90 lines
2.3 KiB
C
90 lines
2.3 KiB
C
#include "matrix.h"
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#include <math.h>
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inline M33 m33_zero(void) { return (M33){{{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}}; }
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inline M33 m33_identity(void) {
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return (M33){{{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}};
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}
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inline M33 m33_translate(double tx, double ty) {
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return (M33){{{1, 0, tx}, {0, 1, ty}, {0, 0, 1}}};
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}
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inline M33 m33_scale(double sx, double sy) {
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return (M33){{{sx, 0, 0}, {0, sy, 0}, {0, 0, 1}}};
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}
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inline M33 m33_rotate(double theta) {
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return (M33){
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{{cos(theta), -sin(theta), 0}, {sin(theta), cos(theta), 0}, {0, 0, 1}}};
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}
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inline M33 m33_shear(double theta_x, double theta_y) {
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return (M33){{{1, tan(theta_x), 0}, {tan(theta_y), 1, 0}, {0, 0, 0}}};
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}
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M33 m33_add(const M33 m1, const M33 m2) {
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M33 res;
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for (int i = 0; i < 3; ++i)
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for (int j = 0; j < 3; ++j)
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res.m[i][j] = m1.m[i][j] + m2.m[i][j];
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return res;
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}
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M33 m33_sub(const M33 m1, const M33 m2) {
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M33 res;
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for (int i = 0; i < 3; ++i)
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for (int j = 0; j < 3; ++j)
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res.m[i][j] = m1.m[i][j] - m2.m[i][j];
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return res;
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}
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M33 m33_mul(const M33 m1, const M33 m2) {
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M33 res = {{{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}};
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for (int i = 0; i < 3; ++i)
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for (int j = 0; j < 3; ++j)
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for (int k = 0; k < 3; ++k)
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res.m[i][j] += m1.m[i][k] * m2.m[k][j];
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return res;
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}
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M33 m33_transpose(const M33 m) {
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M33 res;
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for (int i = 0; i < 3; ++i)
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for (int j = 0; j < 3; ++j)
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res.m[i][j] = m.m[j][i];
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return res;
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}
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// 2D affine transform inversion (not general 3x3 inversion)
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M33 m33_inverse(const M33 m) {
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M33 inv;
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double det;
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det = m.m[0][0] * m.m[1][1] - m.m[0][1] * m.m[1][0];
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if (det == 0.0) {
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return m33_identity();
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}
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double invDet = 1.0 / det;
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inv.m[0][0] = m.m[1][1] * invDet;
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inv.m[0][1] = -m.m[0][1] * invDet;
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inv.m[1][0] = -m.m[1][0] * invDet;
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inv.m[1][1] = m.m[0][0] * invDet;
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inv.m[0][2] = -(inv.m[0][0] * m.m[0][2] + inv.m[0][1] * m.m[1][2]);
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inv.m[1][2] = -(inv.m[1][0] * m.m[0][2] + inv.m[1][1] * m.m[1][2]);
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inv.m[2][0] = 0;
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inv.m[2][1] = 0;
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inv.m[2][2] = 1;
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return inv;
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}
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V2 m33_transform(const M33 mat, const V2 v) {
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return (V2){mat.m[0][0] * v.x + mat.m[0][1] * v.y + mat.m[0][2],
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mat.m[1][0] * v.x + mat.m[1][1] * v.y + mat.m[1][2]};
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}
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