tests: test for ray, reflect, refract and faceforward

test/src/test_ray.h

@@ -32,3 +32,43 @@ TEST_IMPL(GLM_PREFIX, ray_triangle) {
 
   TEST_SUCCESS
 }
+
+TEST_IMPL(GLM_PREFIX, ray_sphere) {
+  vec4  sphere = {5.0f, 0.0f, 0.0f, 1.0f}; /* Sphere: center at (5, 0, 0) with radius 1 */
+  float t1, t2;
+  bool  hit;
+
+  /* Case 1: Ray misses the sphere */
+  hit = GLM(ray_sphere)((vec3){10.0f, 3.0f, 0.0f}, (vec3){1.0f, 0.0f, 0.0f}, sphere, &t1, &t2);
+  ASSERT(!hit); /* Expect no intersection */
+
+  /* Case 2: Ray starts inside the sphere */
+  hit = GLM(ray_sphere)((vec3){5.0f, 0.5f, 0.0f}, (vec3){1.0f, 0.0f, 0.0f}, sphere, &t1, &t2);
+  ASSERT(hit); /* Expect an intersection */
+  ASSERT(t1 < 0 && t2 > 0); /* Ray exits at t2 */
+
+  /* Case 3: Ray intersects the sphere from outside */
+  hit = GLM(ray_sphere)((vec3){0.0f, 0.0f, 0.0f}, (vec3){1.0f, 0.0f, 0.0f}, sphere, &t1, &t2);
+  ASSERT(hit); /* Expect an intersection */
+  ASSERT(t1 > 0 && t2 > 0); /* Intersections at t1 and t2 */
+
+  TEST_SUCCESS
+}
+
+TEST_IMPL(GLM_PREFIX, ray_at) {
+  vec3 origin    = {0.0f, 0.0f, 0.0f};
+  vec3 direction = {1.0f, 1.0f, 1.0f};  /* Diagonal direction */
+  float distance = sqrtf(3.0f);         /* Distance along the ray; sqrt(3) for unit length due to direction normalization */
+  vec3 result;
+
+  /* Normalize the direction to ensure accurate distance measurement */
+  glm_vec3_normalize(direction);
+
+  GLM(ray_at)(origin, direction, distance, result);
+  ASSERT(fabsf(result[0] - 1.0f) <= 0.0000009);  /* Expecting to be 1 unit along the x-axis */
+  ASSERT(fabsf(result[1] - 1.0f) <= 0.0000009);  /* Expecting to be 1 unit along the y-axis */
+  ASSERT(fabsf(result[2] - 1.0f) <= 0.0000009);  /* Expecting to be 1 unit along the z-axis */
+
+  TEST_SUCCESS
+}
+