src/gen/mkillum4.c

#ifndef lint
static const char RCSid[] = "$Id: mkillum4.c,v 2.8 2007/12/13 07:03:37 greg Exp $";
#endif
/*
 * Routines for handling BSDF data within mkillum
 */

#include "mkillum.h"
#include "paths.h"
#include "ezxml.h"

#define MAXLATS         46              /* maximum number of latitudes */

/* BSDF angle specification (terminate with nphi = -1) */
typedef struct {
        char    name[64];               /* basis name */
        int     nangles;                /* total number of directions */
        struct {
                float   tmin;                   /* starting theta */
                short   nphis;                  /* number of phis (0 term) */
        }       lat[MAXLATS+1];         /* latitudes */
} ANGLE_BASIS;

#define MAXABASES       3               /* limit on defined bases */

ANGLE_BASIS     abase_list[MAXABASES] = {
        {
                "LBNL/Klems Full", 145,
                { {-5., 1},
                {5., 8},
                {15., 16},
                {25., 20},
                {35., 24},
                {45., 24},
                {55., 24},
                {65., 16},
                {75., 12},
                {90., 0} }
        }, {
                "LBNL/Klems Half", 73,
                { {-6.5, 1},
                {6.5, 8},
                {19.5, 12},
                {32.5, 16},
                {46.5, 20},
                {61.5, 12},
                {76.5, 4},
                {90., 0} }
        }, {
                "LBNL/Klems Quarter", 41,
                { {-9., 1},
                {9., 8},
                {27., 12},
                {46., 12},
                {66., 8},
                {90., 0} }
        }
};

static int      nabases = 3;    /* current number of defined bases */


static int
ab_getvec(              /* get vector for this angle basis index */
        FVECT v,
        int ndx,
        void *p
)
{
        ANGLE_BASIS  *ab = (ANGLE_BASIS *)p;
        int     li;
        double  alt, azi, d;
        
        if ((ndx < 0) | (ndx >= ab->nangles))
                return(0);
        for (li = 0; ndx >= ab->lat[li].nphis; li++)
                ndx -= ab->lat[li].nphis;
        alt = PI/180.*0.5*(ab->lat[li].tmin + ab->lat[li+1].tmin);
        azi = 2.*PI*ndx/ab->lat[li].nphis;
        d = sin(alt);
        v[0] = cos(azi)*d;
        v[1] = sin(azi)*d;
        v[2] = cos(alt);
        return(1);
}


static int
ab_getndx(              /* get index corresponding to the given vector */
        FVECT v,
        void *p
)
{
        ANGLE_BASIS  *ab = (ANGLE_BASIS *)p;
        int     li, ndx;
        double  alt, azi, d;

        if ((v[2] < -1.0) | (v[2] > 1.0))
                return(-1);
        alt = 180.0/PI*acos(v[2]);
        azi = 180.0/PI*atan2(v[1], v[0]);
        if (azi < 0.0) azi += 360.0;
        for (li = 1; ab->lat[li].tmin <= alt; li++)
                if (!ab->lat[li].nphis)
                        return(-1);
        --li;
        ndx = (int)((1./360.)*azi*ab->lat[li].nphis + 0.5);
        if (ndx >= ab->lat[li].nphis) ndx = 0;
        while (li--)
                ndx += ab->lat[li].nphis;
        return(ndx);
}


static double
ab_getohm(              /* get solid angle for this angle basis index */
        int ndx,
        void *p
)
{
        ANGLE_BASIS  *ab = (ANGLE_BASIS *)p;
        int     li;
        double  tdia, pdia;
        
        if ((ndx < 0) | (ndx >= ab->nangles))
                return(0);
        for (li = 0; ndx >= ab->lat[li].nphis; li++)
                ndx -= ab->lat[li].nphis;
        if (ab->lat[li].nphis == 1) {           /* special case */
                if (ab->lat[li].tmin > FTINY)
                        error(USER, "unsupported BSDF coordinate system");
                tdia = PI/180. * ab->lat[li+1].tmin;
                return(PI*tdia*tdia);
        }
        tdia = PI/180.*(ab->lat[li+1].tmin - ab->lat[li].tmin);
        tdia *= sin(PI/180.*(ab->lat[li].tmin + ab->lat[li+1].tmin));
        pdia = 2.*PI/ab->lat[li].nphis;
        return(tdia*pdia);
}


static int
ab_getvecR(             /* get reverse vector for this angle basis index */
        FVECT v,
        int ndx,
        void *p
)
{
        if (!ab_getvec(v, ndx, p))
                return(0);

        v[0] = -v[0];
        v[1] = -v[1];

