/*
* R T _ S P E C T _ C U R V E _ T O _ X Y Z
*
* Convenience routine.
* Serves same function as Roy Hall's CLR_spect_to_xyz(), pg 233.
* The normalization xyz_scale = 1.0 / bn_tabdata_area2(cie_y);
* has been folded into spect_make_CIE_XYZ();
*/
void
spect_curve_to_xyz(point_t xyz,
const struct bn_tabdata *tabp,
const struct bn_tabdata *cie_x,
const struct bn_tabdata *cie_y,
const struct bn_tabdata *cie_z)
{
fastf_t tab_area;
BN_CK_TABDATA(tabp);
#if 0
tab_area = bn_tabdata_area2(tabp);
bu_log(" tab_area = %g\n", tab_area);
if (fabs(tab_area) < VDIVIDE_TOL) {
bu_log("spect_curve_to_xyz(): Area = 0 (no luminance) in this part of the spectrum\n");
VSETALL(xyz, 0);
return;
}
tab_area = 1 / tab_area;
#else
/* This is what Roy says to do, but I'm not certain */
tab_area = 1;
#endif
xyz[X] = bn_tabdata_mul_area2(tabp, cie_x) * tab_area;
xyz[Y] = bn_tabdata_mul_area2(tabp, cie_y) * tab_area;
xyz[Z] = bn_tabdata_mul_area2(tabp, cie_z) * tab_area;
}
/**
* R T _ S P E C T _ R E F L E C T A N C E _ R G B
*
* Given reflectance data (in range 0..1) in terms of RGB color,
* convert that to a spectral reflectance curve.
*
* The assumption here is that the spectrum is made up of exactly
* three non-overlapping bands, and the reflectance is constant over
* each:
*
* red 572nm to 1, 000, 000nm (includes the full IR band)
* green 492nm to 572nm (just green)
* blue 1nm to 492nm (includes Ultraviolet)
*
* As the caller may be doing a lot of this, the caller is expected to
* provide a pointer to a valid bn_tabdata structure which is to be
* filled in. Allowing caller to re-cycle them rather than doing
* constant malloc/free cycle.
*/
void
rt_spect_reflectance_rgb(struct bn_tabdata *curve, const float *rgb)
{
register int i;
register const struct bn_table *tabp;
BN_CK_TABDATA(curve);
tabp = curve->table;
BN_CK_TABLE(tabp);
/* Fill in blue values, everything up to but not including 492nm */
for ( i=0; i < tabp->nx; i++ ) {
if ( tabp->x[i] >= 492 ) break;
curve->y[i] = rgb[2];
}
/* Fill in green values, everything up to but not including 572nm */
for (; i < tabp->nx; i++ ) {
if ( tabp->x[i] >= 572 ) break;
curve->y[i] = rgb[1];
}
/* Fill in red values, everything from here up to end of table */
for (; i < tabp->nx; i++ ) {
curve->y[i] = rgb[0];
}
}
/**
* R T _ S P E C T _ B L A C K _ B O D Y
*
* Integrate Planck's Radiation Formula for a black body radiator
* across the given spectrum. Returns radiant emittance in W/cm**2
* for each wavelength interval.
*
* Based upon code kindly provided by Russ Moulton, Jr., EOSoft Inc.
* Compute at 'n-1' wavelengths evenly spaced between ax and bx.
*/
void
rt_spect_black_body(struct bn_tabdata *data, double temp, unsigned int n)
/* Degrees Kelvin */
/* # wavelengths to eval at */
{
const struct bn_table *tabp;
int j;
BN_CK_TABDATA(data);
tabp = data->table;
BN_CK_TABLE(tabp);
if (bu_debug&BU_DEBUG_TABDATA) {
bu_log("rt_spect_black_body( x%x, %g degK ) %g um to %g um\n",
data, temp,
tabp->x[0] * 0.001, /* nm to um */
tabp->x[tabp->nx] * 0.001 /* nm to um */
);
}
if ( n < 3 ) n = 3;
for ( j = 0; j < tabp->nx; j++ ) {
double ax; /* starting wavelength, um */
double bx; /* ending wavelength, um */
double dx; /* wavelength interval, um */
double w_sum; /* sum over wavelengths */
double wavlen; /* current wavelength */
unsigned long i;
ax = tabp->x[j] * 0.001; /* nm to um */
bx = tabp->x[j+1] * 0.001; /* nm to um */
dx = (bx - ax) / (double)n;
w_sum = 0;
wavlen = ax;
for (i=0; i<n; i++) {
w_sum += PLANCK(wavlen, temp);
wavlen += dx;
}
w_sum *= dx;
data->y[j] = w_sum;
}
}
/**
* R T _ S P E C T _ B L A C K _ B O D Y _ P O I N T S
*
* Returns point-sampled values of spectral radiant emittance, in
* units of watts/cm**2/um, straight from Planck's black-body
* radiation formula.
