src/rt/t_func.c

/* Copyright (c) 1986 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 *  t_func.c - routine for procedural textures.
 *
 *     4/8/86
 */

#include  "ray.h"

/*
 *      A procedural texture perturbs the surface normal
 *  at the point of intersection with an object.  It has
 *  the form:
 *
 *      modifier texfunc name
 *      4+ xvarname yvarname zvarname filename xf
 *      0
 *      n A1 A2 ..
 *
 *  Filename is the name of the file where the variable definitions
 *  can be found.  The list of real arguments can be accessed by
 *  definitions in the file.  The xf is a transformation to get
 *  from the original coordinates to the current coordinates.
 */

typedef struct {
        struct {
                double  sca;            /* scale factor */
                double  xfm[4][4];      /* transformation matrix */
        }  fore, back;
}  XFORM;


t_func(m, r)                    /* compute texture for ray */
register OBJREC  *m;
register RAY  *r;
{
        extern double  varvalue();
        extern int  errno;
        FVECT  disp;
        register XFORM  *mxf;
        register int  i;
        register char  **sa;

        if (m->oargs.nsargs < 4)
                objerror(m, USER, "bad # arguments");
        sa = m->oargs.sarg;

        if ((mxf = (XFORM *)m->os) == NULL) {
                mxf = (XFORM *)malloc(sizeof(XFORM));
                if (mxf == NULL)
                        goto memerr;
                mxf->fore.sca = 1.0;
                setident4(mxf->fore.xfm);
                if (xf(mxf->fore.xfm, &mxf->fore.sca,
                        m->oargs.nsargs-4, sa+4) != m->oargs.nsargs-4)
                        objerror(m, USER, "bad transform");
                if (mxf->fore.sca < 0.0)
                        mxf->fore.sca = -mxf->fore.sca;
                mxf->back.sca = 1.0;
                setident4(mxf->back.xfm);
                invxf(mxf->back.xfm, &mxf->back.sca,
                                m->oargs.nsargs-4, sa+4);
                if (mxf->back.sca < 0.0)
                        mxf->back.sca = -mxf->back.sca;
                m->os = (char *)mxf;
        }

        setmap(m, r, mxf->back.xfm, mxf->back.sca);

        if (!vardefined(sa[0]))
                loadfunc(sa[3]);
        errno = 0;
        for (i = 0; i < 3; i++)
                disp[i] = varvalue(sa[i]);
        if (errno) {
                objerror(m, WARNING, "compute error");
                return;
        }
        if (mxf->fore.xfm == NULL)
                for (i = 0; i < 3; i++)
                        r->pert[i] += disp[i];
        else
                for (i = 0; i < 3; i++)
                        r->pert[i] += ( disp[0]*mxf->fore.xfm[0][i] +
                                        disp[1]*mxf->fore.xfm[1][i] +
                                        disp[2]*mxf->fore.xfm[2][i] )
                                                / mxf->fore.sca;
        return;
memerr:
        error(SYSTEM, "out of memory in t_func");
}
Revision:	1.3
Committed:	Tue Mar 14 10:41:23 1989 UTC (35 years, 1 month ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+1 -1 lines
Log Message:	changed order of parameters to setmap() for consistency with xfm()
#	User	Rev	Content
1	greg	1.1	/* Copyright (c) 1986 Regents of the University of California */
2
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* t_func.c - routine for procedural textures.
9			*
10			* 4/8/86
11			*/
12
13			#include "ray.h"
14
15			/*
16			* A procedural texture perturbs the surface normal
17			* at the point of intersection with an object. It has
18			* the form:
19			*
20			* modifier texfunc name
21			* 4+ xvarname yvarname zvarname filename xf
22			* 0
23			* n A1 A2 ..
24			*
25			* Filename is the name of the file where the variable definitions
26			* can be found. The list of real arguments can be accessed by
27			* definitions in the file. The xf is a transformation to get
28			* from the original coordinates to the current coordinates.
29			*/
30
31			typedef struct {
32			struct {
33			double sca; /* scale factor */
34			double xfm[4][4]; /* transformation matrix */
35			} fore, back;
36			} XFORM;
37
38
39			t_func(m, r) /* compute texture for ray */
40			register OBJREC *m;
41			register RAY *r;
42			{
43			extern double varvalue();
44			extern int errno;
45			FVECT disp;
46	greg	1.2	register XFORM *mxf;
47	greg	1.1	register int i;
48			register char **sa;
49
50			if (m->oargs.nsargs < 4)
51			objerror(m, USER, "bad # arguments");
52			sa = m->oargs.sarg;
53
54	greg	1.2	if ((mxf = (XFORM *)m->os) == NULL) {
55	greg	1.1	mxf = (XFORM *)malloc(sizeof(XFORM));
56			if (mxf == NULL)
57			goto memerr;
58			mxf->fore.sca = 1.0;
59			setident4(mxf->fore.xfm);
60			if (xf(mxf->fore.xfm, &mxf->fore.sca,
61			m->oargs.nsargs-4, sa+4) != m->oargs.nsargs-4)
62			objerror(m, USER, "bad transform");
63			if (mxf->fore.sca < 0.0)
64			mxf->fore.sca = -mxf->fore.sca;
65			mxf->back.sca = 1.0;
66			setident4(mxf->back.xfm);
67			invxf(mxf->back.xfm, &mxf->back.sca,
68			m->oargs.nsargs-4, sa+4);
69			if (mxf->back.sca < 0.0)
70			mxf->back.sca = -mxf->back.sca;
71	greg	1.2	m->os = (char *)mxf;
72	greg	1.1	}
73
74	greg	1.3	setmap(m, r, mxf->back.xfm, mxf->back.sca);
75	greg	1.1
76			if (!vardefined(sa[0]))
77			loadfunc(sa[3]);
78			errno = 0;
79			for (i = 0; i < 3; i++)
80			disp[i] = varvalue(sa[i]);
81			if (errno) {
82			objerror(m, WARNING, "compute error");
83			return;
84			}
85			if (mxf->fore.xfm == NULL)
86			for (i = 0; i < 3; i++)
87			r->pert[i] += disp[i];
88			else
89			for (i = 0; i < 3; i++)
90			r->pert[i] += ( disp[0]*mxf->fore.xfm[0][i] +
91			disp[1]*mxf->fore.xfm[1][i] +
92			disp[2]*mxf->fore.xfm[2][i] )
93			/ mxf->fore.sca;
94			return;
95			memerr:
96			error(SYSTEM, "out of memory in t_func");
97			}