33 lines
992 B
Metal
33 lines
992 B
Metal
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#include <metal_stdlib>
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using namespace metal;
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struct Particle {
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float2 center;
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float radius;
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};
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float distanceToParticle(float2 point, Particle p) {
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return length(point - p.center) - p.radius;
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}
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kernel void compute(texture2d<float, access::write> output [[texture(0)]],
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constant float &time [[buffer(0)]],
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uint2 gid [[thread_position_in_grid]]) {
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float width = output.get_width();
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float height = output.get_height();
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float2 uv = float2(gid) / float2(width, height);
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float aspect = width / height;
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uv.x *= aspect;
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float2 center = float2(aspect / 2, time);
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float radius = 0.05;
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float stop = 1 - radius;
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if (time >= stop) { center.y = stop; }
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else center.y = time;
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Particle p = Particle{center, radius};
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float distance = distanceToParticle(uv, p);
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float4 color = float4(1, 0.7, 0, 1);
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if (distance > 0) { color = float4(0.2, 0.5, 0.7, 1); }
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output.write(float4(color), gid);
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}
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