*/
void
rt_spect_black_body_points(struct bn_tabdata *data, double temp)
/* Degrees Kelvin */
{
const struct bn_table *tabp;
int j;
BN_CK_TABDATA(data);
tabp = data->table;
BN_CK_TABLE(tabp);
if (bu_debug&BU_DEBUG_TABDATA) {
bu_log("rt_spect_black_body_points( x%x, %g degK )\n",
data, temp );
}
for ( j = 0; j < tabp->nx; j++ ) {
data->y[j] = PLANCK( (tabp->x[j]*0.001), temp );
}
}
/*
* R R _ R E N D E R
*/
int
rr_render(register struct application *ap,
const struct partition *pp,
struct shadework *swp)
{
struct application sub_ap;
vect_t work;
vect_t incident_dir;
fastf_t shader_fract;
fastf_t reflect;
fastf_t transmit;
#ifdef RT_MULTISPECTRAL
struct bn_tabdata *ms_filter_color = BN_TABDATA_NULL;
struct bn_tabdata *ms_shader_color = BN_TABDATA_NULL;
struct bn_tabdata *ms_reflect_color = BN_TABDATA_NULL;
struct bn_tabdata *ms_transmit_color = BN_TABDATA_NULL;
#else
vect_t filter_color;
vect_t shader_color;
vect_t reflect_color;
vect_t transmit_color;
#endif
fastf_t attenuation;
vect_t to_eye;
int code;
RT_AP_CHECK(ap);
RT_APPLICATION_INIT(&sub_ap);
#ifdef RT_MULTISPECTRAL
sub_ap.a_spectrum = BN_TABDATA_NULL;
ms_reflect_color = bn_tabdata_get_constval(0.0, spectrum);
#endif
/*
* sw_xmitonly is set primarily for light visibility rays.
* Need to compute (partial) transmission through to the light,
* or procedural shaders won't be able to cast shadows
* and light won't be able to get through glass
* (including "stained glass" and "filter glass").
*
* On the other hand, light visibility rays shouldn't be refracted,
* it is pointless to shoot at where the light isn't.
*/
if (swp->sw_xmitonly) {
/* Caller wants transmission term only, don't fire reflected rays */
transmit = swp->sw_transmit + swp->sw_reflect; /* Don't loose energy */
reflect = 0;
} else {
reflect = swp->sw_reflect;
transmit = swp->sw_transmit;
}
if (R_DEBUG&RDEBUG_REFRACT) {
bu_log("rr_render(%s) START: lvl=%d reflect=%g, transmit=%g, xmitonly=%d\n",
pp->pt_regionp->reg_name,
ap->a_level,
reflect, transmit,
swp->sw_xmitonly);
}
if (reflect <= 0 && transmit <= 0)
goto out;
if (ap->a_level > max_bounces) {
/* Nothing more to do for this ray */
static long count = 0; /* Not PARALLEL, should be OK */
if ((R_DEBUG&(RDEBUG_SHOWERR|RDEBUG_REFRACT)) && (
count++ < MSG_PROLOGUE ||
(count%MSG_INTERVAL) == 3
)) {
bu_log("rr_render: %d, %d MAX BOUNCES=%d: %s\n",
ap->a_x, ap->a_y,
ap->a_level,
pp->pt_regionp->reg_name);
}
/*
* Return the basic color of the object, ignoring the
* the fact that it is supposed to be
* filtering or reflecting light here.
