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/* Copyright (c) 1986 Regents of the University of California */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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|
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/* |
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* t_func.c - routine for procedural textures. |
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* |
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* 4/8/86 |
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*/ |
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|
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#include "ray.h" |
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|
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/* |
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* A procedural texture perturbs the surface normal |
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* at the point of intersection with an object. It has |
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* the form: |
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* |
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* modifier texfunc name |
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* 4+ xvarname yvarname zvarname filename xf |
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* 0 |
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* n A1 A2 .. |
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* |
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* Filename is the name of the file where the variable definitions |
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* can be found. The list of real arguments can be accessed by |
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* definitions in the file. The xf is a transformation to get |
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* from the original coordinates to the current coordinates. |
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*/ |
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|
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typedef struct { |
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struct { |
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double sca; /* scale factor */ |
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double xfm[4][4]; /* transformation matrix */ |
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} fore, back; |
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} XFORM; |
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|
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|
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t_func(m, r) /* compute texture for ray */ |
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register OBJREC *m; |
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register RAY *r; |
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{ |
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extern double varvalue(); |
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extern int errno; |
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FVECT disp; |
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double d; |
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register XFORM *mxf; |
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register int i; |
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register char **sa; |
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|
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if (m->oargs.nsargs < 4) |
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objerror(m, USER, "bad # arguments"); |
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sa = m->oargs.sarg; |
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|
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if ((mxf = (XFORM *)m->os) == NULL) { |
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mxf = (XFORM *)malloc(sizeof(XFORM)); |
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if (mxf == NULL) |
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goto memerr; |
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mxf->fore.sca = 1.0; |
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setident4(mxf->fore.xfm); |
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if (xf(mxf->fore.xfm, &mxf->fore.sca, |
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m->oargs.nsargs-4, sa+4) != m->oargs.nsargs-4) |
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objerror(m, USER, "bad transform"); |
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if (mxf->fore.sca < 0.0) |
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mxf->fore.sca = -mxf->fore.sca; |
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mxf->back.sca = 1.0; |
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setident4(mxf->back.xfm); |
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invxf(mxf->back.xfm, &mxf->back.sca, |
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m->oargs.nsargs-4, sa+4); |
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if (mxf->back.sca < 0.0) |
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mxf->back.sca = -mxf->back.sca; |
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m->os = (char *)mxf; |
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} |
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|
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setmap(m, r, mxf->back.xfm, mxf->back.sca); |
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|
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if (!vardefined(sa[0])) |
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loadfunc(sa[3]); |
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errno = 0; |
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for (i = 0; i < 3; i++) |
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disp[i] = varvalue(sa[i]); |
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if (errno) { |
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objerror(m, WARNING, "compute error"); |
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return; |
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} |
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multv3(disp, disp, mxf->fore.xfm); |
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multv3(disp, disp, r->rofx); |
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d = 1.0 / (mxf->fore.sca * r->rofs); |
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for (i = 0; i < 3; i++) |
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r->pert[i] += disp[i] * d; |
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return; |
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memerr: |
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error(SYSTEM, "out of memory in t_func"); |
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} |
