139 lines
3.0 KiB
C
139 lines
3.0 KiB
C
#include "matrix.h"
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mat4_t mat4_identity(void) {
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mat4_t m = {{
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{ 1, 0, 0, 0},
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{ 0, 1, 0, 0},
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{ 0, 0, 1, 0},
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{ 0, 0, 0, 1},
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}};
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return m;
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}
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mat4_t mat4_make_scale(float sx, float sy, float sz) {
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mat4_t m = mat4_identity();
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m.m[0][0] *= sx;
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m.m[1][1] *= sy;
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m.m[2][2] *= sz;
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return m;
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}
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mat4_t mat4_make_translation(float tx, float ty, float tz) {
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/*
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* 1 0 0 tx
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* 0 1 0 ty
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* 0 0 1 tz
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* 0 0 0 1
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*/
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mat4_t m = mat4_identity();
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m.m[0][3] = tx;
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m.m[1][3] = ty;
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m.m[2][3] = tz;
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return m;
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}
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mat4_t mat4_make_rotation_y(float ra) {
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/*
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* cos 0 -sin 0
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* 0 1 0 0
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* sin 0 cos 0
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* 0 0 0 1
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*/
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const float cosine = cosf(ra);
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const float sine = sinf(ra);
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mat4_t m = mat4_identity();
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m.m[0][0] = cosine;
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m.m[0][2] = -sine;
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m.m[2][0] = sine;
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m.m[2][2] = cosine;
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return m;
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}
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mat4_t mat4_make_rotation_x(float ra) {
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/*
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* 1 0 0 0
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* 0 cos sin 0
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* 0 -sin cos 0
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* 0 0 0 1
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*/
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const float cosine = cosf(ra);
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const float sine = sinf(ra);
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mat4_t m = mat4_identity();
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m.m[1][1] = cosine;
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m.m[1][2] = sine;
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m.m[2][1] = -sine;
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m.m[2][2] = cosine;
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return m;
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}
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mat4_t mat4_make_rotation_z(float ra) {
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/*
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* cos sin 0 0
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* -sin cos 0 0
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* 0 0 1 0
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* 0 0 0 1
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*/
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const float cosine = cosf(ra);
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const float sine = sinf(ra);
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mat4_t m = mat4_identity();
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m.m[0][0] = cosine;
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m.m[0][1] = sine;
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m.m[1][0] = -sine;
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m.m[1][1] = cosine;
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return m;
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}
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vec4_t mat4_multiply_vec4(mat4_t m, vec4_t v) {
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vec4_t ret = {};
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ret.x = m.m[0][0] * v.x + m.m[0][1] * v.y + m.m[0][2] * v.z + m.m[0][3] * v.w;
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ret.y = m.m[1][0] * v.x + m.m[1][1] * v.y + m.m[1][2] * v.z + m.m[1][3] * v.w;
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ret.z = m.m[2][0] * v.x + m.m[2][1] * v.y + m.m[2][2] * v.z + m.m[2][3] * v.w;
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ret.w = m.m[3][0] * v.x + m.m[3][1] * v.y + m.m[3][2] * v.z + m.m[3][3] * v.w;
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return ret;
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}
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mat4_t mat4_mul_mat4(mat4_t* a, mat4_t* b) {
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mat4_t ret = {};
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for (int r = 0; r < 4; r++) {
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for (int c = 0; c < 4; c++) {
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ret.m[r][c] = (a->m[r][0] * b->m[0][c]) + (a->m[r][1] * b->m[1][c]) + (a->m[r][2] * b->m[2][c]) + (a->m[r][3] * b->m[3][c]);
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}
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}
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return ret;
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}
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mat4_t mat4_make_perspective(float fov, float aspect, float znear, float zfar) {
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mat4_t m = {{{ 0 }}};
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m.m[0][0] = aspect * (1 / tanf(fov / 2));
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m.m[1][1] = 1 / tanf(fov / 2);
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m.m[2][2] = zfar / (zfar - znear);
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m.m[2][3] = (-zfar * znear) / (zfar - znear);
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m.m[3][2] = 1.0f;
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return m;
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}
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vec4_t mat4_mul_vec4_project(mat4_t mat_proj, vec4_t v) {
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// multiply the projection matrix by our original vector
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vec4_t result = mat4_multiply_vec4(mat_proj, v);
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// perform perspective divide with original z-value
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if (result.w != 0.0) {
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result.x /= result.w;
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result.y /= result.w;
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result.z /= result.w;
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}
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return result;
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} |