90 lines
3.1 KiB
Rust
90 lines
3.1 KiB
Rust
use bytemuck::{Pod, Zeroable};
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/// Texture format used for the RT shadow output (single-channel float).
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pub const RT_SHADOW_FORMAT: wgpu::TextureFormat = wgpu::TextureFormat::R32Float;
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/// Uniform buffer for the RT shadow compute pass.
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///
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/// Layout (32 bytes, 16-byte aligned):
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/// light_direction [f32; 3] + _pad0: f32 → 16 bytes
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/// width: u32, height: u32, _pad1: [u32; 2] → 16 bytes
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#[repr(C)]
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#[derive(Copy, Clone, Debug, Pod, Zeroable)]
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pub struct RtShadowUniform {
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pub light_direction: [f32; 3],
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pub _pad0: f32,
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pub width: u32,
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pub height: u32,
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pub _pad1: [u32; 2],
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}
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/// GPU resources for the RT shadow compute pass.
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pub struct RtShadowResources {
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pub shadow_texture: wgpu::Texture,
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pub shadow_view: wgpu::TextureView,
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pub uniform_buffer: wgpu::Buffer,
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pub width: u32,
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pub height: u32,
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}
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impl RtShadowResources {
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pub fn new(device: &wgpu::Device, width: u32, height: u32) -> Self {
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let (shadow_texture, shadow_view) = create_shadow_texture(device, width, height);
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let uniform_buffer = device.create_buffer(&wgpu::BufferDescriptor {
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label: Some("RT Shadow Uniform Buffer"),
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size: std::mem::size_of::<RtShadowUniform>() as u64,
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usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
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mapped_at_creation: false,
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});
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Self { shadow_texture, shadow_view, uniform_buffer, width, height }
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}
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/// Recreate the shadow texture when the window is resized.
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pub fn resize(&mut self, device: &wgpu::Device, width: u32, height: u32) {
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let (shadow_texture, shadow_view) = create_shadow_texture(device, width, height);
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self.shadow_texture = shadow_texture;
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self.shadow_view = shadow_view;
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self.width = width;
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self.height = height;
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}
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}
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// ── Helpers ──────────────────────────────────────────────────────────────────
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fn create_shadow_texture(
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device: &wgpu::Device,
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width: u32,
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height: u32,
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) -> (wgpu::Texture, wgpu::TextureView) {
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let texture = device.create_texture(&wgpu::TextureDescriptor {
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label: Some("RT Shadow Texture"),
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size: wgpu::Extent3d {
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width,
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height,
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depth_or_array_layers: 1,
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},
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mip_level_count: 1,
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sample_count: 1,
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dimension: wgpu::TextureDimension::D2,
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format: RT_SHADOW_FORMAT,
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usage: wgpu::TextureUsages::STORAGE_BINDING | wgpu::TextureUsages::TEXTURE_BINDING,
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view_formats: &[],
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});
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let view = texture.create_view(&wgpu::TextureViewDescriptor::default());
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(texture, view)
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}
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// ── Tests ─────────────────────────────────────────────────────────────────────
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_rt_shadow_uniform_size() {
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assert_eq!(std::mem::size_of::<RtShadowUniform>(), 32);
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}
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}
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