v.up, gContext.mModel.v.dir,
             -gContext.mCameraDir };

          vec_t cameraToModelNormalized = Normalized(gContext.mModel.v.position - gContext.mCameraEye);
          for (unsigned int i = 0; i < 3; i++)
          {
             vec_t orthoVector = Cross(movePlanNormal[i], cameraToModelNormalized);
             movePlanNormal[i].Cross(orthoVector);
             movePlanNormal[i].Normalize();
          }
            // pickup plan
            gContext.mTranslationPlan = BuildPlan(gContext.mModel.v.position, movePlanNormal[type - MOVE_X]);
            const float len = IntersectRayPlane(gContext.mRayOrigin, gContext.mRayVector, gContext.mTranslationPlan);
            gContext.mTranslationPlanOrigin = gContext.mRayOrigin + gContext.mRayVector * len;
            gContext.mMatrixOrigin = gContext.mModel.v.position;

            gContext.mRelativeOrigin = (gContext.mTranslationPlanOrigin - gContext.mModel.v.position) * (1.f / gContext.mScreenFactor);
         }
      }
   }

   static void HandleScale(float *matrix, float *deltaMatrix, int& type, float *snap)
   {
      ImGuiIO& io = ImGui::GetIO();

      if (!gContext.mbUsing)
      {
         // find new possible way to scale
         type = GetScaleType();
         if(type != NONE)
         {
            ImGui::CaptureMouseFromApp();
         }
         if (CanActivate() && type != NONE)
         {
            gContext.mbUsing = true;
            gContext.mCurrentOperation = type;
            const vec_t movePlanNormal[] = { gContext.mModel.v.up, gContext.mModel.v.dir, gContext.mModel.v.right, gContext.mModel.v.dir, gContext.mModel.v.up, gContext.mModel.v.right, -gContext.mCameraDir };
            // pickup plan

            gContext.mTranslationPlan = BuildPlan(gContext.mModel.v.position, movePlanNormal[type - SCALE_X]);
            const float len = IntersectRayPlane(gContext.mRayOrigin, gContext.mRayVector, gContext.mTranslationPlan);
            gContext.mTranslationPlanOrigin = gContext.mRayOrigin + gContext.mRayVector * len;
            gContext.mMatrixOrigin = gContext.mModel.v.position;
            gContext.mScale.Set(1.f, 1.f, 1.f);
            gContext.mRelativeOrigin = (gContext.mTranslationPlanOrigin - gContext.mModel.v.position) * (1.f / gContext.mScreenFactor);
            gContext.mScaleValueOrigin = makeVect(gContext.mModelSource.v.right.Length(), gContext.mModelSource.v.up.Length(), gContext.mModelSource.v.dir.Length());
            gContext.mSaveMousePosx = io.MousePos.x;
         }
      }
      // scale
      if (gContext.mbUsing)
      {
         ImGui::CaptureMouseFromApp();
         const float len = IntersectRayPlane(gContext.mRayOrigin, gContext.mRayVector, gContext.mTranslationPlan);
         vec_t newPos = gContext.mRayOrigin + gContext.mRayVector * len;
         vec_t newOrigin = newPos - gContext.mRelativeOrigin * gContext.mScreenFactor;
         vec_t delta = newOrigin - gContext.mModel.v.position;

         // 1 axis constraint
         if (gContext.mCurrentOperation >= SCALE_X && gContext.mCurrentOperation <= SCALE_Z)
         {
            int axisIndex = gContext.mCurrentOperation - SCALE_X;
            const vec_t& axisValue = *(vec_t*)&gContext.mModel.m[axisIndex];
            float lengthOnAxis = Dot(axisValue, delta);
            delta = axisValue * lengthOnAxis;

            vec_t baseVector = gContext.mTranslationPlanOrigin - gContext.mModel.v.position;
            float ratio = Dot(axisValue, baseVector + delta) / Dot(axisValue, baseVector);

            gContext.mScale[axisIndex] = max(ratio, 0.001f);
         }
         else
         {
            float scaleDelta = (io.MousePos.x - gContext.mSaveMousePosx)  * 0.01f;
            gContext.mScale.Set(max(1.f + scaleDelta, 0.001f));
         }

         // snap
         if (snap)
         {
            float scaleSnap[] = { snap[0], snap[0], snap[0] };
            ComputeSnap(gContext.mScale, scaleSnap);
         }

         // no 0 allowed
         for (int i = 0; i < 3;i++)
            gContext.mScale[i] = max(gContext.mScale[i], 0.001f);

