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pmapmat.c

#ifndef lint
static const char RCSid[] = "$Id: pmapmat.c,v 2.22 2020/01/13 17:12:19 rschregle Exp $";
#endif
/*
==================================================================
Photon map support routines for scattering by materials.
Roland Schregle (roland.schregle@{hslu.ch, gmail.com})
(c) Fraunhofer Institute for Solar Energy Systems,
(c) Lucerne University of Applied Sciences and Arts,
supported by the Swiss National Science Foundation (SNSF, #147053)
==================================================================
*/
#include "pmapmat.h"
#include "pmapdata.h"
#include "pmaprand.h"
#include "otypes.h"
#include "data.h"
#include "func.h"
#include "bsdf.h"
#include <math.h>
/* Stuff ripped off from material modules */
#define MAXITER 10
#define SP_REFL 01
#define SP_TRAN 02
#define SP_PURE 04
#define SP_FLAT 010
#define SP_BADU 040
#define MLAMBDA 500
#define RINDEX 1.52
#define FRESNE(ci) (exp(-5.85*(ci)) - 0.00287989916)
typedef struct {
OBJREC *mp;
RAY *rp;
short specfl;
COLOR mcolor, scolor;
FVECT vrefl, prdir, pnorm;
double alpha2, rdiff, rspec, trans, tdiff, tspec, pdot;
} NORMDAT;
typedef struct {
OBJREC *mp;
RAY *rp;
short specfl;
COLOR mcolor, scolor;
FVECT vrefl, prdir, u, v, pnorm;
double u_alpha, v_alpha, rdiff, rspec, trans, tdiff, tspec, pdot;
} ANISODAT;
typedef struct {
OBJREC *mp;
RAY *pr;
DATARRAY *dp;
COLOR mcolor;
COLOR rdiff;
COLOR tdiff;
double rspec;
double trans;
double tspec;
FVECT pnorm;
double pdot;
} BRDFDAT;
typedef struct {
OBJREC *mp;
RAY *pr;
FVECT pnorm;
FVECT vray;
double sr_vpsa [2];
RREAL toloc [3][3];
RREAL fromloc [3][3];
double thick;
SDData *sd;
COLOR runsamp;
COLOR rdiff;
COLOR tunsamp;
COLOR tdiff;
} BSDFDAT;
extern const SDCDst SDemptyCD;
/* Per-material scattering function dispatch table; return value is usually
* zero, indicating photon termination */
int (*photonScatter [NUMOTYPE]) (OBJREC*, RAY*);
/* List of antimatter sensor modifier names and associated object set */
char *photonSensorList [MAXSET + 1] = {NULL};
static OBJECT photonSensorSet [MAXSET + 1] = {0};
/* ================ General support routines ================ */
void photonRay (const RAY *rayIn, RAY *rayOut,
int rayOutType, COLOR fluxAtten)
/* Spawn a new photon ray from a previous one; this is effectively a
* customised rayorigin().
* A SPECULAR rayOutType flags this photon as _caustic_ for subsequent hits.
* It is preserved for transferred rays (of type PMAP_XFER).
* fluxAtten specifies the RGB attenuation of the photon flux effected by
* the scattering material. The outgoing flux is then normalised to maintain
* a uniform average of 1 over RGB. If fluxAtten == NULL, the flux remains
* unchanged for the outgoing photon. fluxAtten is ignored for transferred
* rays.
* The ray direction is preserved for transferred rays, and undefined for
* scattered rays and must be subsequently set by the caller. */
{
rayorigin(rayOut, rayOutType, rayIn, NULL);
if (rayIn) {
/* Transfer flux */
copycolor(rayOut -> rcol, rayIn -> rcol);
/* Copy caustic flag & direction for transferred rays */
if (rayOutType == PMAP_XFER) {
/* rayOut -> rtype |= rayIn -> rtype & SPECULAR; */
rayOut -> rtype |= rayIn -> rtype;
VCOPY(rayOut -> rdir, rayIn -> rdir);
}
else if (fluxAtten) {
/* Attenuate and normalise flux for scattered rays */
multcolor(rayOut -> rcol, fluxAtten);
colorNorm(rayOut -> rcol);
}
/* Propagate index of emitting light source */
rayOut -> rsrc = rayIn -> rsrc;
/* Update maximum photon path distance */
rayOut -> rmax = rayIn -> rmax - rayIn -> rot;
}
}
static void addPhotons (const RAY *r)
/* Insert photon hits, where applicable */
{
if (!r -> rlvl)
/* Add direct photon at primary hitpoint */
newPhoton(directPmap, r);
else {
/* Add global or precomputed photon at indirect hitpoint */
newPhoton(preCompPmap ? preCompPmap : globalPmap, r);
/* Store caustic photon if specular flag set */
if (PMAP_CAUSTICRAY(r))
newPhoton(causticPmap, r);
/* Store in contribution photon map */
newPhoton(contribPmap, r);
}
}
void getPhotonSensors (char **sensorList)
/* Find antimatter geometry declared as photon sensors */
{
OBJECT i;
OBJREC *obj;
char **lp;
/* Init sensor set */
photonSensorSet [0] = 0;
if (!sensorList [0])
return;
for (i = 0; i < nobjects; i++) {
obj = objptr(i);
/* Insert object in sensor set if it's in the specified sensor list
* and of type antimatter */
for (lp = sensorList; *lp; lp++) {
if (!strcmp(obj -> oname, *lp)) {
if (obj -> otype != MAT_CLIP) {
sprintf(errmsg, "photon sensor modifier %s is not antimatter",
obj -> oname);
error(USER, errmsg);
}
if (photonSensorSet [0] >= AMBLLEN)
error(USER, "too many photon sensor modifiers");
insertelem(photonSensorSet, i);
}
}
}
if (!photonSensorSet [0])
error(USER, "no photon sensors found");
}
/* ================ Material specific scattering routines ================ */
static int isoSpecPhotonScatter (NORMDAT *nd, RAY *rayOut)
/* Generate direction for isotropically specularly reflected
or transmitted ray. Returns 1 if successful. */
{
FVECT u, v, h;
RAY *rayIn = nd -> rp;
double d, d2, sinp, cosp;
int niter, i = 0;
/* Set up sample coordinates */
getperpendicular(u, nd -> pnorm, 1);
fcross(v, nd -> pnorm, u);
if (nd -> specfl & SP_REFL) {
/* Specular reflection; make MAXITER attempts at getting a ray */
for (niter = 0; niter < MAXITER; niter++) {
d = 2 * PI * pmapRandom(scatterState);
cosp = cos(d);
sinp = sin(d);
d2 = pmapRandom(scatterState);
d = d2 <= FTINY ? 1 : sqrt(nd -> alpha2 * -log(d2));
for (i = 0; i < 3; i++)
h [i] = nd -> pnorm [i] + d * (cosp * u [i] + sinp * v [i]);
d = -2 * DOT(h, rayIn -> rdir) / (1 + d * d);
