| |
| /* |
| * When calling makeShader, pass |
| * radius_scale 0.5 |
| * center x, y |
| * color0 r, g, b, a |
| * color1 r, g, b, a |
| */ |
| function MakeSpiralShaderEffect(CanvasKit) { |
| const _spiralSkSL = ` |
| uniform float rad_scale; |
| uniform float2 in_center; |
| uniform float4 in_colors0; |
| uniform float4 in_colors1; |
| |
| half4 main(float2 p) { |
| float2 pp = p - in_center; |
| float radius = sqrt(dot(pp, pp)); |
| radius = sqrt(radius); |
| float angle = atan(pp.y / pp.x); |
| float t = (angle + 3.1415926/2) / (3.1415926); |
| t += radius * rad_scale; |
| t = fract(t); |
| return half4(mix(in_colors0, in_colors1, t)); |
| }`; |
| |
| return CanvasKit.RuntimeEffect.Make(_spiralSkSL); |
| } |
