/* Traces a shadow through the object,
* pretty much gets the transmission over a ray path */
void shade_volume_shadow(struct ShadeInput *shi, struct ShadeResult *shr, struct Isect *last_is)
{
float hitco[3];
float tr[3] = {1.0,1.0,1.0};
Isect is;
float *startco, *endco;
float density=0.f;
memset(shr, 0, sizeof(ShadeResult));
/* if 1st hit normal is facing away from the camera,
* then we're inside the volume already. */
if (shi->flippednor) {
startco = last_is->start;
endco = shi->co;
}
/* trace to find a backface, the other side bounds of the volume */
/* (ray intersect ignores front faces here) */
else if (vol_get_bounds(shi, shi->co, shi->view, hitco, &is, VOL_BOUNDS_DEPTH)) {
startco = shi->co;
endco = hitco;
}
else {
shr->combined[0] = shr->combined[1] = shr->combined[2] = 0.f;
shr->alpha = shr->combined[3] = 1.f;
return;
}
density = vol_get_density(shi, startco);
vol_get_transmittance(shi, tr, startco, endco);
VecCopyf(shr->combined, tr);
shr->combined[3] = 1.0f - luminance(tr);
}
/* Traces a shadow through the object,
* pretty much gets the transmission over a ray path */
void shade_volume_shadow(struct ShadeInput *shi, struct ShadeResult *shr, struct Isect *last_is)
{
float hitco[3];
float tr[3] = {1.0,1.0,1.0};
Isect is= {{0}};
float *startco, *endco;
int intersect_type = VOL_BOUNDS_DEPTH;
memset(shr, 0, sizeof(ShadeResult));
/* if 1st hit normal is facing away from the camera,
* then we're inside the volume already. */
if (shi->flippednor) {
startco = last_is->start;
endco = shi->co;
intersect_type = VOL_BOUNDS_SS;
}
/* trace to find a backface, the other side bounds of the volume */
/* (ray intersect ignores front faces here) */
else if (vol_get_bounds(shi, shi->co, shi->view, hitco, &is, intersect_type)) {
startco = shi->co;
endco = hitco;
}
else {
shr->combined[0] = shr->combined[1] = shr->combined[2] = 0.f;
shr->alpha = shr->combined[3] = 1.f;
return;
}
vol_get_transmittance(shi, tr, startco, endco);
/* if we hit another face in the same volume bounds */
/* shift raytrace coordinates to the hit point, to avoid shading volume twice */
/* due to idiosyncracy in ray_trace_shadow_tra() */
if (is.hit.ob == shi->obi) {
copy_v3_v3(shi->co, hitco);
last_is->dist -= is.dist;
shi->vlr = (VlakRen *)is.hit.face;
}
copy_v3_v3(shr->combined, tr);
shr->combined[3] = 1.0f - luminance(tr);
shr->alpha = shr->combined[3];
}
/* the main entry point for volume shading */
static void volume_trace(struct ShadeInput *shi, struct ShadeResult *shr, int inside_volume)
{
float hitco[3], col[4] = {0.f, 0.f, 0.f, 0.f};
float *startco, *endco;
int trace_behind = 1;
const int ztransp = ((shi->depth == 0) && (shi->mat->mode & MA_TRANSP) && (shi->mat->mode & MA_ZTRANSP));
Isect is;
/* check for shading an internal face a volume object directly */
if (inside_volume == VOL_SHADE_INSIDE)
trace_behind = 0;
else if (inside_volume == VOL_SHADE_OUTSIDE) {
if (shi->flippednor)
inside_volume = VOL_SHADE_INSIDE;
}
if (ztransp && inside_volume == VOL_SHADE_INSIDE) {
MatInside *mi;
int render_this = 0;
/* don't render the backfaces of ztransp volume materials.
*
* volume shading renders the internal volume from between the
* ' view intersection of the solid volume to the
* intersection on the other side, as part of the shading of
* the front face.