VSUM(rayOut -> rdir, rayIn -> rdir, h, d);
if (DOT(rayOut -> rdir, rayIn -> ron) > FTINY)
return 1;
}
return 0;
}
else {
/* Specular transmission; make MAXITER attempts at getting a ray */
for (niter = 0; niter < MAXITER; niter++) {
d = 2 * PI * pmapRandom(scatterState);
cosp = cos(d);
sinp = sin(d);
d2 = pmapRandom(scatterState);
d = d2 <= FTINY ? 1 : sqrt(-log(d2) * nd -> alpha2);
for (i = 0; i < 3; i++)
rayOut -> rdir [i] = nd -> prdir [i] +
d * (cosp * u [i] + sinp * v [i]);
if (DOT(rayOut -> rdir, rayIn -> ron) < -FTINY) {
normalize(rayOut -> rdir);
return 1;
}
}
return 0;
}
}
static void diffPhotonScatter (FVECT normal, RAY* rayOut)
/* Generate cosine-weighted direction for diffuse ray */
{
const RREAL cosThetaSqr = pmapRandom(scatterState),
cosTheta = sqrt(cosThetaSqr),
sinTheta = sqrt(1 - cosThetaSqr),
phi = 2 * PI * pmapRandom(scatterState),
du = cos(phi) * sinTheta, dv = sin(phi) * sinTheta;
FVECT u, v;
int i = 0;
/* Set up sample coordinates */
getperpendicular(u, normal, 1);
fcross(v, normal, u);
/* Convert theta & phi to cartesian */
for (i = 0; i < 3; i++)
rayOut -> rdir [i] = du * u [i] + dv * v [i] + cosTheta * normal [i];
normalize(rayOut -> rdir);
}
static int normalPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Generate new photon ray for isotropic material and recurse */
{
NORMDAT nd;
int i, hastexture;
float xi, albedo, prdiff, ptdiff, prspec, ptspec;
double d, fresnel;
RAY rayOut;
if (mat -> oargs.nfargs != (mat -> otype == MAT_TRANS ? 7 : 5))
objerror(mat, USER, "bad number of arguments");
/* Check for back side; reorient if back is visible */
if (rayIn -> rod < 0)
if (!backvis && mat -> otype != MAT_TRANS)
return 0;
else {
/* Get modifiers */
raytexture(rayIn, mat -> omod);
flipsurface(rayIn);
}
else raytexture(rayIn, mat -> omod);
nd.mp = mat;
nd.rp = rayIn;
/* Get material color */
copycolor(nd.mcolor, mat -> oargs.farg);
/* Get roughness */
nd.specfl = 0;
nd.alpha2 = mat -> oargs.farg [4];
if ((nd.alpha2 *= nd.alpha2) <= FTINY)
nd.specfl |= SP_PURE;
if (rayIn -> ro != NULL && isflat(rayIn -> ro -> otype))
nd.specfl |= SP_FLAT;
/* Perturb normal */
if ((hastexture = (DOT(rayIn -> pert, rayIn -> pert) > sqr(FTINY)) ))
nd.pdot = raynormal(nd.pnorm, rayIn);
else {
VCOPY(nd.pnorm, rayIn -> ron);
nd.pdot = rayIn -> rod;
}
nd.pdot = max(nd.pdot, .001);
/* Modify material color */
multcolor(nd.mcolor, rayIn -> pcol);
nd.rspec = mat -> oargs.farg [3];
/* Approximate Fresnel term */
if (nd.specfl & SP_PURE && nd.rspec > FTINY) {
fresnel = FRESNE(rayIn -> rod);
nd.rspec += fresnel * (1 - nd.rspec);
}
else fresnel = 0;
/* Transmission params */
if (mat -> otype == MAT_TRANS) {
nd.trans = mat -> oargs.farg [5] * (1 - nd.rspec);
nd.tspec = nd.trans * mat -> oargs.farg [6];
nd.tdiff = nd.trans - nd.tspec;
}
else nd.tdiff = nd.tspec = nd.trans = 0;
/* Specular reflection params */
if (nd.rspec > FTINY) {
/* Specular color */
if (mat -> otype != MAT_METAL)
setcolor(nd.scolor, nd.rspec, nd.rspec, nd.rspec);
else if (fresnel > FTINY) {
d = nd.rspec * (1 - fresnel);
for (i = 0; i < 3; i++)
nd.scolor [i] = fresnel + nd.mcolor [i] * d;
}
else {
copycolor(nd.scolor, nd.mcolor);
scalecolor(nd.scolor, nd.rspec);
}
}
else setcolor(nd.scolor, 0, 0, 0);
/* Diffuse reflection params */
nd.rdiff = 1 - nd.trans - nd.rspec;
/* Set up probabilities */
prdiff = ptdiff = ptspec = colorAvg(nd.mcolor);
prdiff *= nd.rdiff;
ptdiff *= nd.tdiff;
prspec = colorAvg(nd.scolor);
ptspec *= nd.tspec;
albedo = prdiff + ptdiff + prspec + ptspec;
/* Insert direct and indirect photon hits if diffuse component */
if (prdiff > FTINY || ptdiff > FTINY)
addPhotons(rayIn);
xi = pmapRandom(rouletteState);
if (xi > albedo)
/* Absorbed */
return 0;
if (xi > (albedo -= prspec)) {
/* Specular reflection */
nd.specfl |= SP_REFL;
if (nd.specfl & SP_PURE) {
/* Perfect specular reflection */
for (i = 0; i < 3; i++) {
/* Reflected ray */
nd.vrefl [i] = rayIn -> rdir [i] + 2 * nd.pdot * nd.pnorm [i];
}
/* Penetration? */
if (hastexture && DOT(nd.vrefl, rayIn -> ron) <= FTINY)
for (i = 0; i < 3; i++) {
/* Safety measure */
nd.vrefl [i] = rayIn -> rdir [i] +
2 * rayIn -> rod * rayIn -> ron [i];
}
VCOPY(rayOut.rdir, nd.vrefl);
}
else if (!isoSpecPhotonScatter(&nd, &rayOut))
return 0;
photonRay(rayIn, &rayOut, PMAP_SPECREFL, nd.scolor);
}
else if (xi > (albedo -= ptspec)) {
/* Specular transmission */
nd.specfl |= SP_TRAN;
if (hastexture) {
/* Perturb */
for (i = 0; i < 3; i++)
nd.prdir [i] = rayIn -> rdir [i] - rayIn -> pert [i];
if (DOT(nd.prdir, rayIn -> ron) < -FTINY)
normalize(nd.prdir);
else VCOPY(nd.prdir, rayIn -> rdir);
}
else VCOPY(nd.prdir, rayIn -> rdir);
if ((nd.specfl & (SP_TRAN | SP_PURE)) == (SP_TRAN | SP_PURE))
/* Perfect specular transmission */
VCOPY(rayOut.rdir, nd.prdir);
else if (!isoSpecPhotonScatter(&nd, &rayOut))
return 0;
photonRay(rayIn, &rayOut, PMAP_SPECTRANS, nd.mcolor);
}
else if (xi > (albedo -= prdiff)) {
/* Diffuse reflection */
photonRay(rayIn, &rayOut, PMAP_DIFFREFL, nd.mcolor);
diffPhotonScatter(hastexture ? nd.pnorm : rayIn -> ron, &rayOut);
}
else {
/* Diffuse transmission */
flipsurface(rayIn);
photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, nd.mcolor);
if (hastexture) {
FVECT bnorm;
bnorm [0] = -nd.pnorm [0];
bnorm [1] = -nd.pnorm [1];
bnorm [2] = -nd.pnorm [2];
diffPhotonScatter(bnorm, &rayOut);
}
else diffPhotonScatter(rayIn -> ron, &rayOut);
}
tracePhoton(&rayOut);
return 0;
}
static void getacoords (ANISODAT *nd)
/* Set up coordinate system for anisotropic sampling; cloned from aniso.c */
{
MFUNC *mf;
int i;
mf = getfunc(nd -> mp, 3, 0x7, 1);
setfunc(nd -> mp, nd -> rp);
errno = 0;
for (i = 0; i < 3; i++)
nd -> u [i] = evalue(mf -> ep [i]);
