Porta tots els shaders a Vulkan i Metal

shaders/shader_art_coding_introduction/shader_art_coding_introduction.frag.msl

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+#include <metal_stdlib>
+using namespace metal;
+
+// Shader Art Coding Introduction — kishimisu
+// MSL port of shader_art_coding_introduction.vk.glsl.
+
+struct ShadertoyUBO {
+    float iTime;
+    float2 iResolution;
+};
+
+struct PassthroughVOut {
+    float4 pos [[position]];
+    float2 uv;
+};
+
+static float3 palette(float t) {
+    float3 a = float3(0.5, 0.5, 0.5);
+    float3 b = float3(0.5, 0.5, 0.5);
+    float3 c = float3(1.0, 1.0, 1.0);
+    float3 d = float3(0.263, 0.416, 0.557);
+    return a + b * cos(6.28318 * (c * t * d));
+}
+
+fragment float4 shader_art_coding_introduction_fs(PassthroughVOut in [[stage_in]],
+                                                   constant ShadertoyUBO& U [[buffer(0)]]) {
+    float2 fragCoord = in.uv * U.iResolution;
+    float2 uv = (fragCoord * 2.0 - U.iResolution) / U.iResolution.y;
+    float2 uv0 = uv;
+    float3 finalColor = float3(0.0);
+
+    for (float i = 0.0; i < 4.0; i++) {
+        uv = fract(uv * 1.5) - 0.5;
+
+        float d = length(uv) * exp(-length(uv0));
+
+        float3 col = palette(length(uv0) + i * 0.4 + U.iTime * 0.4);
+
+        d = sin(d * 8.0 + U.iTime) / 8.0;
+        d = abs(d);
+        d = pow(0.01 / d, 1.2);
+
+        finalColor += col * d;
+    }
+
+    return float4(finalColor, 1.0);
+}