glsl/glslUtil/glslUtil.c
2011-05-09 16:32:51 -04:00

61 lines
1.3 KiB
C

#include "glslUtil.h"
void guMatrixLoadIdentity(guMatrix4x4 *m)
{
for (int i = 0; i < 4; i++)
{
for (int j = 0; j < 4; j++)
{
m[i][j] = (i == j) ? 1.0 : 0.0;
}
}
}
void guMatrixMult(guMatrix4x4 *m, guMatrix4x4 *a, guMatrix4x4 *b)
{
for (int i = 0; i < 4; i++)
{
for (int j = 0; j < 4; j++)
{
float v = 0.0;
for (int p = 0; p < 4; p++)
{
v += a[i][p] * b[p][j];
}
m[i][j] = v;
}
}
}
void guMatrixTranslate(guMatrix4x4 *m, float x, float y, float z)
{
for (int i = 0; i < 4; i++)
{
m[i][3] += m[i][0] * x + m[i][1] * y + m[i][2] * z;
}
}
void guMatrixFrustum(guMatrix4x4 *m,
float left, float right,
float bottom, float top,
float near, float far)
{
guMatrix4x4 mult;
for (int i = 0; i < 4; i++)
{
for (int j = 0; j < 4; j++)
{
mult[i][j] = 0.0;
}
}
mult[0][0] = 2 * near / (right - left);
mult[0][2] = (right + left) / (right - left);
mult[1][1] = 2 * near / (top - bottom);
mult[1][2] = (top + bottom) / (top - bottom);
mult[2][2] = - (far + near) / (far - near);
mult[2][3] = - 2 * far * near / (far - near);
mult[3][2] = -1.0;
guMatrixMult(m, &mult);
}