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struct GradientVertexInput {
@location(0) v_pos: vec2<f32>,
@location(1) @interpolate(flat) colors_1: vec4<u32>,
@location(2) @interpolate(flat) colors_2: vec4<u32>,
@location(3) @interpolate(flat) colors_3: vec4<u32>,
@location(4) @interpolate(flat) colors_4: vec4<u32>,
@location(5) @interpolate(flat) offsets: vec4<u32>,
@location(6) direction: vec4<f32>,
@location(7) position_and_scale: vec4<f32>,
@location(8) border_color: vec4<f32>,
@location(9) border_radius: vec4<f32>,
@location(10) border_width: f32,
}
struct GradientVertexOutput {
@builtin(position) position: vec4<f32>,
@location(1) @interpolate(flat) colors_1: vec4<u32>,
@location(2) @interpolate(flat) colors_2: vec4<u32>,
@location(3) @interpolate(flat) colors_3: vec4<u32>,
@location(4) @interpolate(flat) colors_4: vec4<u32>,
@location(5) @interpolate(flat) offsets: vec4<u32>,
@location(6) direction: vec4<f32>,
@location(7) position_and_scale: vec4<f32>,
@location(8) border_color: vec4<f32>,
@location(9) border_radius: vec4<f32>,
@location(10) border_width: f32,
}
@vertex
fn gradient_vs_main(input: GradientVertexInput) -> GradientVertexOutput {
var out: GradientVertexOutput;
var pos: vec2<f32> = input.position_and_scale.xy * globals.scale;
var scale: vec2<f32> = input.position_and_scale.zw * globals.scale;
var min_border_radius = min(input.position_and_scale.z, input.position_and_scale.w) * 0.5;
var border_radius: vec4<f32> = vec4<f32>(
min(input.border_radius.x, min_border_radius),
min(input.border_radius.y, min_border_radius),
min(input.border_radius.z, min_border_radius),
min(input.border_radius.w, min_border_radius)
);
var transform: mat4x4<f32> = mat4x4<f32>(
vec4<f32>(scale.x + 1.0, 0.0, 0.0, 0.0),
vec4<f32>(0.0, scale.y + 1.0, 0.0, 0.0),
vec4<f32>(0.0, 0.0, 1.0, 0.0),
vec4<f32>(pos - vec2<f32>(0.5, 0.5), 0.0, 1.0)
);
out.position = globals.transform * transform * vec4<f32>(input.v_pos, 0.0, 1.0);
out.colors_1 = input.colors_1;
out.colors_2 = input.colors_2;
out.colors_3 = input.colors_3;
out.colors_4 = input.colors_4;
out.offsets = input.offsets;
out.direction = input.direction * globals.scale;
out.position_and_scale = vec4<f32>(pos, scale);
out.border_color = input.border_color;
out.border_radius = border_radius * globals.scale;
out.border_width = input.border_width * globals.scale;
return out;
}
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) {
let from_ = colors_arr[i];
let to_ = colors_arr[i+1];
let factor = smoothstep(curr_offset, next_offset, coord_offset);
color = interpolate_color(from_, to_, factor);
}
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,
);
//TODO could just pass this in to the shader but is probably more performant to just check it here
var last_index = 7;
for (var i: i32 = 0; i <= 7; i++) {
if (offsets[i] > 1.0) {
last_index = i - 1;
break;
}
}
var mixed_color: vec4<f32> = gradient(input.position.xy, input.direction, colors, offsets, last_index);
let pos = input.position_and_scale.xy;
let scale = input.position_and_scale.zw;
var border_radius = select_border_radius(
input.border_radius,
input.position.xy,
(pos + scale * 0.5).xy
);
if (input.border_width > 0.0) {
var internal_border: f32 = max(border_radius - input.border_width, 0.0);
var internal_distance: f32 = distance_alg(
input.position.xy,
pos + vec2<f32>(input.border_width, input.border_width),
scale - vec2<f32>(input.border_width * 2.0, input.border_width * 2.0),
internal_border
);
var border_mix: f32 = smoothstep(
max(internal_border - 0.5, 0.0),
internal_border + 0.5,
internal_distance
);
mixed_color = mix(mixed_color, input.border_color, vec4<f32>(border_mix, border_mix, border_mix, border_mix));
}
var dist: f32 = distance_alg(
input.position.xy,
pos,
scale,
border_radius
);
var radius_alpha: f32 = 1.0 - smoothstep(
max(border_radius - 0.5, 0.0),
border_radius + 0.5,
dist);
return vec4<f32>(mixed_color.x, mixed_color.y, mixed_color.z, mixed_color.w * radius_alpha);
}
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);
}
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