Introduces GBuffer struct with 4 render target TextureViews (position/
normal/albedo/material) plus depth, and a fullscreen oversized triangle
for screen-space passes. Exports format constants and create helpers.
Updates lib.rs with new module declarations and re-exports.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
wgpu's default max_bind_groups is 4 (groups 0-3), but the PBR shader was
using group(4) for BRDF LUT bindings. This merges IBL bindings into the
shadow bind group (group 3) at binding slots 3-4, removes the standalone
IBL bind group layout/creation, and updates all examples accordingly.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Implements CPU-based BRDF LUT generation using the split-sum IBL
approximation (Hammersley sampling, GGX importance sampling, Smith
geometry with IBL k=a²/2). Wraps the 256×256 Rgba8Unorm LUT in
IblResources for GPU upload via wgpu 28.0 API.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
WGSL vec3<f32> requires 16-byte alignment, causing the shader to expect
1056 bytes while Rust struct was 1040. Added padding fields to match.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Implements parse_bmp (24/32-bit uncompressed BMP to RGBA), GpuTexture with
wgpu 28.0 write_texture API (TexelCopyTextureInfo/TexelCopyBufferLayout),
bind_group_layout, white_1x1 fallback, and 3 BMP parser unit tests.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