        return(1);
}


static int
ab_getndxR(             /* get index corresponding to the reverse vector */
        FVECT v,
        void *p
)
{
        FVECT  v2;
        
        v2[0] = -v[0];
        v2[1] = -v[1];
        v2[2] = v[2];

        return ab_getndx(v2, p);
}


static void
load_bsdf_data(         /* load BSDF distribution for this wavelength */
        struct BSDF_data *dp,
        ezxml_t wdb
)
{
        char  *cbasis = ezxml_txt(ezxml_child(wdb,"ColumnAngleBasis"));
        char  *rbasis = ezxml_txt(ezxml_child(wdb,"RowAngleBasis"));
        char  *sdata;
        int  i;
        
        if ((cbasis == NULL) | (rbasis == NULL)) {
                error(WARNING, "missing column/row basis for BSDF");
                return;
        }
        /* XXX need to add routines for loading in foreign bases */
        for (i = nabases; i--; )
                if (!strcmp(cbasis, abase_list[i].name)) {
                        dp->ninc = abase_list[i].nangles;
                        dp->ib_priv = (void *)&abase_list[i];
                        dp->ib_vec = ab_getvec;
                        dp->ib_ndx = ab_getndx;
                        dp->ib_ohm = ab_getohm;
                        break;
                }
        if (i < 0) {
                sprintf(errmsg, "unsupported ColumnAngleBasis '%s'", cbasis);
                error(WARNING, errmsg);
                return;
        }
        for (i = nabases; i--; )
                if (!strcmp(rbasis, abase_list[i].name)) {
                        dp->nout = abase_list[i].nangles;
                        dp->ob_priv = (void *)&abase_list[i];
                        dp->ob_vec = ab_getvecR;
                        dp->ob_ndx = ab_getndxR;
                        dp->ob_ohm = ab_getohm;
                        break;
                }
        if (i < 0) {
                sprintf(errmsg, "unsupported RowAngleBasis '%s'", cbasis);
                error(WARNING, errmsg);
                return;
        }
                                /* read BSDF data */
        sdata  = ezxml_txt(ezxml_child(wdb,"ScatteringData"));
        if (sdata == NULL) {
                error(WARNING, "missing BSDF ScatteringData");
                return;
        }
        dp->bsdf = (float *)malloc(sizeof(float)*dp->ninc*dp->nout);
        if (dp->bsdf == NULL)
                error(SYSTEM, "out of memory in load_bsdf_data");
        for (i = 0; i < dp->ninc*dp->nout; i++) {
                char  *sdnext = fskip(sdata);
                if (sdnext == NULL) {
                        error(WARNING, "bad/missing BSDF ScatteringData");
                        free(dp->bsdf); dp->bsdf = NULL;
                        return;
                }
                while (*sdnext && isspace(*sdnext))
                        sdnext++;
                if (*sdnext == ',') sdnext++;
                dp->bsdf[i] = atof(sdata);
                sdata = sdnext;
        }
        while (isspace(*sdata))
                sdata++;
        if (*sdata) {
                sprintf(errmsg, "%d extra characters after BSDF ScatteringData",
                                strlen(sdata));
                error(WARNING, errmsg);
        }
}


struct BSDF_data *
load_BSDF(              /* load BSDF data from file */
        char *fname
)
{
        char                    *path;
        ezxml_t                 fl, wld, wdb;
        struct BSDF_data        *dp;
        
        path = getpath(fname, getrlibpath(), R_OK);
        if (path == NULL) {
                sprintf(errmsg, "cannot find BSDF file \"%s\"", fname);
                error(WARNING, errmsg);
                return(NULL);
        }
        fl = ezxml_parse_file(path);
        if (fl == NULL) {
                sprintf(errmsg, "cannot open BSDF \"%s\"", path);
                error(WARNING, errmsg);
                return(NULL);
        }
        if (ezxml_error(fl)[0]) {
                sprintf(errmsg, "BSDF \"%s\": %s", path, ezxml_error(fl));
                error(WARNING, errmsg);
                ezxml_free(fl);
                return(NULL);
        }
        dp = (struct BSDF_data *)calloc(1, sizeof(struct BSDF_data));
        for (wld = ezxml_child(fl, "WavelengthData");
                                wld != NULL; wld = wld->next) {
                if (strcmp(ezxml_txt(ezxml_child(wld,"Wavelength")), "Visible"))
                        continue;
                wdb = ezxml_child(wld, "WavelengthDataBlock");
                if (wdb == NULL) continue;
                if (strcmp(ezxml_txt(ezxml_child(wdb,"WavelengthDataDirection")),
                                        "Transmission Front"))
                        continue;
                load_bsdf_data(dp, wdb);        /* load front BTDF */
                break;                          /* ignore the rest */
        }
        ezxml_free(fl);                         /* done with XML file */
        if (dp->bsdf == NULL) {
                sprintf(errmsg, "bad/missing BTDF data in \"%s\"", path);
                error(WARNING, errmsg);
                free_BSDF(dp);
                dp = NULL;
        }
        return(dp);
}


