void ciMsaFluidSolver::advectRGB(int bound, const ci::Vec2f* duv) {
int i0, j0;
float x, y, s0, t0, s1, t1, dt0x, dt0y;
int index;
dt0x = _dt * _NX;
dt0y = _dt * _NY;
for (int j = _NY; j > 0; --j)
{
for (int i = _NX; i > 0; --i)
{
index = FLUID_IX(i, j);
x = i - dt0x * duv[index].x;
y = j - dt0y * duv[index].y;
if (x > _NX + 0.5) x = _NX + 0.5f;
if (x < 0.5) x = 0.5f;
i0 = (int) x;
if (y > _NY + 0.5) y = _NY + 0.5f;
if (y < 0.5) y = 0.5f;
j0 = (int) y;
s1 = x - i0;
s0 = 1 - s1;
t1 = y - j0;
t0 = 1 - t1;
i0 = FLUID_IX(i0, j0); //we don't need col/row index any more but index in 1 dimension
j0 = i0 + (_NX + 2);
r[index] = s0 * ( t0 * rOld[i0] + t1 * rOld[j0] ) + s1 * ( t0 * rOld[i0+1] + t1 * rOld[j0+1] );
g[index] = s0 * ( t0 * gOld[i0] + t1 * gOld[j0] ) + s1 * ( t0 * gOld[i0+1] + t1 * gOld[j0+1] );
b[index] = s0 * ( t0 * bOld[i0] + t1 * bOld[j0] ) + s1 * ( t0 * bOld[i0+1] + t1 * bOld[j0+1] );
}
}
setBoundaryRGB();
}
void FluidSolver::advectRGB(int bound, const ofVec2f* duv) {
int i0, j0;
float x, y, s0, t0, s1, t1, dt0x, dt0y;
int index;
dt0x = deltaT * _NX;
dt0y = deltaT * _NY;
for (int j = _NY; j > 0; --j)
{
for (int i = _NX; i > 0; --i)
{
index = FLUID_IX(i, j);
x = i - dt0x * duv[index].x;
y = j - dt0y * duv[index].y;
if (x > _NX + 0.5) x = _NX + 0.5f;
if (x < 0.5) x = 0.5f;
i0 = (int) x;
if (y > _NY + 0.5) y = _NY + 0.5f;
if (y < 0.5) y = 0.5f;
j0 = (int) y;
s1 = x - i0;
s0 = 1 - s1;
t1 = y - j0;
t0 = 1 - t1;
i0 = FLUID_IX(i0, j0); //we don't need col/row index any more but index in 1 dimension
j0 = i0 + (_NX + 2);
color[index] = ( colorOld[i0] * t0 + colorOld[j0] * t1 ) * s0 + ( colorOld[i0+1] * t0 + colorOld[j0+1] * t1) * s1;
}
}
setBoundaryRGB();
}
