143 lines
2.9 KiB
Plaintext
143 lines
2.9 KiB
Plaintext
#pragma kernel InitDust
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#pragma kernel UpdateDust
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struct Particle {
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float3 position;
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float3 velocity;
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uint enabled;
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uint airborne;
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};
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RWStructuredBuffer<float4> positions;
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RWStructuredBuffer<Particle> particles;
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RWStructuredBuffer<uint> numParticlesConsumed;
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RWStructuredBuffer<uint> freeParticles;
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uint numParticles;
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uint particlesToInitialize;
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float3 particleInitPos;
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float3 initialVelocity;
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float deltaTime;
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float3 mop1Pos;
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float3 mop2Pos;
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float CleanRadius;
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float size;
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float gravity;
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float particleVel;
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// Hash function www.cs.ubc.ca/~rbridson/docs/schechter-sca08-turbulence.pdf
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uint hash(uint state)
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{
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state ^= 2747636419u;
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state *= 2654435769u;
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state ^= state >> 16;
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state *= 2654435769u;
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state ^= state >> 16;
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state *= 2654435769u;
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return state;
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}
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float scaleToRange01(uint state)
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{
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return state / 4294967295.0;
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}
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[numthreads(64,1,1)]
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void InitDust (uint3 id : SV_DispatchThreadID)
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{
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if (id.x > particlesToInitialize) {
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return;
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}
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uint i = freeParticles[id.x];
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// if (particles[id.x].enabled != 0 || numParticlesInitialized[0] >= numParticles ) {
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while (i <= numParticles) {
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if (i == numParticles) {
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return;
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}
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if (particles[i].enabled == 0) {
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break;
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}
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i++;
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}
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uint randState = i;
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randState = hash(randState);
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float dv = scaleToRange01(randState) * 3.14f*2.0f;
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float dx = cos(dv);
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float dy = sin(dv);
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randState = hash(randState);
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float dz = scaleToRange01(randState);
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float3 nvel = float3(dx, dy, dz) * particleVel;
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randState = hash(randState);
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nvel.xy *= scaleToRange01(randState);
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randState = hash(randState);
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float3 iv = initialVelocity * scaleToRange01(randState);
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particles[i].velocity = iv + nvel;
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particles[i].position = particleInitPos;
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particles[i].position.z = 0.01;
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particles[i].enabled = 1;
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particles[i].airborne = 1;
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positions[i] = float4(particles[i].position, 1 * size);
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// particles[i].position = positions[i].xyz;
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// InterlockedAdd(numParticlesInitialized[0],1);
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}
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[numthreads(64,1,1)]
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void UpdateDust (uint3 id : SV_DispatchThreadID)
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{
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uint i = id.x;
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if (particles[i].enabled == 0) {
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return;
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}
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float3 pos = particles[i].position;
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if (particles[i].position.z > 0) {
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particles[i].velocity.z -= gravity * deltaTime;
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} else {
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particles[i].velocity -= particles[i].velocity * deltaTime * 15;
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if (particles[i].airborne == 1) {
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particles[i].airborne = 0;
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// Increase splattered particles
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InterlockedAdd(numParticlesConsumed[1],1);
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}
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float3 offset1 = mop1Pos - pos;
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offset1.z = 0;
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float dist1 = dot(offset1, offset1);
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float3 offset2 = mop2Pos - pos;
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offset2.z = 0;
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float dist2 = dot(offset2, offset2);
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float dist = min(dist1, dist2);
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if (dist < CleanRadius) {
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particles[i].enabled = 0;
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// Increase cleaned particles
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InterlockedAdd(numParticlesConsumed[0],1);
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}
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}
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particles[i].position += particles[i].velocity * deltaTime;
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positions[i] = float4(particles[i].position, particles[i].enabled * size);
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}
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