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#ifndef lint |
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static const char RCSid[] = "$Id: mkillum4.c,v 2.3 2007/11/21 18:51:05 greg Exp $"; |
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#endif |
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/* |
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* Routines for handling BSDF data within mkillum |
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*/ |
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|
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#include "mkillum.h" |
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#include "paths.h" |
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#include "random.h" |
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#include "ezxml.h" |
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|
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|
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struct BSDF_data * |
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load_BSDF( /* load BSDF data from file */ |
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char *fname |
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) |
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{ |
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char *path; |
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ezxml_t fl, wld, wdb; |
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struct BSDF_data *dp; |
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|
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path = getpath(fname, getrlibpath(), R_OK); |
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if (path == NULL) { |
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sprintf(errmsg, "cannot find BSDF file \"%s\"", fname); |
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error(WARNING, errmsg); |
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return(NULL); |
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} |
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fl = ezxml_parse_file(path); |
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if (fl == NULL) { |
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sprintf(errmsg, "cannot open BSDF \"%s\"", path); |
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error(WARNING, errmsg); |
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return(NULL); |
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} |
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dp = (struct BSDF_data *)malloc(sizeof(struct BSDF_data)); |
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if (dp == NULL) |
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goto memerr; |
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for (wld = ezxml_child(fl, "WavelengthData"); |
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fl != NULL; fl = fl->next) { |
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if (strcmp(ezxml_child(wld, "Wavelength")->txt, "Visible")) |
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continue; |
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wdb = ezxml_child(wld, "WavelengthDataBlock"); |
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if (wdb == NULL) continue; |
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if (strcmp(ezxml_child(wdb, "WavelengthDataDirection")->txt, |
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"Transmission Front")) |
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continue; |
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} |
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/* etc... */ |
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ezxml_free(fl); |
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return(dp); |
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memerr: |
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error(SYSTEM, "out of memory in load_BSDF"); |
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return NULL; /* pro forma return */ |
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} |
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|
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|
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void |
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free_BSDF( /* free BSDF data structure */ |
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struct BSDF_data *b |
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) |
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{ |
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if (b == NULL) |
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return; |
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free(b->inc_dir); |
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free(b->inc_rad); |
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free(b->out_dir); |
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free(b->out_rad); |
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free(b->bsdf); |
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free(b); |
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} |
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|
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|
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void |
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r_BSDF_incvec( /* compute random input vector at given location */ |
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FVECT v, |
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struct BSDF_data *b, |
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int i, |
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double rv, |
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MAT4 xm |
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) |
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{ |
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FVECT pert; |
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double rad; |
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int j; |
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|
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getBSDF_incvec(v, b, i); |
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rad = getBSDF_incrad(b, i); |
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multisamp(pert, 3, rv); |
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for (j = 0; j < 3; j++) |
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v[j] += rad*(2.*pert[j] - 1.); |
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if (xm != NULL) |
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multv3(v, v, xm); |
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normalize(v); |
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} |
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|
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|
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void |
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r_BSDF_outvec( /* compute random output vector at given location */ |
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FVECT v, |
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struct BSDF_data *b, |
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int o, |
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double rv, |
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MAT4 xm |
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) |
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{ |
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FVECT pert; |
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double rad; |
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int j; |
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|
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getBSDF_outvec(v, b, o); |
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rad = getBSDF_outrad(b, o); |
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multisamp(pert, 3, rv); |
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for (j = 0; j < 3; j++) |
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v[j] += rad*(2.*pert[j] - 1.); |
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if (xm != NULL) |
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multv3(v, v, xm); |
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normalize(v); |
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} |
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|
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|
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#define FEQ(a,b) ((a)-(b) <= 1e-7 && (b)-(a) <= 1e-7) |
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|
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static int |
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addrot( /* compute rotation (x,y,z) => (xp,yp,zp) */ |
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char *xfarg[], |
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FVECT xp, |
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FVECT yp, |
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FVECT zp |
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) |
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{ |
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static char bufs[3][16]; |
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int bn = 0; |
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char **xfp = xfarg; |
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double theta; |
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|
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theta = atan2(yp[2], zp[2]); |
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if (!FEQ(theta,0.0)) { |
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*xfp++ = "-rx"; |
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sprintf(bufs[bn], "%f", theta*(180./PI)); |
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*xfp++ = bufs[bn++]; |
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} |
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theta = asin(-xp[2]); |
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if (!FEQ(theta,0.0)) { |
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*xfp++ = "-ry"; |
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sprintf(bufs[bn], " %f", theta*(180./PI)); |
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*xfp++ = bufs[bn++]; |
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} |
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theta = atan2(xp[1], xp[0]); |
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if (!FEQ(theta,0.0)) { |
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*xfp++ = "-rz"; |
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sprintf(bufs[bn], "%f", theta*(180./PI)); |
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*xfp++ = bufs[bn++]; |
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} |
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*xfp = NULL; |
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return(xfp - xfarg); |
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} |
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|
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|
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int |
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getBSDF_xfm( /* compute transform for the given surface */ |