if (errno == EDOM || errno == ERANGE)
nd -> u [0] = nd -> u [1] = nd -> u [2] = 0.0;
if (mf -> fxp != &unitxf)
multv3(nd -> u, nd -> u, mf -> fxp -> xfm);
fcross(nd -> v, nd -> pnorm, nd -> u);
if (normalize(nd -> v) == 0.0) {
if (fabs(nd -> u_alpha - nd -> v_alpha) > 0.001)
objerror(nd -> mp, WARNING, "illegal orientation vector");
getperpendicular(nd -> u, nd -> pnorm, 1);
fcross(nd -> v, nd -> pnorm, nd -> u);
nd -> u_alpha = nd -> v_alpha =
sqrt(0.5 * (sqr(nd -> u_alpha) + sqr(nd -> v_alpha)));
}
else fcross(nd -> u, nd -> v, nd -> pnorm);
}
static int anisoSpecPhotonScatter (ANISODAT *nd, RAY *rayOut)
/* Generate direction for anisotropically specularly reflected
or transmitted ray. Returns 1 if successful. */
{
FVECT h;
double d, d2, sinp, cosp;
int niter, i;
RAY *rayIn = nd -> rp;
if (rayIn -> ro != NULL && isflat(rayIn -> ro -> otype))
nd -> specfl |= SP_FLAT;
/* set up coordinates */
getacoords(nd);
if (rayOut -> rtype & TRANS) {
/* Specular transmission */
if (DOT(rayIn -> pert, rayIn -> pert) <= sqr(FTINY))
VCOPY(nd -> prdir, rayIn -> rdir);
else {
/* perturb */
for (i = 0; i < 3; i++)
nd -> prdir [i] = rayIn -> rdir [i] - rayIn -> pert [i];
if (DOT(nd -> prdir, rayIn -> ron) < -FTINY)
normalize(nd -> prdir);
else VCOPY(nd -> prdir, rayIn -> rdir);
}
/* Make MAXITER attempts at getting a ray */
for (niter = 0; niter < MAXITER; niter++) {
d = 2 * PI * pmapRandom(scatterState);
cosp = cos(d) * nd -> u_alpha;
sinp = sin(d) * nd -> v_alpha;
d = sqrt(sqr(cosp) + sqr(sinp));
cosp /= d;
sinp /= d;
d2 = pmapRandom(scatterState);
d = d2 <= FTINY ? 1
: sqrt(-log(d2) /
(sqr(cosp) / sqr(nd -> u_alpha) +
sqr(sinp) / (nd -> v_alpha * nd -> u_alpha)));
for (i = 0; i < 3; i++)
rayOut -> rdir [i] = nd -> prdir [i] + d *
(cosp * nd -> u [i] + sinp * nd -> v [i]);
if (DOT(rayOut -> rdir, rayIn -> ron) < -FTINY) {
normalize(rayOut -> rdir);
return 1;
}
}
return 0;
}
else {
/* Specular reflection */
/* Make MAXITER attempts at getting a ray */
for (niter = 0; niter < MAXITER; niter++) {
d = 2 * PI * pmapRandom(scatterState);
cosp = cos(d) * nd -> u_alpha;
sinp = sin(d) * nd -> v_alpha;
d = sqrt(sqr(cosp) + sqr(sinp));
cosp /= d;
sinp /= d;
d2 = pmapRandom(scatterState);
d = d2 <= FTINY ? 1
: sqrt(-log(d2) /
(sqr(cosp) / sqr(nd -> u_alpha) +
sqr(sinp) / (nd->v_alpha * nd->v_alpha)));
for (i = 0; i < 3; i++)
h [i] = nd -> pnorm [i] +
d * (cosp * nd -> u [i] + sinp * nd -> v [i]);
d = -2 * DOT(h, rayIn -> rdir) / (1 + d * d);
VSUM(rayOut -> rdir, rayIn -> rdir, h, d);
if (DOT(rayOut -> rdir, rayIn -> ron) > FTINY)
return 1;
}
return 0;
}
}
static int anisoPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Generate new photon ray for anisotropic material and recurse */
{
ANISODAT nd;
float xi, albedo, prdiff, ptdiff, prspec, ptspec;
RAY rayOut;
if (mat -> oargs.nfargs != (mat -> otype == MAT_TRANS2 ? 8 : 6))
objerror(mat, USER, "bad number of real arguments");
nd.mp = mat;
nd.rp = rayIn;
/* get material color */
copycolor(nd.mcolor, mat -> oargs.farg);
/* get roughness */
nd.specfl = 0;
nd.u_alpha = mat -> oargs.farg [4];
nd.v_alpha = mat -> oargs.farg [5];
if (nd.u_alpha < FTINY || nd.v_alpha <= FTINY)
objerror(mat, USER, "roughness too small");
/* check for back side; reorient if back is visible */
if (rayIn -> rod < 0)
if (!backvis && mat -> otype != MAT_TRANS2)
return 0;
else {
/* get modifiers */
raytexture(rayIn, mat -> omod);
flipsurface(rayIn);
}
else raytexture(rayIn, mat -> omod);
/* perturb normal */
nd.pdot = max(raynormal(nd.pnorm, rayIn), .001);
/* modify material color */
multcolor(nd.mcolor, rayIn -> pcol);
nd.rspec = mat -> oargs.farg [3];
/* transmission params */
if (mat -> otype == MAT_TRANS2) {
nd.trans = mat -> oargs.farg [6] * (1 - nd.rspec);
nd.tspec = nd.trans * mat -> oargs.farg [7];
nd.tdiff = nd.trans - nd.tspec;
if (nd.tspec > FTINY)
nd.specfl |= SP_TRAN;
}
else nd.tdiff = nd.tspec = nd.trans = 0;
/* specular reflection params */
if (nd.rspec > FTINY) {
nd.specfl |= SP_REFL;
/* compute specular color */
if (mat -> otype == MAT_METAL2)
copycolor(nd.scolor, nd.mcolor);
else setcolor(nd.scolor, 1, 1, 1);
scalecolor(nd.scolor, nd.rspec);
}
else setcolor(nd.scolor, 0, 0, 0);
/* diffuse reflection params */
nd.rdiff = 1 - nd.trans - nd.rspec;
/* Set up probabilities */
prdiff = ptdiff = ptspec = colorAvg(nd.mcolor);
prdiff *= nd.rdiff;
ptdiff *= nd.tdiff;
prspec = colorAvg(nd.scolor);
ptspec *= nd.tspec;
albedo = prdiff + ptdiff + prspec + ptspec;
/* Insert direct and indirect photon hits if diffuse component */
if (prdiff > FTINY || ptdiff > FTINY)
addPhotons(rayIn);
xi = pmapRandom(rouletteState);
if (xi > albedo)
/* Absorbed */
return 0;
if (xi > (albedo -= prspec))
/* Specular reflection */
if (!(nd.specfl & SP_BADU)) {
photonRay(rayIn, &rayOut, PMAP_SPECREFL, nd.scolor);
if (!anisoSpecPhotonScatter(&nd, &rayOut))
return 0;
}
else return 0;
else if (xi > (albedo -= ptspec))
/* Specular transmission */
if (!(nd.specfl & SP_BADU)) {
/* Specular transmission */
photonRay(rayIn, &rayOut, PMAP_SPECTRANS, nd.mcolor);
if (!anisoSpecPhotonScatter(&nd, &rayOut))
return 0;
}
else return 0;
else if (xi > (albedo -= prdiff)) {
/* Diffuse reflection */
photonRay(rayIn, &rayOut, PMAP_DIFFREFL, nd.mcolor);
diffPhotonScatter(nd.pnorm, &rayOut);
}
else {
/* Diffuse transmission */
FVECT bnorm;
flipsurface(rayIn);
bnorm [0] = -nd.pnorm [0];
bnorm [1] = -nd.pnorm [1];
bnorm [2] = -nd.pnorm [2];
photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, nd.mcolor);
diffPhotonScatter(bnorm, &rayOut);
}
tracePhoton(&rayOut);
return 0;
}
static double mylog (double x)
/* special log for extinction coefficients; cloned from dielectric.c */
{
if (x < 1e-40)
return(-100.);
if (x >= 1.)
