struct VertexOut {
@builtin(position) position: vec4<f32>,
@location(0) uv: vec2<f32>,
};
struct PostUniform {
viewport: vec4<f32>,
config: vec4<f32>,
};
@group(0) @binding(0)
var source_texture: texture_2d<f32>;
@group(0) @binding(1)
var<uniform> post: PostUniform;
@vertex
fn vs_main(@builtin(vertex_index) vertex_index: u32) -> VertexOut {
var positions = array<vec2<f32>, 3>(
vec2<f32>(-1.0, -3.0),
vec2<f32>(-1.0, 1.0),
vec2<f32>(3.0, 1.0),
);
let position = positions[vertex_index];
var out: VertexOut;
out.position = vec4<f32>(position, 0.0, 1.0);
out.uv = position * vec2<f32>(0.5, -0.5) + vec2<f32>(0.5, 0.5);
return out;
}
@fragment
fn fs_main(in: VertexOut) -> @location(0) vec4<f32> {
let dims = vec2<i32>(textureDimensions(source_texture));
let coord = clamp(vec2<i32>(in.uv * vec2<f32>(dims)), vec2<i32>(0), dims - vec2<i32>(1));
if coord.x <= 0 || coord.y <= 0 || coord.x >= dims.x - 1 || coord.y >= dims.y - 1 {
return textureLoad(source_texture, coord, 0);
}
let offsets = array<vec2<i32>, 5>(
vec2<i32>(0, -1),
vec2<i32>(-1, 0),
vec2<i32>(0, 0),
vec2<i32>(1, 0),
vec2<i32>(0, 1),
);
let center = textureLoad(source_texture, coord, 0);
let center_luma = luma(center.rgb);
var min_luma = 1.0e9;
var max_luma = -1.0e9;
var bright_neighbors = 0u;
var dark_neighbors = 0u;
var sum = vec4<f32>(0.0);
for (var index = 0u; index < 5u; index = index + 1u) {
let sample = textureLoad(source_texture, coord + offsets[index], 0);
let sample_luma = luma(sample.rgb);
min_luma = min(min_luma, sample_luma);
max_luma = max(max_luma, sample_luma);
if sample_luma - center_luma >= 16.0 / 255.0 {
bright_neighbors = bright_neighbors + 1u;
}
if center_luma - sample_luma >= 16.0 / 255.0 {
dark_neighbors = dark_neighbors + 1u;
}
sum = sum + sample;
}
if max_luma - min_luma < 16.0 / 255.0 {
return center;
}
let dark_edge = center_luma - min_luma <= 1.0 / 255.0 && bright_neighbors >= 2u;
let light_edge = max_luma - center_luma <= 1.0 / 255.0 && dark_neighbors >= 2u;
if !dark_edge && !light_edge {
return center;
}
return sum / 5.0;
}
fn luma(rgb: vec3<f32>) -> f32 {
return dot(rgb, vec3<f32>(0.299, 0.587, 0.114));
}