bevy/assets/shaders/custom_material_chromatic_aberration.wgsl
robtfm 503c2a9677 adjust cluster index for viewport origin (#5947)
# Objective

fixes #5946

## Solution

adjust cluster index calculation for viewport origin.

from reading point 2 of the rasterization algorithm description in https://gpuweb.github.io/gpuweb/#rasterization, it looks like framebuffer space (and so @bulitin(position)) is not meant to be adjusted for viewport origin, so we need to subtract that to get the right cluster index.

- add viewport origin to rust `ExtractedView` and wgsl `View` structs
- subtract from frag coord for cluster index calculation
2022-09-15 21:58:14 +00:00

28 lines
871 B
WebGPU Shading Language

#import bevy_pbr::mesh_view_bindings
#import bevy_pbr::utils
@group(1) @binding(0)
var texture: texture_2d<f32>;
@group(1) @binding(1)
var our_sampler: sampler;
@fragment
fn fragment(
@builtin(position) position: vec4<f32>,
#import bevy_sprite::mesh2d_vertex_output
) -> @location(0) vec4<f32> {
// Get screen position with coordinates from 0 to 1
let uv = coords_to_viewport_uv(position.xy, view.viewport);
let offset_strength = 0.02;
// Sample each color channel with an arbitrary shift
var output_color = vec4<f32>(
textureSample(texture, our_sampler, uv + vec2<f32>(offset_strength, -offset_strength)).r,
textureSample(texture, our_sampler, uv + vec2<f32>(-offset_strength, 0.0)).g,
textureSample(texture, our_sampler, uv + vec2<f32>(0.0, offset_strength)).b,
1.0
);
return output_color;
}