* This is much better than returning just black,
* but something better might be done.
*/
#ifdef RT_MULTISPECTRAL
BN_CK_TABDATA(swp->msw_color);
BN_CK_TABDATA(swp->msw_basecolor);
bn_tabdata_copy(swp->msw_color, swp->msw_basecolor);
#else
VMOVE(swp->sw_color, swp->sw_basecolor);
#endif
ap->a_cumlen += pp->pt_inhit->hit_dist;
goto out;
}
#ifdef RT_MULTISPECTRAL
BN_CK_TABDATA(swp->msw_basecolor);
ms_filter_color = bn_tabdata_dup(swp->msw_basecolor);
#else
VMOVE(filter_color, swp->sw_basecolor);
#endif
if ((swp->sw_inputs & (MFI_HIT|MFI_NORMAL)) != (MFI_HIT|MFI_NORMAL))
shade_inputs(ap, pp, swp, MFI_HIT|MFI_NORMAL);
/*
* If this ray is being fired from the exit point of
* an object, and is directly entering another object,
* (i.e., there is no intervening air-gap), and
* the two refractive indices match, then do not fire a
* reflected ray -- just take the transmission contribution.
* This is important, e.g., for glass gun tubes projecting
* through a glass armor plate. :-)
*/
if (NEAR_ZERO(pp->pt_inhit->hit_dist, AIR_GAP_TOL)
&& ZERO(ap->a_refrac_index - swp->sw_refrac_index))
{
transmit += reflect;
reflect = 0;
}
/*
* Diminish base color appropriately, and add in
* contributions from mirror reflection & transparency
*/
shader_fract = 1 - (reflect + transmit);
if (shader_fract < 0) {
shader_fract = 0;
} else if (shader_fract >= 1) {
goto out;
}
if (R_DEBUG&RDEBUG_REFRACT) {
bu_log("rr_render: lvl=%d start shader=%g, reflect=%g, transmit=%g %s\n",
ap->a_level,
shader_fract, reflect, transmit,
pp->pt_regionp->reg_name);
}
#ifdef RT_MULTISPECTRAL
BN_GET_TABDATA(ms_shader_color, swp->msw_color->table);
bn_tabdata_scale(ms_shader_color, swp->msw_color, shader_fract);
#else
VSCALE(shader_color, swp->sw_color, shader_fract);
#endif
/*
* Compute transmission through an object.
* There may be a mirror reflection, which will be handled
* by the reflection code later
*/
if (transmit > 0) {
if (R_DEBUG&RDEBUG_REFRACT) {
bu_log("rr_render: lvl=%d transmit=%g. Calculate refraction at entrance to %s.\n",
ap->a_level, transmit,
pp->pt_regionp->reg_name);
}
/*
* Calculate refraction at entrance.
*/
sub_ap = *ap; /* struct copy */
#ifdef RT_MULTISPECTRAL
sub_ap.a_spectrum = bn_tabdata_dup((struct bn_tabdata *)ap->a_spectrum);
#endif
sub_ap.a_level = 0; /* # of internal reflections */
sub_ap.a_cumlen = 0; /* distance through the glass */
sub_ap.a_user = -1; /* sanity */
sub_ap.a_rbeam = ap->a_rbeam + swp->sw_hit.hit_dist * ap->a_diverge;
sub_ap.a_diverge = 0.0;
sub_ap.a_uptr = (genptr_t)(pp->pt_regionp);
VMOVE(sub_ap.a_ray.r_pt, swp->sw_hit.hit_point);
VMOVE(incident_dir, ap->a_ray.r_dir);
/* If there is an air gap, reset ray's RI to air */
if (pp->pt_inhit->hit_dist > AIR_GAP_TOL)
sub_ap.a_refrac_index = RI_AIR;
if (!ZERO(sub_ap.a_refrac_index - swp->sw_refrac_index)
&& !rr_refract(incident_dir, /* input direction */
swp->sw_hit.hit_normal, /* exit normal */
sub_ap.a_refrac_index, /* current RI */
swp->sw_refrac_index, /* next RI */
sub_ap.a_ray.r_dir /* output direction */
))
{
/*
* Ray was mirror reflected back outside solid.