void
free_BSDF(              /* free BSDF data structure */
        struct BSDF_data *b
)
{
        if (b == NULL)
                return;
        if (b->bsdf != NULL)
                free(b->bsdf);
        free(b);
}


int
r_BSDF_incvec(          /* compute random input vector at given location */
        FVECT v,
        struct BSDF_data *b,
        int i,
        double rv,
        MAT4 xm
)
{
        FVECT   pert;
        double  rad;
        int     j;
        
        if (!getBSDF_incvec(v, b, i))
                return(0);
        rad = sqrt(getBSDF_incohm(b, i) / PI);
        multisamp(pert, 3, rv);
        for (j = 0; j < 3; j++)
                v[j] += rad*(2.*pert[j] - 1.);
        if (xm != NULL)
                multv3(v, v, xm);
        return(normalize(v) != 0.0);
}


int
r_BSDF_outvec(          /* compute random output vector at given location */
        FVECT v,
        struct BSDF_data *b,
        int o,
        double rv,
        MAT4 xm
)
{
        FVECT   pert;
        double  rad;
        int     j;
        
        if (!getBSDF_outvec(v, b, o))
                return(0);
        rad = sqrt(getBSDF_outohm(b, o) / PI);
        multisamp(pert, 3, rv);
        for (j = 0; j < 3; j++)
                v[j] += rad*(2.*pert[j] - 1.);
        if (xm != NULL)
                multv3(v, v, xm);
        return(normalize(v) != 0.0);
}


#define  FEQ(a,b)       ((a)-(b) <= 1e-7 && (b)-(a) <= 1e-7)

static int
addrot(                 /* compute rotation (x,y,z) => (xp,yp,zp) */
        char *xfarg[],
        FVECT xp,
        FVECT yp,
        FVECT zp
)
{
        static char     bufs[3][16];
        int     bn = 0;
        char    **xfp = xfarg;
        double  theta;

        if (yp[2]*yp[2] + zp[2]*zp[2] < 2.*FTINY*FTINY) {
                /* Special case for X' along Z-axis */
                theta = -atan2(yp[0], yp[1]);
                *xfp++ = "-ry";
                *xfp++ = xp[2] < 0.0 ? "90" : "-90";
                *xfp++ = "-rz";
                sprintf(bufs[bn], "%f", theta*(180./PI));
                *xfp++ = bufs[bn++];
                return(xfp - xfarg);
        }
        theta = atan2(yp[2], zp[2]);
        if (!FEQ(theta,0.0)) {
                *xfp++ = "-rx";
                sprintf(bufs[bn], "%f", theta*(180./PI));
                *xfp++ = bufs[bn++];
        }
        theta = asin(-xp[2]);
        if (!FEQ(theta,0.0)) {
                *xfp++ = "-ry";
                sprintf(bufs[bn], " %f", theta*(180./PI));
                *xfp++ = bufs[bn++];
        }
        theta = atan2(xp[1], xp[0]);
        if (!FEQ(theta,0.0)) {
                *xfp++ = "-rz";
                sprintf(bufs[bn], "%f", theta*(180./PI));
                *xfp++ = bufs[bn++];
        }
        *xfp = NULL;
        return(xfp - xfarg);
}


int
getBSDF_xfm(            /* compute BSDF orient. -> world orient. transform */
        MAT4 xm,
        FVECT nrm,
        UpDir ud
)
{
        char    *xfargs[7];
        XF      myxf;
        FVECT   updir, xdest, ydest;

        updir[0] = updir[1] = updir[2] = 0.;
        switch (ud) {
        case UDzneg:
                updir[2] = -1.;
                break;
        case UDyneg:
                updir[1] = -1.;
                break;
        case UDxneg:
                updir[0] = -1.;
                break;
        case UDxpos:
                updir[0] = 1.;
                break;
        case UDypos:
                updir[1] = 1.;
                break;
        case UDzpos:
                updir[2] = 1.;
                break;
        case UDunknown:
                return(0);
        }
        fcross(xdest, updir, nrm);
        if (normalize(xdest) == 0.0)
                return(0);
        fcross(ydest, nrm, xdest);
        xf(&myxf, addrot(xfargs, xdest, ydest, nrm), xfargs);
        copymat4(xm, myxf.xfm);
        return(1);
}


