src/rt/p_func.c

#ifndef lint
static const char       RCSid[] = "$Id: p_func.c,v 2.11 2023/12/13 23:26:16 greg Exp $";
#endif
/*
 *  p_func.c - routine for procedural patterns.
 */

#include "copyright.h"

#include  "ray.h"
#include  "func.h"
#include  "random.h"
#include  "rtotypes.h"

/*
 *      A procedural pattern can either be a brightness or a
 *  color function.  A brightness function is given as:
 *
 *      modifier brightfunc name
 *      2+ bvarname filename xf
 *      0
 *      n A1 A2 ..
 *
 *  A color function is given as:
 *
 *      modifier colorfunc name
 *      4+ rvarname gvarname bvarname filename xf
 *      0
 *      n A1 A2 ..
 *
 *  A spectral function is given as:
 *
 *      modifier specfunc name
 *      2+ sfunc filename xf
 *      0
 *      2+ nmA nmB A3 ..
 *
 *  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.
 *  For the "specfunc" primitive, sfunc(nm) is a function of wavelength
 *  and must be defined from nmA to nmB, and should average to 1 over
 *  its range.
 */


int
p_bfunc(                        /* compute brightness pattern */
        OBJREC  *m,
        RAY  *r
)
{
        double  bval;
        MFUNC  *mf;

        if (m->oargs.nsargs < 2)
                objerror(m, USER, "bad # arguments");
        mf = getfunc(m, 1, 0x1, 0);
        setfunc(m, r);
        errno = 0;
        bval = evalue(mf->ep[0]);
        if ((errno == EDOM) | (errno == ERANGE)) {
                objerror(m, WARNING, "compute error");
                return(0);
        }
        scalescolor(r->pcol, bval);
        return(0);
}


int
p_cfunc(                        /* compute color pattern */
        OBJREC  *m,
        RAY  *r
)
{
        SCOLOR  scval;
        MFUNC  *mf;

        if (m->oargs.nsargs < 4)
                objerror(m, USER, "bad # arguments");
        mf = getfunc(m, 3, 0x7, 0);
        setfunc(m, r);
        errno = 0;
        setscolor(scval, evalue(mf->ep[0]),
                        evalue(mf->ep[1]),
                        evalue(mf->ep[2]));
        if ((errno == EDOM) | (errno == ERANGE)) {
                objerror(m, WARNING, "compute error");
                return(0);
        }
        smultscolor(r->pcol, scval);
        return(0);
}


int
p_specfunc(                     /* compute spectral pattern */
        OBJREC  *m,
        RAY  *r
)
{
        SCOLOR  scsamp;
        SCOLOR  scval;
        double  wl, wlmin, wlmax, wlstep;
        int     ns, i;

