Now rendering black frames rather than empty frames when scene isn't loaded, preventing some Vulkan validation errors.

Added keepColor, clearColor, and finalLayout attributes to KRRenderPass::RenderPassInfo.
Now able to render debug text on macOS.

kraken/KRCamera.cpp

@@ -404,10 +404,23 @@ void KRCamera::renderFrame(VkCommandBuffer& commandBuffer, KRSurface& compositeS
 
   //    fprintf(stderr, "VBO Mem: %i Kbyte    Texture Mem: %i/%i Kbyte (active/total)     Shader Handles: %i   Visible Bounds: %i  Max Texture LOD: %i\n", (int)m_pContext->getMeshManager()->getMemUsed() / 1024, (int)m_pContext->getTextureManager()->getActiveMemUsed() / 1024, (int)m_pContext->getTextureManager()->getMemUsed() / 1024, (int)m_pContext->getPipelineManager()->getShaderHandlesUsed(), (int)m_visibleBounds.size(), m_pContext->getTextureManager()->getLODDimCap());
 
+  GL_PUSH_GROUP_MARKER("Debug Overlays");
+
+  renderDebug(commandBuffer, compositeSurface);
+  
+  
+  GL_POP_GROUP_MARKER;
+  
   GL_PUSH_GROUP_MARKER("Post Processing");
 
+  KRRenderPass& postCompositePass = compositeSurface.getPostCompositePass();
+  postCompositePass.begin(commandBuffer, compositeSurface, Vector4::Create(0.0f, 0.0f, 0.0f, 1.0f));
+  
   renderPost(commandBuffer, compositeSurface);
 
+  postCompositePass.end(commandBuffer);
+  
+  
   GL_POP_GROUP_MARKER;
 }
 
@@ -629,6 +642,11 @@ void KRCamera::renderPost(VkCommandBuffer& commandBuffer, KRSurface& surface)
   //        m_pContext->getTextureManager()->_setActiveTexture(0);
   //        GLDEBUG(glBindTexture(GL_TEXTURE_2D, 0));
   //    }
+  
+}
+
+void KRCamera::renderDebug(VkCommandBuffer& commandBuffer, KRSurface& surface)
+{
   const char* szText = settings.m_debug_text.c_str();
 
   std::string debug_text;
@@ -756,6 +774,11 @@ void KRCamera::renderPost(VkCommandBuffer& commandBuffer, KRSurface& surface)
       }
     }
     
+    m_debug_text_vbo_data.load(commandBuffer);
+    
+    KRRenderPass& debugPass = surface.getDebugPass();
+    debugPass.begin(commandBuffer, surface, Vector4::Create(0.0f, 0.0f, 0.0f, 1.0f));
+
     KRTexture* fontTexture = m_pContext->getTextureManager()->getTexture("font");
     fontTexture->resetPoolExpiry(0.0f, KRTexture::TEXTURE_USAGE_UI);
 
@@ -772,11 +795,12 @@ void KRCamera::renderPost(VkCommandBuffer& commandBuffer, KRSurface& surface)
     fontShader->setImageBinding("fontTexture", fontTexture, getContext().getSamplerManager()->DEFAULT_CLAMPED_SAMPLER);
     fontShader->bind(commandBuffer, *this, m_viewport, Matrix4(), nullptr, nullptr, nullptr, KRNode::RENDER_PASS_FORWARD_TRANSPARENT);
 
-    m_debug_text_vbo_data.load(commandBuffer);
     m_debug_text_vbo_data.bind(commandBuffer);
 
     vkCmdDraw(commandBuffer, vertex_count, 1, 0, 0);
     
+    debugPass.end(commandBuffer);
+
     m_debug_text_vertices.unlock();
 