void
redistribute(           /* pass distarr ray sums through BSDF */
        struct BSDF_data *b,
        int nalt,
        int nazi,
        FVECT u,
        FVECT v,
        FVECT w,
        MAT4 xm
)
{
        int     nout = 0;
        MAT4    mymat, inmat;
        COLORV  *idist;
        COLORV  *cp, *csum;
        FVECT   dv;
        double  wt;
        int     i, j, k, o;
        COLOR   col, cinc;
                                        /* copy incoming distribution */
        if (b->ninc != distsiz)
                error(INTERNAL, "error 1 in redistribute");
        idist = (COLORV *)malloc(sizeof(COLOR)*distsiz);
        if (idist == NULL)
                error(SYSTEM, "out of memory in redistribute");
        memcpy(idist, distarr, sizeof(COLOR)*distsiz);
                                        /* compose direction transform */
        for (i = 3; i--; ) {
                mymat[i][0] = u[i];
                mymat[i][1] = v[i];
                mymat[i][2] = w[i];
                mymat[i][3] = 0.;
        }
        mymat[3][0] = mymat[3][1] = mymat[3][2] = 0.;
        mymat[3][3] = 1.;
        if (xm != NULL)
                multmat4(mymat, xm, mymat);
        for (i = 3; i--; ) {            /* make sure it's normalized */
                wt = 1./sqrt(   mymat[0][i]*mymat[0][i] +
                                mymat[1][i]*mymat[1][i] +
                                mymat[2][i]*mymat[2][i] );
                for (j = 3; j--; )
                        mymat[j][i] *= wt;
        }
        if (!invmat4(inmat, mymat))     /* need inverse as well */
                error(INTERNAL, "cannot invert BSDF transform");
        newdist(nalt*nazi);             /* resample distribution */
        for (i = b->ninc; i--; ) {
                getBSDF_incvec(dv, b, i);       /* compute incident irrad. */
                multv3(dv, dv, mymat);
                if (dv[2] < 0.0) dv[2] = -dv[2];
                wt = getBSDF_incohm(b, i);
                wt *= dv[2];                    /* solid_angle*cosine(theta) */
                cp = &idist[3*i];
                copycolor(cinc, cp);
                scalecolor(cinc, wt);
                for (k = nalt; k--; )           /* loop over distribution */
                    for (j = nazi; j--; ) {
                        flatdir(dv, (k + .5)/nalt, (double)j/nazi);
                        multv3(dv, dv, inmat);
                                                /* evaluate BSDF @ outgoing */
                        o = getBSDF_outndx(b, dv);
                        if (o < 0) {
                                nout++;
                                continue;
                        }
                        wt = BSDF_value(b, i, o);
                        copycolor(col, cinc);
                        scalecolor(col, wt);
                        csum = &distarr[3*(k*nazi + j)];
                        addcolor(csum, col);    /* sum into distribution */
                    }
        }
        free(idist);                    /* free temp space */
        if (nout) {
                sprintf(errmsg, "missing %.1f%% of BSDF directions",
                                100.*nout/(b->ninc*nalt*nazi));
                error(WARNING, errmsg);
        }
}
Revision:	2.9
Committed:	Fri Jan 25 02:11:13 2008 UTC (16 years, 3 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.8:	+11 -1 lines
Log Message:	Fixed bug in rotation computation when X' is aligned with Z-axis
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.9	static const char RCSid[] = "$Id: mkillum4.c,v 2.8 2007/12/13 07:03:37 greg Exp $";
