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ParticleCompute.hlsl
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ParticleCompute.hlsl
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#include "ParticleCommon.hlsli"
#include "TileConstants.h"
float GetRandomNumber(inout uint seed)
{
seed = (seed ^ 61) ^ (seed >> 16);
seed *= 9;
seed = seed ^ (seed >> 4);
seed *= 0x27d4eb2d;
seed = seed ^ (seed >> 15);
// Generate a random float in [0, 1)...
return float(seed) * (1.0 / 4294967296.0);
}
void GenerateNewParticle(uint rndSeed, out Particle particle)
{
particle.pos = float2(0, 0);
particle.timeLeft = -1.0f;
particle.velocity = float2(GetRandomNumber(rndSeed) * 2.0f - 1.0f, GetRandomNumber(rndSeed) * 2.0f - 1.0f);
particle.color = float4(GetRandomNumber(rndSeed), GetRandomNumber(rndSeed), GetRandomNumber(rndSeed), 0.02f);
//particle.color = saturate(particle.color * 3);
particle.scale = float2(0.01, 0.01);
#ifdef DISABLE_ROTATION
particle.rotate = 0;
#else
particle.rotate = GetRandomNumber(rndSeed);
#endif
}
[numthreads(1000, 1, 1)]
void CSGenerate(uint3 Gid : SV_GroupID, uint3 DTid : SV_DispatchThreadID, uint3 GTid : SV_GroupThreadID, uint GI : SV_GroupIndex)
{
if (DTid.x < g_nEmitCount)
{
uint nPrevParticleCount = g_deadList.IncrementCounter();
if (nPrevParticleCount < g_nParticleBufferSize)
{
//There's still space left for a new particle. Mark one for creation
uint nLastParticle = g_deadList[g_nParticleBufferSize - nPrevParticleCount];
g_deadList[g_nParticleBufferSize - nPrevParticleCount] = 9;
Particle newParticle;
GenerateNewParticle(g_nRandomSeed + DTid.x, newParticle);
g_particlePositionsOut[nLastParticle] = newParticle.pos;
g_particleScalesOut[nLastParticle] = newParticle.scale;
g_particleVelocitiesOut[nLastParticle] = newParticle.velocity;
g_particleRotationsOut[nLastParticle] = newParticle.rotate;
g_particleLifetimesOut[nLastParticle] = newParticle.timeLeft;
g_particleColorsOut[nLastParticle] = newParticle.color;
}
else
{
uint nTmp;
InterlockedMin(g_deadList[0], g_nParticleBufferSize, nTmp);
}
}
}
[numthreads(1000, 1, 1)]
void CSUpdate(uint3 Gid : SV_GroupID, uint3 DTid : SV_DispatchThreadID, uint3 GTid : SV_GroupThreadID, uint GI : SV_GroupIndex)
{
if (DTid.x >= g_nParticleBufferSize)
{
return;
}
Particle particle;
particle.pos = g_particlePositions[DTid.x];
particle.scale = g_particleScales[DTid.x];
particle.velocity = g_particleVelocities[DTid.x];
particle.rotate = g_particleRotations[DTid.x];
particle.timeLeft = g_particleLifetimes[DTid.x];
particle.color = g_particleColors[DTid.x];
if (particle.timeLeft == 0.0)
{
g_particlePositionsOut[DTid.x] = particle.pos;
g_particleScalesOut[DTid.x] = particle.scale;
g_particleVelocitiesOut[DTid.x] = particle.velocity;
g_particleRotationsOut[DTid.x] = particle.rotate;
g_particleLifetimesOut[DTid.x] = particle.timeLeft;
g_particleColorsOut[DTid.x] = particle.color;
return;
}
// Negative time means it lives forever (sounds like a bad idea tbh)
if (particle.timeLeft > 0.0)
{
particle.timeLeft -= g_fElapsedTime;
particle.timeLeft = max(0.0, particle.timeLeft);
}
particle.pos += particle.velocity * g_fElapsedTime;
#ifndef DISABLE_ROTATION
particle.rotate += g_fElapsedTime * 0.5f;
#endif
if (particle.pos.x < -1)
{
particle.pos.x = -1;
particle.velocity.x *= -1;
}
else if (particle.pos.x > 1)
{
particle.pos.x = 1;
particle.velocity.x *= -1;
}
if (particle.pos.y < -1)
{
particle.pos.y = -1;
particle.velocity.y *= -1;
}
else if (particle.pos.y > 1)
{
particle.pos.y = 1;
particle.velocity.y *= -1;
}
if (particle.timeLeft == 0)
{
int nNewParticleCount = g_deadList.DecrementCounter();
g_deadList[g_nParticleBufferSize - nNewParticleCount] = DTid.x;
}
g_particlePositionsOut[DTid.x] = particle.pos;
g_particleScalesOut[DTid.x] = particle.scale;
g_particleVelocitiesOut[DTid.x] = particle.velocity;
g_particleRotationsOut[DTid.x] = particle.rotate;
g_particleLifetimesOut[DTid.x] = particle.timeLeft;
g_particleColorsOut[DTid.x] = particle.color;
}
[numthreads(1000, 1, 1)]
void CSDestroy(uint3 Gid : SV_GroupID, uint3 DTid : SV_DispatchThreadID, uint3 GTid : SV_GroupThreadID, uint GI : SV_GroupIndex)
{
}