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#include <assert.h>
#include <string.h>
#include <wayland-server-protocol.h>
#include <wlr/util/box.h>
#include "util/matrix.h"
void wlr_matrix_identity(float mat[static 9]) {
static const float identity[9] = {
1.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 1.0f,
};
memcpy(mat, identity, sizeof(identity));
}
void wlr_matrix_multiply(float mat[static 9], const float a[static 9],
const float b[static 9]) {
float product[9];
product[0] = a[0]*b[0] + a[1]*b[3] + a[2]*b[6];
product[1] = a[0]*b[1] + a[1]*b[4] + a[2]*b[7];
product[2] = a[0]*b[2] + a[1]*b[5] + a[2]*b[8];
product[3] = a[3]*b[0] + a[4]*b[3] + a[5]*b[6];
product[4] = a[3]*b[1] + a[4]*b[4] + a[5]*b[7];
product[5] = a[3]*b[2] + a[4]*b[5] + a[5]*b[8];
product[6] = a[6]*b[0] + a[7]*b[3] + a[8]*b[6];
product[7] = a[6]*b[1] + a[7]*b[4] + a[8]*b[7];
product[8] = a[6]*b[2] + a[7]*b[5] + a[8]*b[8];
memcpy(mat, product, sizeof(product));
}
void wlr_matrix_translate(float mat[static 9], float x, float y) {
float translate[9] = {
1.0f, 0.0f, x,
0.0f, 1.0f, y,
0.0f, 0.0f, 1.0f,
};
wlr_matrix_multiply(mat, mat, translate);
}
void wlr_matrix_scale(float mat[static 9], float x, float y) {
float scale[9] = {
x, 0.0f, 0.0f,
0.0f, y, 0.0f,
0.0f, 0.0f, 1.0f,
};
wlr_matrix_multiply(mat, mat, scale);
}
static const float transforms[][9] = {
[WL_OUTPUT_TRANSFORM_NORMAL] = {
1.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_90] = {
0.0f, 1.0f, 0.0f,
-1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_180] = {
-1.0f, 0.0f, 0.0f,
0.0f, -1.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_270] = {
0.0f, -1.0f, 0.0f,
1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_FLIPPED] = {
-1.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_FLIPPED_90] = {
0.0f, 1.0f, 0.0f,
1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_FLIPPED_180] = {
1.0f, 0.0f, 0.0f,
0.0f, -1.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
[WL_OUTPUT_TRANSFORM_FLIPPED_270] = {
0.0f, -1.0f, 0.0f,
-1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f,
},
};
void wlr_matrix_transform(float mat[static 9],
enum wl_output_transform transform) {
wlr_matrix_multiply(mat, mat, transforms[transform]);
}
void matrix_projection(float mat[static 9], int width, int height,
enum wl_output_transform transform) {
memset(mat, 0, sizeof(*mat) * 9);
const float *t = transforms[transform];
float x = 2.0f / width;
float y = 2.0f / height;
// Rotation + reflection
mat[0] = x * t[0];
mat[1] = x * t[1];
mat[3] = y * -t[3];
mat[4] = y * -t[4];
// Translation
mat[2] = -copysign(1.0f, mat[0] + mat[1]);
mat[5] = -copysign(1.0f, mat[3] + mat[4]);
// Identity
mat[8] = 1.0f;
}
void wlr_matrix_project_box(float mat[static 9], const struct wlr_box *box,
enum wl_output_transform transform, const float projection[static 9]) {
int x = box->x;
int y = box->y;
int width = box->width;
int height = box->height;
wlr_matrix_identity(mat);
wlr_matrix_translate(mat, x, y);
wlr_matrix_scale(mat, width, height);
if (transform != WL_OUTPUT_TRANSFORM_NORMAL) {
wlr_matrix_translate(mat, 0.5, 0.5);
wlr_matrix_transform(mat, transform);
wlr_matrix_translate(mat, -0.5, -0.5);
}
wlr_matrix_multiply(mat, projection, mat);
}
void matrix_invert(float out[static 9], float m[static 9]) {
float a = m[0], b = m[1], c = m[2], d = m[3], e = m[4], f = m[5], g = m[6], h = m[7], i = m[8];
// See: https://en.wikipedia.org/wiki/Determinant
float det = a*e*i + b*f*g + c*d*h - c*e*g - b*d*i - a*f*h;
assert(det != 0);
float inv_det = 1 / det;
// See: https://en.wikipedia.org/wiki/Invertible_matrix#Inversion_of_3_%C3%97_3_matrices
float result[] = {
inv_det * (e*i - f*h),
inv_det * -(b*i - c*h),
inv_det * (b*f - c*e),
inv_det * -(d*i - f*g),
inv_det * (a*i - c*g),
inv_det * -(a*f - c*d),
inv_det * (d*h - e*g),
inv_det * -(a*h - b*g),
inv_det * (a*e - b*d),
};
memcpy(out, result, sizeof(result));
}
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