3	greg	2.1	#endif
4			/*
5			* Routines for handling BSDF data within mkillum
6			*/
7
8			#include "mkillum.h"
9			#include "paths.h"
10	greg	2.2	#include "ezxml.h"
11	greg	2.1
12	greg	2.6	#define MAXLATS 46 /* maximum number of latitudes */
13
14			/* BSDF angle specification (terminate with nphi = -1) */
15			typedef struct {
16	greg	2.7	char name[64]; /* basis name */
17	greg	2.6	int nangles; /* total number of directions */
18			struct {
19			float tmin; /* starting theta */
20			short nphis; /* number of phis (0 term) */
21			} lat[MAXLATS+1]; /* latitudes */
22			} ANGLE_BASIS;
23
24	greg	2.7	#define MAXABASES 3 /* limit on defined bases */
25	greg	2.6
26	greg	2.7	ANGLE_BASIS abase_list[MAXABASES] = {
27	greg	2.6	{
28			"LBNL/Klems Full", 145,
29			{ {-5., 1},
30			{5., 8},
31			{15., 16},
32			{25., 20},
33			{35., 24},
34			{45., 24},
35			{55., 24},
36			{65., 16},
37			{75., 12},
38			{90., 0} }
39			}, {
40			"LBNL/Klems Half", 73,
41			{ {-6.5, 1},
42			{6.5, 8},
43			{19.5, 12},
44			{32.5, 16},
45			{46.5, 20},
46			{61.5, 12},
47			{76.5, 4},
48			{90., 0} }
49			}, {
50			"LBNL/Klems Quarter", 41,
51			{ {-9., 1},
52			{9., 8},
53			{27., 12},
54			{46., 12},
55			{66., 8},
56			{90., 0} }
57			}
58			};
59
60	greg	2.7	static int nabases = 3; /* current number of defined bases */
61
62	greg	2.6
63			static int
64			ab_getvec( /* get vector for this angle basis index */
65			FVECT v,
66			int ndx,
67			void *p
68			)
69			{
70			ANGLE_BASIS ab = (ANGLE_BASIS )p;
71			int li;
72			double alt, azi, d;
73
74			if ((ndx < 0) \| (ndx >= ab->nangles))
75			return(0);
76			for (li = 0; ndx >= ab->lat[li].nphis; li++)
77			ndx -= ab->lat[li].nphis;
78			alt = PI/180.0.5(ab->lat[li].tmin + ab->lat[li+1].tmin);
79			azi = 2.PIndx/ab->lat[li].nphis;
80			d = sin(alt);
81			v[0] = cos(azi)*d;
82			v[1] = sin(azi)*d;
83			v[2] = cos(alt);
84			return(1);
85			}
86
87
88			static int
89			ab_getndx( /* get index corresponding to the given vector */
90			FVECT v,
91			void *p
92			)
93			{
94			ANGLE_BASIS ab = (ANGLE_BASIS )p;
95			int li, ndx;
96			double alt, azi, d;
97
98	greg	2.7	if ((v[2] < -1.0) \| (v[2] > 1.0))
99	greg	2.6	return(-1);
100			alt = 180.0/PI*acos(v[2]);
101			azi = 180.0/PI*atan2(v[1], v[0]);
102			if (azi < 0.0) azi += 360.0;
103			for (li = 1; ab->lat[li].tmin <= alt; li++)
104			if (!ab->lat[li].nphis)
105			return(-1);
106			--li;
107			ndx = (int)((1./360.)aziab->lat[li].nphis + 0.5);
108			if (ndx >= ab->lat[li].nphis) ndx = 0;
109			while (li--)
110			ndx += ab->lat[li].nphis;
111			return(ndx);
112			}
113
114
115			static double
116			ab_getohm( /* get solid angle for this angle basis index */
117			int ndx,
118			void *p
119			)
120			{
121			ANGLE_BASIS ab = (ANGLE_BASIS )p;
122			int li;
123			double tdia, pdia;
124
125			if ((ndx < 0) \| (ndx >= ab->nangles))
126			return(0);
127			for (li = 0; ndx >= ab->lat[li].nphis; li++)
128			ndx -= ab->lat[li].nphis;
129	greg	2.7	if (ab->lat[li].nphis == 1) { /* special case */
130			if (ab->lat[li].tmin > FTINY)
131			error(USER, "unsupported BSDF coordinate system");
132			tdia = PI/180. * ab->lat[li+1].tmin;
133			return(PItdiatdia);
134			}
135	greg	2.6	tdia = PI/180.*(ab->lat[li+1].tmin - ab->lat[li].tmin);
136	greg	2.7	tdia = sin(PI/180.(ab->lat[li].tmin + ab->lat[li+1].tmin));
137	greg	2.6	pdia = 2.*PI/ab->lat[li].nphis;
138			return(tdia*pdia);
139			}
140
141
142			static int
143			ab_getvecR( /* get reverse vector for this angle basis index */
