Removed offscreen texture target, sample directly from framebuffer color attachment

offscreen/offscreen.cpp

@@ -113,8 +113,7 @@ public:
 		int32_t width, height;
 		VkFramebuffer frameBuffer;		
 		FrameBufferAttachment color, depth;
-		// Texture target for offscreen framebuffer
+		VkSampler colorSampler;
-		vkTools::VulkanTexture textureTarget;
 	} offScreenFrameBuf;
 
 	VkCommandBuffer offScreenCmdBuffer = VK_NULL_HANDLE;
@@ -141,8 +140,8 @@ public:
 		// Note : Inherited destructor cleans up resources stored in base class
 
 		// Textures
-		textureLoader->destroyTexture(offScreenFrameBuf.textureTarget);
 		textureLoader->destroyTexture(textures.colorMap);
+		vkDestroySampler(device, offScreenFrameBuf.colorSampler, nullptr);
 
 		// Frame buffer
 
@@ -184,91 +183,9 @@ public:
 		vkDestroySemaphore(device, offscreenSemaphore, nullptr);
 	}
 
-	// Preapre an empty texture as the blit target from 
+	// Setup the offscreen framebuffer for rendering the mirrored scene
-	// the offscreen framebuffer
+	// The color attachment of this framebuffer will then be used
-	void prepareTextureTarget(uint32_t width, uint32_t height, VkFormat format)
+	// to sample frame in the fragment shader of the final pass
-	{
-		// Get device properties for the requested texture format
-		VkFormatProperties formatProperties;
-		vkGetPhysicalDeviceFormatProperties(physicalDevice, format, &formatProperties);
-		// Check if blit destination is supported for the requested format
-		// Only try for optimal tiling, linear tiling usually won't support blit as destination anyway
-		assert(formatProperties.optimalTilingFeatures & VK_FORMAT_FEATURE_BLIT_DST_BIT);
-
-		// Prepare blit target texture
-		offScreenFrameBuf.textureTarget.width = width;
-		offScreenFrameBuf.textureTarget.height = height;
-
-		VkImageCreateInfo imageCreateInfo = vkTools::initializers::imageCreateInfo();
-		imageCreateInfo.imageType = VK_IMAGE_TYPE_2D;
-		imageCreateInfo.format = format;
-		imageCreateInfo.extent = { width, height, 1 };
-		imageCreateInfo.mipLevels = 1;
-		imageCreateInfo.arrayLayers = 1;
-		imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
-		imageCreateInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
-		// Texture will be sampled in a shader and is also the blit destination
-		imageCreateInfo.usage = VK_IMAGE_USAGE_SAMPLED_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
-		imageCreateInfo.initialLayout = VK_IMAGE_LAYOUT_PREINITIALIZED;
-
-		VkMemoryAllocateInfo memAllocInfo = vkTools::initializers::memoryAllocateInfo();
-		VkMemoryRequirements memReqs;
-
-		VK_CHECK_RESULT(vkCreateImage(device, &imageCreateInfo, nullptr, &offScreenFrameBuf.textureTarget.image));
-		vkGetImageMemoryRequirements(device, offScreenFrameBuf.textureTarget.image, &memReqs);
-		memAllocInfo.allocationSize = memReqs.size;
-		memAllocInfo.memoryTypeIndex = getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
-		VK_CHECK_RESULT(vkAllocateMemory(device, &memAllocInfo, nullptr, &offScreenFrameBuf.textureTarget.deviceMemory));
-		VK_CHECK_RESULT(vkBindImageMemory(device, offScreenFrameBuf.textureTarget.image, offScreenFrameBuf.textureTarget.deviceMemory, 0));
-
-		// Get a primary command buffer for submitting image layout transition
-		VkCommandBuffer layoutCmd = VulkanExampleBase::createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);
-
-		// Image memory barrier
-		// Set initial layout for the offscreen texture transfer destination
-		// Will be transformed while updating the texture
-		offScreenFrameBuf.textureTarget.imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
-		vkTools::setImageLayout(
-			layoutCmd, 
-			offScreenFrameBuf.textureTarget.image,
-			VK_IMAGE_ASPECT_COLOR_BIT, 
-			VK_IMAGE_LAYOUT_PREINITIALIZED,
-			offScreenFrameBuf.textureTarget.imageLayout);
-
-		// Submit the command buffer to apply the image memory barrier
-		VulkanExampleBase::flushCommandBuffer(layoutCmd, queue, true);
-
-		// Create sampler
-		VkSamplerCreateInfo sampler = vkTools::initializers::samplerCreateInfo();
-		sampler.magFilter = TEX_FILTER;
-		sampler.minFilter = TEX_FILTER;
-		sampler.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
-		sampler.addressModeU = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
-		sampler.addressModeV = sampler.addressModeU;
-		sampler.addressModeW = sampler.addressModeU;
-		sampler.mipLodBias = 0.0f;
-		sampler.maxAnisotropy = 0;
-		sampler.compareOp = VK_COMPARE_OP_NEVER;
-		sampler.minLod = 0.0f;
-		sampler.maxLod = 0.0f;
-		sampler.borderColor = VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE;
-		VK_CHECK_RESULT(vkCreateSampler(device, &sampler, nullptr, &offScreenFrameBuf.textureTarget.sampler));
-
-		// Create image view
-		VkImageViewCreateInfo view = {};
-		view.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
-		view.pNext = NULL;
-		view.viewType = VK_IMAGE_VIEW_TYPE_2D;
-		view.format = format;
-		view.components = { VK_COMPONENT_SWIZZLE_R, VK_COMPONENT_SWIZZLE_G, VK_COMPONENT_SWIZZLE_B, VK_COMPONENT_SWIZZLE_A };
-		view.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
-		view.image = offScreenFrameBuf.textureTarget.image;
-		VK_CHECK_RESULT(vkCreateImageView(device, &view, nullptr, &offScreenFrameBuf.textureTarget.view));
-	}
-
-	// Prepare a new framebuffer for offscreen rendering
-	// The contents of this framebuffer are then
-	// blitted to our render target
 	void prepareOffscreenFramebuffer()
 	{
 		offScreenFrameBuf.width = FB_DIM;
@@ -292,9 +209,8 @@ public:
 		image.arrayLayers = 1;
 		image.samples = VK_SAMPLE_COUNT_1_BIT;
 		image.tiling = VK_IMAGE_TILING_OPTIMAL;
-		// Image of the framebuffer is blit source
+		// We will sample directly from the color attachment
-		image.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
+		image.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;
-		image.flags = 0;
 
