feat(assets): Add Texture Asset support (Task #18.0 prep)

- Integrated stb_image for image decompression in asset_packer.
- Added GetTextureAsset helper in asset_manager.
- Updated procedural asset generation to include dimensions header for consistency.
- Updated test_assets to verify new asset format.

1 files changed, 46 insertions, 7 deletions

diff --git a/tools/asset_packer.cc b/tools/asset_packer.cc
index 004561b..39169e4 100644
--- a/tools/asset_packer.cc
+++ b/tools/asset_packer.cc
@@ -10,6 +10,14 @@
 #include <string>
 #include <vector>
 
+#define STB_IMAGE_IMPLEMENTATION
+#define STBI_NO_LINEAR // Don't apply gamma correction, we want raw bytes
+#define STBI_ONLY_PNG
+#define STBI_ONLY_JPEG
+#define STBI_ONLY_TGA
+#define STBI_ONLY_BMP
+#include "stb_image.h"
+
 #include "procedural/generator.h" // For ProcGenFunc and procedural functions
 #include "util/asset_manager.h"   // For AssetRecord and AssetId
 
@@ -21,6 +29,13 @@ static const std::map<std::string, ProcGenFunc> kAssetPackerProcGenFuncMap = {
     {"make_periodic", procedural::make_periodic},
 };
 
+static bool HasImageExtension(const std::string& filename) {
+  std::string ext = filename.substr(filename.find_last_of(".") + 1);
+  // simple case-insensitive check (assuming lowercase for simplicity or just basic checks)
+  if (ext == "png" || ext == "jpg" || ext == "jpeg" || ext == "tga" || ext == "bmp") return true;
+  return false;
+}
+
 // Helper struct to hold all information about an asset during parsing
 struct AssetBuildInfo {
   std::string name;
@@ -207,14 +222,38 @@ int main(int argc, char* argv[]) {
     if (!info.is_procedural) {
       std::string base_dir =
           assets_txt_path.substr(0, assets_txt_path.find_last_of("/\\") + 1);
-      std::ifstream asset_file(base_dir + info.filename, std::ios::binary);
-      if (!asset_file.is_open()) {
-        fprintf(stderr, "Error: Could not open asset file: %s\n",
-                (base_dir + info.filename).c_str());
-        return 1;
+      std::string full_path = base_dir + info.filename;
+      
+      std::vector<uint8_t> buffer;
+      bool is_image = HasImageExtension(info.filename);
+
+      if (is_image) {
+        int w, h, channels;
+        unsigned char* img_data = stbi_load(full_path.c_str(), &w, &h, &channels, 4); // Force 4 channels (RGBA)
+        if (!img_data) {
+          fprintf(stderr, "Error: Could not load image file: %s (Reason: %s)\n", full_path.c_str(), stbi_failure_reason());
+          return 1;
+        }
+        
+        // Format: [Width(4)][Height(4)][Pixels...]
+        buffer.resize(sizeof(uint32_t) * 2 + w * h * 4);
+        uint32_t* header = reinterpret_cast<uint32_t*>(buffer.data());
+        header[0] = (uint32_t)w;
+        header[1] = (uint32_t)h;
+        std::memcpy(buffer.data() + sizeof(uint32_t) * 2, img_data, w * h * 4);
+        
+        stbi_image_free(img_data);
+        printf("Processed image asset %s: %dx%d RGBA\n", info.name.c_str(), w, h);
+      } else {
+        std::ifstream asset_file(full_path, std::ios::binary);
+        if (!asset_file.is_open()) {
+          fprintf(stderr, "Error: Could not open asset file: %s\n", full_path.c_str());
+          return 1;
+        }
+        buffer.assign((std::istreambuf_iterator<char>(asset_file)),
+                      std::istreambuf_iterator<char>());
       }
-      std::vector<uint8_t> buffer((std::istreambuf_iterator<char>(asset_file)),
-                                  std::istreambuf_iterator<char>());
+
       size_t original_size = buffer.size();
       buffer.push_back(0); // Null terminator for safety