144			FVECT v,
145			int ndx,
146			void *p
147			)
148			{
149			if (!ab_getvec(v, ndx, p))
150			return(0);
151
152			v[0] = -v[0];
153			v[1] = -v[1];
154
155			return(1);
156			}
157
158
159			static int
160			ab_getndxR( /* get index corresponding to the reverse vector */
161			FVECT v,
162			void *p
163			)
164			{
165			FVECT v2;
166
167			v2[0] = -v[0];
168			v2[1] = -v[1];
169			v2[2] = v[2];
170
171			return ab_getndx(v2, p);
172			}
173
174	greg	2.7
175	greg	2.6	static void
176			load_bsdf_data( /* load BSDF distribution for this wavelength */
177			struct BSDF_data *dp,
178			ezxml_t wdb
179			)
180			{
181	greg	2.7	char *cbasis = ezxml_txt(ezxml_child(wdb,"ColumnAngleBasis"));
182			char *rbasis = ezxml_txt(ezxml_child(wdb,"RowAngleBasis"));
183			char *sdata;
184	greg	2.6	int i;
185
186	greg	2.7	if ((cbasis == NULL) \| (rbasis == NULL)) {
187			error(WARNING, "missing column/row basis for BSDF");
188			return;
189			}
190			/* XXX need to add routines for loading in foreign bases */
191			for (i = nabases; i--; )
192	greg	2.6	if (!strcmp(cbasis, abase_list[i].name)) {
193			dp->ninc = abase_list[i].nangles;
194			dp->ib_priv = (void *)&abase_list[i];
195			dp->ib_vec = ab_getvec;
196			dp->ib_ndx = ab_getndx;
197			dp->ib_ohm = ab_getohm;
198			break;
199			}
200			if (i < 0) {
201	greg	2.7	sprintf(errmsg, "unsupported ColumnAngleBasis '%s'", cbasis);
202			error(WARNING, errmsg);
203			return;
204	greg	2.6	}
205	greg	2.7	for (i = nabases; i--; )
206	greg	2.6	if (!strcmp(rbasis, abase_list[i].name)) {
207			dp->nout = abase_list[i].nangles;
208			dp->ob_priv = (void *)&abase_list[i];
209			dp->ob_vec = ab_getvecR;
210			dp->ob_ndx = ab_getndxR;
211			dp->ob_ohm = ab_getohm;
212			break;
213			}
214			if (i < 0) {
215	greg	2.7	sprintf(errmsg, "unsupported RowAngleBasis '%s'", cbasis);
216			error(WARNING, errmsg);
217			return;
218			}
219			/* read BSDF data */
220			sdata = ezxml_txt(ezxml_child(wdb,"ScatteringData"));
221			if (sdata == NULL) {
222			error(WARNING, "missing BSDF ScatteringData");
223			return;
224			}
225			dp->bsdf = (float )malloc(sizeof(float)dp->ninc*dp->nout);
226			if (dp->bsdf == NULL)
227			error(SYSTEM, "out of memory in load_bsdf_data");
228			for (i = 0; i < dp->ninc*dp->nout; i++) {
229			char *sdnext = fskip(sdata);
230			if (sdnext == NULL) {
231			error(WARNING, "bad/missing BSDF ScatteringData");
232			free(dp->bsdf); dp->bsdf = NULL;
233			return;
234			}
235			while (sdnext && isspace(sdnext))
236			sdnext++;
237			if (*sdnext == ',') sdnext++;
238			dp->bsdf[i] = atof(sdata);
239			sdata = sdnext;
240			}
241			while (isspace(*sdata))
242			sdata++;
243			if (*sdata) {
244			sprintf(errmsg, "%d extra characters after BSDF ScatteringData",
245			strlen(sdata));
246			error(WARNING, errmsg);
247	greg	2.6	}
248			}
249
250	greg	2.1
251			struct BSDF_data *
252			load_BSDF( /* load BSDF data from file */
253			char *fname
254			)
255			{
256			char *path;
257	greg	2.2	ezxml_t fl, wld, wdb;
258	greg	2.1	struct BSDF_data *dp;
259
260			path = getpath(fname, getrlibpath(), R_OK);
261			if (path == NULL) {
262			sprintf(errmsg, "cannot find BSDF file \"%s\"", fname);
263			error(WARNING, errmsg);
264			return(NULL);
265			}
266	greg	2.2	fl = ezxml_parse_file(path);
267			if (fl == NULL) {
268	greg	2.1	sprintf(errmsg, "cannot open BSDF \"%s\"", path);
269			error(WARNING, errmsg);
270			return(NULL);
271			}
272	greg	2.6	if (ezxml_error(fl)[0]) {
273			sprintf(errmsg, "BSDF \"%s\": %s", path, ezxml_error(fl));