 		VkMemoryAllocateInfo memAlloc = vkTools::initializers::memoryAllocateInfo();
 		VkMemoryRequirements memReqs;
@@ -302,7 +218,6 @@ public:
 		VkImageViewCreateInfo colorImageView = vkTools::initializers::imageViewCreateInfo();
 		colorImageView.viewType = VK_IMAGE_VIEW_TYPE_2D;
 		colorImageView.format = fbColorFormat;
-		colorImageView.flags = 0;
 		colorImageView.subresourceRange = {};
 		colorImageView.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
 		colorImageView.subresourceRange.baseMipLevel = 0;
@@ -320,16 +235,34 @@ public:
 		// Get a primary command buffer for submitting image layout transitions for the framebuffer attachments
 		VkCommandBuffer layoutCmd = VulkanExampleBase::createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);
 
+		// Set the initial layout to shader read instead of attachment 
+		// This is done as the render loop does the actualy image layout transitions
 		vkTools::setImageLayout(
 			layoutCmd,
 			offScreenFrameBuf.color.image,
 			VK_IMAGE_ASPECT_COLOR_BIT,
 			VK_IMAGE_LAYOUT_UNDEFINED,
-			VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);
+			VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);
 
 		colorImageView.image = offScreenFrameBuf.color.image;
 		VK_CHECK_RESULT(vkCreateImageView(device, &colorImageView, nullptr, &offScreenFrameBuf.color.view));
 
