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Move PRNG to Random.hh

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This commit is contained in:
Eryn Wells 2018-11-22 07:58:36 -07:00
parent 18f8c141af
commit cd9bf6c1a9
3 changed files with 48 additions and 32 deletions
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2
Terrain.xcodeproj/project.pbxproj
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@ -51,6 +51,7 @@
C018AD3F21978E690094BE3C /* Queue.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Queue.swift; sourceTree = "<group>"; };
C018AD412197907B0094BE3C /* QueueTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = QueueTests.swift; sourceTree = "<group>"; };
C028A6A121A46796005DE718 /* Math.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Math.swift; sourceTree = "<group>"; };
C04A27A421A6FB4B00FCABFB /* Random.hh */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Random.hh; sourceTree = "<group>"; };
C08C589F218F46F000EAFC2D /* Algorithms.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Algorithms.swift; sourceTree = "<group>"; };
C08C58A1218F474E00EAFC2D /* TerrainAlgorithms.metal */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.metal; path = TerrainAlgorithms.metal; sourceTree = "<group>"; };
C0C15A8A218DDD85007494E2 /* Terrain.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Terrain.app; sourceTree = BUILT_PRODUCTS_DIR; };
@ -121,6 +122,7 @@
isa = PBXGroup;
children = (
C0C15ABA218E2A90007494E2 /* ShaderTypes.h */,
C04A27A421A6FB4B00FCABFB /* Random.hh */,
C0C15AB8218E2A90007494E2 /* Shaders.metal */,
C08C58A1218F474E00EAFC2D /* TerrainAlgorithms.metal */,
);

44
Terrain2/Shaders/Random.hh Normal file
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@ -0,0 +1,44 @@
//
// Random.hh
// Terrain
//
// Created by Eryn Wells on 11/22/18.
// Copyright © 2018 Eryn Wells. All rights reserved.
//
#ifndef Random_hh
#define Random_hh
/// A pseudo-random number generator providing several algorithms.
/// - http://reedbeta.com/blog/quick-and-easy-gpu-random-numbers-in-d3d11/
struct PRNG {
PRNG(uint seed) : mSeed(wangHash(seed)) { }
/// Generate a random unsigned integer using a linear congruential generator.
uint lcg() {
mSeed = 1664525 * mSeed + 1013904223;
return mSeed;
}
/// Generate a random unsigned integer using the Xorshift algorithm from George Marsaglia's paper.
uint xorShift() {
mSeed ^= (mSeed << 13);
mSeed ^= (mSeed >> 17);
mSeed ^= (mSeed << 5);
return mSeed;
}
uint wangHash(uint seed) {
seed = (seed ^ 61) ^ (seed >> 16);
seed *= 9;
seed = seed ^ (seed >> 4);
seed *= 0x27d4eb2d;
seed = seed ^ (seed >> 15);
return seed;
}
private:
uint mSeed;
};
#endif /* Random_hh */

34
Terrain2/Shaders/TerrainAlgorithms.metal
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@ -9,40 +9,10 @@
#include <metal_stdlib>
#include <metal_types>
#include "ShaderTypes.h"
#include "Random.hh"
using namespace metal;
/// A pseudo-random number generator providing several algorithms.
/// - http://reedbeta.com/blog/quick-and-easy-gpu-random-numbers-in-d3d11/
struct PRNG {
PRNG(uint seed) : mSeed(wangHash(seed)) { }
/// Generate a random unsigned integer using a linear congruential generator.
uint lcg() {
mSeed = 1664525 * mSeed + 1013904223;
return mSeed;
}
/// Generate a random unsigned integer using the Xorshift algorithm from George Marsaglia's paper.
uint xorShift() {
mSeed ^= (mSeed << 13);
mSeed ^= (mSeed >> 17);
mSeed ^= (mSeed << 5);
return mSeed;
}
uint wangHash(uint seed) {
seed = (seed ^ 61) ^ (seed >> 16);
seed *= 9;
seed = seed ^ (seed >> 4);
seed *= 0x27d4eb2d;
seed = seed ^ (seed >> 15);
return seed;
}
private:
uint mSeed;
};
kernel void updateGeometryHeights(texture2d<float> texture [[texture(GeneratorTextureIndexIn)]],
constant float2 *texCoords [[buffer(GeneratorBufferIndexTexCoords)]],
constant Uniforms &uniforms [[buffer(GeneratorBufferIndexUniforms)]],