// Full-screen quad vertex shader shared by all single-pass nodes.
struct VertexOutput {
@builtin(position) position: vec4<f32>,
@location(0) uv: vec2<f32>,
}
@vertex
fn vs_main(@builtin(vertex_index) vertex_idx: u32) -> VertexOutput {
// Two triangles covering the full NDC clip space.
// NDC Y is up; texture UV Y is down — mapping is inverted on Y.
var positions = array<vec2<f32>, 6>(
vec2<f32>(-1.0, 1.0), vec2<f32>( 1.0, 1.0), vec2<f32>(-1.0, -1.0),
vec2<f32>(-1.0, -1.0), vec2<f32>( 1.0, 1.0), vec2<f32>( 1.0, -1.0),
);
var uvs = array<vec2<f32>, 6>(
vec2<f32>(0.0, 0.0), vec2<f32>(1.0, 0.0), vec2<f32>(0.0, 1.0),
vec2<f32>(0.0, 1.0), vec2<f32>(1.0, 0.0), vec2<f32>(1.0, 1.0),
);
var out: VertexOutput;
out.position = vec4<f32>(positions[vertex_idx], 0.0, 1.0);
out.uv = uvs[vertex_idx];
return out;
}
// ── Fragment ──────────────────────────────────────────────────────────────────
@group(0) @binding(0) var input_tex: texture_2d<f32>;
@group(0) @binding(1) var tex_sampler: sampler;
@group(0) @binding(2) var<uniform> u: ColorGradeUniforms;
struct ColorGradeUniforms {
brightness: f32,
contrast: f32,
saturation: f32,
temperature: f32,
tint: f32,
_pad0: f32,
_pad1: f32,
_pad2: f32,
}
@fragment
fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
let color = textureSample(input_tex, tex_sampler, in.uv);
var rgb = color.rgb;
// Brightness: additive offset.
rgb = rgb + u.brightness;
// Contrast: pivot at 0.5.
rgb = (rgb - 0.5) * u.contrast + 0.5;
// Temperature (warm/cool): shift R and B in opposite directions.
rgb.r = rgb.r + u.temperature * 0.1;
rgb.b = rgb.b - u.temperature * 0.1;
// Tint (green ↔ magenta): shift G.
rgb.g = rgb.g + u.tint * 0.1;
// Saturation: blend toward luma (BT.709 coefficients).
let luma = dot(rgb, vec3<f32>(0.2126, 0.7152, 0.0722));
rgb = mix(vec3<f32>(luma), rgb, u.saturation);
rgb = clamp(rgb, vec3<f32>(0.0), vec3<f32>(1.0));
return vec4<f32>(rgb, color.a);
}