1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
|
#include "mat4.h"
#include <string.h>
#include <math.h>
void mat4_identity(mat4 m)
{
memset(m, 0, sizeof(mat4));
m[0][0] = 1;
m[1][1] = 1;
m[2][2] = 1;
m[3][3] = 1;
}
void mat4_translate(mat4 m, float x, float y)
{
mat4_identity(m);
m[0][3] = x;
m[1][3] = y;
}
void mat4_scale(mat4 m, float x, float y)
{
mat4_identity(m);
m[0][0] = x;
m[1][1] = y;
}
void mat4_ortho(
mat4 m,
float l, float r,
float t, float b,
float n, float f
)
{
mat4_identity(m);
m[0][0] = 2.0 / (r - l);
m[1][1] = 2.0 / (t - b);
m[2][2] = -2.0 / (f - n);
m[0][3] = -(r + l) / (r - l);
m[1][3] = -(t + b) / (t - b);
m[2][3] = -(f + n) / (f - n);
}
void mat4_perspective(mat4 mat, float yfov, float a, float n, float f)
{
memset(mat, 0, sizeof(mat4));
// 1000
// 0100
// 0010
// 0001
//
// 00 01 02 03
// 10 11 12 13
// 20 21 22 23
// 30 31 32 33
//
// 0 4 8 12
// 1 5 9 14
// 2 6 10 15
// 3 7 11 16
float cotan = 1.0 / tanf(yfov * DEG2RAD * 0.5);
mat[0][0] = cotan / a;
mat[1][1] = cotan;
mat[2][2] = (f + n) / (n - f);
mat[3][2] = -1.0;
mat[2][3] = 2.0 * n * f / (n - f);
}
void mat4_mult(mat4 dst, mat4 a, mat4 b)
{
mat4 res;
for (int r = 0; r < 4; r++)
for (int c = 0; c < 4; c++)
for (int k = 0; k < 4; k++)
res[r][c] = a[r][k] * b[k][c];
// memcpy after so that dst can be one of a or b
memcpy(dst, res, sizeof(mat4));
}
|