274			error(WARNING, errmsg);
275			ezxml_free(fl);
276			return(NULL);
277			}
278	greg	2.5	dp = (struct BSDF_data *)calloc(1, sizeof(struct BSDF_data));
279	greg	2.2	for (wld = ezxml_child(fl, "WavelengthData");
280	greg	2.8	wld != NULL; wld = wld->next) {
281	greg	2.6	if (strcmp(ezxml_txt(ezxml_child(wld,"Wavelength")), "Visible"))
282	greg	2.2	continue;
283			wdb = ezxml_child(wld, "WavelengthDataBlock");
284			if (wdb == NULL) continue;
285	greg	2.6	if (strcmp(ezxml_txt(ezxml_child(wdb,"WavelengthDataDirection")),
286	greg	2.2	"Transmission Front"))
287			continue;
288	greg	2.6	load_bsdf_data(dp, wdb); /* load front BTDF */
289			break; /* ignore the rest */
290			}
291			ezxml_free(fl); /* done with XML file */
292			if (dp->bsdf == NULL) {
293			sprintf(errmsg, "bad/missing BTDF data in \"%s\"", path);
294			error(WARNING, errmsg);
295			free_BSDF(dp);
296			dp = NULL;
297	greg	2.2	}
298	greg	2.1	return(dp);
299			}
300
301
302			void
303			free_BSDF( /* free BSDF data structure */
304			struct BSDF_data *b
305			)
306			{
307			if (b == NULL)
308			return;
309	greg	2.6	if (b->bsdf != NULL)
310			free(b->bsdf);
311	greg	2.1	free(b);
312			}
313
314
315	greg	2.6	int
316	greg	2.1	r_BSDF_incvec( /* compute random input vector at given location */
317			FVECT v,
318			struct BSDF_data *b,
319			int i,
320			double rv,
321			MAT4 xm
322			)
323			{
324			FVECT pert;
325			double rad;
326			int j;
327
328	greg	2.6	if (!getBSDF_incvec(v, b, i))
329			return(0);
330			rad = sqrt(getBSDF_incohm(b, i) / PI);
331	greg	2.1	multisamp(pert, 3, rv);
332			for (j = 0; j < 3; j++)
333			v[j] += rad(2.pert[j] - 1.);
334			if (xm != NULL)
335			multv3(v, v, xm);
336	greg	2.7	return(normalize(v) != 0.0);
337	greg	2.1	}
338
339
340	greg	2.6	int
341	greg	2.1	r_BSDF_outvec( /* compute random output vector at given location */
342			FVECT v,
343			struct BSDF_data *b,
344			int o,
345			double rv,
346			MAT4 xm
347			)
348			{
349			FVECT pert;
350			double rad;
351			int j;
352
353	greg	2.6	if (!getBSDF_outvec(v, b, o))
354			return(0);
355			rad = sqrt(getBSDF_outohm(b, o) / PI);
356	greg	2.1	multisamp(pert, 3, rv);
357			for (j = 0; j < 3; j++)
358			v[j] += rad(2.pert[j] - 1.);
359			if (xm != NULL)
360			multv3(v, v, xm);
361	greg	2.7	return(normalize(v) != 0.0);
362	greg	2.1	}
363	greg	2.2
364
365			#define FEQ(a,b) ((a)-(b) <= 1e-7 && (b)-(a) <= 1e-7)
366
367			static int
368			addrot( /* compute rotation (x,y,z) => (xp,yp,zp) */
369			char *xfarg[],
370			FVECT xp,
371			FVECT yp,
372			FVECT zp
373			)
374			{
375			static char bufs[3][16];
376			int bn = 0;
377			char **xfp = xfarg;
378			double theta;
379
380	greg	2.9	if (yp[2]yp[2] + zp[2]zp[2] < 2.FTINYFTINY) {
381			/* Special case for X' along Z-axis */
382			theta = -atan2(yp[0], yp[1]);
383			*xfp++ = "-ry";
384			*xfp++ = xp[2] < 0.0 ? "90" : "-90";
385			*xfp++ = "-rz";
386			sprintf(bufs[bn], "%f", theta*(180./PI));
387			*xfp++ = bufs[bn++];
388			return(xfp - xfarg);
389			}
390	greg	2.2	theta = atan2(yp[2], zp[2]);
391			if (!FEQ(theta,0.0)) {
392			*xfp++ = "-rx";
393			sprintf(bufs[bn], "%f", theta*(180./PI));
394			*xfp++ = bufs[bn++];
395			}
396			theta = asin(-xp[2]);
397			if (!FEQ(theta,0.0)) {
398			*xfp++ = "-ry";
399			sprintf(bufs[bn], " %f", theta*(180./PI));
400			*xfp++ = bufs[bn++];
401			}
402			theta = atan2(xp[1], xp[0]);
403			if (!FEQ(theta,0.0)) {
404			*xfp++ = "-rz";
405			sprintf(bufs[bn], "%f", theta*(180./PI));
406			*xfp++ = bufs[bn++];
407			}
408			*xfp = NULL;
