src/gen/mkillum4.c

#ifndef lint
static const char RCSid[] = "$Id: mkillum4.c,v 2.10 2008/03/27 01:40:30 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 */
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;
        v[2] = d = cos(alt);
        d = sqrt(1. - d*d);     /* sin(alt) */
        v[0] = cos(azi)*d;
        v[1] = sin(azi)*d;
        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];
        v[2] = -v[2];

        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_getvecR;
                        dp->ib_ndx = ab_getndxR;
                        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_getvec;
                        dp->ob_ndx = ab_getndx;
                        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, wtl, 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);
        }
        if (strcmp(ezxml_name(fl), "WindowElement")) {
                sprintf(errmsg,
                        "BSDF \"%s\": top level node not 'WindowElement'",
                                path);
                error(WARNING, errmsg);
                ezxml_free(fl);
                return(NULL);
        }
        wtl = ezxml_child(ezxml_child(fl, "Optical"), "Layer");
        dp = (struct BSDF_data *)calloc(1, sizeof(struct BSDF_data));
        for (wld = ezxml_child(wtl, "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:	2.11
Committed:	Fri Apr 11 20:07:12 2008 UTC (16 years, 1 month ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R9
Changes since 2.10:	+10 -9 lines
Log Message:	Fixed angle orientation
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.11	static const char RCSid[] = "$Id: mkillum4.c,v 2.10 2008/03/27 01:40:30 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	greg	2.11	/* BSDF angle specification */
15	greg	2.6	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	greg	2.11	v[2] = d = cos(alt);
81			d = sqrt(1. - dd); / sin(alt) */
82	greg	2.6	v[0] = cos(azi)*d;
83			v[1] = sin(azi)*d;
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	greg	2.11	v[2] = -v[2];
155	greg	2.6
156			return(1);
157			}
158
159
160			static int
161			ab_getndxR( /* get index corresponding to the reverse vector */
162			FVECT v,
163			void *p
164			)
165			{
166			FVECT v2;
167
168			v2[0] = -v[0];
169			v2[1] = -v[1];
170	greg	2.11	v2[2] = -v[2];
171	greg	2.6
172			return ab_getndx(v2, p);
173			}
174
175	greg	2.7
176	greg	2.6	static void
177			load_bsdf_data( /* load BSDF distribution for this wavelength */
178			struct BSDF_data *dp,
179			ezxml_t wdb
180			)
181			{
182	greg	2.7	char *cbasis = ezxml_txt(ezxml_child(wdb,"ColumnAngleBasis"));
183			char *rbasis = ezxml_txt(ezxml_child(wdb,"RowAngleBasis"));
184			char *sdata;
185	greg	2.6	int i;
186
187	greg	2.7	if ((cbasis == NULL) \| (rbasis == NULL)) {
188			error(WARNING, "missing column/row basis for BSDF");
189			return;
190			}
191			/* XXX need to add routines for loading in foreign bases */
192			for (i = nabases; i--; )
193	greg	2.6	if (!strcmp(cbasis, abase_list[i].name)) {
194			dp->ninc = abase_list[i].nangles;
195			dp->ib_priv = (void *)&abase_list[i];
196	greg	2.11	dp->ib_vec = ab_getvecR;
197			dp->ib_ndx = ab_getndxR;
198	greg	2.6	dp->ib_ohm = ab_getohm;
