Code cleanup and readme for vertex attributes sample

examples/vertexattributes/README.md

@@ -2,4 +2,60 @@
 
 ## Synopsis
 
-This sample demonstrates how to pass vertex attributes using interleaved or separate buffers.
+This sample demonstrates two different ways of providing vertex data to the GPU using either interleaved or separate buffers for vertex attributes.
+
+## Shader interface
+
+The shader interface for passing the vertex attributes is the same, no matter if the data provided is coming from a single interleaved or multiple separate buffers.
+
+```glsl
+layout (location = 0) in vec3 inPos;
+layout (location = 1) in vec3 inNormal;
+layout (location = 2) in vec2 inUV;
+layout (location = 3) in vec4 inTangent;
+```
+
+## Interleaved vertex attributes
+
+In an interleaved vertex buffer, the components that make up a single vertex are stored after each other, so the stride of a single vertex is the sum of it's component's sizes.
+
+![Interleaved buffer layout](interleavedbuffer.png)
+
+```cpp
+// Binding
+const std::vector<VkVertexInputBindingDescription> vertexInputBindingsInterleaved = {
+    { 0, sizeof(Vertex), VK_VERTEX_INPUT_RATE_VERTEX },
+};
+
+// Attribute
+const std::vector<VkVertexInputAttributeDescription> vertexInputAttributesInterleaved = {
+    { 0, 0, VK_FORMAT_R32G32B32_SFLOAT, offsetof(Vertex, pos) },
+    { 1, 0, VK_FORMAT_R32G32B32_SFLOAT, offsetof(Vertex, normal) },
+    { 2, 0, VK_FORMAT_R32G32_SFLOAT, offsetof(Vertex, uv) },
+    { 3, 0, VK_FORMAT_R32G32B32A32_SFLOAT, offsetof(Vertex, tangent) },
+};
+```
+
+## Separate vertex attributes
+
+When using separate buffers, each component is stored in it's own buffer. So e.g. the position buffer only contains vertex positions stored consecutively.
+
+![Interleaved buffer layout](separatebuffers.png)
+
+```cpp
+// Bindings
+const std::vector<VkVertexInputBindingDescription> vertexInputBindingsSeparate = {
+    { 0, sizeof(glm::vec3), VK_VERTEX_INPUT_RATE_VERTEX },
+    { 1, sizeof(glm::vec3), VK_VERTEX_INPUT_RATE_VERTEX },
+    { 2, sizeof(glm::vec2), VK_VERTEX_INPUT_RATE_VERTEX },
+    { 3, sizeof(glm::vec4), VK_VERTEX_INPUT_RATE_VERTEX },
+};
+
+// Attributes
+const std::vector<VkVertexInputAttributeDescription> vertexInputAttributesSeparate = {
+    { 0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0 },
+    { 1, 1, VK_FORMAT_R32G32B32_SFLOAT, 0 },
+    { 2, 2, VK_FORMAT_R32G32_SFLOAT, 0 },
+    { 3, 3, VK_FORMAT_R32G32B32A32_SFLOAT, 0 },
+};
+```

examples/vertexattributes/vertexattributes.cpp

@@ -90,7 +90,7 @@ void VulkanExample::loadSceneNode(const tinygltf::Node& inputNode, const tinyglt
 				vert.normal = glm::normalize(glm::vec3(normalsBuffer ? glm::make_vec3(&normalsBuffer[v * 3]) : glm::vec3(0.0f)));
 				vert.uv = texCoordsBuffer ? glm::make_vec2(&texCoordsBuffer[v * 2]) : glm::vec3(0.0f);
 				vert.tangent = tangentsBuffer ? glm::make_vec4(&tangentsBuffer[v * 4]) : glm::vec4(0.0f);
- 				vertexBuffer.push_back(vert);
+				vertexBuffer.push_back(vert);
 