409			return(xfp - xfarg);
410			}
411
412
413			int
414	greg	2.6	getBSDF_xfm( /* compute BSDF orient. -> world orient. transform */
415	greg	2.2	MAT4 xm,
416			FVECT nrm,
417			UpDir ud
418			)
419			{
420			char *xfargs[7];
421			XF myxf;
422			FVECT updir, xdest, ydest;
423
424			updir[0] = updir[1] = updir[2] = 0.;
425			switch (ud) {
426			case UDzneg:
427			updir[2] = -1.;
428			break;
429			case UDyneg:
430			updir[1] = -1.;
431			break;
432			case UDxneg:
433			updir[0] = -1.;
434			break;
435			case UDxpos:
436			updir[0] = 1.;
437			break;
438			case UDypos:
439			updir[1] = 1.;
440			break;
441			case UDzpos:
442			updir[2] = 1.;
443			break;
444			case UDunknown:
445			return(0);
446			}
447			fcross(xdest, updir, nrm);
448			if (normalize(xdest) == 0.0)
449			return(0);
450			fcross(ydest, nrm, xdest);
451			xf(&myxf, addrot(xfargs, xdest, ydest, nrm), xfargs);
452			copymat4(xm, myxf.xfm);
453			return(1);
454			}
455
456
457			void
458			redistribute( /* pass distarr ray sums through BSDF */
459			struct BSDF_data *b,
460			int nalt,
461			int nazi,
462			FVECT u,
463			FVECT v,
464			FVECT w,
465			MAT4 xm
466			)
467			{
468	greg	2.6	int nout = 0;
469	greg	2.5	MAT4 mymat, inmat;
470			COLORV *idist;
471	greg	2.2	COLORV cp, csum;
472			FVECT dv;
473	greg	2.5	double wt;
474	greg	2.6	int i, j, k, o;
475	greg	2.5	COLOR col, cinc;
476			/* copy incoming distribution */
477			if (b->ninc != distsiz)
478			error(INTERNAL, "error 1 in redistribute");
479			idist = (COLORV )malloc(sizeof(COLOR)distsiz);
480			if (idist == NULL)
481	greg	2.2	error(SYSTEM, "out of memory in redistribute");
482	greg	2.5	memcpy(idist, distarr, sizeof(COLOR)*distsiz);
483			/* compose direction transform */
484	greg	2.2	for (i = 3; i--; ) {
485			mymat[i][0] = u[i];
486			mymat[i][1] = v[i];
487			mymat[i][2] = w[i];
488			mymat[i][3] = 0.;
489			}
490			mymat[3][0] = mymat[3][1] = mymat[3][2] = 0.;
491			mymat[3][3] = 1.;
492			if (xm != NULL)
493			multmat4(mymat, xm, mymat);
494			for (i = 3; i--; ) { /* make sure it's normalized */
495	greg	2.5	wt = 1./sqrt( mymat[0][i]*mymat[0][i] +
496	greg	2.2	mymat[1][i]*mymat[1][i] +
497			mymat[2][i]*mymat[2][i] );
498			for (j = 3; j--; )
499	greg	2.5	mymat[j][i] *= wt;
500	greg	2.2	}
501	greg	2.5	if (!invmat4(inmat, mymat)) /* need inverse as well */
502			error(INTERNAL, "cannot invert BSDF transform");
503			newdist(naltnazi); / resample distribution */
504	greg	2.4	for (i = b->ninc; i--; ) {
505	greg	2.5	getBSDF_incvec(dv, b, i); /* compute incident irrad. */
506	greg	2.2	multv3(dv, dv, mymat);
507	greg	2.5	if (dv[2] < 0.0) dv[2] = -dv[2];
508	greg	2.6	wt = getBSDF_incohm(b, i);
509			wt = dv[2]; / solid_anglecosine(theta) /
510	greg	2.5	cp = &idist[3*i];
511			copycolor(cinc, cp);
512			scalecolor(cinc, wt);
513			for (k = nalt; k--; ) /* loop over distribution */
514			for (j = nazi; j--; ) {
515			flatdir(dv, (k + .5)/nalt, (double)j/nazi);
516			multv3(dv, dv, inmat);
517			/* evaluate BSDF @ outgoing */
518	greg	2.6	o = getBSDF_outndx(b, dv);
519			if (o < 0) {
520			nout++;
521			continue;
522			}
523	greg	2.7	wt = BSDF_value(b, i, o);
524	greg	2.5	copycolor(col, cinc);
525			scalecolor(col, wt);
526			csum = &distarr[3(knazi + j)];
527			addcolor(csum, col); /* sum into distribution */
528			}
529	greg	2.2	}
530	greg	2.5	free(idist); /* free temp space */
531	greg	2.6	if (nout) {
532			sprintf(errmsg, "missing %.1f%% of BSDF directions",
533			100.nout/(b->nincnalt*nazi));
534			error(WARNING, errmsg);
535			}
536	greg	2.2	}