+		// Create sampler to sample from to collor attachment 
+		// Used to sample in the fragment shader for final rendering
+		VkSamplerCreateInfo sampler = vkTools::initializers::samplerCreateInfo();
+		sampler.magFilter = VK_FILTER_LINEAR;
+		sampler.minFilter = VK_FILTER_LINEAR;
+		sampler.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
+		sampler.addressModeU = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
+		sampler.addressModeV = sampler.addressModeU;
+		sampler.addressModeW = sampler.addressModeU;
+		sampler.mipLodBias = 0.0f;
+		sampler.maxAnisotropy = 0;
+		sampler.minLod = 0.0f;
+		sampler.maxLod = 1.0f;
+		sampler.borderColor = VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE;
+		VK_CHECK_RESULT(vkCreateSampler(device, &sampler, nullptr, &offScreenFrameBuf.colorSampler));
+
 		// Depth stencil attachment
 		image.format = fbDepthFormat;
 		image.usage = VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
@@ -408,6 +341,14 @@ public:
 
 		VK_CHECK_RESULT(vkBeginCommandBuffer(offScreenCmdBuffer, &cmdBufInfo));
 
+		// Change back layout of the color attachment after sampling in the fragment shader
+		vkTools::setImageLayout(
+			offScreenCmdBuffer,
+			offScreenFrameBuf.color.image,
+			VK_IMAGE_ASPECT_DEPTH_BIT,
+			VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
+			VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);
+
 		vkCmdBeginRenderPass(offScreenCmdBuffer, &renderPassBeginInfo, VK_SUBPASS_CONTENTS_INLINE);
 
 		VkViewport viewport = vkTools::initializers::viewport((float)offScreenFrameBuf.width, (float)offScreenFrameBuf.height, 0.0f, 1.0f);
@@ -427,74 +368,12 @@ public:
 
 		vkCmdEndRenderPass(offScreenCmdBuffer);
 
-		// Make sure color writes to the framebuffer are finished before using it as transfer source
+		// Change layout of the color attachment for sampling in the fragment shader
 		vkTools::setImageLayout(
 			offScreenCmdBuffer,
 			offScreenFrameBuf.color.image,
-			VK_IMAGE_ASPECT_COLOR_BIT,
+			VK_IMAGE_ASPECT_DEPTH_BIT,
 			VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
-			VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL);
-
-		// Transform texture target to transfer source
-		vkTools::setImageLayout(
-			offScreenCmdBuffer,
-			offScreenFrameBuf.textureTarget.image,
-			VK_IMAGE_ASPECT_COLOR_BIT,
-			VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
-			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL);
-
-		// Blit offscreen color buffer to our texture target
-		VkImageBlit imgBlit;
-
-		imgBlit.srcSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
-		imgBlit.srcSubresource.mipLevel = 0;
-		imgBlit.srcSubresource.baseArrayLayer = 0;
-		imgBlit.srcSubresource.layerCount = 1;
-
-		imgBlit.srcOffsets[0] = { 0, 0, 0 };
-		imgBlit.srcOffsets[1].x = offScreenFrameBuf.width;
-		imgBlit.srcOffsets[1].y = offScreenFrameBuf.height;
-		imgBlit.srcOffsets[1].z = 1;
-
-		imgBlit.dstSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
-		imgBlit.dstSubresource.mipLevel = 0;
-		imgBlit.dstSubresource.baseArrayLayer = 0;
-		imgBlit.dstSubresource.layerCount = 1;
-
-		imgBlit.dstOffsets[0] = { 0, 0, 0 };
-		imgBlit.dstOffsets[1].x = offScreenFrameBuf.textureTarget.width;
-		imgBlit.dstOffsets[1].y = offScreenFrameBuf.textureTarget.height;
-		imgBlit.dstOffsets[1].z = 1;
-
-		// Blit from framebuffer image to texture image
-		// vkCmdBlitImage does scaling and (if necessary and possible) also does format conversions
-		vkCmdBlitImage(
-			offScreenCmdBuffer,
-			offScreenFrameBuf.color.image,
-			VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
-			offScreenFrameBuf.textureTarget.image,
-			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
-			1,
-			&imgBlit,
-			VK_FILTER_LINEAR
-			);
-
-		// Transform framebuffer color attachment back 
-		vkTools::setImageLayout(
-			offScreenCmdBuffer,
-			offScreenFrameBuf.color.image,
-			VK_IMAGE_ASPECT_COLOR_BIT,
-			VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
-			VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);
-
-		// Transform texture target back to shader read
-		// Makes sure that writes to the textuer are finished before
-		// it's accessed in the shader
-		vkTools::setImageLayout(
-			offScreenCmdBuffer,
-			offScreenFrameBuf.textureTarget.image,
-			VK_IMAGE_ASPECT_COLOR_BIT,
-			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
 			VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);
 
