particle render issue

[lwkobe]

Hi, i want use your particle render to render my simulation result. But i find something confused. What "temp_data" means?(temperature field) And could you explain that why you arrange the particles in a different size that is not your solver field size? Thank you!

[zhxx1987]

Temp data if provided from a fire simulation, renders particle with temperatures,giving a rendering result like a burning fire and burnt dusts. I used to scale all particle data to 0~1 so that it's easy for me to navigate in another previewed, please comment the corresponding codes so that scaling doesn't happen.

Thank you!

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On Apr 20, 2017, at 6:16 AM, lwkobe [email protected] wrote:

Hi, i want use your particle render to render my simulation result. But i find something confused. What "temp_data" means?(temperature field) And could you explain that why you arrange the particles in a different size that is not your solver field size? Thank you!

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[lwkobe]

`void setEmitter(Vec3f & pos, float r, uint n) { emitter_pos = pos; emitter_r = r; emitter_n = n; } void emit_tracers() { //cout<<"emitting tracers:"<<endl; vector<Vec4f> tracers_temp; tracers_temp.resize(0); for (uint i=0;i<tracers.size();i++) { if (tracers[i][0]>2*_hx && tracers[i][1]>2*_hx && tracers[i][2]>2*_hx && tracers[i][0]<_lx-2*_hx && tracers[i][1]<0.86*_ly-_hx && tracers[i][2]<_lz-2*_hx && tracers[i][3]>0.01) { tracers_temp.push_back(tracers[i]); } } tracers.swap(tracers_temp); uint num = 0; while(num<emitter_n) { float r = emitter_r; float x = frand(-r-_hx, r+_hx); float y = frand(-r-_hx, r+_hx); float z = frand(-r-_hx, r+_hx);

		if (x*x + y*y + z*z <= r*r)
		{
			tracers.push_back(Vec4f(emitter_pos[0]+x,
								    emitter_pos[1]+y,
									emitter_pos[2]+z,
									1.0)
							 );
			num++;
		}
	}
	//cout<<"emitting tracers done:"<<tracers.size()<<" tracers"<<endl;
}`

Hi,thanks for your answer. (1) In the emit_tracers() function,When you judge whether the particle is in the solver domain,you use the if (tracers[i][0]>2*_hx && tracers[i][1]>2*_hx && tracers[i][2]>2*_hx && tracers[i][0]<_lx-2*_hx && tracers[i][1]<0.86*_ly-_hx && tracers[i][2]<_lz-2*_hx && tracers[i][3]>0.01)condition. But i read your initial code for _hx,_hy,_hz. _nx=nx; _ny=ny; _nz=nz; _hx = L/(float)_nx; _hz = _hy = _hx; Could you explain what '_hx,_hy,_hz' mean? And why you choose a vec4 vector to save particles? What does the fourth dimesion of vec4 means? (2) In the particle_render project' read_particles() function ,you have somethings like for(int i=0; i<x.n; ++i){ // read x y z for particle i std::fread(&x[i], sizeof(float), 3, in); // skip 0.f x[i][0] = -x[i][0]; //float z = x[i][2]; x[i][2] = -x[i][2]; //x[i][0] = -z; //std::fread(&zero, sizeof(float), 1, in); std::fread(&d[i],sizeof(float), 1, in); } x[i][0] = -x[i][0]; x[i][2] = -x[i][2]; make me confused. Could you explain it ? Thank you!

[zhxx1987]

The forth component is to store density value which is a time evolving ode so that particles fade out smoothly. And for those axis it's just rotating or mirroring the particles which can be done in arbitrary way, without particular purpose.

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On Apr 20, 2017, at 10:03 AM, lwkobe [email protected] wrote:

`void setEmitter(Vec3f & pos, float r, uint n) { emitter_pos = pos; emitter_r = r; emitter_n = n; } void emit_tracers() { //cout<<"emitting tracers:"<<endl; vector tracers_temp; tracers_temp.resize(0); for (uint i=0;i<tracers.size();i++) { if (tracers[i][0]>2*_hx && tracers[i][1]>2*_hx && tracers[i][2]>2*_hx && tracers[i][0]<_lx-2*_hx && tracers[i][1]<0.86*_ly-_hx && tracers[i][2]<_lz-2*_hx && tracers[i][3]>0.01) { tracers_temp.push_back(tracers[i]); } } tracers.swap(tracers_temp); uint num = 0; while(num<emitter_n) { float r = emitter_r; float x = frand(-r-_hx, r+_hx); float y = frand(-r-_hx, r+_hx); float z = frand(-r-_hx, r+_hx);

  if (x*x + y*y + z*z <= r*r)
  {
  	tracers.push_back(Vec4f(emitter_pos[0]+x,
  						    emitter_pos[1]+y,
  							emitter_pos[2]+z,
  							1.0)
  					 );
  	num++;
  }

} //cout<<"emitting tracers done:"<<tracers.size()<<" tracers"<<endl; }` Hi,thanks for your answer. (1) In the emit_tracers() function,When you judge whether the particle is in the solver domain,you use the if (tracers[i][0]>2*_hx && tracers[i][1]>2*_hx && tracers[i][2]>2*_hx && tracers[i][0]<_lx-2*_hx && tracers[i][1]<0.86*_ly-_hx && tracers[i][2]<_lz-2*_hx && tracers[i][3]>0.01)condition. But i read your initial code for _hx,_hy,_hz. _nx=nx; _ny=ny; _nz=nz; _hx = L/(float)_nx; _hz = _hy = _hx; Could you explain what '_hx,_hy,_hz' mean? And why you choose a vec4 vector to save particles? What does the fourth dimesion of vec4 means? (2) In the particle_render project' read_particles() function ,you have somethings like for(int i=0; i<x.n; ++i){ // read x y z for particle i std::fread(&x[i], sizeof(float), 3, in); // skip 0.f x[i][0] = -x[i][0]; //float z = x[i][2]; x[i][2] = -x[i][2]; //x[i][0] = -z; //std::fread(&zero, sizeof(float), 1, in); std::fread(&d[i],sizeof(float), 1, in); } x[i][0] = -x[i][0]; x[i][2] = -x[i][2]; make me confused. Could you explain it ? Thank you!

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[lwkobe]

Thank you very much!

[lwkobe]

Hi in your particle_render project <radius> <density_scale> <opacity> <light_x> <light_y> <light_z> [quality], how to set the paramater? Thank you！

[zhxx1987]

here is the an example The parameters could be: file folder where particledata0000.bin is stored. 0.008(particle size) 1(density scale) 0.006(particle transparency) 3 10 -5(light position) 10(shadow map quality) 0(start frame) 100(end frame)

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On Apr 21, 2017, at 4:29 AM, lwkobe [email protected] wrote:

Hi in your particle_render project <density_scale> <light_x> <light_y> <light_z> [quality], how to set the paramater? Thank you！

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[lwkobe]

Hi， when i see your simulator code, i find that you add 12288 particles every times. Could you get high rate of computations? Or Do I get your code understood wrong?