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Create linear algebra module

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Camden Dixie O'Brien committed 2025-09-28 13:57:09 +01:00
1 parent 74f15dd132
commit f546f27a42
5 files changed
+165 -144
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main.c
+9 -131
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@@ -5,10 +5,6 @@
#include <stdio.h>
#include <string.h>
#ifndef M_PI
#define M_PI 3.14159265358979324
#endif
#define W 800
#define H 600
@@ -31,54 +27,6 @@ typedef enum {
static axis_t rot_axis = AXIS_Y;
#define ID \
{ \
{ 1, 0, 0, 0 }, \
{ 0, 1, 0, 0 }, \
{ 0, 0, 1, 0 }, \
{ 0, 0, 0, 1 }, \
}
#define SCALE(sf) \
{ \
{ sf, 0, 0, 0 }, \
{ 0, sf, 0, 0 }, \
{ 0, 0, sf, 0 }, \
{ 0, 0, 0, 1 }, \
}
#define TRANSLATE(x, y, z) \
{ \
{ 1, 0, 0, 0 }, \
{ 0, 1, 0, 0 }, \
{ 0, 0, 1, 0 }, \
{ x, y, z, 1 }, \
}
#define ROT_X(a) \
{ \
{ 1, 0, 0, 0 }, \
{ 0, cosf(a), sinf(a), 0 }, \
{ 0, -sinf(a), cosf(a), 0 }, \
{ 0, 0, 0, 1 }, \
}
#define ROT_Y(a) \
{ \
{ cosf(a), 0, -sinf(a), 0 }, \
{ 0, 1, 0, 0 }, \
{ sinf(a), 0, cosf(a), 0 }, \
{ 0, 0, 0, 1 }, \
}
#define ROT_Z(a) \
{ \
{ cosf(a), sinf(a), 0, 0 }, \
{ -sinf(a), cosf(a), 0, 0 }, \
{ 0, 0, 1, 0 }, \
{ 0, 0, 0, 1 }, \
}
static void
key_callback(GLFWwindow *window, int key, int scancode, int action, int mods)
{
@@ -106,76 +54,6 @@ key_callback(GLFWwindow *window, int key, int scancode, int action, int mods)
}
}
static vec3_t sub(vec3_t v, vec3_t u)
{
return (vec3_t) { v.x - u.x, v.y - u.y, v.z - u.z };
}
static float len(vec3_t v)
{
return sqrtf(v.x * v.x + v.y * v.y + v.z * v.z);
}
static vec3_t norm(vec3_t v)
{
const float s = len(v);
return (vec3_t) { v.x / s, v.y / s, v.z / s };
}
static float dot(vec3_t v, vec3_t u)
{
return v.x * u.x + v.y * u.y + v.z * u.z;
}
static vec3_t cross(vec3_t v, vec3_t u)
{
return (vec3_t) {
v.y * u.z - v.z * u.y,
v.z * u.x - v.x * u.z,
v.x * u.y - v.y * u.x,
};
}
static mat4_t mul(mat4_t m, mat4_t n)
{
#define ELEM(i, j) m.x.i *n.j.x + m.y.i *n.j.y + m.z.i *n.j.z + m.w.i *n.j.w
return (mat4_t) {
{ ELEM(x, x), ELEM(y, x), ELEM(z, x), ELEM(w, x) },
{ ELEM(x, y), ELEM(y, y), ELEM(z, y), ELEM(w, y) },
{ ELEM(x, z), ELEM(y, z), ELEM(z, z), ELEM(w, z) },
{ ELEM(x, w), ELEM(y, w), ELEM(z, w), ELEM(w, w) },
};
#undef MUL_ELEM
}
static mat4_t lookat(vec3_t cam, vec3_t tgt, vec3_t up)
{
const vec3_t s = sub(tgt, cam);
const vec3_t s_hat = norm(s);
const vec3_t u_hat = norm(cross(up, s_hat));
const vec3_t v_hat = cross(s_hat, u_hat);
return (mat4_t) {
{ u_hat.x, v_hat.x, s_hat.x, 0 },
{ u_hat.y, v_hat.y, s_hat.y, 0 },
{ u_hat.z, v_hat.z, s_hat.z, 0 },
{ -dot(u_hat, cam), -dot(v_hat, cam), -dot(s_hat, cam), 1 },
};
}
static mat4_t persp(float aspect, float fov, float ncp, float fcp)
{
const float r = 2 * ncp * tanf(fov / 2);
const float t = r * aspect;
return (mat4_t) {
{ ncp / t, 0, 0, 0 },
{ 0, -ncp / r, 0, 0 },
{ 0, 0, fcp / (fcp - ncp), 1 },
{ 0, 0, -fcp * ncp / (fcp - ncp), 0 },
};
}
int main()
{
// Set up window
@@ -203,27 +81,27 @@ int main()
const vec3_t cam = { 2, 2, -2 };
const vec3_t tgt = { 0, 0, 0 };
mvp_t mvp = {
.model = SCALE(2),
.view = lookat(cam, tgt, (vec3_t) { 0, 1, 0 }),
.proj = persp((float)W / H, M_PI / 6, 0.1, 10.0),
.model = MAT4_SCALE(2),
.view = mat4_lookat(cam, tgt, (vec3_t) { 0, 1, 0 }),
.proj = mat4_perspective((float)W / H, PI / 6, 0.1, 10.0),
};
const mat4_t rotx = ROT_X(M_PI / 128);
const mat4_t roty = ROT_Y(M_PI / 128);
const mat4_t rotz = ROT_Z(M_PI / 128);
const mat4_t rotx = MAT4_ROTATE_X(PI / 128);
const mat4_t roty = MAT4_ROTATE_Y(PI / 128);
const mat4_t rotz = MAT4_ROTATE_Z(PI / 128);
while (!glfwWindowShouldClose(window)) {
glfwPollEvents();
switch (rot_axis) {
case AXIS_X:
mvp.model = mul(rotx, mvp.model);
mvp.model = mat4_mul(rotx, mvp.model);
break;
case AXIS_Y:
mvp.model = mul(roty, mvp.model);
mvp.model = mat4_mul(roty, mvp.model);
break;
case AXIS_Z:
mvp.model = mul(rotz, mvp.model);
mvp.model = mat4_mul(rotz, mvp.model);
break;
}