FIX: AO/Emissive loading fix

shaders/gbuffer.frag

@@ -68,9 +68,15 @@ void main() {
     outNorm = vec4(Nw, roughness);
     outAlbedo = vec4(albedo, metallic);
     // Extra G-buffer: x = AO, yzw = emissive
+    // extra[0].y = AO strength, extra[0].z = hasAO flag (1 = use AO texture)
+    float hasAO = materialData.extra[0].z;
     float aoStrength = clamp(materialData.extra[0].y, 0.0, 1.0);
     float aoTex = texture(occlusionTex, inUV).r;
-    float ao = 1.0 - aoStrength + aoStrength * aoTex;
+    float ao = 1.0;
+    if (hasAO > 0.5)
+    {
+        ao = 1.0 - aoStrength + aoStrength * aoTex;
+    }
     vec3 emissiveFactor = materialData.extra[1].rgb;
     vec3 emissiveTex = texture(emissiveTex, inUV).rgb;
     vec3 emissive = emissiveTex * emissiveFactor;

shaders/mesh.frag

@@ -70,9 +70,15 @@ void main()
     vec3 diffIBL = (1.0 - metallic) * albedo * sh_eval_irradiance(N);
 
     // Ambient occlusion from texture + strength (indirect only)
+    // extra[0].y = AO strength, extra[0].z = hasAO flag (1 = use AO texture)
+    float hasAO = materialData.extra[0].z;
     float aoStrength = clamp(materialData.extra[0].y, 0.0, 1.0);
     float aoTex = texture(occlusionTex, inUV).r;
-    float ao = 1.0 - aoStrength + aoStrength * aoTex;
+    float ao = 1.0;
+    if (hasAO > 0.5)
+    {
+        ao = 1.0 - aoStrength + aoStrength * aoTex;
+    }
 
     // Emissive from texture and factor
     vec3 emissiveFactor = materialData.extra[1].rgb;

src/core/assets/manager.cpp

@@ -220,8 +220,28 @@ std::shared_ptr<MeshAsset> AssetManager::createMesh(const MeshCreateInfo &info)
     {
         const auto &opt = info.material.options;
 
-        // Fallbacks are bound now; real textures will patch in via TextureCache
+        GLTFMetallic_Roughness::MaterialConstants constants = opt.constants;
-        AllocatedBuffer matBuffer = createMaterialBufferWithConstants(opt.constants);
+
+        if (!opt.occlusionPath.empty())
+        {
+            if (constants.extra[0].y == 0.0f && constants.extra[0].z == 0.0f)
+            {
+                constants.extra[0].y = 1.0f; // AO strength
+                constants.extra[0].z = 1.0f; // hasAO flag
+            }
+        }
+
+        if (!opt.emissivePath.empty())
+        {
+            if (constants.extra[1].x == 0.0f &&
+                constants.extra[1].y == 0.0f &&
+                constants.extra[1].z == 0.0f)
+            {
+                constants.extra[1] = glm::vec4(1.0f, 1.0f, 1.0f, constants.extra[1].w);
+            }
+        }
+
+        AllocatedBuffer matBuffer = createMaterialBufferWithConstants(constants);
 
         GLTFMetallic_Roughness::MaterialResources res{};
         res.colorImage = _engine->_errorCheckerboardImage;
@@ -519,10 +539,6 @@ AllocatedBuffer AssetManager::createMaterialBufferWithConstants(
     {
         matConstants->extra[0].x = 1.0f; // normal scale default
     }
-    if (matConstants->extra[0].y == 0.0f)
-    {
-        matConstants->extra[0].y = 1.0f;
-    }
     // Ensure writes are visible on non-coherent memory
     vmaFlushAllocation(_engine->_deviceManager->allocator(), matBuffer.allocation, 0,
                        sizeof(GLTFMetallic_Roughness::MaterialConstants));

src/render/passes/geometry.cpp

@@ -91,12 +91,12 @@ void GeometryPass::register_graph(RenderGraph *graph,
             builder.write_color(gbufferPosition, true, clear);
             builder.write_color(gbufferNormal, true, clear);
             builder.write_color(gbufferAlbedo, true, clear);
-            VkClearValue clearExtra{};
-            clearExtra.color = {{1.f, 0.f, 0.f, 0.f}}; // AO=1, emissive=0
-            builder.write_color(gbufferExtra, true, clearExtra);
             VkClearValue clearID{};
             clearID.color.uint32[0] = 0u;
             builder.write_color(idHandle, true, clearID);
+            VkClearValue clearExtra{};
+            clearExtra.color = {{1.f, 0.f, 0.f, 0.f}}; // AO=1, emissive=0
+            builder.write_color(gbufferExtra, true, clearExtra);
 
             // Reverse-Z: clear depth to 0.0
             VkClearValue depthClear{};

src/scene/vk_loader.cpp

@@ -389,12 +389,35 @@ std::optional<std::shared_ptr<LoadedGLTF> > loadGltf(VulkanEngine *engine,
         constants.metal_rough_factors.y = mat.pbrData.roughnessFactor;
         // extra[0].x: normalScale (default 1.0)
         constants.extra[0].x = 1.0f;
-        // extra[0].y: occlusionStrength (0..1, default 1.0)
+        // extra[0].y: occlusionStrength (0..1)
-        constants.extra[0].y = mat.occlusionTexture.has_value() ? mat.occlusionTexture->strength : 1.0f;
+        // extra[0].z: hasAO flag (1.0 if an occlusionTexture is present, 0.0 otherwise)
+        if (mat.occlusionTexture.has_value())
+        {
+            constants.extra[0].y = mat.occlusionTexture->strength;
+            constants.extra[0].z = 1.0f;
+        }
+        else
+        {
+            constants.extra[0].y = 0.0f;
+            constants.extra[0].z = 0.0f;
+        }
         // extra[1].rgb: emissiveFactor
         constants.extra[1].x = mat.emissiveFactor[0];
         constants.extra[1].y = mat.emissiveFactor[1];
         constants.extra[1].z = mat.emissiveFactor[2];
+        // If an emissive texture is present but the factor is left at 0,
+        // default to white so the texture is visible (common authoring pattern).
+        if (mat.emissiveTexture.has_value())
+        {
+            if (constants.extra[1].x == 0.0f &&
+                constants.extra[1].y == 0.0f &&
+                constants.extra[1].z == 0.0f)
+            {
+                constants.extra[1].x = 1.0f;
+                constants.extra[1].y = 1.0f;
+                constants.extra[1].z = 1.0f;
+            }
+        }
         // extra[2].x: alphaCutoff for MASK materials (>0 enables alpha test)
         constants.extra[2].x = 0.0f;
         if (mat.alphaMode == fastgltf::AlphaMode::Mask)