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root/radiance/ray/src/rt/t_data.c
Revision: 1.4
Committed: Wed Apr 19 21:20:28 1989 UTC (35 years ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.3: +3 -1 lines
Log Message:
added loop invariant

File Contents

# User Rev Content
1 greg 1.1 /* Copyright (c) 1989 Regents of the University of California */
2    
3     #ifndef lint
4     static char SCCSid[] = "$SunId$ LBL";
5     #endif
6    
7     /*
8     * t_data.c - routine for stored textures
9     *
10     * 6/4/86
11     */
12    
13     #include "ray.h"
14    
15     #include "data.h"
16    
17     /*
18     * A stored texture is specified as follows:
19     *
20     * modifier texdata name
21     * 8+ xfunc yfunc zfunc xdfname ydfname zdfname vfname v0 v1 .. xf
22     * 0
23     * n A1 A2 .. An
24     *
25     * Vfname 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 dfnames are the data file
28     * names. The dimensions of the data files and the number
29     * of variables must match. The funcs take three arguments to produce
30     * interpolated values from the file. The xf is a transformation
31     * to get from the original coordinates to the current coordinates.
32     */
33    
34     typedef struct {
35     struct {
36     double sca; /* scale factor */
37     double xfm[4][4]; /* transformation matrix */
38     } fore, back;
39     } XFORM;
40    
41    
42     t_data(m, r) /* interpolate texture data */
43     register OBJREC *m;
44     RAY *r;
45     {
46     extern double varvalue(), funvalue(), datavalue();
47     extern int errno;
48     int nv;
49     FVECT dval, disp;
50     double pt[MAXDIM];
51 greg 1.4 double d;
52 greg 1.1 DATARRAY *dp;
53     register XFORM *mxf;
54     register char **sa;
55     register int i;
56    
57     if (m->oargs.nsargs < 8)
58     objerror(m, USER, "bad # arguments");
59     sa = m->oargs.sarg;
60    
61 greg 1.2 for (i = 7; i < m->oargs.nsargs && sa[i][0] != '-'; i++)
62     ;
63     nv = i-7;
64 greg 1.1 if ((mxf = (XFORM *)m->os) == NULL) {
65     mxf = (XFORM *)malloc(sizeof(XFORM));
66     if (mxf == NULL)
67     goto memerr;
68     mxf->fore.sca = 1.0;
69     setident4(mxf->fore.xfm);
70     if (xf(mxf->fore.xfm, &mxf->fore.sca,
71     m->oargs.nsargs-i, sa+i) != m->oargs.nsargs-i)
72     objerror(m, USER, "bad transform");
73     if (mxf->fore.sca < 0.0)
74     mxf->fore.sca = -mxf->fore.sca;
75     mxf->back.sca = 1.0;
76     setident4(mxf->back.xfm);
77     invxf(mxf->back.xfm, &mxf->back.sca,
78     m->oargs.nsargs-i, sa+i);
79     if (mxf->back.sca < 0.0)
80     mxf->back.sca = -mxf->back.sca;
81     m->os = (char *)mxf;
82     }
83    
84     setmap(m, r, mxf->back.xfm, mxf->back.sca);
85    
86     if (nv > MAXDIM)
87     goto dimerr;
88     if (!vardefined(sa[7]))
89     loadfunc(sa[6]);
90     errno = 0;
91     for (i = 0; i < nv; i++)
92     pt[i] = varvalue(sa[i+7]);
93     if (errno)
94     goto computerr;
95     for (i = 0; i < 3; i++) {
96     dp = getdata(sa[i+3]);
97     if (dp->nd != nv)
98     goto dimerr;
99     dval[i] = datavalue(dp, pt);
100     }
101     errno = 0;
102     for (i = 0; i < 3; i++)
103     disp[i] = funvalue(sa[i], 3, dval);
104     if (errno)
105     goto computerr;
106    
107 greg 1.3 multv3(disp, disp, mxf->fore.xfm);
108     multv3(disp, disp, r->rofx);
109 greg 1.4 d = 1.0 / (mxf->fore.sca * r->rofs);
110 greg 1.1 for (i = 0; i < 3; i++)
111 greg 1.4 r->pert[i] += disp[i] * d;
112 greg 1.1 return;
113     dimerr:
114     objerror(m, USER, "dimension error");
115     memerr:
116     error(SYSTEM, "out of memory in t_data");
117     computerr:
118     objerror(m, WARNING, "compute error");
119     return;
120     }