return(0.);
return(log(x));
}
static int dielectricPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Generate new photon ray for dielectric material and recurse */
{
double cos1, cos2, nratio, d1, d2, refl;
COLOR ctrans, talb;
FVECT dnorm;
int hastexture, i;
RAY rayOut;
if (mat -> oargs.nfargs != (mat -> otype == MAT_DIELECTRIC ? 5 : 8))
objerror(mat, USER, "bad arguments");
/* get modifiers */
raytexture(rayIn, mat -> omod);
if ((hastexture = (DOT(rayIn -> pert, rayIn -> pert) > sqr(FTINY))))
/* Perturb normal */
cos1 = raynormal(dnorm, rayIn);
else {
VCOPY(dnorm, rayIn -> ron);
cos1 = rayIn -> rod;
}
/* index of refraction */
nratio = mat -> otype ==
MAT_DIELECTRIC ? mat->oargs.farg[3] + mat->oargs.farg[4] / MLAMBDA
: mat->oargs.farg[3] / mat->oargs.farg[7];
if (cos1 < 0) {
/* inside */
hastexture = -hastexture;
cos1 = -cos1;
dnorm [0] = -dnorm [0];
dnorm [1] = -dnorm [1];
dnorm [2] = -dnorm [2];
setcolor(rayIn -> cext,
-mylog(mat -> oargs.farg [0] * rayIn -> pcol [0]),
-mylog(mat -> oargs.farg [1] * rayIn -> pcol [1]),
-mylog(mat -> oargs.farg [2] * rayIn -> pcol [2]));
setcolor(rayIn -> albedo, 0, 0, 0);
rayIn -> gecc = 0;
if (mat -> otype == MAT_INTERFACE) {
setcolor(ctrans,
-mylog(mat -> oargs.farg [4] * rayIn -> pcol [0]),
-mylog(mat -> oargs.farg [5] * rayIn -> pcol [1]),
-mylog(mat -> oargs.farg [6] * rayIn -> pcol [2]));
setcolor(talb, 0, 0, 0);
}
else {
copycolor(ctrans, cextinction);
copycolor(talb, salbedo);
}
}
else {
/* outside */
nratio = 1.0 / nratio;
setcolor(ctrans,
-mylog(mat -> oargs.farg [0] * rayIn -> pcol [0]),
-mylog(mat -> oargs.farg [1] * rayIn -> pcol [1]),
-mylog(mat -> oargs.farg [2] * rayIn -> pcol [2]));
setcolor(talb, 0, 0, 0);
if (mat -> otype == MAT_INTERFACE) {
setcolor(rayIn -> cext,
-mylog(mat -> oargs.farg [4] * rayIn -> pcol [0]),
-mylog(mat -> oargs.farg [5] * rayIn -> pcol [1]),
-mylog(mat -> oargs.farg [6] * rayIn -> pcol [2]));
setcolor(rayIn -> albedo, 0, 0, 0);
rayIn -> gecc = 0;
}
}
/* compute cos theta2 */
d2 = 1 - sqr(nratio) * (1 - sqr(cos1));
if (d2 < FTINY) {
/* Total reflection */
refl = cos2 = 1.0;
}
else {
/* Refraction, compute Fresnel's equations */
cos2 = sqrt(d2);
d1 = cos1;
d2 = nratio * cos2;
d1 = (d1 - d2) / (d1 + d2);
refl = sqr(d1);
d1 = 1 / cos1;
d2 = nratio / cos2;
d1 = (d1 - d2) / (d1 + d2);
refl += sqr(d1);
refl *= 0.5;
}
if (pmapRandom(rouletteState) > refl) {
/* Refraction */
photonRay(rayIn, &rayOut, PMAP_REFRACT, NULL);
d1 = nratio * cos1 - cos2;
for (i = 0; i < 3; i++)
rayOut.rdir [i] = nratio * rayIn -> rdir [i] + d1 * dnorm [i];
if (hastexture && DOT(rayOut.rdir, rayIn->ron)*hastexture >= -FTINY) {
d1 *= hastexture;
for (i = 0; i < 3; i++)
rayOut.rdir [i] = nratio * rayIn -> rdir [i] +
d1 * rayIn -> ron [i];
normalize(rayOut.rdir);
}
copycolor(rayOut.cext, ctrans);
copycolor(rayOut.albedo, talb);
}
else {
/* Reflection */
photonRay(rayIn, &rayOut, PMAP_SPECREFL, NULL);
VSUM(rayOut.rdir, rayIn -> rdir, dnorm, 2 * cos1);
if (hastexture && DOT(rayOut.rdir, rayIn->ron) * hastexture <= FTINY)
for (i = 0; i < 3; i++)
rayOut.rdir [i] = rayIn -> rdir [i] +
2 * rayIn -> rod * rayIn -> ron [i];
}
/* Ray is modified by medium defined by cext and albedo in
* photonParticipate() */
tracePhoton(&rayOut);
return 0;
}
static int glassPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Generate new photon ray for glass material and recurse */
{
float albedo, xi, ptrans;
COLOR mcolor, refl, trans;
double pdot, cos2, d, r1e, r1m, rindex = 0.0;
FVECT pnorm, pdir;
int hastexture, i;
RAY rayOut;
/* check arguments */
if (mat -> oargs.nfargs == 3)
rindex = RINDEX;
else if (mat -> oargs.nfargs == 4)
rindex = mat -> oargs.farg [3];
else objerror(mat, USER, "bad arguments");
copycolor(mcolor, mat -> oargs.farg);
/* get modifiers */
raytexture(rayIn, mat -> omod);
/* reorient if necessary */
if (rayIn -> rod < 0)
flipsurface(rayIn);
if ((hastexture = (DOT(rayIn -> pert, rayIn -> pert) > sqr(FTINY))))
pdot = raynormal(pnorm, rayIn);
else {
VCOPY(pnorm, rayIn -> ron);
pdot = rayIn -> rod;
}
/* Modify material color */
multcolor(mcolor, rayIn -> pcol);
/* angular transmission */
cos2 = sqrt((1 - 1 / sqr(rindex)) + sqr(pdot / rindex));
setcolor(mcolor, pow(mcolor [0], 1 / cos2), pow(mcolor [1], 1 / cos2),
pow(mcolor [2], 1 / cos2));
/* compute reflection */
r1e = (pdot - rindex * cos2) / (pdot + rindex * cos2);
r1e *= r1e;
r1m = (1 / pdot - rindex / cos2) / (1 / pdot + rindex / cos2);
r1m *= r1m;
for (i = 0; i < 3; i++) {
double r1ed2, r1md2, d2;
d = mcolor [i];
d2 = sqr(d);
r1ed2 = sqr(r1e) * d2;
r1md2 = sqr(r1m) * d2;
/* compute transmittance */
trans [i] = 0.5 * d *
(sqr(1 - r1e) / (1 - r1ed2) + sqr(1 - r1m) / (1 - r1md2));
/* compute reflectance */
refl [i] = 0.5 * (r1e * (1 + (1 - 2 * r1e) * d2) / (1 - r1ed2) +
r1m * (1 + (1 - 2 * r1m) * d2) / (1 - r1md2));
}
/* Set up probabilities */
ptrans = colorAvg(trans);
albedo = colorAvg(refl) + ptrans;
xi = pmapRandom(rouletteState);
if (xi > albedo)
/* Absorbed */
return 0;
if (xi > (albedo -= ptrans)) {
/* Transmitted */
if (hastexture) {
/* perturb direction */
VSUM(pdir, rayIn -> rdir, rayIn -> pert, 2 * (1 - rindex));
if (normalize(pdir) == 0) {
objerror(mat, WARNING, "bad perturbation");
VCOPY(pdir, rayIn -> rdir);
}
}
else VCOPY(pdir, rayIn -> rdir);
VCOPY(rayOut.rdir, pdir);
photonRay(rayIn, &rayOut, PMAP_SPECTRANS, mcolor);
}
else {
/* reflected ray */
VSUM(rayOut.rdir, rayIn -> rdir, pnorm, 2 * pdot);
photonRay(rayIn, &rayOut, PMAP_SPECREFL, mcolor);
}
tracePhoton(&rayOut);
return 0;
}
static int aliasPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Transfer photon scattering to alias target */
{
OBJECT aliasObj;
OBJREC aliasRec, *aliasPtr;
/* Straight replacement? */
if (!mat -> oargs.nsargs) {
/* Skip void modifier! */
if (mat -> omod != OVOID) {
mat = objptr(mat -> omod);
photonScatter [mat -> otype] (mat, rayIn);
}
return 0;
}
/* Else replace alias */
if (mat -> oargs.nsargs != 1)
objerror(mat, INTERNAL, "bad # string arguments");
