Added simple transparency.

FIX: Possible problems based on rendering order. Ensure opaque then transparent, and back-to-front/front-to-back orders.

samples/04_scenes/asset_loader.cpp

@@ -540,7 +540,8 @@ AssetLoader::ProcessNode(tinygltf::Model *model, eastl::vector<vec4> *vertexPosi
                        perspective);
         dynamicTransform.m_Rotation = glm::conjugate(dynamicTransform.m_Rotation);
     }
-    else {
+    else
+    {
         dynamicTransform = {
             .m_Position = VectorToVec3(node->translation),
             .m_Rotation = VectorToQuat(node->rotation),
@@ -861,6 +862,17 @@ AssetLoader::LoadModelToGpu(cstr path, cstr name)
 
         u32 index = Cast<u32>(materials.size());
         auto *material = &model.materials[materialIdx];
+
+        f32 alphaBlendValue = -1;
+        if (material->alphaMode == "BLEND")
+        {
+            alphaBlendValue = 2;
+        }
+        else if (material->alphaMode == "MASK")
+        {
+            alphaBlendValue = material->alphaCutoff;
+        }
+
         materials.push_back({
             .m_AlbedoFactor = VectorToVec4(material->pbrMetallicRoughness.baseColorFactor),
             .m_EmissionFactor = VectorToVec3(material->emissiveFactor),
@@ -871,6 +883,7 @@ AssetLoader::LoadModelToGpu(cstr path, cstr name)
             .m_MetalRoughTex = getTextureHandle(material->pbrMetallicRoughness.metallicRoughnessTexture.index, false),
             .m_OcclusionTex = getTextureHandle(material->occlusionTexture.index, false),
             .m_EmissionTex = getTextureHandle(material->emissiveTexture.index, true),
+            .m_AlphaBlend = alphaBlendValue,
         });
         materialsIndirection[materialIdx] = index;
         return index;

samples/04_scenes/asset_loader.h

@@ -35,9 +35,14 @@ struct Material
     TextureHandle m_MetalRoughTex; // 04   48
     TextureHandle m_OcclusionTex;  // 04   52
     TextureHandle m_EmissionTex;   // 04   56
+    f32 m_AlphaBlend;              /* 04   60
+ AlphaBlend < 0 means Opaque
+ AlphaBlend > 1 means Blend
+ AlphaBlend in [0,1] means cutoff */
 };
 
-static_assert(sizeof(Material) == 56);
+// If this is changed, ensure the shaders are changed accordingly.
+static_assert(sizeof(Material) == 60);
 
 struct VertexData
 {
@@ -61,7 +66,9 @@ struct Model
     void Destroy(RenderResourceManager *resourceManager, EcsRegistry *registry);
 };
 
-struct CModel {};
+struct CModel
+{
+};
 
 struct AssetLoader
 {
@@ -97,7 +104,8 @@ struct AssetLoader
     TextureHandle LoadImageToGpu(StagingBuffer *stagingBuffer, tinygltf::Image *image, bool isSrgb) const;
     void
     ProcessNode(tinygltf::Model *model, eastl::vector<vec4> *vertexPositions, eastl::vector<VertexData> *vertexData,
-                eastl::vector<u32> *indices, eastl::vector<Entity> *entities, const std::function<u32(i32)> &loadMaterial, int current, Entity parent);
+                eastl::vector<u32> *indices, eastl::vector<Entity> *entities,
+                const std::function<u32(i32)> &loadMaterial, int current, Entity parent);
 
   public:
     DISALLOW_COPY_AND_ASSIGN(AssetLoader);

samples/04_scenes/main.cpp

@@ -26,7 +26,7 @@
 
 constexpr u32 MAX_FRAMES_IN_FLIGHT = 3;
 constexpr auto PIPELINE_CACHE_FILE = "PipelineCacheData.bin";
-constexpr auto MODEL_FILE = "model/DamagedHelmet.glb";
+constexpr auto MODEL_FILE = "model/AlphaBlendModeTest.glb";
 constexpr auto MODEL_FILE2 = "model/Box.glb";
 constexpr auto BACKDROP_FILE = "image/photo_studio_loft_hall_4k.hdr";
 constexpr u32 INIT_WIDTH = 640;
@@ -46,7 +46,7 @@ main(int, char *[])
     vk::Extent2D internalResolution = {1920, 1080};
     internalResolution.width = (internalResolution.height * INIT_WIDTH) / INIT_HEIGHT;
 
-    CameraController cameraController = {vec3{0.0f, 2.0f, 4.0f}, vec3{0.0f, 0.0f, 0.0f}, 70_deg,
+    CameraController cameraController = {vec3{0.0f, 1.0f, 4.0f}, vec3{0.0f, 0.0f, 0.0f}, 70_deg,
                                          Cast<f32>(internalResolution.width) / Cast<f32>(internalResolution.height)};
 
