protot/3rdparty/tinygltf/examples/raytrace/matrix.cc

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2018-03-19 23:00:51 +01:00
#include <cstdio>
#include <cmath>
#include "matrix.h"
//using namespace mallie;
static inline float vdot(float a[3], float b[3]) {
return a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
}
static inline void vcross(float c[3], float a[3], float b[3]) {
c[0] = a[1] * b[2] - a[2] * b[1];
c[1] = a[2] * b[0] - a[0] * b[2];
c[2] = a[0] * b[1] - a[1] * b[0];
}
static inline float vlength(float v[3]) {
float len2 = vdot(v, v);
if (std::abs(len2) > 1.0e-30) {
return sqrt(len2);
}
return 0.0f;
}
static void vnormalize(float v[3]) {
float len = vlength(v);
if (std::abs(len) > 1.0e-30) {
float inv_len = 1.0f / len;
v[0] *= inv_len;
v[1] *= inv_len;
v[2] *= inv_len;
}
}
void Matrix::Print(float m[4][4]) {
for (int i = 0; i < 4; i++) {
printf("m[%d] = %f, %f, %f, %f\n", i, m[i][0], m[i][1], m[i][2], m[i][3]);
}
}
void Matrix::LookAt(float m[4][4], float eye[3], float lookat[3],
float up[3]) {
float u[3], v[3];
float look[3];
look[0] = lookat[0] - eye[0];
look[1] = lookat[1] - eye[1];
look[2] = lookat[2] - eye[2];
vnormalize(look);
vcross(u, look, up);
vnormalize(u);
vcross(v, u, look);
vnormalize(v);
#if 0
m[0][0] = u[0];
m[0][1] = v[0];
m[0][2] = -look[0];
m[0][3] = 0.0;
m[1][0] = u[1];
m[1][1] = v[1];
m[1][2] = -look[1];
m[1][3] = 0.0;
m[2][0] = u[2];
m[2][1] = v[2];
m[2][2] = -look[2];
m[2][3] = 0.0;
m[3][0] = eye[0];
m[3][1] = eye[1];
m[3][2] = eye[2];
m[3][3] = 1.0;
#else
m[0][0] = u[0];
m[1][0] = v[0];
m[2][0] = -look[0];
m[3][0] = eye[0];
m[0][1] = u[1];
m[1][1] = v[1];
m[2][1] = -look[1];
m[3][1] = eye[1];
m[0][2] = u[2];
m[1][2] = v[2];
m[2][2] = -look[2];
m[3][2] = eye[2];
m[0][3] = 0.0;
m[1][3] = 0.0;
m[2][3] = 0.0;
m[3][3] = 1.0;
#endif
}
void Matrix::Inverse(float m[4][4]) {
/*
* codes from intel web
* cramer's rule version
*/
int i, j;
float tmp[12]; /* tmp array for pairs */
float tsrc[16]; /* array of transpose source matrix */
float det; /* determinant */
/* transpose matrix */
for (i = 0; i < 4; i++) {
tsrc[i] = m[i][0];
tsrc[i + 4] = m[i][1];
tsrc[i + 8] = m[i][2];
tsrc[i + 12] = m[i][3];
}
/* calculate pair for first 8 elements(cofactors) */
tmp[0] = tsrc[10] * tsrc[15];
tmp[1] = tsrc[11] * tsrc[14];
tmp[2] = tsrc[9] * tsrc[15];
tmp[3] = tsrc[11] * tsrc[13];
tmp[4] = tsrc[9] * tsrc[14];
tmp[5] = tsrc[10] * tsrc[13];
tmp[6] = tsrc[8] * tsrc[15];
tmp[7] = tsrc[11] * tsrc[12];
tmp[8] = tsrc[8] * tsrc[14];
tmp[9] = tsrc[10] * tsrc[12];
tmp[10] = tsrc[8] * tsrc[13];
tmp[11] = tsrc[9] * tsrc[12];
/* calculate first 8 elements(cofactors) */
m[0][0] = tmp[0] * tsrc[5] + tmp[3] * tsrc[6] + tmp[4] * tsrc[7];
m[0][0] -= tmp[1] * tsrc[5] + tmp[2] * tsrc[6] + tmp[5] * tsrc[7];
m[0][1] = tmp[1] * tsrc[4] + tmp[6] * tsrc[6] + tmp[9] * tsrc[7];
m[0][1] -= tmp[0] * tsrc[4] + tmp[7] * tsrc[6] + tmp[8] * tsrc[7];
m[0][2] = tmp[2] * tsrc[4] + tmp[7] * tsrc[5] + tmp[10] * tsrc[7];
m[0][2] -= tmp[3] * tsrc[4] + tmp[6] * tsrc[5] + tmp[11] * tsrc[7];
m[0][3] = tmp[5] * tsrc[4] + tmp[8] * tsrc[5] + tmp[11] * tsrc[6];
