//The main fluid simulation step
void FluidSim::advance(float dt) {
float t = 0;
while(t < dt) {
float substep = cfl();
if(t + substep > dt)
substep = dt - t;
//Passively advect particles
advect_particles(substep);
//Estimate the liquid signed distance
compute_phi();
//Advance the velocity
advect(substep);
add_force(substep);
apply_viscosity(substep);
apply_projection(substep);
//Pressure projection only produces valid velocities in faces with non-zero associated face area.
//Because the advection step may interpolate from these invalid faces,
//we must extrapolate velocities from the fluid domain into these zero-area faces.
extrapolate(u, u_valid);
extrapolate(v, v_valid);
//For extrapolated velocities, replace the normal component with
//that of the object.
constrain_velocity();
t+=substep;
}
}
static void reshape(int w, int h)
{
window_x = w;
window_y = h;
glViewport(0, 0, (GLint)w, (GLint)h);
apply_projection();
glMatrixMode(GL_MODELVIEW);
}
void mnehs_affine_warp(float *warp,
float *h, int wh, int hh, int pd,
float *a, int wa, int ha,
float *b, int wb, int hb,
double PA[8], double PB[8])
{
for (int j = 0; j < hh; j++)
for (int i = 0; i < wh; i++)
{
float vh = getsample_nan(h, wh, hh, 1, i, j, 0);
double ijh[3] = {i, j, vh};
double paijh[3], pbijh[3];
apply_projection(paijh, PA, ijh);
apply_projection(pbijh, PB, ijh);
float va[pd], vb[pd];
bicubic_interpolation(va, a, wa, ha, pd, paijh[0], paijh[1]);
bicubic_interpolation(vb, b, wb, hb, pd, pbijh[0], pbijh[1]);
for (int l = 0; l < pd; l++)
warp[pd*(j*wh+i)+l] = va[l] - vb[l];
}
}
static void draw()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
apply_projection();
glPushMatrix();
glLoadIdentity();
if (camera_type == 1 || camera_type == 2)
cm_apply_target_camera(tcamera);
else
cm_apply_fps_camera(fcamera);
/* +/-X Cubes */
rh_draw_cube((VEC3){ 3, 0, 0 }, (VEC3){ 1, 1, 1 }, (VEC3){ 0, cuberot, 0 });
rh_draw_cube((VEC3){ -3, 0, 0 }, (VEC3){ 1, 1, 1 }, (VEC3){ 0, cuberot, 0 });
/* +/-Z Cubes */
rh_draw_cube((VEC3){ 0, 0, 3 }, (VEC3){ 1.25, 1.25, 1.25 }, (VEC3){ 0, -cuberot, 0 });
rh_draw_cube((VEC3){ 0, 0, -3 }, (VEC3){ 1.25, 1.25, 1.25 }, (VEC3){ 0, -cuberot, 0 });
/* Sphere stack of varing sizes and qualities */
rh_draw_sphere((VEC3){ 0, 0, 0 }, (VEC3){ 1, 1, 1 }, (VEC3){ spherot, 0, 0 }, 3);
rh_draw_sphere((VEC3){ 0, -1, 0 }, (VEC3){ .5, .5, .5 }, (VEC3){ -spherot, 0, 0 }, 2);
rh_draw_sphere((VEC3){ 0, -1.5, 0 }, (VEC3){ .25, .25, .25 }, (VEC3){ spherot, 0, 0 }, 1);
/* Polygon stack of various edge counts and rotations */
rh_draw_extended_polygon((VEC3){ 0, 1, 0 }, (VEC3){ 1, .25, 1 }, (VEC3){ 0, polyrot, 0 }, 3);
rh_draw_extended_polygon((VEC3){ 0, 1.75, 0 }, (VEC3){ 1, .25, 1 }, (VEC3){ 0, -polyrot, 0 }, 4);
rh_draw_extended_polygon((VEC3){ 0, 2.5, 0 }, (VEC3){ 1, .25, 1 }, (VEC3){ 0, polyrot, 0 }, 5);
rh_draw_extended_polygon((VEC3){ 0, 3.25, 0 }, (VEC3){ 1, .25, 1 }, (VEC3){ 0, -polyrot, 0 }, 7);
rh_draw_extended_polygon((VEC3){ 0, 4, 0 }, (VEC3){ 1, .25, 1 }, (VEC3){ 0, polyrot, 0 }, 10);
draw_gui();
glPopMatrix();
glFlush();
glutSwapBuffers();
}
// Modèle Numérique d'Élévation Horn Schunck (cas affine)
void mnehs_affine(float *out_h, float *init_h, int ow, int oh,
float *a, int wa, int ha,
float *b, int wb, int hb,
double PA[8], double PB[8],
float alpha2, int niter)
{
// allocate temporary images
float *h = xmalloc(ow * oh * sizeof*h); // h-increment
float *Q = xmalloc(ow * oh * sizeof*Q); // Q
float *amb = xmalloc(ow * oh * sizeof*amb); // A-B (warped)
float *ga = xmalloc(2 * wa * ha * sizeof*ga); // grad(A)
float *gb = xmalloc(2 * wb * hb * sizeof*gb); // grad(B)
// gradient of A and B
fill_gradient(ga, a, wa, ha);
fill_gradient(gb, b, wb, hb);
// fill images q and amb (a minus b)
for (int j = 0; j < oh; j++)
for (int i = 0; i < ow; i++)
{
float h0 = getsample_nan(init_h, ow, oh, 1, i, j, 0);
double ijh[3] = {i, j, h0}, paijh[3], pbijh[3];
apply_projection(paijh, PA, ijh);
apply_projection(pbijh, PB, ijh);
float va, vb, vga[2], vgb[2];
bicubic_interpolation_nans(&va, a, wa, ha, 1, paijh[0], paijh[1]);
bicubic_interpolation_nans(&vb, b, wb, hb, 1, pbijh[0], pbijh[1]);
bicubic_interpolation(vga, ga, wa, ha, 2, paijh[0], paijh[1]);
bicubic_interpolation(vgb, gb, wb, hb, 2, pbijh[0], pbijh[1]);
float gapa = vga[0] * PA[2] + vga[1] * PA[6];
float gbpb = vgb[0] * PB[2] + vgb[1] * PB[6];
Q [j*ow+i] = gapa - gbpb;
amb[j*ow+i] = va - vb;
}
nusavec("Q_%d.tiff", global_scale, Q, ow, oh, 1);
nusavec("amb_%d.tiff", global_scale, amb, ow, oh, 1);
// initialize h
for (int i = 0; i < ow * oh; i++)
h[i] = 0;
// run the iterations (without warps)
for (int iter = 0; iter < niter; iter++)
{
for (int j = 0; j < oh; j++)
for (int i = 0; i < ow; i++)
{
int ij = j * ow + i;
if (!isfinite(amb[ij])) continue;
float ax = laplacian_at(h, ow, oh, i, j);
ax -= Q[ij] * (Q[ij] * h[ij] + amb[ij]) / alpha2;
h[ij] += TAU() * ax;
}
}
nusavec("h_%d.tiff", global_scale, h, ow, oh, 1);
// update result
for (int i = 0; i < ow * oh; i++)
out_h[i] = init_h[i] + h[i];
// cleanup and exit
free(h);
free(Q);
free(amb);
free(ga);
free(gb);
}