199			break;
200			}
201			if (i < 0) {
202	greg	2.7	sprintf(errmsg, "unsupported ColumnAngleBasis '%s'", cbasis);
203			error(WARNING, errmsg);
204			return;
205	greg	2.6	}
206	greg	2.7	for (i = nabases; i--; )
207	greg	2.6	if (!strcmp(rbasis, abase_list[i].name)) {
208			dp->nout = abase_list[i].nangles;
209			dp->ob_priv = (void *)&abase_list[i];
210	greg	2.11	dp->ob_vec = ab_getvec;
211			dp->ob_ndx = ab_getndx;
212	greg	2.6	dp->ob_ohm = ab_getohm;
213			break;
214			}
215			if (i < 0) {
216	greg	2.7	sprintf(errmsg, "unsupported RowAngleBasis '%s'", cbasis);
217			error(WARNING, errmsg);
218			return;
219			}
220			/* read BSDF data */
221			sdata = ezxml_txt(ezxml_child(wdb,"ScatteringData"));
222			if (sdata == NULL) {
223			error(WARNING, "missing BSDF ScatteringData");
224			return;
225			}
226			dp->bsdf = (float )malloc(sizeof(float)dp->ninc*dp->nout);
227			if (dp->bsdf == NULL)
228			error(SYSTEM, "out of memory in load_bsdf_data");
229			for (i = 0; i < dp->ninc*dp->nout; i++) {
230			char *sdnext = fskip(sdata);
231			if (sdnext == NULL) {
232			error(WARNING, "bad/missing BSDF ScatteringData");
233			free(dp->bsdf); dp->bsdf = NULL;
234			return;
235			}
236			while (sdnext && isspace(sdnext))
237			sdnext++;
238			if (*sdnext == ',') sdnext++;
239			dp->bsdf[i] = atof(sdata);
240			sdata = sdnext;
241			}
242			while (isspace(*sdata))
243			sdata++;
244			if (*sdata) {
245			sprintf(errmsg, "%d extra characters after BSDF ScatteringData",
246			strlen(sdata));
247			error(WARNING, errmsg);
248	greg	2.6	}
249			}
250
251	greg	2.1
252			struct BSDF_data *
253			load_BSDF( /* load BSDF data from file */
254			char *fname
255			)
256			{
257			char *path;
258	greg	2.10	ezxml_t fl, wtl, wld, wdb;
259	greg	2.1	struct BSDF_data *dp;
260
261			path = getpath(fname, getrlibpath(), R_OK);
262			if (path == NULL) {
263			sprintf(errmsg, "cannot find BSDF file \"%s\"", fname);
264			error(WARNING, errmsg);
265			return(NULL);
266			}
267	greg	2.2	fl = ezxml_parse_file(path);
268			if (fl == NULL) {
269	greg	2.1	sprintf(errmsg, "cannot open BSDF \"%s\"", path);
270			error(WARNING, errmsg);
271			return(NULL);
272			}
273	greg	2.6	if (ezxml_error(fl)[0]) {
274	greg	2.10	sprintf(errmsg, "BSDF \"%s\" %s", path, ezxml_error(fl));
275	greg	2.6	error(WARNING, errmsg);
276			ezxml_free(fl);
277			return(NULL);
278			}
279	greg	2.10	if (strcmp(ezxml_name(fl), "WindowElement")) {
280			sprintf(errmsg,
281			"BSDF \"%s\": top level node not 'WindowElement'",
282			path);
283			error(WARNING, errmsg);
284			ezxml_free(fl);
285			return(NULL);
286			}
287			wtl = ezxml_child(ezxml_child(fl, "Optical"), "Layer");
288	greg	2.5	dp = (struct BSDF_data *)calloc(1, sizeof(struct BSDF_data));
289	greg	2.10	for (wld = ezxml_child(wtl, "WavelengthData");
290	greg	2.8	wld != NULL; wld = wld->next) {
291	greg	2.6	if (strcmp(ezxml_txt(ezxml_child(wld,"Wavelength")), "Visible"))
292	greg	2.2	continue;
293			wdb = ezxml_child(wld, "WavelengthDataBlock");
294			if (wdb == NULL) continue;
295	greg	2.6	if (strcmp(ezxml_txt(ezxml_child(wdb,"WavelengthDataDirection")),
296	greg	2.2	"Transmission Front"))
297			continue;
298	greg	2.6	load_bsdf_data(dp, wdb); /* load front BTDF */
