feat: Implement 3D system and procedural texture manager

- Extended mini_math.h with mat4 multiplication and affine transforms.
- Implemented TextureManager for runtime procedural texture generation and GPU upload.
- Added 3D system components: Camera, Object, Scene, and Renderer3D.
- Created test_3d_render mini-demo for interactive 3D verification.
- Fixed WebGPU validation errors regarding depthSlice and unimplemented WaitAny.

1 files changed, 70 insertions, 0 deletions

diff --git a/src/tests/test_3d.cc b/src/tests/test_3d.cc
new file mode 100644
index 0000000..33e6a04
--- /dev/null
+++ b/src/tests/test_3d.cc
@@ -0,0 +1,70 @@
+// This file is part of the 64k demo project.
+// It tests the 3D system components (Camera, Object, Scene).
+
+#include "3d/camera.h"
+#include "3d/object.h"
+#include "3d/scene.h"
+#include <cassert>
+#include <cmath>
+#include <iostream>
+
+bool near(float a, float b, float e = 0.001f) {
+  return std::abs(a - b) < e;
+}
+
+void test_camera() {
+  std::cout << "Testing Camera..." << std::endl;
+  Camera cam;
+  cam.position = vec3(0, 0, 10);
+  cam.target = vec3(0, 0, 0);
+
+  mat4 view = cam.get_view_matrix();
+  // 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));
+
+  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);
+}
+
+void test_object_transform() {
+  std::cout << "Testing Object Transform..." << std::endl;
+  Object3D obj;
+  obj.position = vec3(10, 0, 0);
+  
+  // 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);
+  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));
+}
+
+void test_scene() {
+  std::cout << "Testing Scene..." << std::endl;
+  Scene scene;
+  scene.add_object(Object3D());
+  assert(scene.objects.size() == 1);
+  scene.clear();
+  assert(scene.objects.empty());
+}
+
+int main() {
+  test_camera();
+  test_object_transform();
+  test_scene();
+  std::cout << "--- 3D SYSTEM TESTS PASSED ---" << std::endl;
+  return 0;
+}