Jérôme Bousquié
52 lines
2.3 KiB
Rust
52 lines
2.3 KiB
Rust
//! # Mesh Module
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//!
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//! Defines `Mesh`, a persistent GPU geometry container. Mesh data is uploaded to the GPU once at creation time
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//! and remains valid across all frames until dropped. It holds no rendering knowledge—only raw geometric data.
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use crate::vertex::Vertex;
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use wgpu::util::DeviceExt;
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/// Persistent GPU geometry: vertex positions, optional indices, and draw call counters.
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/// Created once via `Mesh::new()` during scene setup; referenced by Renderer for every frame.
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pub struct Mesh {
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/// GPU buffer containing vertex attribute data (position, UV, color).
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pub vertex_buffer: wgpu::Buffer,
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/// Optional GPU buffer for indexed drawing. Present when the mesh uses index-based rendering instead of simple vertex iteration.
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pub index_buffer: Option<wgpu::Buffer>,
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/// Number of vertices in the mesh. Used as `0..num_vertices` for non-indexed draws.
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pub num_vertices: u32,
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/// Number of indices in the index buffer. Used as `0..num_indices` for indexed draws.
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pub num_indices: u32,
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}
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impl Mesh {
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/// Creates a new Mesh by uploading vertex and optional index data to GPU buffers.
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/// Inputs: device (GPU command source), vertices (CPU-side vertex array), indices (optional CPU-side index array).
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/// Returns a Mesh with two GPU buffers ready for rendering. Called at scene initialization time only.
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pub fn new(device: &wgpu::Device, vertices: &[Vertex], indices: Option<&[u16]>) -> Self {
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let vertex_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
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label: Some("Mesh Vertex Buffer"),
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contents: bytemuck::cast_slice(vertices),
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usage: wgpu::BufferUsages::VERTEX,
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});
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// Create optional index buffer and count indices if provided
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let (index_buffer, num_indices) = if let Some(data) = indices {
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let buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
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label: Some("Mesh Index Buffer"),
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usage: wgpu::BufferUsages::INDEX,
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contents: bytemuck::cast_slice(data),
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});
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(Some(buffer), data.len() as u32)
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} else {
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(None, 0)
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};
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Self {
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vertex_buffer,
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index_buffer,
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num_vertices: vertices.len() as u32,
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num_indices,
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}
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}
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}
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