feat(assets): Implement procedural asset generation pipeline

- Updated asset_packer to parse PROC(...) syntax.
- Implemented runtime dispatch in AssetManager for procedural generation.
- Added procedural generator functions (noise, grid, periodic).
- Added comprehensive tests for procedural asset lifecycle.

2 files changed, 70 insertions, 21 deletions

diff --git a/src/util/asset_manager.cc b/src/util/asset_manager.cc
index 3874535..2ad8ef9 100644
--- a/src/util/asset_manager.cc
+++ b/src/util/asset_manager.cc
@@ -8,9 +8,21 @@
 #include "generated/assets.h"
 #endif /* defined(USE_TEST_ASSETS) */
 
-#include <vector> // For potential dynamic allocation for procedural assets
-#include <new>    // For placement new
-#include <cstdlib> // For free
+#include <vector>    // For potential dynamic allocation for procedural assets
+#include <new>       // For placement new
+#include <cstdlib>   // For free
+#include <iostream>  // For std::cerr
+#include <map>       // For kAssetManagerProcGenFuncMap
+#include <string>    // For std::string in map
+
+#include "procedural/generator.h" // For ProcGenFunc and procedural functions
+
+// Map of procedural function names to their pointers (for runtime dispatch)
+static const std::map<std::string, ProcGenFunc> kAssetManagerProcGenFuncMap = {
+    {"gen_noise", procedural::gen_noise},
+    {"gen_grid", procedural::gen_grid},
+    {"make_periodic", procedural::make_periodic},
+};
 
 // These are defined in the generated assets_data.cc
 #if defined(USE_TEST_ASSETS)
@@ -47,20 +59,54 @@ const uint8_t* GetAsset(AssetId asset_id, size_t* out_size) {
     return g_asset_cache[index].data;
   }
 
-  // Not in cache, retrieve from static data (packed in binary)
+  // Not in cache, retrieve from static data (packed in binary) or generate procedurally
   if (index >= g_assets_count) {
     if (out_size)
       *out_size = 0;
-    return nullptr; // This asset is not in the static packed data either.
+    return nullptr; // Invalid asset_id or asset not in static packed data.
   }
 
-  // Store static record in cache for future use
-  g_asset_cache[index] = g_assets[index];
-  g_asset_cache[index].is_procedural = false;
+  AssetRecord source_record = g_assets[index];
+  AssetRecord cached_record = source_record;
+
+  if (source_record.is_procedural) {
+    // Dynamically generate the asset
+    auto it = kAssetManagerProcGenFuncMap.find(source_record.proc_func_name_str);
+    if (it == kAssetManagerProcGenFuncMap.end()) {
+        std::cerr << "Error: Unknown procedural function at runtime: " << source_record.proc_func_name_str << std::endl;
+        if (out_size) *out_size = 0; 
+        return nullptr; // Procedural asset without a generation function.
+    }
+    ProcGenFunc proc_gen_func_ptr = it->second;
+
+    // For this demo, assuming procedural textures are RGBA8 256x256 (for simplicity and bump mapping).
+    // A more generic solution would pass dimensions in proc_params.
+    int width = 256, height = 256;
+    size_t data_size = width * height * 4; // RGBA8
+    uint8_t* generated_data = new (std::nothrow) uint8_t[data_size];
+    if (!generated_data) {
+        std::cerr << "Error: Failed to allocate memory for procedural asset." << std::endl;
+        if (out_size) *out_size = 0;
+        return nullptr;
+    }
+    proc_gen_func_ptr(generated_data, width, height, source_record.proc_params, source_record.num_proc_params);
+    
+    cached_record.data = generated_data;
+    cached_record.size = data_size;
+    cached_record.is_procedural = true;
+    // proc_gen_func, proc_params, num_proc_params already copied from source_record
+
+  } else {
+    // Static asset (copy from g_assets)
+    cached_record.is_procedural = false;
+  }
+  
+  // Store in cache for future use
+  g_asset_cache[index] = cached_record;
 
   if (out_size)
-    *out_size = g_asset_cache[index].size;
-  return g_asset_cache[index].data;
+    *out_size = cached_record.size;
+  return cached_record.data;
 }
 
 void DropAsset(AssetId asset_id, const uint8_t* asset) {
@@ -69,14 +115,11 @@ void DropAsset(AssetId asset_id, const uint8_t* asset) {
     return; // Invalid asset_id
   }
 
-  // Only free memory for procedural assets.
-  if (g_asset_cache[index].is_procedural && g_asset_cache[index].data == asset) {
-    // In a more complex scenario, we might track ref counts.
-    // For this demo, we assume a single owner for dynamically allocated assets.
-    delete[] g_asset_cache[index].data; // Assuming `new uint8_t[]` was used for procedural
-    g_asset_cache[index].data = nullptr;
-    g_asset_cache[index].size = 0;
-    g_asset_cache[index].is_procedural = false;
+  // Check if the asset is in cache and is procedural, and if the pointer matches.
+  // This prevents accidentally freeing static data or freeing twice.
+  if (g_asset_cache[index].data == asset && g_asset_cache[index].is_procedural) {
+    delete[] g_asset_cache[index].data;
+    g_asset_cache[index] = {}; // Zero out the struct to force re-generation
   }
   // For static assets, no dynamic memory to free.
 }
diff --git a/src/util/asset_manager.h b/src/util/asset_manager.h
index 6b09430..00aafc0 100644
--- a/src/util/asset_manager.h
+++ b/src/util/asset_manager.h
@@ -8,10 +8,16 @@
 
 enum class AssetId : uint16_t; // Forward declaration
 
+// Type for procedural generation functions: (buffer, width, height, params, num_params)
+typedef void (*ProcGenFunc)(uint8_t*, int, int, const float*, int);
+
 struct AssetRecord {
-  const uint8_t* data;
-  size_t size;
-  bool is_procedural; // Flag to indicate if memory was allocated dynamically
+  const uint8_t* data;       // Pointer to asset data (static or dynamic)
+  size_t size;               // Size of the asset data
+  bool is_procedural;        // True if data was dynamically allocated by a procedural generator
+  const char* proc_func_name_str; // Name of procedural generation function (string literal)
+  const float* proc_params;  // Parameters for procedural generation (static, from assets.txt)
+  int num_proc_params;       // Number of procedural parameters
 };
 
 // Generic interface