* Just add contribution to reflection,
* and quit.
*/
reflect += transmit;
transmit = 0;
#ifdef RT_MULTISPECTRAL
ms_transmit_color = bn_tabdata_get_constval(0.0, spectrum);
#else
VSETALL(transmit_color, 0);
#endif
if (R_DEBUG&RDEBUG_REFRACT) {
bu_log("rr_render: lvl=%d change xmit into reflection %s\n",
ap->a_level,
pp->pt_regionp->reg_name);
}
goto do_reflection;
}
if (R_DEBUG&RDEBUG_REFRACT) {
bu_log("rr_render: lvl=%d begin transmission through %s.\n",
ap->a_level,
pp->pt_regionp->reg_name);
}
/*
* Find new exit point from the inside.
* We will iterate, but not recurse, due to the special
* (non-recursing) hit and miss routines used here for
* internal reflection.
*
* a_onehit is set to 3, so that where possible,
* rr_hit() will be given three accurate hit points:
* the entry and exit points of this glass region,
* and the entry point into the next region.
* This permits calculation of the departing
* refraction angle based on the RI of the current and
* *next* regions along the ray.
*/
sub_ap.a_purpose = "rr first glass transmission ray";
sub_ap.a_flag = 0;
do_inside:
sub_ap.a_hit = rr_hit;
sub_ap.a_miss = rr_miss;
sub_ap.a_logoverlap = ap->a_logoverlap;
sub_ap.a_onehit = 3;
sub_ap.a_rbeam = ap->a_rbeam + swp->sw_hit.hit_dist * ap->a_diverge;
sub_ap.a_diverge = 0.0;
switch (code = rt_shootray(&sub_ap)) {
case 3:
/* More glass to come.
* uvec=exit_pt, vvec=N, a_refrac_index = next RI.
*/
break;
case 2:
/* No more glass to come.
* uvec=exit_pt, vvec=N, a_refrac_index = next RI.
*/
break;
case 1:
/* Treat as escaping ray */
if (R_DEBUG&RDEBUG_REFRACT)
bu_log("rr_refract: Treating as escaping ray\n");
goto do_exit;
case 0:
default:
/* Dreadful error */
#ifdef RT_MULTISPECTRAL
bu_bomb("rr_refract: Stuck in glass. Very green pixel, unsupported in multi-spectral mode\n");
#else
VSET(swp->sw_color, 0, 99, 0); /* very green */
#endif
goto out; /* abandon hope */
}
if (R_DEBUG&RDEBUG_REFRACT) {
bu_log("rr_render: calculating refraction @ exit from %s (green)\n", pp->pt_regionp->reg_name);
bu_log("Start point to exit point:\n\
vdraw open rr;vdraw params c 00ff00; vdraw write n 0 %g %g %g; vdraw wwrite n 1 %g %g %g; vdraw send\n",
V3ARGS(sub_ap.a_ray.r_pt),
V3ARGS(sub_ap.a_uvec));
}
/* NOTE: rr_hit returns EXIT Point in sub_ap.a_uvec,
* and returns EXIT Normal in sub_ap.a_vvec,
* and returns next RI in sub_ap.a_refrac_index
*/
if (R_DEBUG&RDEBUG_RAYWRITE) {
wraypts(sub_ap.a_ray.r_pt,
sub_ap.a_ray.r_dir,
sub_ap.a_uvec,
2, ap, stdout); /* 2 = ?? */
}
if (R_DEBUG&RDEBUG_RAYPLOT) {
/* plotfp */
bu_semaphore_acquire(BU_SEM_SYSCALL);
pl_color(stdout, 0, 255, 0);
pdv_3line(stdout,
sub_ap.a_ray.r_pt,
sub_ap.a_uvec);
bu_semaphore_release(BU_SEM_SYSCALL);
}
/* Advance. Exit point becomes new start point */
VMOVE(sub_ap.a_ray.r_pt, sub_ap.a_uvec);
VMOVE(incident_dir, sub_ap.a_ray.r_dir);
/*
* Calculate refraction at exit point.
* Use "look ahead" RI value from rr_hit.
