From 371e68c5284359daea0446dfc674473a1461614a Mon Sep 17 00:00:00 2001
From: skal <pascal.massimino@gmail.com>
Date: Thu, 5 Feb 2026 16:41:14 +0100
Subject: 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.
---
 src/tests/test_assets.cc  | 15 +++++++++------
 src/util/asset_manager.cc | 23 +++++++++++++++++++++--
 src/util/asset_manager.h  |  9 +++++++++
 3 files changed, 39 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/tests/test_assets.cc b/src/tests/test_assets.cc
index 128bb1c..a1ae795 100644
--- a/src/tests/test_assets.cc
+++ b/src/tests/test_assets.cc
@@ -54,13 +54,15 @@ int main() {
   const uint8_t* proc_data_1 =
       GetAsset(AssetId::ASSET_PROC_NOISE_256, &proc_size);
   assert(proc_data_1 != nullptr);
-  assert(proc_size == 256 * 256 * 4); // 256x256 RGBA8
+  // Expect 256x256 RGBA8 + 8 byte header
+  assert(proc_size == 256 * 256 * 4 + 8); 
 
-  // Verify first few bytes are not all zero (noise should produce non-zero
-  // data)
+  // Verify first few bytes of DATA (skip header)
+  // Header is 8 bytes
+  const uint8_t* pixel_data_1 = proc_data_1 + 8;
   bool non_zero_data = false;
-  for (size_t i = 0; i < 16; ++i) { // Check first 16 bytes
-    if (proc_data_1[i] != 0) {
+  for (size_t i = 0; i < 16; ++i) { // Check first 16 bytes of pixels
+    if (pixel_data_1[i] != 0) {
       non_zero_data = true;
       break;
     }
@@ -79,8 +81,9 @@ int main() {
 
   // Verify content again to ensure it was re-generated correctly
   non_zero_data = false;
+  const uint8_t* pixel_data_2 = proc_data_2 + 8;
   for (size_t i = 0; i < 16; ++i) {
-    if (proc_data_2[i] != 0) {
+    if (pixel_data_2[i] != 0) {
       non_zero_data = true;
       break;
     }
diff --git a/src/util/asset_manager.cc b/src/util/asset_manager.cc
index ce495ac..e5d0291 100644
--- a/src/util/asset_manager.cc
+++ b/src/util/asset_manager.cc
@@ -95,7 +95,8 @@ const uint8_t* GetAsset(AssetId asset_id, size_t* out_size) {
     // simplicity and bump mapping). A more generic solution would pass
     // dimensions in proc_params.
     int width = 256, height = 256;
-    size_t data_size = (size_t)width * height * 4; // RGBA8
+    size_t header_size = sizeof(uint32_t) * 2;
+    size_t data_size = header_size + (size_t)width * height * 4; // RGBA8
     uint8_t* generated_data = new (std::nothrow) uint8_t[data_size];
     if (!generated_data) {
       fprintf(stderr,
@@ -104,7 +105,14 @@ const uint8_t* GetAsset(AssetId asset_id, size_t* out_size) {
         *out_size = 0;
       return nullptr;
     }
-    if (!proc_gen_func_ptr(generated_data, width, height,
+    
+    // Write header
+    uint32_t* header = reinterpret_cast<uint32_t*>(generated_data);
+    header[0] = (uint32_t)width;
+    header[1] = (uint32_t)height;
+
+    // Generate data after header
+    if (!proc_gen_func_ptr(generated_data + header_size, width, height,
                            source_record.proc_params,
                            source_record.num_proc_params)) {
       fprintf(stderr, "Error: Procedural generation failed for asset: %s\n",
@@ -134,6 +142,17 @@ const uint8_t* GetAsset(AssetId asset_id, size_t* out_size) {
   return cached_record.data;
 }
 
+TextureAsset GetTextureAsset(AssetId asset_id) {
+  size_t size = 0;
+  const uint8_t* data = GetAsset(asset_id, &size);
+  if (!data || size < 8) {
+    return {0, 0, nullptr};
+  }
+  
+  const uint32_t* header = reinterpret_cast<const uint32_t*>(data);
+  return { (int)header[0], (int)header[1], data + 8 };
+}
+
 void DropAsset(AssetId asset_id, const uint8_t* asset) {
   uint16_t index = (uint16_t)asset_id;
   if (index >= (uint16_t)AssetId::ASSET_LAST_ID) {
diff --git a/src/util/asset_manager.h b/src/util/asset_manager.h
index 964b7af..7d332f2 100644
--- a/src/util/asset_manager.h
+++ b/src/util/asset_manager.h
@@ -32,3 +32,12 @@ struct AssetRecord {
 // - 'out_size' returns the original asset size (excluding the null terminator).
 const uint8_t* GetAsset(AssetId asset_id, size_t* out_size = nullptr);
 void DropAsset(AssetId asset_id, const uint8_t* asset);
+
+struct TextureAsset {
+  int width;
+  int height;
+  const uint8_t* pixels;
+};
+
+// Helper to retrieve and parse a simple texture asset (from packer's [w][h][pixels] format)
+TextureAsset GetTextureAsset(AssetId asset_id);
-- 
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