   } else {

kraken/KRCamera.h

@@ -90,6 +90,7 @@ private:
   int volumetricLightAccumulationBuffer, volumetricLightAccumulationTexture;
 
   void renderPost(VkCommandBuffer& commandBuffer, KRSurface& surface);
+  void renderDebug(VkCommandBuffer& commandBuffer, KRSurface& surface);
 
   void destroyBuffers();
 

kraken/KRPresentationThread.cpp

@@ -162,6 +162,8 @@ void KRPresentationThread::renderFrame()
     float deltaTime = 0.005; // TODO - Replace dummy value
     if (scene) {
       scene->renderFrame(commandBuffer, surface, deltaTime);
+    } else {
+      surface.renderBlackFrame(commandBuffer);
     }
 
     if (vkEndCommandBuffer(commandBuffer) != VK_SUCCESS) {

kraken/KRRenderPass.cpp

@@ -56,12 +56,16 @@ void KRRenderPass::create(KRDevice& device, VkFormat swapChainImageFormat, VkFor
   VkAttachmentDescription colorAttachment{};
   colorAttachment.format = swapChainImageFormat;
   colorAttachment.samples = VK_SAMPLE_COUNT_1_BIT;
-  colorAttachment.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
+  colorAttachment.loadOp = info.clearColor ? VK_ATTACHMENT_LOAD_OP_CLEAR : VK_ATTACHMENT_LOAD_OP_LOAD;
-  colorAttachment.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
+  colorAttachment.storeOp = info.keepColor ? VK_ATTACHMENT_STORE_OP_STORE : VK_ATTACHMENT_STORE_OP_DONT_CARE;
   colorAttachment.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
   colorAttachment.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
-  colorAttachment.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
+  colorAttachment.initialLayout = info.clearColor ? VK_IMAGE_LAYOUT_UNDEFINED : VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
-  colorAttachment.finalLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
+  if (info.finalPass) {
+    colorAttachment.finalLayout = info.keepColor ? VK_IMAGE_LAYOUT_PRESENT_SRC_KHR : VK_IMAGE_LAYOUT_UNDEFINED;
+  } else {
+    colorAttachment.finalLayout = info.keepColor ? VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL : VK_IMAGE_LAYOUT_UNDEFINED;
+  }
 
 
   VkAttachmentDescription depthAttachment{};

kraken/KRRenderPass.h

@@ -44,8 +44,11 @@ public:
 
   struct RenderPassInfo
   {
+    bool clearColor;
+    bool keepColor;
     bool clearDepth;
     bool keepDepth;
+    bool finalPass;
   };
 
   void create(KRDevice& device, VkFormat swapChainImageFormat, VkFormat depthImageFormat, const RenderPassInfo& info);

kraken/KRSurface.cpp

@@ -49,6 +49,9 @@ KRSurface::KRSurface(KRContext& context, KrSurfaceHandle handle, void* platformH
   m_forwardOpaquePass = std::make_unique<KRRenderPass>(context);
   m_deferredGBufferPass = std::make_unique<KRRenderPass>(context);
   m_deferredOpaquePass = std::make_unique<KRRenderPass>(context);
+  m_postCompositePass = std::make_unique<KRRenderPass>(context);
+  m_debugPass = std::make_unique<KRRenderPass>(context);
+  m_blackFramePass = std::make_unique<KRRenderPass>(context);
   m_swapChain = std::make_unique<KRSwapchain>(context);
 }
 
@@ -125,6 +128,18 @@ void KRSurface::destroy()
     m_deferredOpaquePass->destroy(*device);
   }
   
+  if (m_postCompositePass) {
+    m_postCompositePass->destroy(*device);
+  }
+  
+  if (m_debugPass) {
+    m_debugPass->destroy(*device);
+  }
+  
+  if (m_blackFramePass) {
+    m_blackFramePass->destroy(*device);
+  }
+
   for (int i=0; i < KRENGINE_MAX_FRAMES_IN_FLIGHT; i++) {
     if (device && m_renderFinishedSemaphores[i] != VK_NULL_HANDLE) {
       vkDestroySemaphore(device->m_logicalDevice, m_renderFinishedSemaphores[i], nullptr);
@@ -184,17 +199,47 @@ KrResult KRSurface::createSwapChain()
 
