/* Uses same physically based scattering parameter as in transmission calculations,
* along with artificial reflection scale/reflection color tint */
static void vol_get_reflection_color(ShadeInput *shi, float ref_col[3], const float co[3])
{
float scatter = shi->mat->vol.scattering;
float reflection = shi->mat->vol.reflection;
copy_v3_v3(ref_col, shi->mat->vol.reflection_col);
if (shi->mat->mapto_textured & (MAP_SCATTERING + MAP_REFLECTION_COL))
do_volume_tex(shi, co, MAP_SCATTERING + MAP_REFLECTION_COL, ref_col, &scatter, &R);
/* only one single float parameter at a time... :s */
if (shi->mat->mapto_textured & (MAP_REFLECTION))
do_volume_tex(shi, co, MAP_REFLECTION, NULL, &reflection, &R);
ref_col[0] = reflection * ref_col[0] * scatter;
ref_col[1] = reflection * ref_col[1] * scatter;
ref_col[2] = reflection * ref_col[2] * scatter;
}
/* compute emission component, amount of radiance to add per segment
* can be textured with 'emit' */
static void vol_get_emission(ShadeInput *shi, float emission_col[3], const float co[3])
{
float emission = shi->mat->vol.emission;
copy_v3_v3(emission_col, shi->mat->vol.emission_col);
if (shi->mat->mapto_textured & (MAP_EMISSION + MAP_EMISSION_COL))
do_volume_tex(shi, co, MAP_EMISSION + MAP_EMISSION_COL, emission_col, &emission, &R);
emission_col[0] = emission_col[0] * emission;
emission_col[1] = emission_col[1] * emission;
emission_col[2] = emission_col[2] * emission;
}
/* compute emission component, amount of radiance to add per segment
* can be textured with 'emit' */
static void vol_get_emission(ShadeInput *shi, float *emission_col, float *co)
{
float emission = shi->mat->vol.emission;
VECCOPY(emission_col, shi->mat->vol.emission_col);
if (shi->mat->mapto_textured & (MAP_EMISSION+MAP_EMISSION_COL))
do_volume_tex(shi, co, MAP_EMISSION+MAP_EMISSION_COL, emission_col, &emission);
emission_col[0] = emission_col[0] * emission;
emission_col[1] = emission_col[1] * emission;
emission_col[2] = emission_col[2] * emission;
}
/* A combination of scattering and absorption -> known as sigma T.
* This can possibly use a specific scattering color,
* and absorption multiplier factor too, but these parameters are left out for simplicity.
* It's easy enough to get a good wide range of results with just these two parameters. */
static void vol_get_sigma_t(ShadeInput *shi, float sigma_t[3], const float co[3])
{
/* technically absorption, but named transmission color
* since it describes the effect of the coloring *after* absorption */
float transmission_col[3] = {shi->mat->vol.transmission_col[0], shi->mat->vol.transmission_col[1], shi->mat->vol.transmission_col[2]};
float scattering = shi->mat->vol.scattering;
if (shi->mat->mapto_textured & (MAP_SCATTERING + MAP_TRANSMISSION_COL))
do_volume_tex(shi, co, MAP_SCATTERING + MAP_TRANSMISSION_COL, transmission_col, &scattering, &R);
sigma_t[0] = (1.0f - transmission_col[0]) + scattering;
sigma_t[1] = (1.0f - transmission_col[1]) + scattering;
sigma_t[2] = (1.0f - transmission_col[2]) + scattering;
}
float vol_get_density(struct ShadeInput *shi, const float co[3])
{
float density = shi->mat->vol.density;
float density_scale = shi->mat->vol.density_scale;
if (shi->mat->mapto_textured & MAP_DENSITY)
do_volume_tex(shi, co, MAP_DENSITY, NULL, &density, &R);
/* if meta-object, modulate by metadensity without increasing it */
if (shi->obi->obr->ob->type == OB_MBALL) {
const float md = metadensity(shi->obi->obr->ob, co);
if (md < 1.f) density *= md;
}
return density * density_scale;
}
