Refactor: extract setup_standard_textures helper

Eliminates repetitive Renderer3D texture initialization across 3 test files.
Creates setup_standard_textures() helper that configures standard noise
(256x256, GPU procedural) and sky (512x256, Perlin) textures.

- New: src/3d/renderer_helpers.{h,cc}
- Refactor: test_3d_physics, test_3d_render, test_mesh use helper
- Build: Added renderer_helpers.cc to CMake 3D_SOURCES
- Result: -52 lines of boilerplate across 3 files

Production effects (Hybrid3DEffect, FlashCubeEffect) use asset-based
textures and retain custom initialization.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

3 files changed, 7 insertions, 49 deletions

diff --git a/src/tests/3d/test_3d_physics.cc b/src/tests/3d/test_3d_physics.cc
index 736cfc0..9b8bf11 100644
--- a/src/tests/3d/test_3d_physics.cc
+++ b/src/tests/3d/test_3d_physics.cc
@@ -6,6 +6,7 @@
 #include "3d/object.h"
 #include "3d/physics.h"
 #include "3d/renderer.h"
+#include "3d/renderer_helpers.h"
 #include "3d/scene.h"
 #include "gpu/effects/shaders.h"
 #include "gpu/texture_manager.h"
@@ -125,25 +126,7 @@ int main(int argc, char** argv) {
   g_renderer.init(g_device, g_queue, g_format);
   g_renderer.resize(platform_state.width, platform_state.height);
 
-  g_textures.init(g_device, g_queue);
-  ProceduralTextureDef noise_def;
-  noise_def.width = 256;
-  noise_def.height = 256;
-  noise_def.gen_func = gen_periodic_noise;
-  noise_def.params.push_back(1234.0f);
-  noise_def.params.push_back(16.0f);
-  g_textures.create_procedural_texture("noise", noise_def);
-
-  g_renderer.set_noise_texture(g_textures.get_texture_view("noise"));
-
-  ProceduralTextureDef sky_def;
-  sky_def.width = 512;
-  sky_def.height = 256;
-  sky_def.gen_func = procedural::gen_perlin;
-  sky_def.params = {42.0f, 4.0f, 1.0f, 0.5f, 6.0f};
-  g_textures.create_procedural_texture("sky", sky_def);
-
-  g_renderer.set_sky_texture(g_textures.get_texture_view("sky"));
+  setup_standard_textures(g_renderer, g_textures, g_device, g_queue);
 
   setup_scene();
 
diff --git a/src/tests/3d/test_3d_render.cc b/src/tests/3d/test_3d_render.cc
index 06e95c4..87d7b76 100644
--- a/src/tests/3d/test_3d_render.cc
+++ b/src/tests/3d/test_3d_render.cc
@@ -4,6 +4,7 @@
 #include "3d/camera.h"
 #include "3d/object.h"
 #include "3d/renderer.h"
+#include "3d/renderer_helpers.h"
 #include "3d/scene.h"
 #include "generated/assets.h"
 #include "gpu/effects/shaders.h"
@@ -131,29 +132,9 @@ int main(int argc, char** argv) {
   g_renderer.init(g_device, g_queue, g_format);
   g_renderer.resize(platform_state.width, platform_state.height);
 
-  g_textures.init(g_device, g_queue);
+  setup_standard_textures(g_renderer, g_textures, g_device, g_queue);
 
-  // GPU Noise texture (replaces CPU procedural)
-  GpuProceduralParams noise_params = {};
-  noise_params.width = 256;
-  noise_params.height = 256;
-  float noise_vals[2] = {1234.0f, 16.0f};
-  noise_params.params = noise_vals;
-  noise_params.num_params = 2;
-  g_textures.create_gpu_noise_texture("noise", noise_params);
-  g_renderer.set_noise_texture(g_textures.get_texture_view("noise"));
-
-  // GPU Perlin texture for sky (replaces CPU procedural)
-  GpuProceduralParams sky_params = {};
-  sky_params.width = 512;
-  sky_params.height = 256;
-  float sky_vals[5] = {42.0f, 4.0f, 1.0f, 0.5f, 6.0f};
-  sky_params.params = sky_vals;
-  sky_params.num_params = 5;
-  g_textures.create_gpu_perlin_texture("sky", sky_params);
-  g_renderer.set_sky_texture(g_textures.get_texture_view("sky"));
-
-  // GPU Grid texture (new!)
+  // GPU Grid texture (additional texture for this test)
   GpuProceduralParams grid_params = {};
   grid_params.width = 256;
   grid_params.height = 256;
diff --git a/src/tests/3d/test_mesh.cc b/src/tests/3d/test_mesh.cc
index 0374ed8..4a1d97b 100644
--- a/src/tests/3d/test_mesh.cc
+++ b/src/tests/3d/test_mesh.cc
@@ -4,6 +4,7 @@
 #include "3d/camera.h"
 #include "3d/object.h"
 #include "3d/renderer.h"
+#include "3d/renderer_helpers.h"
 #include "3d/scene.h"
 #include "gpu/effects/shaders.h"
 #include "gpu/texture_manager.h"
@@ -256,14 +257,7 @@ int main(int argc, char** argv) {
   }
 #endif /* !defined(STRIP_ALL) */
 
-  g_textures.init(g_device, g_queue);
-  ProceduralTextureDef noise_def;
-  noise_def.width = 256;
-  noise_def.height = 256;
-  noise_def.gen_func = procedural::gen_noise;
-  noise_def.params = {1234.0f, 16.0f};
-  g_textures.create_procedural_texture("noise", noise_def);
-  g_renderer.set_noise_texture(g_textures.get_texture_view("noise"));
+  setup_standard_textures(g_renderer, g_textures, g_device, g_queue);
 
   // --- Create Scene ---
   Object3D floor(ObjectType::BOX);