*/
if (!ZERO(sub_ap.a_refrac_index - swp->sw_refrac_index)
&& !rr_refract(incident_dir, /* input direction */
sub_ap.a_vvec, /* exit normal */
swp->sw_refrac_index, /* current RI */
sub_ap.a_refrac_index, /* next RI */
sub_ap.a_ray.r_dir /* output direction */
))
{
static long count = 0; /* not PARALLEL, should be OK */
/* Reflected internally -- keep going */
if ((++sub_ap.a_level) <= max_ireflect) {
sub_ap.a_purpose = "rr reflected internal ray, probing for glass exit point";
sub_ap.a_flag = 0;
goto do_inside;
}
/*
* Internal Reflection limit exceeded -- just let
* the ray escape, continuing on current course.
* This will cause some energy from somewhere in the
* scene to be received through this glass,
* which is much better than just returning
* grey or black, as before.
*/
if ((R_DEBUG&(RDEBUG_SHOWERR|RDEBUG_REFRACT)) && (
count++ < MSG_PROLOGUE ||
(count%MSG_INTERVAL) == 3
)) {
bu_log("rr_render: %d, %d Int.reflect=%d: %s lvl=%d\n",
sub_ap.a_x, sub_ap.a_y,
sub_ap.a_level,
pp->pt_regionp->reg_name,
ap->a_level);
}
VMOVE(sub_ap.a_ray.r_dir, incident_dir);
goto do_exit;
}
do_exit:
/*
* Compute internal spectral transmittance.
* Bouger's law. pg 30 of "color science"
*
* Apply attenuation factor due to thickness of the glass.
* sw_extinction is in terms of fraction of light absorbed
* per linear meter of glass. a_cumlen is in mm.
*/
/* XXX extinction should be a spectral curve, not scalor */
if (swp->sw_extinction > 0 && sub_ap.a_cumlen > 0) {
attenuation = pow(10.0, -1.0e-3 * sub_ap.a_cumlen *
swp->sw_extinction);
} else {
attenuation = 1;
}
/*
* Process the escaping refracted ray.
* This is the only place we might recurse dangerously,
* so we are careful to use our caller's recursion level+1.
* NOTE: point & direction already filled in
*/
sub_ap.a_hit = ap->a_hit;
sub_ap.a_miss = ap->a_miss;
sub_ap.a_logoverlap = ap->a_logoverlap;
sub_ap.a_onehit = ap->a_onehit;
sub_ap.a_level = ap->a_level+1;
sub_ap.a_uptr = ap->a_uptr;
sub_ap.a_rbeam = ap->a_rbeam + swp->sw_hit.hit_dist * ap->a_diverge;
sub_ap.a_diverge = 0.0;
if (code == 3) {
sub_ap.a_purpose = "rr recurse on next glass";
sub_ap.a_flag = 0;
} else {
sub_ap.a_purpose = "rr recurse on escaping internal ray";
sub_ap.a_flag = 1;
sub_ap.a_onehit = sub_ap.a_onehit > -3 ? -3 : sub_ap.a_onehit;
}
/* sub_ap.a_refrac_index was set to RI of next material by rr_hit().
*/
sub_ap.a_cumlen = 0;
(void) rt_shootray(&sub_ap);
/* a_user has hit/miss flag! */
if (sub_ap.a_user == 0) {
#ifdef RT_MULTISPECTRAL
ms_transmit_color = bn_tabdata_dup(background);
#else
VMOVE(transmit_color, background);
#endif
sub_ap.a_cumlen = 0;
} else {
#ifdef RT_MULTISPECTRAL
ms_transmit_color = bn_tabdata_dup(sub_ap.a_spectrum);
#else
VMOVE(transmit_color, sub_ap.a_color);
#endif
}
transmit *= attenuation;
#ifdef RT_MULTISPECTRAL
bn_tabdata_mul(ms_transmit_color, ms_filter_color, ms_transmit_color);
#else
VELMUL(transmit_color, filter_color, transmit_color);
#endif
if (R_DEBUG&RDEBUG_REFRACT) {
bu_log("rr_render: lvl=%d end of xmit through %s\n",
ap->a_level,
pp->pt_regionp->reg_name);
}
} else {