 				// Append separate attributes
 				vertexAttributes.pos.push_back(glm::make_vec3(&positionBuffer[v * 3]));
@@ -230,7 +230,8 @@ void VulkanExample::buildCommandBuffers()
 			VkDeviceSize offsets[4] = { 0, 0, 0, 0 };
 			std::array<VkBuffer, 4> buffers = { separateVertexBuffers.pos.buffer, separateVertexBuffers.normal.buffer, separateVertexBuffers.uv.buffer, separateVertexBuffers.tangent.buffer };
 			vkCmdBindVertexBuffers(drawCmdBuffers[i], 0, static_cast<uint32_t>(buffers.size()), buffers.data(), offsets);
-		} else {
+		}
+		else {
 			// Using interleaved attribute bindings only requires one buffer to be bound
 			VkDeviceSize offsets[1] = { 0 };
 			vkCmdBindVertexBuffers(drawCmdBuffers[i], 0, 1, &interleavedVertexBuffer.buffer, offsets);
@@ -492,13 +493,13 @@ void VulkanExample::preparePipelines()
 	// Interleaved vertex attributes 
 	// One Binding (one buffer) and multiple attributes
 	const std::vector<VkVertexInputBindingDescription> vertexInputBindingsInterleaved = {
-		vks::initializers::vertexInputBindingDescription(0, sizeof(Vertex), VK_VERTEX_INPUT_RATE_VERTEX),
+		{ 0, sizeof(Vertex), VK_VERTEX_INPUT_RATE_VERTEX },
 	};
 	const std::vector<VkVertexInputAttributeDescription> vertexInputAttributesInterleaved = {
-		vks::initializers::vertexInputAttributeDescription(0, 0, VK_FORMAT_R32G32B32_SFLOAT, offsetof(Vertex, pos)),
+		{ 0, 0, VK_FORMAT_R32G32B32_SFLOAT, offsetof(Vertex, pos) },
-		vks::initializers::vertexInputAttributeDescription(0, 1, VK_FORMAT_R32G32B32_SFLOAT, offsetof(Vertex, normal)),
+		{ 1, 0, VK_FORMAT_R32G32B32_SFLOAT, offsetof(Vertex, normal) },
-		vks::initializers::vertexInputAttributeDescription(0, 2, VK_FORMAT_R32G32_SFLOAT, offsetof(Vertex, uv)),
+		{ 2, 0, VK_FORMAT_R32G32_SFLOAT, offsetof(Vertex, uv) },
-		vks::initializers::vertexInputAttributeDescription(0, 3, VK_FORMAT_R32G32B32A32_SFLOAT, offsetof(Vertex, tangent)),
+		{ 3, 0, VK_FORMAT_R32G32B32A32_SFLOAT, offsetof(Vertex, tangent) },
 	};
 
 	vertexInputStateCI = vks::initializers::pipelineVertexInputStateCreateInfo(vertexInputBindingsInterleaved, vertexInputAttributesInterleaved);
@@ -507,17 +508,18 @@ void VulkanExample::preparePipelines()
 	// Separate vertex attribute
 	// Multiple bindings (for each attribute buffer) and multiple attribues
 	const std::vector<VkVertexInputBindingDescription> vertexInputBindingsSeparate = {
-		vks::initializers::vertexInputBindingDescription(0, sizeof(glm::vec3), VK_VERTEX_INPUT_RATE_VERTEX),
+		{ 0, sizeof(glm::vec3), VK_VERTEX_INPUT_RATE_VERTEX },
-		vks::initializers::vertexInputBindingDescription(1, sizeof(glm::vec3), VK_VERTEX_INPUT_RATE_VERTEX),
+		{ 1, sizeof(glm::vec3), VK_VERTEX_INPUT_RATE_VERTEX },
-		vks::initializers::vertexInputBindingDescription(2, sizeof(glm::vec2), VK_VERTEX_INPUT_RATE_VERTEX),
+		{ 2, sizeof(glm::vec2), VK_VERTEX_INPUT_RATE_VERTEX },
-		vks::initializers::vertexInputBindingDescription(3, sizeof(glm::vec4), VK_VERTEX_INPUT_RATE_VERTEX),
+		{ 3, sizeof(glm::vec4), VK_VERTEX_INPUT_RATE_VERTEX },
 	};
 	const std::vector<VkVertexInputAttributeDescription> vertexInputAttributesSeparate = {
-		vks::initializers::vertexInputAttributeDescription(0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0),
+		{ 0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0 },
-		vks::initializers::vertexInputAttributeDescription(1, 1, VK_FORMAT_R32G32B32_SFLOAT, 0),
+		{ 1, 1, VK_FORMAT_R32G32B32_SFLOAT, 0 },
-		vks::initializers::vertexInputAttributeDescription(2, 2, VK_FORMAT_R32G32_SFLOAT, 0),
+		{ 2, 2, VK_FORMAT_R32G32_SFLOAT, 0 },
-		vks::initializers::vertexInputAttributeDescription(3, 3, VK_FORMAT_R32G32B32A32_SFLOAT, 0),
+		{ 3, 3, VK_FORMAT_R32G32B32A32_SFLOAT, 0 },
 	};
+
 	vertexInputStateCI = vks::initializers::pipelineVertexInputStateCreateInfo(vertexInputBindingsSeparate, vertexInputAttributesSeparate);
 	VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCI, nullptr, &pipelines.vertexAttributesSeparate));
 }