299			break; /* ignore the rest */
300			}
301			ezxml_free(fl); /* done with XML file */
302			if (dp->bsdf == NULL) {
303			sprintf(errmsg, "bad/missing BTDF data in \"%s\"", path);
304			error(WARNING, errmsg);
305			free_BSDF(dp);
306			dp = NULL;
307	greg	2.2	}
308	greg	2.1	return(dp);
309			}
310
311
312			void
313			free_BSDF( /* free BSDF data structure */
314			struct BSDF_data *b
315			)
316			{
317			if (b == NULL)
318			return;
319	greg	2.6	if (b->bsdf != NULL)
320			free(b->bsdf);
321	greg	2.1	free(b);
322			}
323
324
325	greg	2.6	int
326	greg	2.1	r_BSDF_incvec( /* compute random input vector at given location */
327			FVECT v,
328			struct BSDF_data *b,
329			int i,
330			double rv,
331			MAT4 xm
332			)
333			{
334			FVECT pert;
335			double rad;
336			int j;
337
338	greg	2.6	if (!getBSDF_incvec(v, b, i))
339			return(0);
340			rad = sqrt(getBSDF_incohm(b, i) / PI);
341	greg	2.1	multisamp(pert, 3, rv);
342			for (j = 0; j < 3; j++)
343			v[j] += rad(2.pert[j] - 1.);
344			if (xm != NULL)
345			multv3(v, v, xm);
346	greg	2.7	return(normalize(v) != 0.0);
347	greg	2.1	}
348
349
350	greg	2.6	int
351	greg	2.1	r_BSDF_outvec( /* compute random output vector at given location */
352			FVECT v,
353			struct BSDF_data *b,
354			int o,
355			double rv,
356			MAT4 xm
357			)
358			{
359			FVECT pert;
360			double rad;
361			int j;
362
363	greg	2.6	if (!getBSDF_outvec(v, b, o))
364			return(0);
365			rad = sqrt(getBSDF_outohm(b, o) / PI);
366	greg	2.1	multisamp(pert, 3, rv);
367			for (j = 0; j < 3; j++)
368			v[j] += rad(2.pert[j] - 1.);
369			if (xm != NULL)
370			multv3(v, v, xm);
371	greg	2.7	return(normalize(v) != 0.0);
372	greg	2.1	}
373	greg	2.2
374
375			#define FEQ(a,b) ((a)-(b) <= 1e-7 && (b)-(a) <= 1e-7)
376
377			static int
378			addrot( /* compute rotation (x,y,z) => (xp,yp,zp) */
379			char *xfarg[],
380			FVECT xp,
381			FVECT yp,
382			FVECT zp
383			)
384			{
385			static char bufs[3][16];
386			int bn = 0;
387			char **xfp = xfarg;
388			double theta;
389
390	greg	2.9	if (yp[2]yp[2] + zp[2]zp[2] < 2.FTINYFTINY) {
391			/* Special case for X' along Z-axis */
392			theta = -atan2(yp[0], yp[1]);
393			*xfp++ = "-ry";
394			*xfp++ = xp[2] < 0.0 ? "90" : "-90";
395			*xfp++ = "-rz";
396			sprintf(bufs[bn], "%f", theta*(180./PI));
397			*xfp++ = bufs[bn++];
398			return(xfp - xfarg);
399			}
400	greg	2.2	theta = atan2(yp[2], zp[2]);
401			if (!FEQ(theta,0.0)) {
402			*xfp++ = "-rx";
403			sprintf(bufs[bn], "%f", theta*(180./PI));
404			*xfp++ = bufs[bn++];
405			}
406			theta = asin(-xp[2]);
407			if (!FEQ(theta,0.0)) {
408			*xfp++ = "-ry";
409			sprintf(bufs[bn], " %f", theta*(180./PI));
410			*xfp++ = bufs[bn++];
411			}
412			theta = atan2(xp[1], xp[0]);
413			if (!FEQ(theta,0.0)) {
414			*xfp++ = "-rz";
415			sprintf(bufs[bn], "%f", theta*(180./PI));
416			*xfp++ = bufs[bn++];
417			}
418			*xfp = NULL;
419			return(xfp - xfarg);
420			}
421
422
423			int
424	greg	2.6	getBSDF_xfm( /* compute BSDF orient. -> world orient. transform */
425	greg	2.2	MAT4 xm,
426			FVECT nrm,
427			UpDir ud
428			)
429			{
430			char *xfargs[7];
431			XF myxf;
432			FVECT updir, xdest, ydest;
433
434			updir[0] = updir[1] = updir[2] = 0.;
