08-august/src/math/vector3f.c


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

#include "vector3f.h"
#include <SDL2/SDL.h>

vec3_t vec3_add(const vec3_t* a, const vec3_t* b)
{
    vec3_t c;
    c.x = a->x + b->x;
    c.y = a->y + b->y;
    c.z = a->z + b->z;
    return c;
}

vec3_t vec3_sub(const vec3_t* a, const vec3_t* b)
{
    vec3_t c;
    c.x = a->x - b->x;
    c.y = a->y - b->y;
    c.z = a->z - b->z;
    return c;
}

vec3_t vec3_scalar_mul(const vec3_t* a, GLfloat scalar)
{
    vec3_t c;
    c.x = a->x * scalar;
    c.y = a->y * scalar;
    c.z = a->z * scalar;
    return c;
}

GLfloat vec3_dot_mul(const vec3_t* a, const vec3_t* b)
{
    return ( (a->x * b->x) + (a->y * b->y) + (a->z * b->z) );
}


vec3_t vec3_cross_mul(const vec3_t* a, const vec3_t* b)
{
    vec3_t c;
    c.x = (a->y * b->z) - (a->z * b->y);
    c.y = (a->z * b->x) - (a->x * b->z);
    c.z = (a->x * b->y) - (a->y * b->x);
    return c;
}

GLfloat vec3_length(vec3_t* a)
{
    return SDL_sqrtf(SDL_pow(a->x, 2.0f) + SDL_pow(a->y, 2.0f) + SDL_pow(a->z, 2.0f));
}

vec3_t vec3_normalize(vec3_t* a)
{
    vec3_t b;
    GLfloat length = vec3_length(a);
    b.x = a->x / length;
    b.y = a->y / length;
    b.z = a->z / length;
    return b;
}