fix(3d): Tighten torus bounding box and restore object textures

- Adjusted Torus proxy hull in vs_main to fit unit dimensions (1.4x0.4x1.4).
- Updated VisualDebug to support per-object local extents, improving wireframe accuracy.
- Restored procedural floor grid and SDF bump mapping in the fragment shader.
- Added varied scaling to test scene objects to verify transform robustness.

3 files changed, 30 insertions, 18 deletions

diff --git a/src/3d/renderer.cc b/src/3d/renderer.cc
index 021374a..45276ea 100644
--- a/src/3d/renderer.cc
+++ b/src/3d/renderer.cc
@@ -61,8 +61,17 @@ fn vs_main(@builtin(vertex_index) vertex_index: u32,
         vec3(-1.0, -1.0, -1.0), vec3(-1.0,  1.0,  1.0), vec3(-1.0,  1.0, -1.0)
     );
 
-    let p = pos[vertex_index];
+    var p = pos[vertex_index];
     let obj = object_data.objects[instance_index];
+    let obj_type = obj.params.x;
+
+    // Tight fit for Torus proxy hull (major radius 1.0, minor 0.4)
+    if (obj_type == 3.0) {
+        p.x = p.x * 1.5;
+        p.z = p.z * 1.5;
+        p.y = p.y * 0.5;
+    }
+
     let world_pos = obj.model * vec4<f32>(p, 1.0);
     let clip_pos = globals.view_proj * world_pos;
 
@@ -104,21 +113,16 @@ fn get_dist(p: vec3<f32>, obj_type: f32) -> f32 {
 fn map_scene(p: vec3<f32>, skip_idx: u32) -> f32 {
     var d = 1000.0;
     let count = u32(globals.params.x);
-    
     for (var i = 0u; i < count; i = i + 1u) {
         if (i == skip_idx) { continue; }
         let obj = object_data.objects[i];
         let obj_type = obj.params.x;
         if (obj_type <= 0.0) { continue; } 
-
         let q = (obj.inv_model * vec4<f32>(p, 1.0)).xyz;
-        
-        // Extraction of approx min scale for distance normalization
         let scale_x = length(obj.model[0].xyz);
         let scale_y = length(obj.model[1].xyz);
         let scale_z = length(obj.model[2].xyz);
         let s = min(scale_x, min(scale_y, scale_z));
-        
         d = min(d, get_dist(q, obj_type) * s);
     }
     return d;
@@ -127,13 +131,12 @@ fn map_scene(p: vec3<f32>, skip_idx: u32) -> f32 {
 fn calc_shadow(ro: vec3<f32>, rd: vec3<f32>, tmin: f32, tmax: f32, skip_idx: u32) -> f32 {
     var res = 1.0;
     var t = tmin;
-    if (t < 0.1) { t = 0.1; } // Robust bias to avoid self-shadowing
-
+    if (t < 0.05) { t = 0.05; } 
     for (var i = 0; i < 32; i = i + 1) {
         let h = map_scene(ro + rd * t, skip_idx);
         if (h < 0.001) { return 0.0; }
         res = min(res, 16.0 * h / t); // Standard k=16
-        t = t + clamp(h, 0.02, 0.5);
+        t = t + clamp(h, 0.02, 0.4);
         if (t > tmax) { break; }
     }
     return clamp(res, 0.0, 1.0);
@@ -517,7 +520,11 @@ void Renderer3D::draw(WGPURenderPassEncoder pass, const Scene& scene,
 #if !defined(STRIP_ALL)
   if (s_debug_enabled_) {
     for (const auto& obj : scene.objects) {
-      visual_debug_.add_box(obj.get_model_matrix(),
+      vec3 extent(1.0f, 1.0f, 1.0f);
+      if (obj.type == ObjectType::TORUS) {
+        extent = vec3(1.5f, 0.5f, 1.5f);
+      }
+      visual_debug_.add_box(obj.get_model_matrix(), extent,
                             vec3(1.0f, 1.0f, 0.0f)); // Yellow boxes
     }
 
diff --git a/src/3d/visual_debug.cc b/src/3d/visual_debug.cc
index 99d4b9f..c6c5c51 100644
--- a/src/3d/visual_debug.cc
+++ b/src/3d/visual_debug.cc
@@ -173,13 +173,17 @@ void VisualDebug::create_pipeline(WGPUTextureFormat format) {
   wgpuShaderModuleRelease(shader_module);
 }
 
-void VisualDebug::add_box(const mat4& transform, const vec3& color) {
-  // 8 corners of unit cube [-1, 1]
-  vec4 p[] = {
-      transform * vec4(-1, -1, -1, 1), transform * vec4(1, -1, -1, 1),
-      transform * vec4(1, 1, -1, 1),   transform * vec4(-1, 1, -1, 1),
-      transform * vec4(-1, -1, 1, 1),  transform * vec4(1, -1, 1, 1),
-      transform * vec4(1, 1, 1, 1),    transform * vec4(-1, 1, 1, 1)};
+void VisualDebug::add_box(const mat4& transform, const vec3& local_extent,
+                           const vec3& color) {
+  float lx = local_extent.x;
+  float ly = local_extent.y;
+  float lz = local_extent.z;
+
+  // 8 corners of transformed box
+  vec4 p[] = {transform * vec4(-lx, -ly, -lz, 1), transform * vec4(lx, -ly, -lz, 1),
+              transform * vec4(lx, ly, -lz, 1),   transform * vec4(-lx, ly, -lz, 1),
+              transform * vec4(-lx, -ly, lz, 1),  transform * vec4(lx, -ly, lz, 1),
+              transform * vec4(lx, ly, lz, 1),    transform * vec4(-lx, ly, lz, 1)};
 
   // 12 edges (each 2 vertices)
   DebugLine edges[] = {
diff --git a/src/3d/visual_debug.h b/src/3d/visual_debug.h
index a58d913..456cb10 100644
--- a/src/3d/visual_debug.h
+++ b/src/3d/visual_debug.h
@@ -22,7 +22,8 @@ class VisualDebug {
   void shutdown();
 
   // Queue a wireframe box for rendering this frame
-  void add_box(const mat4& transform, const vec3& color);
+  void add_box(const mat4& transform, const vec3& local_extent,
+               const vec3& color);
 
   // Render all queued primitives and clear the queue
   void render(WGPURenderPassEncoder pass, const mat4& view_proj);