misc: cleanup comments and formatting in headers

- asset_manager_dcl.h: clarify purpose vs asset_manager.h
- camera_params.h: broaden description to include 3D rendering
- sdf_cpu.h: simplify calc_normal formatting
- platform.h: add missing newline at EOF

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

4 files changed, 9 insertions, 12 deletions

diff --git a/src/3d/sdf_cpu.h b/src/3d/sdf_cpu.h
index e0f1b3f..e7f9f47 100644
--- a/src/3d/sdf_cpu.h
+++ b/src/3d/sdf_cpu.h
@@ -44,13 +44,9 @@ inline float sdPlane(vec3 p, vec3 n, float h) {
  */
 template <typename F>
 inline vec3 calc_normal(vec3 p, F sdf_func, float e = 0.001f) {
-  const float d2e = 2.0f * e;
-  return vec3(sdf_func(vec3(p.x + e, p.y, p.z)) -
-                  sdf_func(vec3(p.x - e, p.y, p.z)),
-              sdf_func(vec3(p.x, p.y + e, p.z)) -
-                  sdf_func(vec3(p.x, p.y - e, p.z)),
-              sdf_func(vec3(p.x, p.y, p.z + e)) -
-                  sdf_func(vec3(p.x, p.y, p.z - e)))
+  return vec3(sdf_func(vec3(p.x + e, p.y, p.z)) - sdf_func(vec3(p.x - e, p.y, p.z)),
+              sdf_func(vec3(p.x, p.y + e, p.z)) - sdf_func(vec3(p.x, p.y - e, p.z)),
+              sdf_func(vec3(p.x, p.y, p.z + e)) - sdf_func(vec3(p.x, p.y, p.z - e)))
       .normalize();
 }
 
diff --git a/src/gpu/camera_params.h b/src/gpu/camera_params.h
index 361f65f..0798c52 100644
--- a/src/gpu/camera_params.h
+++ b/src/gpu/camera_params.h
@@ -1,11 +1,11 @@
 // This file is part of the 64k demo project.
-// It defines CameraParams for raymarching effects.
+// It defines CameraParams for raymarching and 3D effects.
 
 #pragma once
 
 #include "util/mini_math.h"
 
-// Camera parameters for SDF raymarching effects
+// Camera parameters for SDF raymarching effects and 3D rendering
 // Binding convention: @group(0) @binding(3)
 struct CameraParams {
   mat4 inv_view;      // Inverse view matrix (screen→world transform)
diff --git a/src/platform/platform.h b/src/platform/platform.h
index 7bcee9d..03aa2b3 100644
--- a/src/platform/platform.h
+++ b/src/platform/platform.h
@@ -100,4 +100,4 @@ WGPUSurface platform_create_wgpu_surface(WGPUInstance instance,
                                          PlatformState* state);
 
 // Global time query (if needed without state)
-double platform_get_time();
\ No newline at end of file
+double platform_get_time();
diff --git a/src/util/asset_manager_dcl.h b/src/util/asset_manager_dcl.h
index bf618f0..6eee4f3 100644
--- a/src/util/asset_manager_dcl.h
+++ b/src/util/asset_manager_dcl.h
@@ -1,6 +1,7 @@
 // This file is part of the 64k demo project.
-// Forward declarations for asset management system.
-// Use this header when you only need AssetId type.
+// Lightweight forward declarations for AssetId and ProcGenFunc.
+// Include this instead of asset_manager.h when you don't need AssetRecord or
+// the asset API (GetAsset, DropAsset, etc.).
 
 #pragma once
 #include <cstddef>