 		VK_CHECK_RESULT(vkEndCommandBuffer(offScreenCmdBuffer));
@@ -744,11 +623,11 @@ public:
 
 		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &allocInfo, &descriptorSets.mirror));
 
-		// Image descriptor for the offscreen mirror texture
+		// Image descriptor for the offscreen mirror color attachment image
 		VkDescriptorImageInfo texDescriptorMirror =
 			vkTools::initializers::descriptorImageInfo(
-				offScreenFrameBuf.textureTarget.sampler,
+				offScreenFrameBuf.colorSampler,
-				offScreenFrameBuf.textureTarget.view,
+				offScreenFrameBuf.color.view,
 				VK_IMAGE_LAYOUT_GENERAL);
 
 		// Image descriptor for the color map
@@ -789,7 +668,7 @@ public:
 		{
 			// Binding 0 : Vertex shader uniform buffer
 			vkTools::initializers::writeDescriptorSet(
-			descriptorSets.debugQuad,
+				descriptorSets.debugQuad,
 				VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
 				0,
 				&uniformData.vsDebugQuad.descriptor),
@@ -827,7 +706,7 @@ public:
 		{
 			// Binding 0 : Vertex shader uniform buffer
 			vkTools::initializers::writeDescriptorSet(
-			descriptorSets.offscreen,
+				descriptorSets.offscreen,
 				VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
 				0,
 				&uniformData.vsOffScreen.descriptor)
@@ -1081,14 +960,13 @@ public:
 		loadTextures();
 		generateQuad();
 		loadMeshes();
+		prepareOffscreenFramebuffer();
 		setupVertexDescriptions();
 		prepareUniformBuffers();
-		prepareTextureTarget(TEX_DIM, TEX_DIM, TEX_FORMAT);
 		setupDescriptorSetLayout();
 		preparePipelines();
 		setupDescriptorPool();
 		setupDescriptorSet();
-		prepareOffscreenFramebuffer();
 		buildCommandBuffers();
 		buildOffscreenCommandBuffer(); 
 		prepared = true;

shadowmapping/shadowmapping.cpp

@@ -155,6 +155,7 @@ public:
 		// Note : Inherited destructor cleans up resources stored in base class
 
 		// Frame buffer
+		vkDestroySampler(device, offScreenFrameBuf.depthSampler, nullptr);
 
 		// Color attachment
 		vkDestroyImageView(device, offScreenFrameBuf.color.view, nullptr);
@@ -329,7 +330,7 @@ public:
 		VK_CHECK_RESULT(vkBindImageMemory(device, offScreenFrameBuf.depth.image, offScreenFrameBuf.depth.mem, 0));
 
 		// Set the initial layout to shader read instead of attachment 
-		// This is done as teh render loop does the actualy image layout transitions
+		// This is done as the render loop does the actualy image layout transitions
 		vkTools::setImageLayout(
 			layoutCmd,
 			offScreenFrameBuf.depth.image,
@@ -439,7 +440,7 @@ public:
 
 		vkCmdEndRenderPass(offScreenCmdBuffer);
 
-		// Change back layout of the depth attachment after sampling in the fragment shader
+		// Change layout of the depth attachment for sampling in the fragment shader
 		vkTools::setImageLayout(
 			offScreenCmdBuffer,
 			offScreenFrameBuf.depth.image,