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struct Globals {
transform: mat4x4<f32>,
}
@group(0) @binding(0) var<uniform> globals: Globals;
fn unpack_u32(color: vec2<u32>) -> vec4<f32> {
let rg: vec2<f32> = unpack2x16float(color.x);
let ba: vec2<f32> = unpack2x16float(color.y);
return vec4<f32>(rg.y, rg.x, ba.y, ba.x);
}
struct SolidVertexInput {
@location(0) position: vec2<f32>,
@location(1) color: vec4<f32>,
}
struct SolidVertexOutput {
@builtin(position) position: vec4<f32>,
@location(0) color: vec4<f32>,
}
@vertex
fn solid_vs_main(input: SolidVertexInput) -> SolidVertexOutput {
var out: SolidVertexOutput;
out.color = input.color;
out.position = globals.transform * vec4<f32>(input.position, 0.0, 1.0);
return out;
}
@fragment
fn solid_fs_main(input: SolidVertexOutput) -> @location(0) vec4<f32> {
return input.color;
}
struct GradientVertexInput {
@location(0) v_pos: vec2<f32>,
@location(1) colors_1: vec4<u32>,
@location(2) colors_2: vec4<u32>,
@location(3) colors_3: vec4<u32>,
@location(4) colors_4: vec4<u32>,
@location(5) offsets: vec4<u32>,
@location(6) direction: vec4<f32>,
}
struct GradientVertexOutput {
@builtin(position) position: vec4<f32>,
@location(0) raw_position: vec2<f32>,
@location(1) colors_1: vec4<u32>,
@location(2) colors_2: vec4<u32>,
@location(3) colors_3: vec4<u32>,
@location(4) colors_4: vec4<u32>,
@location(5) offsets: vec4<u32>,
@location(6) direction: vec4<f32>,
}
@vertex
fn gradient_vs_main(input: GradientVertexInput) -> GradientVertexOutput {
var output: GradientVertexOutput;
output.position = globals.transform * vec4<f32>(input.v_pos, 0.0, 1.0);
output.raw_position = input.v_pos;
output.colors_1 = input.colors_1;
output.colors_2 = input.colors_2;
output.colors_3 = input.colors_3;
output.colors_4 = input.colors_4;
output.offsets = input.offsets;
output.direction = input.direction;
return output;
}
fn random(coords: vec2<f32>) -> f32 {
return fract(sin(dot(coords, vec2(12.9898,78.233))) * 43758.5453);
}
/// Returns the current interpolated color with a max 8-stop gradient
fn gradient(
raw_position: vec2<f32>,
direction: vec4<f32>,
colors: array<vec4<f32>, 8>,
offsets: array<f32, 8>,
last_index: i32
) -> vec4<f32> {
let start = direction.xy;
let end = direction.zw;
let v1 = end - start;
let v2 = raw_position - start;
let unit = normalize(v1);
let coord_offset = dot(unit, v2) / length(v1);
//need to store these as a var to use dynamic indexing in a loop
//this is already added to wgsl spec but not in wgpu yet
var colors_arr = colors;
var offsets_arr = offsets;
var color: vec4<f32>;
let noise_granularity: f32 = 0.3/255.0;
for (var i: i32 = 0; i < last_index; i++) {
let curr_offset = offsets_arr[i];
let next_offset = offsets_arr[i+1];
if (coord_offset <= offsets_arr[0]) {
color = colors_arr[0];
}
if (curr_offset <= coord_offset && coord_offset <= next_offset) {
color = mix(colors_arr[i], colors_arr[i+1], smoothstep(
curr_offset,
next_offset,
coord_offset,
));
}
if (coord_offset >= offsets_arr[last_index]) {
color = colors_arr[last_index];
}
}
return color + mix(-noise_granularity, noise_granularity, random(raw_position));
}
@fragment
fn gradient_fs_main(input: GradientVertexOutput) -> @location(0) vec4<f32> {
let colors = array<vec4<f32>, 8>(
unpack_u32(input.colors_1.xy),
unpack_u32(input.colors_1.zw),
unpack_u32(input.colors_2.xy),
unpack_u32(input.colors_2.zw),
unpack_u32(input.colors_3.xy),
unpack_u32(input.colors_3.zw),
unpack_u32(input.colors_4.xy),
unpack_u32(input.colors_4.zw),
);
let offsets_1: vec4<f32> = unpack_u32(input.offsets.xy);
let offsets_2: vec4<f32> = unpack_u32(input.offsets.zw);
var offsets = array<f32, 8>(
offsets_1.x,
offsets_1.y,
offsets_1.z,
offsets_1.w,
offsets_2.x,
offsets_2.y,
offsets_2.z,
offsets_2.w,
);
var last_index = 7;
for (var i: i32 = 0; i <= 7; i++) {
if (offsets[i] >= 1.0) {
last_index = i;
break;
}
}
return gradient(input.raw_position, input.direction, colors, offsets, last_index);
}
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