| 1 | // Instanced SDF primitives: rects, rounded rects, borders and dots. Output is premultiplied. |
| 2 | |
| 3 | struct Globals { |
| 4 | viewport: vec2<f32>, |
| 5 | _pad: vec2<f32>, |
| 6 | }; |
| 7 | |
| 8 | @group(0) @binding(0) var<uniform> g: Globals; |
| 9 | |
| 10 | struct Instance { |
| 11 | @location(0) rect: vec4<f32>, // x, y, w, h in physical px |
| 12 | @location(1) color: vec4<f32>, // linear, straight alpha |
| 13 | @location(2) border_color: vec4<f32>, |
| 14 | @location(3) params: vec4<f32>, // x: corner radius, y: border width |
| 15 | }; |
| 16 | |
| 17 | struct VOut { |
| 18 | @builtin(position) pos: vec4<f32>, |
| 19 | @location(0) local: vec2<f32>, |
| 20 | @location(1) half: vec2<f32>, |
| 21 | @location(2) color: vec4<f32>, |
| 22 | @location(3) border_color: vec4<f32>, |
| 23 | @location(4) params: vec4<f32>, |
| 24 | }; |
| 25 | |
| 26 | @vertex |
| 27 | fn vs(@builtin(vertex_index) i: u32, inst: Instance) -> VOut { |
| 28 | var corners = array<vec2<f32>, 6>( |
| 29 | vec2(-1.0, -1.0), vec2(1.0, -1.0), vec2(-1.0, 1.0), |
| 30 | vec2(-1.0, 1.0), vec2(1.0, -1.0), vec2(1.0, 1.0), |
| 31 | ); |
| 32 | let half = inst.rect.zw * 0.5; |
| 33 | // Pad by a pixel so the anti-aliased edge isn't clipped. |
| 34 | let local = corners[i] * (half + 1.0); |
| 35 | let p = inst.rect.xy + half + local; |
| 36 | var out: VOut; |
| 37 | out.pos = vec4(p.x / g.viewport.x * 2.0 - 1.0, 1.0 - p.y / g.viewport.y * 2.0, 0.0, 1.0); |
| 38 | out.local = local; |
| 39 | out.half = half; |
| 40 | out.color = inst.color; |
| 41 | out.border_color = inst.border_color; |
| 42 | out.params = inst.params; |
| 43 | return out; |
| 44 | } |
| 45 | |
| 46 | @fragment |
| 47 | fn fs(in: VOut) -> @location(0) vec4<f32> { |
| 48 | let r = min(in.params.x, min(in.half.x, in.half.y)); |
| 49 | let q = abs(in.local) - in.half + r; |
| 50 | let d = length(max(q, vec2(0.0))) + min(max(q.x, q.y), 0.0) - r; |
| 51 | let coverage = clamp(0.5 - d, 0.0, 1.0); |
| 52 | let fill = vec4(in.color.rgb * in.color.a, in.color.a); |
| 53 | var c = fill; |
| 54 | let bw = in.params.y; |
| 55 | if bw > 0.0 { |
| 56 | let border = vec4(in.border_color.rgb * in.border_color.a, in.border_color.a); |
| 57 | c = mix(border, fill, clamp(0.5 - (d + bw), 0.0, 1.0)); |
| 58 | } |
| 59 | return c * coverage; |
| 60 | } |