test: Add variable-size texture support verification

Phase 3 complete:
- Verify 128x64 and 1024x512 textures work
- Confirms GpuProceduralParams width/height respected

docs: Add Phase 4 design (texture composition)
- Multi-input compute shaders (samplers)
- Composite generators (blend, mask, modulate)
- Asset dependency ordering
- ~830 bytes for 2 composite shaders

1 files changed, 22 insertions, 0 deletions

diff --git a/src/tests/test_gpu_procedural.cc b/src/tests/test_gpu_procedural.cc
index e84996d..f1bade0 100644
--- a/src/tests/test_gpu_procedural.cc
+++ b/src/tests/test_gpu_procedural.cc
@@ -87,6 +87,28 @@ int main() {
   // Test multiple pipelines coexist
   printf("SUCCESS: All three GPU generators work (unified pipeline system)\n");
 
+  // Test variable-size textures
+  float noise_small[2] = {999.0f, 8.0f};
+  GpuProceduralParams small = {128, 64, noise_small, 2};
+  tex_mgr.create_gpu_noise_texture("noise_128x64", small);
+  if (!tex_mgr.get_texture_view("noise_128x64")) {
+    fprintf(stderr, "Error: Variable-size texture (128x64) not created\n");
+    tex_mgr.shutdown();
+    gpu_shutdown();
+    return 1;
+  }
+
+  float noise_large[2] = {777.0f, 2.0f};
+  GpuProceduralParams large = {1024, 512, noise_large, 2};
+  tex_mgr.create_gpu_noise_texture("noise_1024x512", large);
+  if (!tex_mgr.get_texture_view("noise_1024x512")) {
+    fprintf(stderr, "Error: Variable-size texture (1024x512) not created\n");
+    tex_mgr.shutdown();
+    gpu_shutdown();
+    return 1;
+  }
+  printf("SUCCESS: Variable-size textures work (128x64, 1024x512)\n");
+
   // Cleanup
   tex_mgr.shutdown();
   gpu_shutdown();