aliasPtr = mat;
aliasObj = objndx(aliasPtr);
/* Follow alias trail */
do {
aliasObj = aliasPtr -> oargs.nsargs == 1
? lastmod(aliasObj, aliasPtr -> oargs.sarg [0])
: aliasPtr -> omod;
if (aliasObj < 0)
objerror(aliasPtr, USER, "bad reference");
aliasPtr = objptr(aliasObj);
} while (aliasPtr -> otype == MOD_ALIAS);
/* Copy alias object */
aliasRec = *aliasPtr;
/* Substitute modifier */
aliasRec.omod = mat -> omod;
/* Replacement scattering routine */
photonScatter [aliasRec.otype] (&aliasRec, rayIn);
/* Avoid potential memory leak? */
if (aliasRec.os != aliasPtr -> os) {
if (aliasPtr -> os)
free_os(aliasPtr);
aliasPtr -> os = aliasRec.os;
}
return 0;
}
static int clipPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Generate new photon ray for antimatter material and recurse */
{
OBJECT obj = objndx(mat), mod, cset [MAXSET + 1], *modset;
int entering, inside = 0, i;
const RAY *rp;
RAY rayOut;
if ((modset = (OBJECT*)mat -> os) == NULL) {
if (mat -> oargs.nsargs < 1 || mat -> oargs.nsargs > MAXSET)
objerror(mat, USER, "bad # arguments");
modset = (OBJECT*)malloc((mat -> oargs.nsargs + 1) * sizeof(OBJECT));
if (modset == NULL)
error(SYSTEM, "out of memory in clipPhotonScatter");
modset [0] = 0;
for (i = 0; i < mat -> oargs.nsargs; i++) {
if (!strcmp(mat -> oargs.sarg [i], VOIDID))
continue;
if ((mod = lastmod(obj, mat -> oargs.sarg [i])) == OVOID) {
sprintf(errmsg, "unknown modifier \"%s\"", mat->oargs.sarg[i]);
objerror(mat, WARNING, errmsg);
continue;
}
if (inset(modset, mod)) {
objerror(mat, WARNING, "duplicate modifier");
continue;
}
insertelem(modset, mod);
}
mat -> os = (char*)modset;
}
if (rayIn -> clipset != NULL)
setcopy(cset, rayIn -> clipset);
else cset [0] = 0;
entering = rayIn -> rod > 0;
/* Store photon incident from front if material defined as sensor */
if (entering && inset(photonSensorSet, obj))
addPhotons(rayIn);
for (i = modset [0]; i > 0; i--) {
if (entering) {
if (!inset(cset, modset [i])) {
if (cset [0] >= MAXSET)
error(INTERNAL, "set overflow in clipPhotonScatter");
insertelem(cset, modset [i]);
}
}
else if (inset(cset, modset [i]))
deletelem(cset, modset [i]);
}
rayIn -> newcset = cset;
if (strcmp(mat -> oargs.sarg [0], VOIDID)) {
for (rp = rayIn; rp -> parent != NULL; rp = rp -> parent) {
if ( !(rp -> rtype & RAYREFL) && rp->parent->ro != NULL &&
inset(modset, rp -> parent -> ro -> omod)) {
if (rp -> parent -> rod > 0)
inside++;
else inside--;
}
}
if (inside > 0) {
flipsurface(rayIn);
mat = objptr(lastmod(obj, mat -> oargs.sarg [0]));
photonScatter [mat -> otype] (mat, rayIn);
return 0;
}
}
/* Else transfer ray */
photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
tracePhoton(&rayOut);
return 0;
}
static int mirrorPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Generate new photon ray for mirror material and recurse */
{
RAY rayOut;
int rpure = 1, i;
FVECT pnorm;
double pdot;
float albedo;
COLOR mcolor;
/* check arguments */
if (mat -> oargs.nfargs != 3 || mat -> oargs.nsargs > 1)
objerror(mat, USER, "bad number of arguments");
/* back is black */
if (rayIn -> rod < 0)
return 0;
/* get modifiers */
raytexture(rayIn, mat -> omod);
/* assign material color */
copycolor(mcolor, mat -> oargs.farg);
multcolor(mcolor, rayIn -> pcol);
/* Set up probabilities */
albedo = colorAvg(mcolor);
if (pmapRandom(rouletteState) > albedo)
/* Absorbed */
return 0;
/* compute reflected ray */
photonRay(rayIn, &rayOut, PMAP_SPECREFL, mcolor);
if (DOT(rayIn -> pert, rayIn -> pert) > sqr(FTINY)) {
/* use textures */
pdot = raynormal(pnorm, rayIn);
for (i = 0; i < 3; i++)
rayOut.rdir [i] = rayIn -> rdir [i] + 2 * pdot * pnorm [i];
rpure = 0;
}
/* Check for penetration */
if (rpure || DOT(rayOut.rdir, rayIn -> ron) <= FTINY)
for (i = 0; i < 3; i++)
rayOut.rdir [i] = rayIn -> rdir [i] +
2 * rayIn -> rod * rayIn -> ron [i];
tracePhoton(&rayOut);
return 0;
}
static int mistPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Generate new photon ray within mist and recurse */
{
COLOR mext;
RREAL re, ge, be;
RAY rayOut;
/* check arguments */
if (mat -> oargs.nfargs > 7)
objerror(mat, USER, "bad arguments");
if (mat -> oargs.nfargs > 2) {
/* compute extinction */
copycolor(mext, mat -> oargs.farg);
/* get modifiers */
raytexture(rayIn, mat -> omod);
multcolor(mext, rayIn -> pcol);
}
else setcolor(mext, 0, 0, 0);
photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
if (rayIn -> rod > 0) {
/* entering ray */
addcolor(rayOut.cext, mext);
if (mat -> oargs.nfargs > 5)
copycolor(rayOut.albedo, mat -> oargs.farg + 3);
if (mat -> oargs.nfargs > 6)
rayOut.gecc = mat -> oargs.farg [6];
}
else {
/* leaving ray */
re = max(rayIn -> cext [0] - mext [0], cextinction [0]);
ge = max(rayIn -> cext [1] - mext [1], cextinction [1]);
be = max(rayIn -> cext [2] - mext [2], cextinction [2]);
setcolor(rayOut.cext, re, ge, be);
if (mat -> oargs.nfargs > 5)
copycolor(rayOut.albedo, salbedo);
if (mat -> oargs.nfargs > 6)
rayOut.gecc = seccg;
}
tracePhoton(&rayOut);
return 0;
}
static int mx_dataPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Pass photon on to materials selected by mixture data */
{
OBJECT obj;
double coef, pt [MAXDIM];
DATARRAY *dp;
OBJECT mod [2];
MFUNC *mf;
int i;
if (mat -> oargs.nsargs < 6)
objerror(mat, USER, "bad # arguments");
obj = objndx(mat);
for (i = 0; i < 2; i++)
if (!strcmp(mat -> oargs.sarg [i], VOIDID))
mod [i] = OVOID;
else if ((mod [i] = lastmod(obj, mat -> oargs.sarg [i])) == OVOID) {
sprintf(errmsg, "undefined modifier \"%s\"", mat->oargs.sarg[i]);
objerror(mat, USER, errmsg);
}
dp = getdata(mat -> oargs.sarg [3]);
i = (1 << dp -> nd) - 1;
mf = getfunc(mat, 4, i << 5, 0);
setfunc(mat, rayIn);
errno = 0;
for (i = 0; i < dp -> nd; i++) {
pt [i] = evalue(mf -> ep [i]);
if (errno) {
objerror(mat, WARNING, "compute error");
return 0;
}
}
coef = datavalue(dp, pt);
errno = 0;
coef = funvalue(mat -> oargs.sarg [2], 1, &coef);
if (errno)
objerror(mat, WARNING, "compute error");
else {
OBJECT mxMod = mod [pmapRandom(rouletteState) < coef ? 0 : 1];
