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