*
* Because ztransp renders both front and back faces independently
* this will double up, so here we prevent rendering the backface as well,
* which would otherwise render the volume in between the camera and the backface
* --matt */
for (mi = R.render_volumes_inside.first; mi; mi = mi->next) {
/* weak... */
if (mi->ma == shi->mat) render_this = 1;
}
if (!render_this) return;
}
if (inside_volume == VOL_SHADE_INSIDE) {
startco = shi->camera_co;
endco = shi->co;
if (trace_behind) {
if (!ztransp)
/* trace behind the volume object */
vol_trace_behind(shi, shi->vlr, endco, col);
}
else {
/* we're tracing through the volume between the camera
* and a solid surface, so use that pre-shaded radiance */
copy_v4_v4(col, shr->combined);
}
/* shade volume from 'camera' to 1st hit point */
volumeintegrate(shi, col, startco, endco);
}
/* trace to find a backface, the other side bounds of the volume */
/* (ray intersect ignores front faces here) */
else if (vol_get_bounds(shi, shi->co, shi->view, hitco, &is, VOL_BOUNDS_DEPTH)) {
VlakRen *vlr = (VlakRen *)is.hit.face;
startco = shi->co;
endco = hitco;
if (!ztransp) {
/* if it's another face in the same material */
if (vlr->mat == shi->mat) {
/* trace behind the 2nd (raytrace) hit point */
vol_trace_behind(shi, (VlakRen *)is.hit.face, endco, col);
}
else {
shade_intersection(shi, col, &is);
}
}
/* shade volume from 1st hit point to 2nd hit point */
volumeintegrate(shi, col, startco, endco);
}
if (ztransp)
col[3] = col[3] > 1.f ? 1.f : col[3];
else
col[3] = 1.f;
copy_v3_v3(shr->combined, col);
shr->alpha = col[3];
copy_v3_v3(shr->diff, shr->combined);
}
static void vol_shade_one_lamp(struct ShadeInput *shi, const float co[3], const float view[3], LampRen *lar, float lacol[3])
{
float visifac, lv[3], lampdist;
float tr[3] = {1.0, 1.0, 1.0};
float hitco[3], *atten_co;
float p, ref_col[3];
if (lar->mode & LA_LAYER) if ((lar->lay & shi->obi->lay) == 0) return;
if ((lar->lay & shi->lay) == 0) return;
if (lar->energy == 0.0f) return;
if ((visifac = lamp_get_visibility(lar, co, lv, &lampdist)) == 0.f) return;
copy_v3_v3(lacol, &lar->r);
if (lar->mode & LA_TEXTURE) {
shi->osatex = 0;
do_lamp_tex(lar, lv, shi, lacol, LA_TEXTURE);
}
mul_v3_fl(lacol, visifac);
if (ELEM(lar->type, LA_SUN, LA_HEMI))
copy_v3_v3(lv, lar->vec);
negate_v3(lv);
if (shi->mat->vol.shade_type == MA_VOL_SHADE_SHADOWED) {
mul_v3_fl(lacol, vol_get_shadow(shi, lar, co));
}
else if (ELEM3(shi->mat->vol.shade_type, MA_VOL_SHADE_SHADED, MA_VOL_SHADE_MULTIPLE, MA_VOL_SHADE_SHADEDPLUSMULTIPLE)) {
Isect is;
if (shi->mat->vol.shadeflag & MA_VOL_RECV_EXT_SHADOW) {
mul_v3_fl(lacol, vol_get_shadow(shi, lar, co));
if (rgb_to_luma_y(lacol) < 0.001f) return;
}
/* find minimum of volume bounds, or lamp coord */
if (vol_get_bounds(shi, co, lv, hitco, &is, VOL_BOUNDS_SS)) {
float dist = len_v3v3(co, hitco);
VlakRen *vlr = (VlakRen *)is.hit.face;
/* simple internal shadowing */
if (vlr->mat->material_type == MA_TYPE_SURFACE) {
lacol[0] = lacol[1] = lacol[2] = 0.0f;
return;
}
if (ELEM(lar->type, LA_SUN, LA_HEMI))
/* infinite lights, can never be inside volume */
atten_co = hitco;
else if (lampdist < dist) {
atten_co = lar->co;
}
else
atten_co = hitco;
vol_get_transmittance(shi, tr, co, atten_co);
mul_v3_v3v3(lacol, lacol, tr);
}
else {
/* Point is on the outside edge of the volume,
* therefore no attenuation, full transmission.
* Radiance from lamp remains unchanged */
}
}
if (rgb_to_luma_y(lacol) < 0.001f) return;
normalize_v3(lv);
p = vol_get_phasefunc(shi, shi->mat->vol.asymmetry, view, lv);
/* physically based scattering with non-physically based RGB gain */
vol_get_reflection_color(shi, ref_col, co);
lacol[0] *= p * ref_col[0];
lacol[1] *= p * ref_col[1];
lacol[2] *= p * ref_col[2];
}