if (mxMod != OVOID) {
mat = objptr(mxMod);
photonScatter [mat -> otype] (mat, rayIn);
}
else {
/* Transfer ray if no modifier */
RAY rayOut;
photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
tracePhoton(&rayOut);
}
}
return 0;
}
static int mx_pdataPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Pass photon on to materials selected by mixture picture */
{
OBJECT obj;
double col [3], coef, pt [MAXDIM];
DATARRAY *dp;
OBJECT mod [2];
MFUNC *mf;
int i;
if (mat -> oargs.nsargs < 7)
objerror(mat, USER, "bad # arguments");
obj = objndx(mat);
for (i = 0; i < 2; i++)
if (!strcmp(mat -> oargs.sarg [i], VOIDID))
mod [i] = OVOID;
else if ((mod [i] = lastmod(obj, mat -> oargs.sarg [i])) == OVOID) {
sprintf(errmsg, "undefined modifier \"%s\"", mat->oargs.sarg[i]);
objerror(mat, USER, errmsg);
}
dp = getpict(mat -> oargs.sarg [3]);
mf = getfunc(mat, 4, 0x3 << 5, 0);
setfunc(mat, rayIn);
errno = 0;
pt [1] = evalue(mf -> ep [0]);
pt [0] = evalue(mf -> ep [1]);
if (errno) {
objerror(mat, WARNING, "compute error");
return 0;
}
for (i = 0; i < 3; i++)
col [i] = datavalue(dp + i, pt);
errno = 0;
coef = funvalue(mat -> oargs.sarg [2], 3, col);
if (errno)
objerror(mat, WARNING, "compute error");
else {
OBJECT mxMod = mod [pmapRandom(rouletteState) < coef ? 0 : 1];
if (mxMod != OVOID) {
mat = objptr(mxMod);
photonScatter [mat -> otype] (mat, rayIn);
}
else {
/* Transfer ray if no modifier */
RAY rayOut;
photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
tracePhoton(&rayOut);
}
}
return 0;
}
static int mx_funcPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Pass photon on to materials selected by mixture function */
{
OBJECT obj, mod [2];
int i;
double coef;
MFUNC *mf;
if (mat -> oargs.nsargs < 4)
objerror(mat, USER, "bad # arguments");
obj = objndx(mat);
for (i = 0; i < 2; i++)
if (!strcmp(mat -> oargs.sarg [i], VOIDID))
mod [i] = OVOID;
else if ((mod [i] = lastmod(obj, mat -> oargs.sarg [i])) == OVOID) {
sprintf(errmsg, "undefined modifier \"%s\"", mat->oargs.sarg[i]);
objerror(mat, USER, errmsg);
}
mf = getfunc(mat, 3, 0x4, 0);
setfunc(mat, rayIn);
errno = 0;
/* bound coefficient */
coef = min(1, max(0, evalue(mf -> ep [0])));
if (errno)
objerror(mat, WARNING, "compute error");
else {
OBJECT mxMod = mod [pmapRandom(rouletteState) < coef ? 0 : 1];
if (mxMod != OVOID) {
mat = objptr(mxMod);
photonScatter [mat -> otype] (mat, rayIn);
}
else {
/* Transfer ray if no modifier */
RAY rayOut;
photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
tracePhoton(&rayOut);
}
}
return 0;
}
static int pattexPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Generate new photon ray for pattern or texture modifier and recurse.
This code is brought to you by Henkel! :^) */
{
RAY rayOut;
/* Get pattern */
ofun [mat -> otype].funp(mat, rayIn);
if (mat -> omod != OVOID) {
/* Scatter using modifier (if any) */
mat = objptr(mat -> omod);
photonScatter [mat -> otype] (mat, rayIn);
}
else {
/* Transfer ray if no modifier */
photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
tracePhoton(&rayOut);
}
return 0;
}
static int setbrdfunc(BRDFDAT *bd)
/* Set up brdf function and variables; ripped off from m_brdf.c */
{
FVECT v;
if (setfunc(bd -> mp, bd -> pr) == 0)
return 0;
/* (Re)Assign func variables */
multv3(v, bd -> pnorm, funcxf.xfm);
varset("NxP", '=', v [0] / funcxf.sca);
varset("NyP", '=', v [1] / funcxf.sca);
varset("NzP", '=', v [2] / funcxf.sca);
varset("RdotP", '=',
bd -> pdot <= -1. ? -1. : bd -> pdot >= 1. ? 1. : bd -> pdot);
varset("CrP", '=', colval(bd -> mcolor, RED));
varset("CgP", '=', colval(bd -> mcolor, GRN));
varset("CbP", '=', colval(bd -> mcolor, BLU));
return 1;
}
static int brdfPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Generate new photon ray for BRTDfunc material and recurse. Only ideal
reflection and transmission are sampled for the specular componentent. */
{
int hitfront = 1, hastexture, i;
BRDFDAT nd;
RAY rayOut;
COLOR rspecCol, tspecCol;
double prDiff, ptDiff, prSpec, ptSpec, albedo, xi;
MFUNC *mf;
FVECT bnorm;
/* Check argz */
if (mat -> oargs.nsargs < 10 || mat -> oargs.nfargs < 9)
objerror(mat, USER, "bad # arguments");
nd.mp = mat;
nd.pr = rayIn;
/* Dummiez */
nd.rspec = nd.tspec = 1.0;
nd.trans = 0.5;
/* Diffuz reflektanz */
if (rayIn -> rod > 0.0)
setcolor(nd.rdiff, mat -> oargs.farg[0], mat -> oargs.farg [1],
mat -> oargs.farg [2]);
else
setcolor(nd.rdiff, mat-> oargs.farg [3], mat -> oargs.farg [4],
mat -> oargs.farg [5]);
/* Diffuz tranzmittanz */
setcolor(nd.tdiff, mat -> oargs.farg [6], mat -> oargs.farg [7],
mat -> oargs.farg [8]);
/* Get modz */
raytexture(rayIn, mat -> omod);
hastexture = (DOT(rayIn -> pert, rayIn -> pert) > sqr(FTINY));
if (hastexture) {
/* Perturb normal */
nd.pdot = raynormal(nd.pnorm, rayIn);
}
else {
VCOPY(nd.pnorm, rayIn -> ron);
nd.pdot = rayIn -> rod;
}
if (rayIn -> rod < 0.0) {
/* Orient perturbed valuz */
nd.pdot = -nd.pdot;
for (i = 0; i < 3; i++) {
nd.pnorm [i] = -nd.pnorm [i];
rayIn -> pert [i] = -rayIn -> pert [i];
}
hitfront = 0;
}
/* Get pattern kolour, modify diffuz valuz */
copycolor(nd.mcolor, rayIn -> pcol);
multcolor(nd.rdiff, nd.mcolor);
multcolor(nd.tdiff, nd.mcolor);
/* Load cal file, evaluate spekula refl/tranz varz */
nd.dp = NULL;
mf = getfunc(mat, 9, 0x3f, 0);
setbrdfunc(&nd);
errno = 0;
setcolor(rspecCol,
evalue(mf->ep[0]), evalue(mf->ep[1]), evalue(mf->ep[2]));
setcolor(tspecCol,
evalue(mf->ep[3]), evalue(mf->ep[4]), evalue(mf->ep[5]));
if (errno == EDOM || errno == ERANGE)
objerror(mat, WARNING, "compute error");
else {
/* Set up probz */
prDiff = colorAvg(nd.rdiff);
ptDiff = colorAvg(nd.tdiff);
prSpec = colorAvg(rspecCol);
ptSpec = colorAvg(tspecCol);
albedo = prDiff + ptDiff + prSpec + ptSpec;
}
/* Insert direct and indirect photon hitz if diffuz komponent */
if (prDiff > FTINY || ptDiff > FTINY)
addPhotons(rayIn);
/* Stochastically sample absorption or scattering evenz */
if ((xi = pmapRandom(rouletteState)) > albedo)
/* Absorbed */