m[0][3] -= tmp[4] * tsrc[4] + tmp[9] * tsrc[5] + tmp[10] * tsrc[6];
m[1][0] = tmp[1] * tsrc[1] + tmp[2] * tsrc[2] + tmp[5] * tsrc[3];
m[1][0] -= tmp[0] * tsrc[1] + tmp[3] * tsrc[2] + tmp[4] * tsrc[3];
m[1][1] = tmp[0] * tsrc[0] + tmp[7] * tsrc[2] + tmp[8] * tsrc[3];
m[1][1] -= tmp[1] * tsrc[0] + tmp[6] * tsrc[2] + tmp[9] * tsrc[3];
m[1][2] = tmp[3] * tsrc[0] + tmp[6] * tsrc[1] + tmp[11] * tsrc[3];
m[1][2] -= tmp[2] * tsrc[0] + tmp[7] * tsrc[1] + tmp[10] * tsrc[3];
m[1][3] = tmp[4] * tsrc[0] + tmp[9] * tsrc[1] + tmp[10] * tsrc[2];
m[1][3] -= tmp[5] * tsrc[0] + tmp[8] * tsrc[1] + tmp[11] * tsrc[2];
/* calculate pairs for second 8 elements(cofactors) */
tmp[0] = tsrc[2] * tsrc[7];
tmp[1] = tsrc[3] * tsrc[6];
tmp[2] = tsrc[1] * tsrc[7];
tmp[3] = tsrc[3] * tsrc[5];
tmp[4] = tsrc[1] * tsrc[6];
tmp[5] = tsrc[2] * tsrc[5];
tmp[6] = tsrc[0] * tsrc[7];
tmp[7] = tsrc[3] * tsrc[4];
tmp[8] = tsrc[0] * tsrc[6];
tmp[9] = tsrc[2] * tsrc[4];
tmp[10] = tsrc[0] * tsrc[5];
tmp[11] = tsrc[1] * tsrc[4];
/* calculate second 8 elements(cofactors) */
m[2][0] = tmp[0] * tsrc[13] + tmp[3] * tsrc[14] + tmp[4] * tsrc[15];
m[2][0] -= tmp[1] * tsrc[13] + tmp[2] * tsrc[14] + tmp[5] * tsrc[15];
m[2][1] = tmp[1] * tsrc[12] + tmp[6] * tsrc[14] + tmp[9] * tsrc[15];
m[2][1] -= tmp[0] * tsrc[12] + tmp[7] * tsrc[14] + tmp[8] * tsrc[15];
m[2][2] = tmp[2] * tsrc[12] + tmp[7] * tsrc[13] + tmp[10] * tsrc[15];
m[2][2] -= tmp[3] * tsrc[12] + tmp[6] * tsrc[13] + tmp[11] * tsrc[15];
m[2][3] = tmp[5] * tsrc[12] + tmp[8] * tsrc[13] + tmp[11] * tsrc[14];
m[2][3] -= tmp[4] * tsrc[12] + tmp[9] * tsrc[13] + tmp[10] * tsrc[14];
m[3][0] = tmp[2] * tsrc[10] + tmp[5] * tsrc[11] + tmp[1] * tsrc[9];
m[3][0] -= tmp[4] * tsrc[11] + tmp[0] * tsrc[9] + tmp[3] * tsrc[10];
m[3][1] = tmp[8] * tsrc[11] + tmp[0] * tsrc[8] + tmp[7] * tsrc[10];
m[3][1] -= tmp[6] * tsrc[10] + tmp[9] * tsrc[11] + tmp[1] * tsrc[8];
m[3][2] = tmp[6] * tsrc[9] + tmp[11] * tsrc[11] + tmp[3] * tsrc[8];
m[3][2] -= tmp[10] * tsrc[11] + tmp[2] * tsrc[8] + tmp[7] * tsrc[9];
m[3][3] = tmp[10] * tsrc[10] + tmp[4] * tsrc[8] + tmp[9] * tsrc[9];
m[3][3] -= tmp[8] * tsrc[9] + tmp[11] * tsrc[0] + tmp[5] * tsrc[8];
/* calculate determinant */
det = tsrc[0] * m[0][0] + tsrc[1] * m[0][1] + tsrc[2] * m[0][2] +
tsrc[3] * m[0][3];
/* calculate matrix inverse */
det = 1.0f / det;
for (j = 0; j < 4; j++) {
for (i = 0; i < 4; i++) {
m[j][i] *= det;
}
}
}
void Matrix::Mult(float dst[4][4], float m0[4][4], float m1[4][4]) {
for (int i = 0; i < 4; ++i) {
for (int j = 0; j < 4; ++j) {
dst[i][j] = 0;
for (int k = 0; k < 4; ++k) {
dst[i][j] += m0[k][j] * m1[i][k];
}
}
}
}
void Matrix::MultV(float dst[3], float m[4][4], float v[3]) {
// printf("v = %f, %f, %f\n", v[0], v[1], v[2]);
dst[0] = m[0][0] * v[0] + m[1][0] * v[1] + m[2][0] * v[2] + m[3][0];
dst[1] = m[0][1] * v[0] + m[1][1] * v[1] + m[2][1] * v[2] + m[3][1];
dst[2] = m[0][2] * v[0] + m[1][2] * v[1] + m[2][2] * v[2] + m[3][2];
// printf("m = %f, %f, %f\n", m[3][0], m[3][1], m[3][2]);
// printf("dst = %f, %f, %f\n", dst[0], dst[1], dst[2]);
}