     INFO("Using {} as the primary device.", deviceToUse.m_DeviceProperties.deviceName.data());
@@ -111,15 +111,8 @@ main(int, char *[])
     lightManager.SetEnvironment(&environment);
 
     eastl::vector<Model> models;
-    for (int i = -1; i <= 1; ++i)
+    models.emplace_back(assetLoader.LoadModelToGpu(MODEL_FILE, "Main Model"));
-    {
+    //registry.get<CDynamicTransform>(model.m_RootEntity).m_Position = vec3(2 * i, 0, 2 * j);
-        for (int j = -1; j <= 1; ++j)
-        {
-            INFO("{}, {}", i, j);
-            auto &model = models.emplace_back(assetLoader.LoadModelToGpu(MODEL_FILE, "Main Model"));
-            registry.get<CDynamicTransform>(model.m_RootEntity).m_Position = vec3(2 * i, 0, 2 * j);
-        }
-    }
 
     UniformBuffer ubo;
     constexpr usize uboLightManagerOffset = sizeof cameraController.m_Camera;
@@ -355,12 +348,12 @@ main(int, char *[])
     {
         Time::Update();
 
-        u32 index = 0;
+        //u32 index = 0;
-        for (auto [entity, dynTrans] : rootModel.each())
+        //for (auto [entity, dynTrans] : rootModel.each())
-        {
+        //{
-            dynTrans.m_Rotation =
+        //    dynTrans.m_Rotation =
-                glm::rotate(dynTrans.m_Rotation, Cast<f32>(30_deg * (++index) * Time::m_Delta), vec3{0.0f, 1.0f, 0.0f});
+        //        glm::rotate(dynTrans.m_Rotation, Cast<f32>(30_deg * (++index) * Time::m_Delta), vec3{0.0f, 1.0f, 0.0f});
-        }
+        //}
 
         Frame *currentFrame = frameManager.GetNextFrame(&swapchain, &window);
 

samples/04_scenes/pipeline_utils.cpp

@@ -102,9 +102,9 @@ CreatePipeline(const Device *device, vk::Format attachmentFormat, const RenderRe
         .depthCompareOp = vk::CompareOp::eLess,
     };
     vk::PipelineColorBlendAttachmentState colorBlendAttachmentState = {
-        .blendEnable = false,
+        .blendEnable = true,
-        .srcColorBlendFactor = vk::BlendFactor::eSrcColor,
+        .srcColorBlendFactor = vk::BlendFactor::eSrcAlpha,
-        .dstColorBlendFactor = vk::BlendFactor::eOneMinusSrcColor,
+        .dstColorBlendFactor = vk::BlendFactor::eOneMinusSrcAlpha,
         .colorBlendOp = vk::BlendOp::eAdd,
         .srcAlphaBlendFactor = vk::BlendFactor::eSrcAlpha,
         .dstAlphaBlendFactor = vk::BlendFactor::eOneMinusSrcAlpha,

samples/04_scenes/shader/bindless_structs.glsl

@@ -17,6 +17,12 @@ struct Material
     uint m_MetalRoughTex;   // 04   48
     uint m_OcclusionTex;    // 04   52
     uint m_EmissionTex;     // 04   56
+    /*
+    AlphaBlend < 0 means Opaque
+    AlphaBlend > 1 means Blend
+    AlphaBlend in [0,1] means cutoff
+    */
+    float AlphaBlend;       // 04   60
     // We might be able to go upto 64 without pains.
 };
 

samples/04_scenes/shader/model.frag.glsl

@@ -276,13 +276,23 @@ vec3 GetAmbientInfluence(vec3 albedo, float metal, float roughness, vec3 Positio
     return (K_Diffuse * DiffuseIrradiance + Specular) * Occlusion;
 }
 
+float processAlpha(float sourceAlpha, float alphaBlendValue) {
+    if (alphaBlendValue < 0) {
+        return 1.0;
+    } else if (alphaBlendValue > 1) {
+        return sourceAlpha;
+    } else {
+        return step(alphaBlendValue, sourceAlpha); 
+    }
+}
+
 void main() {
 
     Material material = nodes.nodes[nonuniformEXT(in_DrawID)].pMaterial.material;
     
     vec4 albedoA = GetAlbedo(material.m_AlbedoFactor, material.m_AlbedoTex, in_Color0, in_TexCoord0);
     vec3 albedo = albedoA.rgb;
-    float alpha = albedoA.a;
+    float alpha = processAlpha(albedoA.a, material.AlphaBlend);
     
     vec3 normal = GetNormal(material.m_NormalTex, in_Position.xyz, normalize(in_Normal.xyz), in_TexCoord0);