return 0;
if (xi > (albedo -= prSpec)) {
/* Ideal spekula reflekzion */
photonRay(rayIn, &rayOut, PMAP_SPECREFL, rspecCol);
VSUM(rayOut.rdir, rayIn -> rdir, nd.pnorm, 2 * nd.pdot);
checknorm(rayOut.rdir);
}
else if (xi > (albedo -= ptSpec)) {
/* Ideal spekula tranzmission */
photonRay(rayIn, &rayOut, PMAP_SPECTRANS, tspecCol);
if (hastexture) {
/* Perturb direkzion */
VSUB(rayOut.rdir, rayIn -> rdir, rayIn -> pert);
if (normalize(rayOut.rdir) == 0.0) {
objerror(mat, WARNING, "illegal perturbation");
VCOPY(rayOut.rdir, rayIn -> rdir);
}
else VCOPY(rayOut.rdir, rayIn -> rdir);
}
}
else if (xi > (albedo -= prDiff)) {
/* Diffuz reflekzion */
if (!hitfront)
flipsurface(rayIn);
photonRay(rayIn, &rayOut, PMAP_DIFFREFL, nd.mcolor);
diffPhotonScatter(nd.pnorm, &rayOut);
}
else {
/* Diffuz tranzmission */
if (hitfront)
flipsurface(rayIn);
photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, nd.mcolor);
bnorm [0] = -nd.pnorm [0];
bnorm [1] = -nd.pnorm [1];
bnorm [2] = -nd.pnorm [2];
diffPhotonScatter(bnorm, &rayOut);
}
tracePhoton(&rayOut);
return 0;
}
int brdf2PhotonScatter (OBJREC *mat, RAY *rayIn)
/* Generate new photon ray for procedural or data driven BRDF material and
recurse. Only diffuse reflection and transmission are sampled. */
{
BRDFDAT nd;
RAY rayOut;
double dtmp, prDiff, ptDiff, albedo, xi;
MFUNC *mf;
FVECT bnorm;
/* Check argz */
if (mat -> oargs.nsargs < (hasdata(mat -> otype) ? 4 : 2) ||
mat -> oargs.nfargs < (mat -> otype == MAT_TFUNC ||
mat -> otype == MAT_TDATA ? 6 : 4))
objerror(mat, USER, "bad # arguments");
if (rayIn -> rod < 0.0) {
/* Hit backside; reorient if visible, else transfer photon */
if (!backvis) {
photonRay(rayIn, &rayOut, PMAP_XFER, NULL);
tracePhoton(&rayOut);
return 0;
}
raytexture(rayIn, mat -> omod);
flipsurface(rayIn);
}
else raytexture(rayIn, mat -> omod);
nd.mp = mat;
nd.pr = rayIn;
/* Material kolour */
setcolor(nd.mcolor, mat -> oargs.farg [0], mat -> oargs.farg [1],
mat -> oargs.farg [2]);
/* Spekula komponent */
nd.rspec = mat -> oargs.farg [3];
/* Tranzmittanz */
if (mat -> otype == MAT_TFUNC || mat -> otype == MAT_TDATA) {
nd.trans = mat -> oargs.farg [4] * (1.0 - nd.rspec);
nd.tspec = nd.trans * mat -> oargs.farg [5];
dtmp = nd.trans - nd.tspec;
setcolor(nd.tdiff, dtmp, dtmp, dtmp);
}
else {
nd.tspec = nd.trans = 0.0;
setcolor(nd.tdiff, 0.0, 0.0, 0.0);
}
/* Reflektanz */
dtmp = 1.0 - nd.trans - nd.rspec;
setcolor(nd.rdiff, dtmp, dtmp, dtmp);
/* Perturb normal */
nd.pdot = raynormal(nd.pnorm, rayIn);
/* Modify material kolour */
multcolor(nd.mcolor, rayIn -> pcol);
multcolor(nd.rdiff, nd.mcolor);
multcolor(nd.tdiff, nd.mcolor);
/* Load auxiliary filez */
if (hasdata(mat -> otype)) {
nd.dp = getdata(mat -> oargs.sarg [1]);
getfunc(mat, 2, 0, 0);
}
else {
nd.dp = NULL;
getfunc(mat, 1, 0, 0);
}
/* Set up probz */
prDiff = colorAvg(nd.rdiff);
ptDiff = colorAvg(nd.tdiff);
albedo = prDiff + ptDiff;
/* Insert direct and indirect photon hitz if diffuz komponent */
if (prDiff > FTINY || ptDiff > FTINY)
addPhotons(rayIn);
/* Stochastically sample absorption or scattering evenz */
if ((xi = pmapRandom(rouletteState)) > albedo)
/* Absorbed */
return 0;
if (xi > (albedo -= prDiff)) {
/* Diffuz reflekzion */
photonRay(rayIn, &rayOut, PMAP_DIFFREFL, nd.rdiff);
diffPhotonScatter(nd.pnorm, &rayOut);
}
else {
/* Diffuz tranzmission */
flipsurface(rayIn);
photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, nd.tdiff);
bnorm [0] = -nd.pnorm [0];
bnorm [1] = -nd.pnorm [1];
bnorm [2] = -nd.pnorm [2];
diffPhotonScatter(bnorm, &rayOut);
}
tracePhoton(&rayOut);
return 0;
}
/*
==================================================================
The following code is
(c) Lucerne University of Applied Sciences and Arts,
supported by the Swiss National Science Foundation (SNSF, #147053)
==================================================================
*/
static int bsdfPhotonScatter (OBJREC *mat, RAY *rayIn)
/* Generate new photon ray for BSDF modifier and recurse. */
{
int hasthick = (mat->otype == MAT_BSDF);
int hitFront;
SDError err;
SDValue bsdfVal;
FVECT upvec;
MFUNC *mf;
BSDFDAT nd;
RAY rayOut;
COLOR bsdfRGB;
int transmitted;
double prDiff, ptDiff, prDiffSD, ptDiffSD, prSpecSD, ptSpecSD,
albedo, xi;
const double patAlb = bright(rayIn -> pcol);
/* Following code adapted from m_bsdf() */
/* Check arguments */
if (mat -> oargs.nsargs < hasthick+5 || mat -> oargs.nfargs > 9 ||
mat -> oargs.nfargs % 3)
objerror(mat, USER, "bad # arguments");
hitFront = (rayIn -> rod > 0);
/* Load cal file */
mf = hasthick ? getfunc(mat, 5, 0x1d, 1) : getfunc(mat, 4, 0xe, 1);
/* Get thickness */
nd.thick = 0;
if (hasthick) {
nd.thick = evalue(mf -> ep [0]);
if ((-FTINY <= nd.thick) & (nd.thick <= FTINY))
nd.thick = .0;
}
/* Get BSDF data */
nd.sd = loadBSDF(mat -> oargs.sarg [hasthick]);
/* Extra diffuse reflectance from material def */
if (hitFront) {
if (mat -> oargs.nfargs < 3)
setcolor(nd.rdiff, .0, .0, .0);
else setcolor(nd.rdiff, mat -> oargs.farg [0], mat -> oargs.farg [1],
mat -> oargs.farg [2]);
}
else if (mat -> oargs.nfargs < 6) {
/* Check for absorbing backside */
if (!backvis && !nd.sd -> rb && !nd.sd -> tf) {
SDfreeCache(nd.sd);
return 0;
}
setcolor(nd.rdiff, .0, .0, .0);
}
else setcolor(nd.rdiff, mat -> oargs.farg [3], mat -> oargs.farg [4],
mat -> oargs.farg [5]);
/* Extra diffuse transmittance from material def */
if (mat -> oargs.nfargs < 9)
setcolor(nd.tdiff, .0, .0, .0);
else setcolor(nd.tdiff, mat -> oargs.farg [6], mat -> oargs.farg [7],
mat -> oargs.farg [8]);
nd.mp = mat;
nd.pr = rayIn;
/* Get modifiers */
raytexture(rayIn, mat -> omod);
/* Modify diffuse values */
multcolor(nd.rdiff, rayIn -> pcol);
multcolor(nd.tdiff, rayIn -> pcol);
/* Get up vector & xform to world coords */
upvec [0] = evalue(mf -> ep [hasthick+0]);
upvec [1] = evalue(mf -> ep [hasthick+1]);
upvec [2] = evalue(mf -> ep [hasthick+2]);
if (mf -> fxp != &unitxf) {
multv3(upvec, upvec, mf -> fxp -> xfm);
nd.thick *= mf -> fxp -> sca;
}
