61 lines
No EOL
2.2 KiB
Markdown
61 lines
No EOL
2.2 KiB
Markdown
# Vertex attributes
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## Synopsis
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This sample demonstrates two different ways of providing vertex data to the GPU using either interleaved or separate buffers for vertex attributes.
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## Shader interface
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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.
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```glsl
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layout (location = 0) in vec3 inPos;
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layout (location = 1) in vec3 inNormal;
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layout (location = 2) in vec2 inUV;
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layout (location = 3) in vec4 inTangent;
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```
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## Interleaved vertex attributes
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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.
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```cpp
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// Binding
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const std::vector<VkVertexInputBindingDescription> vertexInputBindingsInterleaved = {
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{ 0, sizeof(Vertex), VK_VERTEX_INPUT_RATE_VERTEX },
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};
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// Attribute
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const std::vector<VkVertexInputAttributeDescription> vertexInputAttributesInterleaved = {
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{ 0, 0, VK_FORMAT_R32G32B32_SFLOAT, offsetof(Vertex, pos) },
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{ 1, 0, VK_FORMAT_R32G32B32_SFLOAT, offsetof(Vertex, normal) },
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{ 2, 0, VK_FORMAT_R32G32_SFLOAT, offsetof(Vertex, uv) },
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{ 3, 0, VK_FORMAT_R32G32B32A32_SFLOAT, offsetof(Vertex, tangent) },
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};
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```
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## Separate vertex attributes
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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.
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```cpp
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// Bindings
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const std::vector<VkVertexInputBindingDescription> vertexInputBindingsSeparate = {
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{ 0, sizeof(glm::vec3), VK_VERTEX_INPUT_RATE_VERTEX },
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{ 1, sizeof(glm::vec3), VK_VERTEX_INPUT_RATE_VERTEX },
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{ 2, sizeof(glm::vec2), VK_VERTEX_INPUT_RATE_VERTEX },
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{ 3, sizeof(glm::vec4), VK_VERTEX_INPUT_RATE_VERTEX },
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};
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// Attributes
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const std::vector<VkVertexInputAttributeDescription> vertexInputAttributesSeparate = {
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{ 0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0 },
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{ 1, 1, VK_FORMAT_R32G32B32_SFLOAT, 0 },
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{ 2, 2, VK_FORMAT_R32G32_SFLOAT, 0 },
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{ 3, 3, VK_FORMAT_R32G32B32A32_SFLOAT, 0 },
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};
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``` |