Vegastrike 0.5.1 rc1  1.0
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IceMatrix4x4.cpp
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38 // Precompiled Header
39 #include "Stdafx.h"
40 
41 
42 using namespace Opcode;
43 
45 
54 
56 void Opcode::InvertPRMatrix(Matrix4x4& dest, const Matrix4x4& src)
57 {
58  dest.m[0][0] = src.m[0][0];
59  dest.m[1][0] = src.m[0][1];
60  dest.m[2][0] = src.m[0][2];
61  dest.m[3][0] = -(src.m[3][0]*src.m[0][0] + src.m[3][1]*src.m[0][1] + src.m[3][2]*src.m[0][2]);
62 
63  dest.m[0][1] = src.m[1][0];
64  dest.m[1][1] = src.m[1][1];
65  dest.m[2][1] = src.m[1][2];
66  dest.m[3][1] = -(src.m[3][0]*src.m[1][0] + src.m[3][1]*src.m[1][1] + src.m[3][2]*src.m[1][2]);
67 
68  dest.m[0][2] = src.m[2][0];
69  dest.m[1][2] = src.m[2][1];
70  dest.m[2][2] = src.m[2][2];
71  dest.m[3][2] = -(src.m[3][0]*src.m[2][0] + src.m[3][1]*src.m[2][1] + src.m[3][2]*src.m[2][2]);
72 
73  dest.m[0][3] = 0.0f;
74  dest.m[1][3] = 0.0f;
75  dest.m[2][3] = 0.0f;
76  dest.m[3][3] = 1.0f;
77 }
78 
80 // Compute the cofactor of the Matrix at a specified location
82 float Matrix4x4::CoFactor(udword row, udword col) const
83 {
84  return (( m[(row+1)&3][(col+1)&3]*m[(row+2)&3][(col+2)&3]*m[(row+3)&3][(col+3)&3] +
85  m[(row+1)&3][(col+2)&3]*m[(row+2)&3][(col+3)&3]*m[(row+3)&3][(col+1)&3] +
86  m[(row+1)&3][(col+3)&3]*m[(row+2)&3][(col+1)&3]*m[(row+3)&3][(col+2)&3])
87  - (m[(row+3)&3][(col+1)&3]*m[(row+2)&3][(col+2)&3]*m[(row+1)&3][(col+3)&3] +
88  m[(row+3)&3][(col+2)&3]*m[(row+2)&3][(col+3)&3]*m[(row+1)&3][(col+1)&3] +
89  m[(row+3)&3][(col+3)&3]*m[(row+2)&3][(col+1)&3]*m[(row+1)&3][(col+2)&3])) * ((row + col) & 1 ? -1.0f : +1.0f);
90 }
91 
93 // Compute the determinant of the Matrix
95 float Matrix4x4::Determinant() const
96 {
97  return m[0][0] * CoFactor(0, 0) +
98  m[0][1] * CoFactor(0, 1) +
99  m[0][2] * CoFactor(0, 2) +
100  m[0][3] * CoFactor(0, 3);
101 }
102 
104 // Compute the inverse of the matrix
106 Matrix4x4& Matrix4x4::Invert()
107 {
108  float Det = Determinant();
109  Matrix4x4 Temp;
110 
111  if(fabsf(Det) < MATRIX4X4_EPSILON)
112  return *this; // The matrix is not invertible! Singular case!
113 
114  float IDet = 1.0f / Det;
115 
116  Temp.m[0][0] = CoFactor(0,0) * IDet;
117  Temp.m[1][0] = CoFactor(0,1) * IDet;
118  Temp.m[2][0] = CoFactor(0,2) * IDet;
119  Temp.m[3][0] = CoFactor(0,3) * IDet;
120  Temp.m[0][1] = CoFactor(1,0) * IDet;
121  Temp.m[1][1] = CoFactor(1,1) * IDet;
122  Temp.m[2][1] = CoFactor(1,2) * IDet;
123  Temp.m[3][1] = CoFactor(1,3) * IDet;
124  Temp.m[0][2] = CoFactor(2,0) * IDet;
125  Temp.m[1][2] = CoFactor(2,1) * IDet;
126  Temp.m[2][2] = CoFactor(2,2) * IDet;
127  Temp.m[3][2] = CoFactor(2,3) * IDet;
128  Temp.m[0][3] = CoFactor(3,0) * IDet;
129  Temp.m[1][3] = CoFactor(3,1) * IDet;
130  Temp.m[2][3] = CoFactor(3,2) * IDet;
131  Temp.m[3][3] = CoFactor(3,3) * IDet;
132 
133  *this = Temp;
134 
135  return *this;
136 }
137