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MAT4 xm, |
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FVECT nrm, |
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UpDir ud |
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) |
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{ |
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char *xfargs[7]; |
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XF myxf; |
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FVECT updir, xdest, ydest; |
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|
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updir[0] = updir[1] = updir[2] = 0.; |
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switch (ud) { |
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case UDzneg: |
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updir[2] = -1.; |
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break; |
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case UDyneg: |
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updir[1] = -1.; |
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break; |
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case UDxneg: |
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updir[0] = -1.; |
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break; |
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case UDxpos: |
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updir[0] = 1.; |
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break; |
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case UDypos: |
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updir[1] = 1.; |
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break; |
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case UDzpos: |
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updir[2] = 1.; |
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break; |
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case UDunknown: |
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error(WARNING, "unspecified up direction"); |
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return(0); |
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} |
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fcross(xdest, updir, nrm); |
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if (normalize(xdest) == 0.0) |
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return(0); |
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fcross(ydest, nrm, xdest); |
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xf(&myxf, addrot(xfargs, xdest, ydest, nrm), xfargs); |
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copymat4(xm, myxf.xfm); |
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return(1); |
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} |
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|
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|
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void |
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redistribute( /* pass distarr ray sums through BSDF */ |
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struct BSDF_data *b, |
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int nalt, |
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int nazi, |
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FVECT u, |
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FVECT v, |
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FVECT w, |
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MAT4 xm |
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) |
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{ |
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MAT4 mymat; |
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COLORV *outarr; |
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COLORV *cp, *csum; |
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uint16 *distcnt; |
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FVECT dv; |
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double wt0, wt1; |
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int i, j, o; |
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int cnt; |
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COLOR col; |
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/* allocate temporary memory */ |
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outarr = (COLORV *)calloc(b->nout, sizeof(COLOR)); |
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distcnt = (uint16 *)calloc(nalt*nazi, sizeof(uint16)); |
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if ((outarr == NULL) | (distcnt == NULL)) |
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error(SYSTEM, "out of memory in redistribute"); |
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/* compose matrix */ |
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for (i = 3; i--; ) { |
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mymat[i][0] = u[i]; |
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mymat[i][1] = v[i]; |
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mymat[i][2] = w[i]; |
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mymat[i][3] = 0.; |
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} |
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mymat[3][0] = mymat[3][1] = mymat[3][2] = 0.; |
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mymat[3][3] = 1.; |
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if (xm != NULL) |
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multmat4(mymat, xm, mymat); |
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for (i = 3; i--; ) { /* make sure it's normalized */ |
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wt0 = 1./sqrt( mymat[0][i]*mymat[0][i] + |
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mymat[1][i]*mymat[1][i] + |
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mymat[2][i]*mymat[2][i] ); |
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for (j = 3; j--; ) |
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mymat[j][i] *= wt0; |
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} |
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/* pass through BSDF */ |
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for (i = b->ninc; i--; ) { |
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getBSDF_incvec(dv, b, i); |
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multv3(dv, dv, mymat); |
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wt0 = getBSDF_incrad(b, i); |
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wt0 *= PI*wt0 * dv[2]; /* solid_angle*cosine(theta) */ |
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for (o = b->nout; o--; ) { |
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cp = &distarr[3*i]; |
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csum = &outarr[3*o]; |
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wt1 = wt0 * BSDF_data(b,i,o); |
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copycolor(col, cp); |
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scalecolor(col, wt1); |
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addcolor(csum, col); |
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} |
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} |
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newdist(nalt*nazi); /* resample distribution */ |
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for (o = b->nout; o--; ) { |
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getBSDF_outvec(dv, b, o); |
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multv3(dv, dv, mymat); |
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j = (.5 + atan2(dv[1],dv[0])*(.5/PI))*nazi + .5; |
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if (j >= nazi) j = 0; |
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i = (0.9999 - dv[2]*dv[2])*nalt; |
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csum = &distarr[3*(i*nazi + j)]; |
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cp = &outarr[3*o]; |
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addcolor(csum, cp); |
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++distcnt[i*nazi + j]; |
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} |
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free(outarr); |
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/* fill in missing bits */ |
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for (i = nalt; i--; ) |
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for (j = nazi; j--; ) { |
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int ii, jj, alt, azi; |
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if (distcnt[i*nazi + j]) |
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continue; |
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csum = &distarr[3*(i*nazi + j)]; |
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setcolor(csum, 0., 0., 0.); |
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cnt = 0; |
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for (o = 0; !cnt; o++) |
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for (ii = -o; ii <= o; ii++) { |
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alt = i + ii; |
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if (alt < 0) continue; |
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if (alt >= nalt) break; |
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for (jj = -o; jj <= o; jj++) { |
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if (ii*ii + jj*jj != o*o) |
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continue; |
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azi = j + jj; |
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if (azi >= nazi) azi -= nazi; |
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else if (azi < 0) azi += nazi; |
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if (!distcnt[alt*nazi + azi]) |
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continue; |
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cp = &distarr[3*(alt*nazi + azi)]; |
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addcolor(csum, cp); |
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cnt += distcnt[alt*nazi + azi]; |
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} |
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} |
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wt0 = 1./cnt; |
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scalecolor(csum, wt0); |
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} |
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/* finish averages */ |
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for (i = nalt; i--; ) |
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for (j = nazi; j--; ) { |
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if ((cnt = distcnt[i*nazi + j]) <= 1) |
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continue; |
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csum = &distarr[3*(i*nazi + j)]; |
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wt0 = 1./cnt; |
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scalecolor(csum, wt0); |
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} |
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free(distcnt); |
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} |
