/*
* S T K _ R E N D E R
*
* Evaluate all of the rendering functions in the stack.
*
* Returns:
* 0 stack processing aborted
* 1 stack processed to completion
*/
HIDDEN int
sh_stk_render(struct application *ap, struct partition *pp, struct shadework *swp, char *dp)
{
register struct stk_specific *sp =
(struct stk_specific *)dp;
int i;
int ret_status;
char tmp[128];
for ( i = 0; i < 16 && sp->mfuncs[i] != NULL; i++ ) {
if (rdebug&RDEBUG_SHADE) {
snprintf(tmp, 128, "before stacked \"%s\" shader", sp->mfuncs[i]->mf_name);
pr_shadework( tmp, swp );
}
/*
* Every shader takes the shadework structure as its
* input and updates it as the "output".
*/
ret_status = sp->mfuncs[i]->mf_render( ap, pp, swp,
sp->udata[i] );
if ( ! ret_status ) return ret_status;
}
return(1);
}
/*
* Evaluate all of the rendering functions in the stack.
*
* Returns:
* 0 stack processing aborted
* 1 stack processed to completion
*/
HIDDEN int
sh_stk_render(struct application *ap, const struct partition *pp, struct shadework *swp, void *dp)
{
register struct stk_specific *sp =
(struct stk_specific *)dp;
int i;
int ret_status = 0;
char tmp[128];
if (sp == NULL) {
bu_log("sh_stk_render: Null pointer\n");
return 0;
}
for (i = 0; i < 16 && sp->mfuncs[i] != NULL; i++) {
if (rdebug&RDEBUG_SHADE) {
snprintf(tmp, 128, "before stacked \"%s\" shader", sp->mfuncs[i]->mf_name);
pr_shadework(tmp, swp);
}
/*
* Every shader takes the shadework structure as its
* input and updates it as the "output".
*/
if (sp && sp->mfuncs[i] && sp->mfuncs[i]->mf_render)
ret_status = sp->mfuncs[i]->mf_render(ap, pp, swp, sp->udata[i]);
if (ret_status != 1)
return 0;
}
return 1;
}
int
scloud_render(struct application *ap, const struct partition *pp, struct shadework *swp, void *dp)
{
register struct scloud_specific *scloud_sp =
(struct scloud_specific *)dp;
point_t in_pt; /* point where ray enters scloud solid */
point_t out_pt; /* point where ray leaves scloud solid */
point_t pt;
vect_t v_cloud;/* vector representing ray/solid intersection */
double thickness; /* magnitude of v_cloud (distance through solid) */
int steps; /* # of samples along ray/solid intersection */
double step_delta;/* distance between sample points, texture space */
int i;
double val;
double trans;
point_t incident_light = VINIT_ZERO;
double delta_dpmm;
double density;
struct shadework sub_sw;
struct light_specific *lp;
RT_CHECK_PT(pp);
RT_AP_CHECK(ap);
RT_CK_REGION(pp->pt_regionp);
/* compute the ray/solid in and out points,
* and transform them into "shader space" coordinates
*/
VJOIN1(pt, ap->a_ray.r_pt, pp->pt_inhit->hit_dist, ap->a_ray.r_dir);
MAT4X3PNT(in_pt, scloud_sp->mtos, pt);
VJOIN1(pt, ap->a_ray.r_pt, pp->pt_outhit->hit_dist, ap->a_ray.r_dir);
MAT4X3PNT(out_pt, scloud_sp->mtos, pt);
/* get ray/solid intersection vector (in noise space)
* and compute thickness of solid (in noise space) along ray path
*/
VSUB2(v_cloud, out_pt, in_pt);
thickness = MAGNITUDE(v_cloud);
/* The noise field used by the bn_noise_turb and bn_noise_fbm routines
* has a maximum frequency of about 1 cycle per integer step in
* noise space. Each octave increases this frequency by the
* "lacunarity" factor. To sample this space adequately we need
*
* 4 samples per integer step for the first octave,
* lacunarity * 4 samples/step for the second octave,
* lacunarity^2 * 4 samples/step for the third octave,
* lacunarity^3 * 4 samples/step for the forth octave,
*
* so for a computation with 4 octaves we need something on the
* order of lacunarity^3 * 4 samples per integer step in noise space.