         // compute matrix & delta
         matrix_t deltaMatrixScale;
         deltaMatrixScale.Scale(gContext.mScale * gContext.mScaleValueOrigin);

         matrix_t res = deltaMatrixScale * gContext.mModel;
         *(matrix_t*)matrix = res;

         if (deltaMatrix)
         {
            deltaMatrixScale.Scale(gContext.mScale);
            memcpy(deltaMatrix, deltaMatrixScale.m16, sizeof(float) * 16);
         }

         if (!io.MouseDown[0])
            gContext.mbUsing = false;

         type = gContext.mCurrentOperation;
      }
   }

   static void HandleRotation(float *matrix, float *deltaMatrix, int& type, float *snap)
   {
      ImGuiIO& io = ImGui::GetIO();
      bool applyRotationLocaly = gContext.mMode == LOCAL;

      if (!gContext.mbUsing)
      {
         type = GetRotateType();

         if(type != NONE)
         {
            ImGui::CaptureMouseFromApp();
         }

         if (type == ROTATE_SCREEN)
         {
            applyRotationLocaly = true;
         }

         if (CanActivate() && type != NONE)
         {
            gContext.mbUsing = true;
            gContext.mCurrentOperation = type;
            const vec_t rotatePlanNormal[] = { gContext.mModel.v.right, gContext.mModel.v.up, gContext.mModel.v.dir, -gContext.mCameraDir };
            // pickup plan
            if (applyRotationLocaly)
            {
               gContext.mTranslationPlan = BuildPlan(gContext.mModel.v.position, rotatePlanNormal[type - ROTATE_X]);
            }
            else
            {
               gContext.mTranslationPlan = BuildPlan(gContext.mModelSource.v.position, directionUnary[type - ROTATE_X]);
            }

            const float len = IntersectRayPlane(gContext.mRayOrigin, gContext.mRayVector, gContext.mTranslationPlan);
            vec_t localPos = gContext.mRayOrigin + gContext.mRayVector * len - gContext.mModel.v.position;
            gContext.mRotationVectorSource = Normalized(localPos);
            gContext.mRotationAngleOrigin = ComputeAngleOnPlan();
         }
      }

      // rotation
      if (gContext.mbUsing)
      {
         ImGui::CaptureMouseFromApp();
         gContext.mRotationAngle = ComputeAngleOnPlan();
         if (snap)
         {
            float snapInRadian = snap[0] * DEG2RAD;
            ComputeSnap(&gContext.mRotationAngle, snapInRadian);
         }
         vec_t rotationAxisLocalSpace;

         rotationAxisLocalSpace.TransformVector(makeVect(gContext.mTranslationPlan.x, gContext.mTranslationPlan.y, gContext.mTranslationPlan.z, 0.f), gContext.mModelInverse);
         rotationAxisLocalSpace.Normalize();

         matrix_t deltaRotation;
         deltaRotation.RotationAxis(rotationAxisLocalSpace, gContext.mRotationAngle - gContext.mRotationAngleOrigin);
         gContext.mRotationAngleOrigin = gContext.mRotationAngle;

         matrix_t scaleOrigin;
         scaleOrigin.Scale(gContext.mModelScaleOrigin);

         if (applyRotationLocaly)
         {
            *(matrix_t*)matrix = scaleOrigin * deltaRotation * gContext.mModel;
         }
         else
         {
            matrix_t res = gContext.mModelSource;
            res.v.position.Set(0.f);

            *(matrix_t*)matrix = res * deltaRotation;
            ((matrix_t*)matrix)->v.position = gContext.mModelSource.v.position;
         }

         if (deltaMatrix)
         {
            *(matrix_t*)deltaMatrix = gContext.mModelInverse * deltaRotation * gContext.mModel;
         }

         if (!io.MouseDown[0])
            gContext.mbUsing = false;

         type = gContext.mCurrentOperation;
      }
   }

   void DecomposeMatrixToComponents(const float *matrix, float *translation, float *rotation, float *scale)
   {
      matrix_t mat = *(matrix_t*)matrix;

      scale[0] = mat.v.right.Length();
      scale[1] = mat.v.up.Length();
      scale[2] = mat.v.dir.Length();

      mat.OrthoNormalize();

      rotation[0] = RAD2DEG * atan2f(mat.m[1][2], mat.m[2][2]);
      rotation[1] = RAD2DEG * atan2f(-mat.m[0][2], sqrtf(mat.m[1][2] * mat.m[1][2] + mat.m[2][2]* mat.m[2][2]));
      rotation[2] = RAD2DEG * atan2f(mat.m[0][1], mat.m[0][0]);

      translation[0] = mat.v.position.x;
      translation[1] = mat.v.position.y;
      translation[2] = mat.v.position.z;
   }

   void RecomposeMatrixFromComponents(const float *translation, const float *rotation, const float *scale, float *matrix)
   {
      matrix_t& mat = *(matrix_t*)matrix;

      matrix_t rot[3];
      for (int i = 0; i < 3;i++)
         rot[i].RotationAxis(directionUnary[i], rotation[i] * DEG2RAD);

      mat = rot[0] * rot[1] * rot[2];

      float validScale[3];
      for (int i = 0; i < 3; i++)
      {
         if (fabsf(scale[i]) < FLT_EPSILON)
            validScale[i] = 0.001f;
         else
            validScale[i] = scale[i];
      }
      mat.v.right *= validScale[0];
      mat.v.up *= validScale[1];
      mat.v.dir *= validScale[2];
      mat.v.position.Set(translation[0], translation[1], translation[2], 1.f);
   }

   void Manipulate(const float *view, const float *projection, OPERATION operation, MODE mode, float *matrix, float *deltaMatrix, float *snap, float *localBounds, float *boundsSnap)
   {
      ComputeContext(view, projection, matrix, mode);

