Jérôme Bousquié
46 lines
2.0 KiB
Rust
46 lines
2.0 KiB
Rust
//! # Vertex Module — CPU-Side Per-Attribute Tuple (GPU Contract)
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//!
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//! Defines `Vertex`, the CPU-side data layout that is sent to the GPU as vertex attribute buffers.
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//! The struct's field order and offsets must exactly match the shader input attributes defined in
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//! PipelineCache::build_pipeline() — any mismatch will corrupt GPU rendering output.
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//!
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//! ## Technical Points
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//! - `#[repr(C)]` ensures fields are laid out contiguously without Rust padding reordering, matching C ABI.
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//! - `bytemuck::Pod + bytemuck::Zeroable` enables safe `cast_slice()` conversion for GPU buffer uploads.
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//! - **Performance**: The 56-byte stride per vertex is the contract between CPU data and GPU shader inputs;
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//! PipelineCache::build_pipeline() reads this layout to construct VertexBufferLayout attributes array.
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/// Per-vertex attribute tuple: position (3D), normal (3D), texture coordinate (2D), color (RGBA).
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/// Must match the vertex buffer layout in PipelineCache::build_pipeline() byte-for-byte.
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#[repr(C)]
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#[derive(Copy, Clone, Debug, bytemuck::Pod, bytemuck::Zeroable)]
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pub struct Vertex {
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/// XYZ coordinates of this vertex in world space. Offset: 0 bytes (12 bytes total as [f32;3]).
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pub position: [f32; 3],
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/// XYZ coordinates of the vertex normal. Offset: 12 bytes (12 bytes total as [f32;3]).
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pub normal: [f32; 3],
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/// UV texture coordinates. Offset: 24 bytes (8 bytes total as [f32;2]).
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pub uv: [f32; 2],
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/// RGBA color values. Offset: 32 bytes (16 bytes total as [f32;4]).
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pub color: [f32; 4],
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}
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impl Default for Vertex {
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// Default values for stability
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fn default() -> Self {
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Self {
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// Default position at center (0, 0)
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position: [0.0, 0.0, 0.0],
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// Normal pointing upward (standard for lighting calculations)
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normal: [0.0, 1.0, 0.0],
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// UV coordinates at the origin of the texture
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uv: [0.0, 0.0],
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// Opaque white color by default
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color: [1.0, 1.0, 1.0, 1.0],
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}
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}
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}
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