435			switch (ud) {
436			case UDzneg:
437			updir[2] = -1.;
438			break;
439			case UDyneg:
440			updir[1] = -1.;
441			break;
442			case UDxneg:
443			updir[0] = -1.;
444			break;
445			case UDxpos:
446			updir[0] = 1.;
447			break;
448			case UDypos:
449			updir[1] = 1.;
450			break;
451			case UDzpos:
452			updir[2] = 1.;
453			break;
454			case UDunknown:
455			return(0);
456			}
457			fcross(xdest, updir, nrm);
458			if (normalize(xdest) == 0.0)
459			return(0);
460			fcross(ydest, nrm, xdest);
461			xf(&myxf, addrot(xfargs, xdest, ydest, nrm), xfargs);
462			copymat4(xm, myxf.xfm);
463			return(1);
464			}
465
466
467			void
468			redistribute( /* pass distarr ray sums through BSDF */
469			struct BSDF_data *b,
470			int nalt,
471			int nazi,
472			FVECT u,
473			FVECT v,
474			FVECT w,
475			MAT4 xm
476			)
477			{
478	greg	2.6	int nout = 0;
479	greg	2.5	MAT4 mymat, inmat;
480			COLORV *idist;
481	greg	2.2	COLORV cp, csum;
482			FVECT dv;
483	greg	2.5	double wt;
484	greg	2.6	int i, j, k, o;
485	greg	2.5	COLOR col, cinc;
486			/* copy incoming distribution */
487			if (b->ninc != distsiz)
488			error(INTERNAL, "error 1 in redistribute");
489			idist = (COLORV )malloc(sizeof(COLOR)distsiz);
490			if (idist == NULL)
491	greg	2.2	error(SYSTEM, "out of memory in redistribute");
492	greg	2.5	memcpy(idist, distarr, sizeof(COLOR)*distsiz);
493			/* compose direction transform */
494	greg	2.2	for (i = 3; i--; ) {
495			mymat[i][0] = u[i];
496			mymat[i][1] = v[i];
497			mymat[i][2] = w[i];
498			mymat[i][3] = 0.;
499			}
500			mymat[3][0] = mymat[3][1] = mymat[3][2] = 0.;
501			mymat[3][3] = 1.;
502			if (xm != NULL)
503			multmat4(mymat, xm, mymat);
504			for (i = 3; i--; ) { /* make sure it's normalized */
505	greg	2.5	wt = 1./sqrt( mymat[0][i]*mymat[0][i] +
506	greg	2.2	mymat[1][i]*mymat[1][i] +
507			mymat[2][i]*mymat[2][i] );
508			for (j = 3; j--; )
509	greg	2.5	mymat[j][i] *= wt;
510	greg	2.2	}
511	greg	2.5	if (!invmat4(inmat, mymat)) /* need inverse as well */
512			error(INTERNAL, "cannot invert BSDF transform");
513			newdist(naltnazi); / resample distribution */
514	greg	2.4	for (i = b->ninc; i--; ) {
515	greg	2.5	getBSDF_incvec(dv, b, i); /* compute incident irrad. */
516	greg	2.2	multv3(dv, dv, mymat);
517	greg	2.5	if (dv[2] < 0.0) dv[2] = -dv[2];
518	greg	2.6	wt = getBSDF_incohm(b, i);
519			wt = dv[2]; / solid_anglecosine(theta) /
520	greg	2.5	cp = &idist[3*i];
521			copycolor(cinc, cp);
522			scalecolor(cinc, wt);
523			for (k = nalt; k--; ) /* loop over distribution */
524			for (j = nazi; j--; ) {
525			flatdir(dv, (k + .5)/nalt, (double)j/nazi);
526			multv3(dv, dv, inmat);
527			/* evaluate BSDF @ outgoing */
528	greg	2.6	o = getBSDF_outndx(b, dv);
529			if (o < 0) {
530			nout++;
531			continue;
532			}
533	greg	2.7	wt = BSDF_value(b, i, o);
534	greg	2.5	copycolor(col, cinc);
535			scalecolor(col, wt);
536			csum = &distarr[3(knazi + j)];
537			addcolor(csum, col); /* sum into distribution */
538			}
539	greg	2.2	}
540	greg	2.5	free(idist); /* free temp space */
541	greg	2.6	if (nout) {
542			sprintf(errmsg, "missing %.1f%% of BSDF directions",
543			100.nout/(b->nincnalt*nazi));
544			error(WARNING, errmsg);
545			}
546	greg	2.2	}