      // set delta to identity
      if (deltaMatrix)
         ((matrix_t*)deltaMatrix)->SetToIdentity();

      // behind camera
      vec_t camSpacePosition;
      camSpacePosition.TransformPoint(makeVect(0.f, 0.f, 0.f), gContext.mMVP);
      if (!gContext.mIsOrthographic && camSpacePosition.z < 0.001f)
         return;

      // --
      int type = NONE;
      if (gContext.mbEnable)
      {
          if (!gContext.mbUsingBounds)
          {
              switch (operation)
              {
              case ROTATE:
                  HandleRotation(matrix, deltaMatrix, type, snap);
                  break;
              case TRANSLATE:
                  HandleTranslation(matrix, deltaMatrix, type, snap);
                  break;
              case SCALE:
                  HandleScale(matrix, deltaMatrix, type, snap);
                  break;
              case BOUNDS:
                  break;
              }
          }
      }

      if (localBounds && !gContext.mbUsing)
          HandleAndDrawLocalBounds(localBounds, (matrix_t*)matrix, boundsSnap, operation);

      if (!gContext.mbUsingBounds)
      {
          switch (operation)
          {
          case ROTATE:
              DrawRotationGizmo(type);
              break;
          case TRANSLATE:
              DrawTranslationGizmo(type);
              break;
          case SCALE:
              DrawScaleGizmo(type);
              break;
          case BOUNDS:
              break;
          }
      }
   }

   void DrawCube(const float *view, const float *projection, const float *matrix)
   {
      matrix_t viewInverse;
      viewInverse.Inverse(*(matrix_t*)view);
      const matrix_t& model = *(matrix_t*)matrix;
      matrix_t res = *(matrix_t*)matrix * *(matrix_t*)view * *(matrix_t*)projection;

      for (int iFace = 0; iFace < 6; iFace++)
      {
         const int normalIndex = (iFace % 3);
         const int perpXIndex = (normalIndex + 1) % 3;
         const int perpYIndex = (normalIndex + 2) % 3;
         const float invert = (iFace > 2) ? -1.f : 1.f;

         const vec_t faceCoords[4] = { directionUnary[normalIndex] + directionUnary[perpXIndex] + directionUnary[perpYIndex],
            directionUnary[normalIndex] + directionUnary[perpXIndex] - directionUnary[perpYIndex],
            directionUnary[normalIndex] - directionUnary[perpXIndex] - directionUnary[perpYIndex],
            directionUnary[normalIndex] - directionUnary[perpXIndex] + directionUnary[perpYIndex],
         };

         // clipping
         bool skipFace = false;
         for (unsigned int iCoord = 0; iCoord < 4; iCoord++)
         {
            vec_t camSpacePosition;
            camSpacePosition.TransformPoint(faceCoords[iCoord] * 0.5f * invert, gContext.mMVP);
            if (camSpacePosition.z < 0.001f)
            {
               skipFace = true;
               break;
            }
         }
         if (skipFace)
            continue;

         // 3D->2D
         ImVec2 faceCoordsScreen[4];
         for (unsigned int iCoord = 0; iCoord < 4; iCoord++)
            faceCoordsScreen[iCoord] = worldToPos(faceCoords[iCoord] * 0.5f * invert, res);

         // back face culling
         vec_t cullPos, cullNormal;
         cullPos.TransformPoint(faceCoords[0] * 0.5f * invert, model);
         cullNormal.TransformVector(directionUnary[normalIndex] * invert, model);
         float dt = Dot(Normalized(cullPos - viewInverse.v.position), Normalized(cullNormal));
         if (dt>0.f)
            continue;

         // draw face with lighter color
         gContext.mDrawList->AddConvexPolyFilled(faceCoordsScreen, 4, directionColor[normalIndex] | 0x808080);
      }
   }

   void DrawGrid(const float *view, const float *projection, const float *matrix, const float gridSize)
   {
      matrix_t res = *(matrix_t*)matrix * *(matrix_t*)view * *(matrix_t*)projection;

      for (float f = -gridSize; f <= gridSize; f += 1.f)
      {
         gContext.mDrawList->AddLine(worldToPos(makeVect(f, 0.f, -gridSize), res), worldToPos(makeVect(f, 0.f, gridSize), res), 0xFF808080);
         gContext.mDrawList->AddLine(worldToPos(makeVect(-gridSize, 0.f, f), res), worldToPos(makeVect(gridSize, 0.f, f), res), 0xFF808080);
      }
   }
};

