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fix division by 0 in PHOT+C5 interaction, shoot the photon off at 90 degrees instead

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This commit is contained in:
jacob1 2017-12-27 18:11:33 -05:00
parent c31267b06f
commit fbf7210814
1 changed files with 19 additions and 9 deletions

28
src/simulation/Simulation.cpp

@ -2416,17 +2416,27 @@ int Simulation::try_move(int i, int x, int y, int nx, int ny)
float vx = ((parts[r>>8].tmp << 16) >> 16) / 255.0f;
float vy = (parts[r>>8].tmp >> 16) / 255.0f;
float vn = parts[i].vx * parts[i].vx + parts[i].vy * parts[i].vy;
parts[i].ctype = (parts[r>>8].ctype & parts[i].ctype) >> 6;
// if the resulting velocity would be 0, that would cause division by 0 inside the else
// shoot the photon off at a 90 degree angle instead (probably particle order dependent)
if (parts[i].vx + vx == 0 && parts[i].vy + vy == 0)
{
parts[i].vx = vy;
parts[i].vy = -vx;
}
else
{
parts[i].ctype = (parts[r>>8].ctype & parts[i].ctype) >> 6;
// add momentum of photons to each other
parts[i].vx += vx;
parts[i].vy += vy;
// normalize velocity to original value
vn /= parts[i].vx * parts[i].vx + parts[i].vy * parts[i].vy;
vn = sqrtf(vn);
parts[i].vx *= vn;
parts[i].vy *= vn;
}
parts[r>>8].life = 0;
parts[r>>8].ctype = 0;
// add momentum of photons to each other
parts[i].vx += vx;
parts[i].vy += vy;
// normalize velocity to original value
vn /= parts[i].vx * parts[i].vx + parts[i].vy * parts[i].vy;
vn = sqrtf(vn);
parts[i].vx *= vn;
parts[i].vy *= vn;
}
else if(!parts[r>>8].ctype && parts[i].ctype & 0xFFFFFFC0)
{