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, 39 insertions, 0 deletions

diff --git a/src/3d/camera.h b/src/3d/camera.h
new file mode 100644
index 0000000..23e26d6
--- /dev/null
+++ b/src/3d/camera.h
@@ -0,0 +1,39 @@
+// This file is part of the 64k demo project.
+// It defines the Camera class for 3D navigation and rendering.
+// Handles view and projection matrix generation.
+
+#pragma once
+
+#include "util/mini_math.h"
+
+class Camera {
+ public:
+  vec3 position;
+  vec3 target;
+  vec3 up;
+
+  float fov_y_rad;
+  float aspect_ratio;
+  float near_plane;
+  float far_plane;
+
+  Camera()
+      : position(0, 0, 5), target(0, 0, 0), up(0, 1, 0), fov_y_rad(0.785398f),
+        aspect_ratio(1.777f), near_plane(0.1f), far_plane(100.0f) {
+  }
+
+  mat4 get_view_matrix() const {
+    return mat4::look_at(position, target, up);
+  }
+
+  mat4 get_projection_matrix() const {
+    return mat4::perspective(fov_y_rad, aspect_ratio, near_plane, far_plane);
+  }
+
+  // Helper to move camera
+  void set_look_at(vec3 pos, vec3 tgt, vec3 up_vec = vec3(0, 1, 0)) {
+    position = pos;
+    target = tgt;
+    up = up_vec;
+  }
+};