void Update()
{
#if true
_particles.Prepare(_kernelUpdate);
compute.SetFloat(PROP_TIME_DELTA, Time.deltaTime);
compute.Dispatch(_kernelUpdate, _particles.NGroupsX, _particles.NGroupsY, 1);
if (splash)
{
var mousePos = Input.mousePosition;
mousePos.z = 10f;
var ray = Camera.main.ScreenPointToRay(mousePos);
var localDir = transform.InverseTransformDirection(ray.direction);
var localPos = transform.InverseTransformPoint(ray.origin);
var particles = new GPUParticle[] { new GPUParticle()
{
life = 5, velocity = speed * localDir, position = localPos
} };
_particles.Emit(particles);
}
#else
if (splash)
{
var particles = new GPUParticle[] {
new GPUParticle()
{
life = 5, position = 10f * Random.insideUnitSphere
}
};
_particles.Emit(particles);
}
#endif
}
void Emit()
{
if (particle == null)
{
particle = GetComponent <GPUParticle>();
}
particle.EmitWithTexture(posTex, normTex, colTex);
}
// Update is called once per frame
void Update()
{
particleMaterial.SetFloat("Brightness", brightness);
frameTime -= Time.deltaTime;
if (frameTime > 0)
{
return;
}
frameTime = 1.0f / FrameRate;
int count = particlesToRender.GetParticles(particles);
if (count != 0)
{
ComputeBuffer particleBuffer = new ComputeBuffer(count, 8 * sizeof(float));
GPUParticle[] gpuParticles = new GPUParticle[count];
for (int i = 0; i < count; i++)
{
gpuParticles[i].pos = particles[i].position;
gpuParticles[i].col = particles[i].GetCurrentColor(particlesToRender);
}
particleBuffer.SetData(gpuParticles);
SimulateShader.SetBuffer(generatePointsKernel, "Particles", particleBuffer);
var mat = transform.localToWorldMatrix.transpose;
SimulateShader.SetFloats("Object2World", new float[] {
mat.m00, mat.m01, mat.m02, mat.m03,
mat.m10, mat.m11, mat.m12, mat.m13,
mat.m20, mat.m21, mat.m22, mat.m23,
mat.m30, mat.m31, mat.m32, mat.m33,
});
SimulateShader.SetInt("Resolution", Resolution);
pointBuffer.SetCounterValue(0);
SimulateShader.SetBuffer(generatePointsKernel, "PointBufferOutput", pointBuffer);
SimulateShader.Dispatch(generatePointsKernel, Resolution / 8, Resolution / 8, Resolution / 8);
particleBuffer.Release();
OnWillRenderObject();
}
}
void InitGPUParticleSystem()
{
if (!particleComputeShader || !particleMat)
{
return;
}
ParticleSize = Marshal.SizeOf(typeof(GPUParticle));
//找到更新函数
gpuUpdateKernelIndex = particleComputeShader.FindKernel(computeShaderEntryPoint);
currentParticleCout = ParticleCout;
cpuParticleBuffer = null;
cpuParticleBuffer = new GPUParticle[currentParticleCout];
gpuThreadGroupNum = Mathf.CeilToInt((float)ParticleCout / WARP_SIZE);
gpuParticleBuffer = new ComputeBuffer(ParticleCout, ParticleSize);
//初始化粒子buffer
for (int i = 0; i < currentParticleCout; i++)
{
cpuParticleBuffer[i] = new GPUParticle();
cpuParticleBuffer[i].position = Random.insideUnitCircle * 10f;
cpuParticleBuffer[i].velocity = Vector2.zero;
}
//传递CPU初始化数据给GPU buffer
gpuParticleBuffer.SetData(cpuParticleBuffer);
//给computeshader中的函数设置数据源
particleComputeShader.SetBuffer(gpuUpdateKernelIndex, computeShaderGPUBufferName, gpuParticleBuffer);
//给shader设置buffer数据，用来做渲染用
particleMat.SetBuffer(computeShaderGPUBufferName, gpuParticleBuffer);
renderCommandBuffer.DrawProcedural(transform.localToWorldMatrix, particleMat, 0, MeshTopology.Points, 1, currentParticleCout);
}
public GPUParticle[] Emit(EmitShapeType shape, Vector3 centerPos, float size)
{
deltaTime += Time.deltaTime * count;
int intDelta = (int)deltaTime;
deltaTime -= intDelta;
if (intDelta == 0)
{
return(null);
}
var particles = new GPUParticle[intDelta];
for (int i = 0; i < particles.Length; i++)
{
particles[i].pos = centerPos + GetPoint(shape, size);
particles[i].velocity = velocity;
particles[i].lifeTime = lifeTime;
}
return(particles);
}