if (rayIn -> rox) {
multv3(upvec, upvec, rayIn -> rox -> f.xfm);
nd.thick *= rayIn -> rox -> f.sca;
}
/* Perturb normal */
raynormal(nd.pnorm, rayIn);
/* Xform incident dir to local BSDF coords */
err = SDcompXform(nd.toloc, nd.pnorm, upvec);
if (!err) {
nd.vray [0] = -rayIn -> rdir [0];
nd.vray [1] = -rayIn -> rdir [1];
nd.vray [2] = -rayIn -> rdir [2];
err = SDmapDir(nd.vray, nd.toloc, nd.vray);
}
if (!err)
err = SDinvXform(nd.fromloc, nd.toloc);
if (err) {
objerror(mat, WARNING, "Illegal orientation vector");
return 0;
}
/* Determine BSDF resolution */
err = SDsizeBSDF(nd.sr_vpsa, nd.vray, NULL,
SDqueryMin + SDqueryMax, nd.sd);
if (err)
objerror(mat, USER, transSDError(err));
nd.sr_vpsa [0] = sqrt(nd.sr_vpsa [0]);
nd.sr_vpsa [1] = sqrt(nd.sr_vpsa [1]);
/* Orient perturbed normal towards incident side */
if (!hitFront) {
nd.pnorm [0] = -nd.pnorm [0];
nd.pnorm [1] = -nd.pnorm [1];
nd.pnorm [2] = -nd.pnorm [2];
}
/* Get scatter probabilities (weighted by pattern except for spec refl)
* prDiff, ptDiff: extra diffuse component in material def
* prDiffSD, ptDiffSD: diffuse (constant) component in SDF
* prSpecSD, ptSpecSD: non-diffuse ("specular") component in SDF
* albedo: sum of above, inverse absorption probability */
prDiff = colorAvg(nd.rdiff);
ptDiff = colorAvg(nd.tdiff);
prDiffSD = patAlb * SDdirectHemi(nd.vray, SDsampDf | SDsampR, nd.sd);
ptDiffSD = patAlb * SDdirectHemi(nd.vray, SDsampDf | SDsampT, nd.sd);
prSpecSD = SDdirectHemi(nd.vray, SDsampSp | SDsampR, nd.sd);
ptSpecSD = patAlb * SDdirectHemi(nd.vray, SDsampSp | SDsampT, nd.sd);
albedo = prDiff + ptDiff + prDiffSD + ptDiffSD + prSpecSD + ptSpecSD;
/*
if (albedo > 1)
objerror(mat, WARNING, "Invalid albedo");
*/
/* Insert direct and indirect photon hits if diffuse component */
if (prDiff + ptDiff + prDiffSD + ptDiffSD > FTINY)
addPhotons(rayIn);
xi = pmapRandom(rouletteState);
if (xi > albedo)
/* Absorbtion */
return 0;
transmitted = 0;
if ((xi -= prDiff) <= 0) {
/* Diffuse reflection (extra component in material def) */
photonRay(rayIn, &rayOut, PMAP_DIFFREFL, nd.rdiff);
diffPhotonScatter(nd.pnorm, &rayOut);
}
else if ((xi -= ptDiff) <= 0) {
/* Diffuse transmission (extra component in material def) */
photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, nd.tdiff);
diffPhotonScatter(nd.pnorm, &rayOut);
transmitted = 1;
}
else { /* Sample SDF */
if ((xi -= prDiffSD) <= 0) {
/* Diffuse SDF reflection (constant component) */
if ((err = SDsampBSDF(&bsdfVal, nd.vray, pmapRandom(scatterState),
SDsampDf | SDsampR, nd.sd)))
objerror(mat, USER, transSDError(err));
/* Apply pattern to spectral component */
ccy2rgb(&bsdfVal.spec, bsdfVal.cieY, bsdfRGB);
multcolor(bsdfRGB, rayIn -> pcol);
photonRay(rayIn, &rayOut, PMAP_DIFFREFL, bsdfRGB);
}
else if ((xi -= ptDiffSD) <= 0) {
/* Diffuse SDF transmission (constant component) */
if ((err = SDsampBSDF(&bsdfVal, nd.vray, pmapRandom(scatterState),
SDsampDf | SDsampT, nd.sd)))
objerror(mat, USER, transSDError(err));
/* Apply pattern to spectral component */
ccy2rgb(&bsdfVal.spec, bsdfVal.cieY, bsdfRGB);
multcolor(bsdfRGB, rayIn -> pcol);
addcolor(bsdfRGB, nd.tdiff);
photonRay(rayIn, &rayOut, PMAP_DIFFTRANS, bsdfRGB);
transmitted = 1;
}
else if ((xi -= prSpecSD) <= 0) {
/* Non-diffuse ("specular") SDF reflection */
if ((err = SDsampBSDF(&bsdfVal, nd.vray, pmapRandom(scatterState),
SDsampSp | SDsampR, nd.sd)))
objerror(mat, USER, transSDError(err));
ccy2rgb(&bsdfVal.spec, bsdfVal.cieY, bsdfRGB);
photonRay(rayIn, &rayOut, PMAP_SPECREFL, bsdfRGB);
}
else {
/* Non-diffuse ("specular") SDF transmission */
if ((err = SDsampBSDF(&bsdfVal, nd.vray, pmapRandom(scatterState),
SDsampSp | SDsampT, nd.sd)))
objerror(mat, USER, transSDError(err));
/* Apply pattern to spectral component */
ccy2rgb(&bsdfVal.spec, bsdfVal.cieY, bsdfRGB);
multcolor(bsdfRGB, rayIn -> pcol);
photonRay(rayIn, &rayOut, PMAP_SPECTRANS, bsdfRGB);
transmitted = 1;
}
/* Xform outgoing dir to world coords */
if ((err = SDmapDir(rayOut.rdir, nd.fromloc, nd.vray))) {
objerror(mat, USER, transSDError(err));
return 0;
}
}
/* Clean up */
SDfreeCache(nd.sd);
/* Offset outgoing photon origin by thickness to bypass proxy geometry */
if (transmitted && nd.thick != 0)
VSUM(rayOut.rorg, rayOut.rorg, rayIn -> ron, -nd.thick);
tracePhoton(&rayOut);
return 0;
}
static int lightPhotonScatter (OBJREC* mat, RAY* ray)
/* Light sources doan' reflect, mang */
{
return 0;
}
void initPhotonScatterFuncs ()
/* Init photonScatter[] dispatch table */
{
int i;
/* Catch-all for inconsistencies */
for (i = 0; i < NUMOTYPE; i++)
photonScatter [i] = o_default;
photonScatter [MAT_LIGHT] = photonScatter [MAT_ILLUM] =
photonScatter [MAT_GLOW] = photonScatter [MAT_SPOT] =
lightPhotonScatter;
photonScatter [MAT_PLASTIC] = photonScatter [MAT_METAL] =
photonScatter [MAT_TRANS] = normalPhotonScatter;
photonScatter [MAT_PLASTIC2] = photonScatter [MAT_METAL2] =
photonScatter [MAT_TRANS2] = anisoPhotonScatter;
photonScatter [MAT_DIELECTRIC] = photonScatter [MAT_INTERFACE] =
dielectricPhotonScatter;
photonScatter [MAT_MIST] = mistPhotonScatter;
photonScatter [MAT_GLASS] = glassPhotonScatter;
photonScatter [MAT_CLIP] = clipPhotonScatter;
photonScatter [MAT_MIRROR] = mirrorPhotonScatter;
photonScatter [MIX_FUNC] = mx_funcPhotonScatter;
photonScatter [MIX_DATA] = mx_dataPhotonScatter;
photonScatter [MIX_PICT]= mx_pdataPhotonScatter;
photonScatter [PAT_BDATA] = photonScatter [PAT_CDATA] =
photonScatter [PAT_BFUNC] = photonScatter [PAT_CFUNC] =
photonScatter [PAT_CPICT] = photonScatter [TEX_FUNC] =
photonScatter [TEX_DATA] = pattexPhotonScatter;
photonScatter [MOD_ALIAS] = aliasPhotonScatter;
photonScatter [MAT_BRTDF] = brdfPhotonScatter;
photonScatter [MAT_PFUNC] = photonScatter [MAT_MFUNC] =
photonScatter [MAT_PDATA] = photonScatter [MAT_MDATA] =
photonScatter [MAT_TFUNC] = photonScatter [MAT_TDATA] =
brdf2PhotonScatter;
photonScatter [MAT_BSDF] = photonScatter [MAT_ABSDF] =
bsdfPhotonScatter;
}

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