*/
steps = pow(scloud_sp->lacunarity, scloud_sp->octaves-1) * 4;
step_delta = thickness / (double)steps;
if (rdebug&RDEBUG_SHADE)
bu_log("steps=%d delta=%g thickness=%g\n",
steps, step_delta, thickness);
VUNITIZE(v_cloud);
VMOVE(pt, in_pt);
trans = 1.0;
delta_dpmm = scloud_sp->max_d_p_mm - scloud_sp->min_d_p_mm;
sub_sw = *swp; /* struct copy */
sub_sw.sw_inputs = MFI_HIT;
for (i=0; i < steps; i++) {
/* compute the next point in the cloud space */
VJOIN1(pt, in_pt, i*step_delta, v_cloud);
/* get turbulence value (0 .. 1) */
val = bn_noise_turb(pt, scloud_sp->h_val,
scloud_sp->lacunarity, scloud_sp->octaves);
density = scloud_sp->min_d_p_mm + val * delta_dpmm;
val = exp(- density * step_delta);
trans *= val;
if (swp->sw_xmitonly) continue;
/* need to set the hit in our fake shadework structure */
MAT4X3PNT(sub_sw.sw_hit.hit_point, scloud_sp->stom, pt);
sub_sw.sw_transmit = trans;
sub_sw.sw_inputs = MFI_HIT;
light_obs(ap, &sub_sw, swp->sw_inputs);
/* now we know how much light has arrived from each
* light source to this point
*/
for (i=ap->a_rt_i->rti_nlights-1; i >= 0; i--) {
lp = (struct light_specific *)swp->sw_visible[i];
if (lp == LIGHT_NULL) continue;
/* compute how much light has arrived at
* this location
*/
incident_light[0] += sub_sw.sw_intensity[3*i+0] *
lp->lt_color[0] * sub_sw.sw_lightfract[i];
incident_light[1] += sub_sw.sw_intensity[3*i+1] *
lp->lt_color[1] * sub_sw.sw_lightfract[i];
incident_light[2] += sub_sw.sw_intensity[3*i+2] *
lp->lt_color[2] * sub_sw.sw_lightfract[i];
}
VSCALE(incident_light, incident_light, trans);
}
/* scloud is basically a white object with partial transparency */
swp->sw_transmit = trans;
if (swp->sw_xmitonly) return 1;
/*
* At the point of maximum opacity, check light visibility
* for light color and cloud shadowing.
* OOPS: Don't use an interior point, or light_visibility()
* will see an attenuated light source.
*/
swp->sw_hit.hit_dist = pp->pt_inhit->hit_dist;
VJOIN1(swp->sw_hit.hit_point, ap->a_ray.r_pt, swp->sw_hit.hit_dist,
ap->a_ray.r_dir);
VREVERSE(swp->sw_hit.hit_normal, ap->a_ray.r_dir);
swp->sw_inputs |= MFI_HIT | MFI_NORMAL;
light_obs(ap, swp, swp->sw_inputs);
VSETALL(incident_light, 0);
for (i=ap->a_rt_i->rti_nlights-1; i>=0; i--) {
struct light_specific *lp2;
if ((lp2 = (struct light_specific *)swp->sw_visible[i]) == LIGHT_NULL)
continue;
/* XXX don't have a macro for this */
incident_light[0] += swp->sw_intensity[3*i+0] * lp2->lt_color[0];
incident_light[1] += swp->sw_intensity[3*i+1] * lp2->lt_color[1];
incident_light[2] += swp->sw_intensity[3*i+2] * lp2->lt_color[2];
}
VELMUL(swp->sw_color, swp->sw_color, incident_light);
if (rdebug&RDEBUG_SHADE) {
pr_shadework("scloud: after light vis, before rr_render", swp);
}
if (swp->sw_reflect > 0 || swp->sw_transmit > 0)
(void)rr_render(ap, pp, swp);
return 1;
}
