// This code was originally retired from iced-rs, which is licensed
// under MIT license https://github.com/iced-rs/iced/blob/master/LICENSE
// The code has suffered changes to fit on Sugarloaf architecture.
struct Globals {
transform: mat4x4<f32>,
scale: f32,
}
@group(0) @binding(0) var<uniform> globals: Globals;
fn distance_alg(
frag_coord: vec2<f32>,
position: vec2<f32>,
size: vec2<f32>,
radius: f32
) -> f32 {
var inner_half_size: vec2<f32> = (size - vec2<f32>(radius, radius) * 2.0) / 2.0;
var top_left: vec2<f32> = position + vec2<f32>(radius, radius);
return rounded_box_sdf(frag_coord - top_left - inner_half_size, inner_half_size, 0.0);
}
// Given a vector from a point to the center of a rounded rectangle of the given `size` and
// border `radius`, determines the point's distance from the nearest edge of the rounded rectangle
fn rounded_box_sdf(to_center: vec2<f32>, size: vec2<f32>, radius: f32) -> f32 {
return length(max(abs(to_center) - size + vec2<f32>(radius, radius), vec2<f32>(0.0, 0.0))) - radius;
}
// Based on the fragment position and the center of the quad, select one of the 4 radii.
// Order matches CSS border radius attribute:
// radii.x = top-left, radii.y = top-right, radii.z = bottom-right, radii.w = bottom-left
fn select_border_radius(radii: vec4<f32>, position: vec2<f32>, center: vec2<f32>) -> f32 {
var rx = radii.x;
var ry = radii.y;
rx = select(radii.x, radii.y, position.x > center.x);
ry = select(radii.w, radii.z, position.x > center.x);
rx = select(rx, ry, position.y > center.y);
return rx;
}
// Compute the normalized quad coordinates based on the vertex index.
fn vertex_position(vertex_index: u32) -> vec2<f32> {
// #: 0 1 2 3 4 5
// x: 1 1 0 0 0 1
// y: 1 0 0 0 1 1
return vec2<f32>((vec2(1u, 2u) + vertex_index) % vec2(6u) < vec2(3u));
}
struct SolidVertexInput {
@builtin(vertex_index) vertex_index: u32,
@location(0) color: vec4<f32>,
@location(1) pos: vec2<f32>,
@location(2) scale: vec2<f32>,
@location(3) border_color: vec4<f32>,
@location(4) border_radius: vec4<f32>,
@location(5) border_width: f32,
@location(6) shadow_color: vec4<f32>,
@location(7) shadow_offset: vec2<f32>,
@location(8) shadow_blur_radius: f32,
}
struct SolidVertexOutput {
@builtin(position) position: vec4<f32>,
@location(0) color: vec4<f32>,
@location(1) border_color: vec4<f32>,
@location(2) pos: vec2<f32>,
@location(3) scale: vec2<f32>,
@location(4) border_radius: vec4<f32>,
@location(5) border_width: f32,
@location(6) shadow_color: vec4<f32>,
@location(7) shadow_offset: vec2<f32>,
@location(8) shadow_blur_radius: f32,
}
@vertex
fn composed_quad_vs_main(input: SolidVertexInput) -> SolidVertexOutput {
var out: SolidVertexOutput;
var pos: vec2<f32> = (input.pos + min(input.shadow_offset, vec2<f32>(0.0, 0.0)) - input.shadow_blur_radius) * globals.scale;
var scale: vec2<f32> = (input.scale + vec2<f32>(abs(input.shadow_offset.x), abs(input.shadow_offset.y)) + input.shadow_blur_radius * 2.0) * globals.scale;
var snap: vec2<f32> = vec2<f32>(0.0, 0.0);
if input.scale.x == 1.0 {
snap.x = round(pos.x) - pos.x;
}
if input.scale.y == 1.0 {
snap.y = round(pos.y) - pos.y;
}
var min_border_radius = min(input.scale.x, input.scale.y) * 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) + snap, 0.0, 1.0)
);
out.position = globals.transform * transform * vec4<f32>(vertex_position(input.vertex_index), 0.0, 1.0);
out.color = input.color;
out.border_color = input.border_color;
out.pos = input.pos * globals.scale + snap;
out.scale = input.scale * globals.scale;
out.border_radius = border_radius * globals.scale;
out.border_width = input.border_width * globals.scale;
out.shadow_color = input.shadow_color;
out.shadow_offset = input.shadow_offset * globals.scale;
out.shadow_blur_radius = input.shadow_blur_radius * globals.scale;
return out;
}
@fragment
fn composed_quad_fs_main(
input: SolidVertexOutput
) -> @location(0) vec4<f32> {
var mixed_color: vec4<f32> = input.color;
var border_radius = select_border_radius(
input.border_radius,
input.position.xy,
(input.pos + input.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,
input.pos + vec2<f32>(input.border_width, input.border_width),
input.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(input.color, input.border_color, vec4<f32>(border_mix, border_mix, border_mix, border_mix));
}
var dist: f32 = distance_alg(
vec2<f32>(input.position.x, input.position.y),
input.pos,
input.scale,
border_radius
);
var radius_alpha: f32 = 1.0 - smoothstep(
max(border_radius - 0.5, 0.0),
border_radius + 0.5,
dist
);
let quad_color = vec4<f32>(mixed_color.x, mixed_color.y, mixed_color.z, mixed_color.w * radius_alpha);
if input.shadow_color.a > 0.0 {
let shadow_radius = select_border_radius(
input.border_radius,
input.position.xy - input.shadow_offset,
(input.pos + input.scale * 0.5).xy
);
let shadow_distance = max(rounded_box_sdf(input.position.xy - input.pos - input.shadow_offset - (input.scale / 2.0), input.scale / 2.0, shadow_radius), 0.);
let shadow_alpha = 1.0 - smoothstep(-input.shadow_blur_radius, input.shadow_blur_radius, shadow_distance);
let shadow_color = input.shadow_color;
let base_color = mix(
vec4<f32>(shadow_color.x, shadow_color.y, shadow_color.z, 0.0),
quad_color,
quad_color.a
);
return mix(base_color, shadow_color, (1.0 - radius_alpha) * shadow_alpha);
} else {
return quad_color;
}
}