31 lines
1.1 KiB
Metal
Executable File
31 lines
1.1 KiB
Metal
Executable File
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#include <metal_stdlib>
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using namespace metal;
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kernel void compute(texture2d<float, access::write> output [[texture(0)]],
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texture2d<float, access::sample> input [[texture(1)]],
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constant float &timer [[buffer(0)]],
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uint2 gid [[thread_position_in_grid]])
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{
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int width = input.get_width();
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int height = input.get_height();
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float2 uv = float2(gid) / float2(width, height);
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uv = uv * 2.0 - 0.5;
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uv = uv * 4;
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float radius = 1;
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float distance = length(uv) - radius;
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constexpr sampler textureSampler(coord::normalized,
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address::repeat,
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min_filter::linear,
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mag_filter::linear,
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mip_filter::linear);
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float3 norm = float3(uv, sqrt(1.0 - dot(uv, uv)));
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float pi = 3.14;
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float s = atan2( norm.z, norm.x ) / (2 * pi);
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float t = asin( norm.y ) / (2 * pi);
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t += 0.5;
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float4 color = input.sample(textureSampler, float2(s + timer * 0.1, t));
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output.write(distance < 0 ? color : float4(0), gid);
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}
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