Vendor dependencies for 0.3.0 release

vendor/metal/examples/mps/shaders.metal

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+//
+//  Created by Sergey Reznik on 9/15/18.
+//  Copyright © 2018 Serhii Rieznik. All rights reserved.
+//
+
+// Taken from https://github.com/sergeyreznik/metal-ray-tracer/tree/part-1/source/Shaders
+// MIT License https://github.com/sergeyreznik/metal-ray-tracer/blob/part-1/LICENSE
+
+#include <MetalPerformanceShaders/MetalPerformanceShaders.h>
+
+using Ray = MPSRayOriginMinDistanceDirectionMaxDistance;
+using Intersection = MPSIntersectionDistancePrimitiveIndexCoordinates;
+
+kernel void generateRays(
+    device Ray* rays [[buffer(0)]],
+    uint2 coordinates [[thread_position_in_grid]],
+    uint2 size [[threads_per_grid]])
+{
+    float2 uv = float2(coordinates) / float2(size - 1);
+
+    uint rayIndex = coordinates.x + coordinates.y * size.x;
+    rays[rayIndex].origin = MPSPackedFloat3(uv.x, uv.y, -1.0);
+    rays[rayIndex].direction = MPSPackedFloat3(0.0, 0.0, 1.0);
+    rays[rayIndex].minDistance = 0.0f;
+    rays[rayIndex].maxDistance = 2.0f;
+}