#pragma kernel GenerateWhiteNoise

#define rnd(seed, constant)  wang_rnd(seed + triple32(_RandSeed) * constant)

uint triple32(uint x)
{
	x ^= x >> 17;
	x *= 0xed5ad4bbU;
	x ^= x >> 11;
	x *= 0xac4c1b51U;
	x ^= x >> 15;
	x *= 0x31848babU;
	x ^= x >> 14;
	return x;
}

float wang_rnd(uint seed)
{
	uint rndint = triple32(seed);
	return ((float)rndint) / float(0xFFFFFFFF);   // 0xFFFFFFFF is max unsigned integer in hexa decimal
}

// Create a RenderTexture with enableRandomWrite flag and set it with cs.SetTexture
RWTexture2D<float4> _WhiteNoise;
uint                _RandSeed;

#define Dimension 512

[numthreads(8, 8, 1)]
void GenerateWhiteNoise(uint3 id : SV_DispatchThreadID)
{
	uint  pixelID      = id.x + id.y * Dimension;
	float randX        = rnd(pixelID, 1);
	float randY        = rnd(pixelID, 861);
	_WhiteNoise[id.xy] = float4(randX, randY, 0.0, 0.0);
}