58 lines
1.4 KiB
Metal
58 lines
1.4 KiB
Metal
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#include <metal_stdlib>
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using namespace metal;
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struct Sphere {
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float3 center;
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float radius;
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Sphere(float3 c, float r) {
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center = c;
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radius = r;
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}
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};
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struct Ray {
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float3 origin;
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float3 direction;
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Ray(float3 o, float3 d) {
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origin = o;
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direction = d;
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}
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};
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float distanceToSphere(Ray r, Sphere s) {
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return length(r.origin - s.center) - s.radius;
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}
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float distanceToScene(Ray r, Sphere s, float range) {
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Ray repeatRay = r;
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repeatRay.origin = fmod(r.origin, range);
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return distanceToSphere(repeatRay, s);
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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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int width = output.get_width();
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int height = output.get_height();
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float2 uv = float2(gid) / float2(width, height);
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uv = uv * 2.0 - 1.0;
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float3 color = float3(0.0);
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// raymarching
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Sphere s = Sphere(float3(1.0), 0.5);
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float3 cameraPosition = float3(1000.0 + sin(time) + 1.0, 1000.0 + cos(time) + 1.0, time);
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Ray ray = Ray(cameraPosition, normalize(float3(uv, 1.0)));
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for (int i = 0.0; i < 100.0; i++) {
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float distance = distanceToScene(ray, s, 2.0);
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if (distance < 0.001) {
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color = float3(1.0);
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break;
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}
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ray.origin += ray.direction * distance;
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}
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float3 positionToCamera = ray.origin - cameraPosition;
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output.write(float4(color * abs(positionToCamera / 10.0), 1.0), gid);
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}
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