Add a Uniform object for RandomAlgorithm

This object contains several random numbers for the GPU kernel to use when generating random points. This isn't right yet (there are still patterns in the generated data) but it's time to move on...

Terrain2/ShaderTypes.h

@@ -53,5 +53,15 @@ typedef struct
     matrix_float4x4 modelViewMatrix;
 } Uniforms;
 
+#define kRandomAlgorithmUniforms_RandomCount (41)
+
+typedef struct {
+    uint randoms[kRandomAlgorithmUniforms_RandomCount];
+} RandomAlgorithmUniforms;
+
+#ifndef __METAL_VERSION__
+extern void RandomAlgorithmUniforms_refreshRandoms(RandomAlgorithmUniforms *uniforms);
+#endif
+
 #endif /* ShaderTypes_h */