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, 51 insertions, 0 deletions

diff --git a/src/3d/object.h b/src/3d/object.h
new file mode 100644
index 0000000..f4215aa
--- /dev/null
+++ b/src/3d/object.h
@@ -0,0 +1,51 @@
+// This file is part of the 64k demo project.
+// It defines the base 3D Object structure.
+// Handles transforms and bounding volumes for hybrid rendering.
+
+#pragma once
+
+#include "util/mini_math.h"
+
+enum class ObjectType {
+  CUBE,
+  SPHERE,
+  PLANE,
+  TORUS
+  // Add more SDF types here
+};
+
+struct BoundingVolume {
+  vec3 min;
+  vec3 max;
+};
+
+class Object3D {
+ public:
+  vec3 position;
+  quat rotation;
+  vec3 scale;
+
+  ObjectType type;
+  // Material parameters could go here (color, roughness, etc.)
+  vec4 color;
+
+  Object3D(ObjectType t = ObjectType::CUBE)
+      : position(0, 0, 0), rotation(0, 0, 0, 1), scale(1, 1, 1), type(t),
+        color(1, 1, 1, 1) {
+  }
+
+  mat4 get_model_matrix() const {
+    mat4 T = mat4::translate(position);
+    mat4 R = rotation.to_mat();
+    mat4 S = mat4::scale(scale);
+    // M = T * R * S
+    return T * (R * S);
+  }
+
+  // Returns the local-space AABB of the primitive (before transform)
+  // Used to generate the proxy geometry for rasterization.
+  BoundingVolume get_local_bounds() const {
+    // Simple defaults for unit primitives
+    return {{-1, -1, -1}, {1, 1, 1}};
+  }
+};