void test_mat4() {
/*
// Matrix
local m = vec.Mat4.frustum(-10, 10, -10, 10, -10, 10)
local m = vec.Mat4.perspective(90, 1, 1, 100)
local m = vec.Mat4.lookAt(vec.Vec3(10, 9, 8), vec.Vec3(1, 2, 3), vec.Vec3(0, 1, 0))
local m = vec.Mat4.ortho(-10, 100, -10, 10, -10, 10)
local m = vec.Mat4.identity()
local m = vec.Mat4.translate(vec.Vec3(1, 2, 3))
local m = vec.Mat4.scale(1, 2, 3)
local m = vec.Mat4.rotate(vec.Quat.new(1, 2, 3, 8))
local m = vec.Mat4.perspective(90, 1, 1, 100):inverse()
local a = vec.Mat4.translate(vec.Vec3(1, 2, 3))
local b = vec.Mat4.perspective(90, 1, 1, 100)
local m = a * b
local v3 = m * vec.Vec4(1, 2, 3, 4)
*/
struct vec3 eye = {0, -15, 30};
struct vec3 at = {0, 0, 0};
struct vec3 up = {0, 1, 0};
struct mat4 m = mat4_look(&eye, &at, &up);
struct vec4 zero = {0, 0, 0, 1};
struct vec4 v4 = mat4_mul_vec4(&m, &zero);
assert(v4.x == 0);
assert(v4.y == 0);
assert((v4.z - (-33.541019)) < 0.00001);
struct mat4 inv = mat4_inverse(&m);
struct vec4 v5 = mat4_mul_vec4(&inv, &zero);
assert(v5.x == 0);
assert(v5.y - (-15) < 0.00001);
assert(v5.z - (30) < 0.00001);
}
Vec3
Util_GetMouseRay(int screenWidth, int screenHeigth, Mat4 *viewMatrix, Mat4 *projectionMatrix,
int mouseX, int mouseY)
{
Vec4 eyeCoords;
Vec3 mouseRay;
/* Normalized device coords NOTE: -y becouse for SDL y = 0 is the top of the screen */
GLfloat normalX = ( 2.0f * (GLfloat)mouseX ) / (GLfloat) screenWidth - 1.0f;
GLfloat normalY = 1.0f - (2.0f * (GLfloat)mouseY) / (GLfloat) screenHeigth;
/* clipCoords include 4th component */
Vec4 clipCoords = { normalX, normalY, -1.0f, 1.0f };
/* Remove perpective */
{
Mat4 invertedProjection = mat4_inverse(projectionMatrix);
eyeCoords = mat4_mul_vec4(&invertedProjection, &clipCoords);
eyeCoords.z = -1.0f;
eyeCoords.w = 0.0f;
}
/* Remove view matrix*/
{
Mat4 invertedViewMatrix = mat4_inverse(viewMatrix);
Vec4 temp = mat4_mul_vec4(&invertedViewMatrix, &eyeCoords);
mouseRay.x = temp.x;
mouseRay.y = temp.y;
mouseRay.z = temp.z;
mouseRay = vec3_normalize(&mouseRay);
}
/* Return the ray in world coordinates */
return mouseRay;
}