 
   KRRenderPass::RenderPassInfo info{};
+  info.clearColor = true;
+  info.keepColor = true;
   info.clearDepth = true;
   info.keepDepth = false;
+  info.finalPass = false;
   m_forwardOpaquePass->create(*device, selectedSurfaceFormat.format, depthImageFormat, info);
 
+  info.clearColor = true;
+  info.keepColor = true;
   info.clearDepth = true;
   info.keepDepth = true;
+  info.finalPass = false;
   m_deferredGBufferPass->create(*device, selectedSurfaceFormat.format, depthImageFormat, info);
 
+  info.clearColor = false;
+  info.keepColor = true;
+  info.clearDepth = false;
+  info.keepDepth = true;
+  info.finalPass = false;
+  m_deferredOpaquePass->create(*device, selectedSurfaceFormat.format, depthImageFormat, info);
+  
+  info.clearColor = false;
+  info.keepColor = true;
+  info.clearDepth = false;
+  info.keepDepth = true;
+  info.finalPass = false;
+  m_debugPass->create(*device, selectedSurfaceFormat.format, depthImageFormat, info);
+  
+  info.clearColor = false;
+  info.keepColor = true;
   info.clearDepth = false;
   info.keepDepth = false;
-  m_deferredOpaquePass->create(*device, selectedSurfaceFormat.format, depthImageFormat, info);
+  info.finalPass = true;
+  m_postCompositePass->create(*device, selectedSurfaceFormat.format, depthImageFormat, info);
+  
+  info.clearColor = true;
+  info.keepColor = true;
+  info.clearDepth = false;
+  info.keepDepth = false;
+  info.finalPass = true;
+  m_blackFramePass->create(*device, selectedSurfaceFormat.format, depthImageFormat, info);
 
   m_swapChain->create(*device, m_surface, selectedSurfaceFormat, depthImageFormat, swapExtent, imageCount, *m_forwardOpaquePass);
 
@@ -264,7 +309,29 @@ KRRenderPass& KRSurface::getDeferredOpaquePass()
   return *m_deferredOpaquePass;
 }
 
+KRRenderPass& KRSurface::getPostCompositePass()
+{
+  return *m_postCompositePass;
+}
+
+KRRenderPass& KRSurface::getDebugPass()
+{
+  return *m_debugPass;
+}
+
+KRRenderPass& KRSurface::getBlackFramePass()
+{
+  return *m_blackFramePass;
+}
+
 void KRSurface::endFrame()
 {
   m_frameIndex++;;
 }
+
+
+void KRSurface::renderBlackFrame(VkCommandBuffer &commandBuffer)
+{
+  m_blackFramePass->begin(commandBuffer, *this, Vector4::Create(0.0f, 0.0f, 0.0f, 1.0f));
+  m_blackFramePass->end(commandBuffer);
+}

kraken/KRSurface.h

@@ -48,6 +48,7 @@ public:
   uint32_t getHeight() const;
   hydra::Vector2i getDimensions() const;
   VkFormat getDepthFormat() const;
+  void renderBlackFrame(VkCommandBuffer &commandBuffer);
 
   KRSurface(const KRSurface&) = delete;
   KRSurface& operator=(const KRSurface&) = delete;
@@ -59,6 +60,9 @@ public:
 
   KRRenderPass& getDeferredGBufferPass();
   KRRenderPass& getDeferredOpaquePass();
+  KRRenderPass& getPostCompositePass();
+  KRRenderPass& getDebugPass();
+  KRRenderPass& getBlackFramePass();
 
   void endFrame();
   KrSurfaceHandle m_handle;
@@ -75,6 +79,10 @@ public:
   std::unique_ptr<KRRenderPass> m_forwardOpaquePass;
   std::unique_ptr<KRRenderPass> m_deferredGBufferPass;
   std::unique_ptr<KRRenderPass> m_deferredOpaquePass;
+  std::unique_ptr<KRRenderPass> m_postCompositePass;
+  std::unique_ptr<KRRenderPass> m_debugPass;
+  std::unique_ptr<KRRenderPass> m_blackFramePass;
+  
 
   // TODO - This needs to be advanced per swap chain
   uint64_t m_frameIndex;