feat(tests): Add comprehensive tests for math and 3d libraries

1 files changed, 65 insertions, 15 deletions

diff --git a/src/tests/test_3d.cc b/src/tests/test_3d.cc
index 88b8db9..90869bf 100644
--- a/src/tests/test_3d.cc
+++ b/src/tests/test_3d.cc
@@ -22,11 +22,29 @@ void test_camera() {
   // Camera at (0,0,10) looking at (0,0,0). World (0,0,0) -> View (0,0,-10)
   assert(near(view.m[14], -10.0f));
 
+  // Test Camera::set_look_at
+  cam.set_look_at({5, 0, 0}, {0, 0, 0}, {0, 1, 0}); // Look at origin from (5,0,0)
+  mat4 view_shifted = cam.get_view_matrix();
+  // The camera's forward vector (0,0,-1) should now point towards (-1,0,0) in world space.
+  // The translation part of the view matrix should be based on -dot(s, eye), -dot(u, eye), dot(f, eye)
+  // s = (0,0,-1), u = (0,1,0), f = (-1,0,0)
+  // m[12] = -dot({0,0,-1}, {5,0,0}) = 0
+  // m[13] = -dot({0,1,0}, {5,0,0}) = 0
+  // m[14] = dot({-1,0,0}, {5,0,0}) = -5
+  assert(near(view_shifted.m[12], 0.0f));
+  assert(near(view_shifted.m[13], 0.0f));
+  assert(near(view_shifted.m[14], -5.0f));
+
+  // Test Camera::get_projection_matrix with varied parameters
+  // Change FOV and aspect ratio
   mat4 proj = cam.get_projection_matrix();
-  // Check aspect ratio influence (m[0] = 1/(tan(fov/2)*asp))
-  // fov ~0.785 (45deg), tan(22.5) ~0.414. asp=1.777.
-  // m[0] should be around 1.35
-  assert(proj.m[0] > 1.0f);
+  cam.fov_y_rad = 1.0472f; // 60 degrees
+  cam.aspect_ratio = 0.5f; // Narrower aspect ratio
+  mat4 proj_varied = cam.get_projection_matrix();
+  // m[0] should increase due to narrower aspect ratio (1/tan(30deg)/0.5)
+  assert(proj_varied.m[0] > proj.m[0]);
+  // m[5] should increase due to larger FOV (1/tan(30deg))
+  assert(proj_varied.m[5] < proj.m[5]);
 }
 
 void test_object_transform() {
@@ -36,21 +54,44 @@ void test_object_transform() {
 
   // Model matrix should translate by (10,0,0)
   mat4 m = obj.get_model_matrix();
-  assert(near(m.m[12], 10.0f)); // Col 3, Row 0 is x translation in Col-Major?
-  // Wait, my mat4 struct:
-  // r.m[12] = t.x; // Index 12 is translation X
   assert(near(m.m[12], 10.0f));
 
-  // Rotate 90 deg Y
-  obj.rotation = quat::from_axis(vec3(0, 1, 0), 1.570796f);
+  // Test composed transformations (translate then rotate)
+  obj.position = vec3(5, 0, 0);
+  obj.rotation = quat::from_axis({0, 1, 0}, 1.570796f); // 90 deg Y rotation
   m = obj.get_model_matrix();
 
-  // Transform point (1,0,0) -> Rot(0,0,-1) -> Trans(10,0,-1)
-  vec4 p(1, 0, 0, 1);
-  vec4 res = m * p;
-  assert(near(res.x, 10.0f)); // Rotated vector is (0,0,-1). + (10,0,0)
-                              // translation -> (10,0,-1)
-  assert(near(res.z, -1.0f));
+  // Transform point (1,0,0). Rotation around Y maps (1,0,0) to (0,0,-1).
+  // Translation moves it by (5,0,0). Final world pos: (5,0,-1).
+  vec4 p_comp(1, 0, 0, 1);
+  vec4 res_comp = m * p_comp;
+  assert(near(res_comp.x, 5.0f));
+  assert(near(res_comp.z, -1.0f));
+
+  // Test Object3D::inv_model calculation
+  // Model matrix for translation (5,0,0) is just translation
+  obj.position = vec3(5, 0, 0);
+  obj.rotation = quat(); // Identity rotation
+  mat4 model_t = obj.get_model_matrix();
+  mat4 inv_model_t = model_t.inverse();
+  // Applying inv_model to a translated point should undo the translation.
+  // Point (5,0,0) should go to (0,0,0)
+  vec4 translated_point(5,0,0,1);
+  vec4 original_space_t = inv_model_t * vec4(translated_point.x, translated_point.y, translated_point.z, 1.0);
+  assert(near(original_space_t.x, 0.0f) && near(original_space_t.y, 0.0f) && near(original_space_t.z, 0.0f));
+
+  // Model matrix with rotation (90 deg Y) and translation (5,0,0)
+  obj.position = vec3(5, 0, 0);
+  obj.rotation = quat::from_axis({0, 1, 0}, 1.570796f);
+  mat4 model_trs = obj.get_model_matrix();
+  mat4 inv_model_trs = model_trs.inverse();
+  // Transform point (1,0,0) (local right) via TRS: Rotates to (0,0,-1), Translates to (5,0,-1)
+  vec4 p_trs(1,0,0,1);
+  vec4 transformed_p = model_trs * p_trs;
+  assert(near(transformed_p.x, 5.0f) && near(transformed_p.z, -1.0f));
+  // Apply inverse to transformed point to get back original point
+  vec4 original_space_trs = inv_model_trs * transformed_p;
+  assert(near(original_space_trs.x, 1.0f) && near(original_space_trs.y, 0.0f) && near(original_space_trs.z, 0.0f));
 }
 
 void test_scene() {
@@ -60,6 +101,15 @@ void test_scene() {
   assert(scene.objects.size() == 1);
   scene.clear();
   assert(scene.objects.empty());
+
+  // Add multiple objects and check count
+  scene.add_object(Object3D());
+  scene.add_object(Object3D());
+  assert(scene.objects.size() == 2);
+
+  // Test clearing the scene
+  scene.clear();
+  assert(scene.objects.empty());
 }
 
 int main() {