        if ((m->oargs.nsargs < 2) | (m->oargs.nfargs < 2))
                objerror(m, USER, "bad # arguments");
        if (m->oargs.farg[0] < m->oargs.farg[1]) {
                wlmin = m->oargs.farg[0];
                wlmax = m->oargs.farg[1];
        } else {
                wlmin = m->oargs.farg[1];
                wlmax = m->oargs.farg[0];
        }
        if (wlmin < WLPART[3]) wlmin = WLPART[3];
        if (wlmax > WLPART[0]) wlmax = WLPART[0];
        if (wlmin >= wlmax) {
                objerror(m, WARNING, "incompatible wavelength sampling");
                return(0);
        }
        wlstep = (wlmax - wlmin)/(double)MAXCSAMP;
        getfunc(m, 1, 0, 0);
        setfunc(m, r);
        errno = 0;
        ns = (wlmax - wlmin)/wlstep + .1;
        wl = wlmax - .5*wlstep;
        for (i = ns; i-- > 0; wl -= wlstep) {
                double  ws = wl + 0.9*(.5-frandom())*wlstep;
                scsamp[i] = funvalue(m->oargs.sarg[0], 1, &ws);
                if ((errno == EDOM) | (errno == ERANGE)) {
                        objerror(m, WARNING, "compute error");
                        return(0);
                }
        }
        convertscolor(scval, NCSAMP, WLPART[0], WLPART[3],
                        scsamp, ns, wlmin, wlmax);
        smultscolor(r->pcol, scval);
        return(0);
}
Revision:	2.12
Committed:	Sun Jan 7 18:04:16 2024 UTC (4 months, 1 week ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.11:	+3 -4 lines
Log Message:	fix(rpict,rtrace,rcontrib,rvu): fixed sampling for "specfunc" primitive
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.12	static const char RCSid[] = "$Id: p_func.c,v 2.11 2023/12/13 23:26:16 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* p_func.c - routine for procedural patterns.
6	greg	2.4	*/
7
8	greg	2.5	#include "copyright.h"
9	greg	1.1
10			#include "ray.h"
11	greg	2.2	#include "func.h"
12	greg	2.10	#include "random.h"
13	schorsch	2.7	#include "rtotypes.h"
14	greg	2.2
15	greg	1.1	/*
16			* A procedural pattern can either be a brightness or a
17			* color function. A brightness function is given as:
18			*
19			* modifier brightfunc name
20			* 2+ bvarname filename xf
21			* 0
22			* n A1 A2 ..
23			*
24			* A color function is given as:
25			*
26			* modifier colorfunc name
27			* 4+ rvarname gvarname bvarname filename xf
28			* 0
29			* n A1 A2 ..
30			*
31	greg	2.9	* A spectral function is given as:
32			*
33			* modifier specfunc name
34	greg	2.11	* 2+ sfunc filename xf
35	greg	2.9	* 0
36			* 2+ nmA nmB A3 ..
37			*
38	greg	1.1	* Filename is the name of the file where the variable definitions
39			* can be found. The list of real arguments can be accessed by
40			* definitions in the file. The xf is a transformation
41			* to get from the original coordinates to the current coordinates.
42	greg	2.11	* For the "specfunc" primitive, sfunc(nm) is a function of wavelength
43	greg	2.9	* and must be defined from nmA to nmB, and should average to 1 over
44			* its range.
45	greg	1.1	*/
46
47
48	greg	2.8	int
49	schorsch	2.7	p_bfunc( /* compute brightness pattern */
50			OBJREC *m,
51			RAY *r
52			)
53	greg	1.1	{
54			double bval;
55	greg	2.8	MFUNC *mf;
56	greg	1.1
57			if (m->oargs.nsargs < 2)
58			objerror(m, USER, "bad # arguments");
59	greg	2.2	mf = getfunc(m, 1, 0x1, 0);
60			setfunc(m, r);
61	greg	1.1	errno = 0;
62	greg	2.2	bval = evalue(mf->ep[0]);
63	greg	2.9	if ((errno == EDOM) \| (errno == ERANGE)) {
64	greg	1.1	objerror(m, WARNING, "compute error");
65	greg	2.3	return(0);
66	greg	1.1	}
67	greg	2.9	scalescolor(r->pcol, bval);
68	greg	2.3	return(0);
69	greg	1.1	}
70
71
72	greg	2.8	int
73	schorsch	2.7	p_cfunc( /* compute color pattern */
74			OBJREC *m,
75			RAY *r
76			)
77	greg	1.1	{
78	greg	2.9	SCOLOR scval;
79	greg	2.8	MFUNC *mf;
80	greg	1.1
81			if (m->oargs.nsargs < 4)
82			objerror(m, USER, "bad # arguments");
83	greg	2.2	mf = getfunc(m, 3, 0x7, 0);
84			setfunc(m, r);
85	greg	1.1	errno = 0;
86	greg	2.9	setscolor(scval, evalue(mf->ep[0]),
87	greg	2.2	evalue(mf->ep[1]),
88			evalue(mf->ep[2]));
89	greg	2.9	if ((errno == EDOM) \| (errno == ERANGE)) {
90	greg	1.1	objerror(m, WARNING, "compute error");
91	greg	2.3	return(0);
92	greg	1.1	}
93	greg	2.9	smultscolor(r->pcol, scval);
94			return(0);
95			}
96
97
98			int
99			p_specfunc( /* compute spectral pattern */
100			OBJREC *m,
101			RAY *r
102			)
103			{
104			SCOLOR scsamp;
105			SCOLOR scval;
106			double wl, wlmin, wlmax, wlstep;
107			int ns, i;
108
109			if ((m->oargs.nsargs < 2) \| (m->oargs.nfargs < 2))
110			objerror(m, USER, "bad # arguments");
111			if (m->oargs.farg[0] < m->oargs.farg[1]) {
112			wlmin = m->oargs.farg[0];
113			wlmax = m->oargs.farg[1];
114			} else {
115			wlmin = m->oargs.farg[1];
116			wlmax = m->oargs.farg[0];
117			}
118			if (wlmin < WLPART[3]) wlmin = WLPART[3];
119			if (wlmax > WLPART[0]) wlmax = WLPART[0];
120			if (wlmin >= wlmax) {
121			objerror(m, WARNING, "incompatible wavelength sampling");
122			return(0);
123			}
124			wlstep = (wlmax - wlmin)/(double)MAXCSAMP;
125	greg	2.12	getfunc(m, 1, 0, 0);
126	greg	2.9	setfunc(m, r);
127			errno = 0;
128			ns = (wlmax - wlmin)/wlstep + .1;
129			wl = wlmax - .5*wlstep;
130			for (i = ns; i-- > 0; wl -= wlstep) {
131	greg	2.12	double ws = wl + 0.9(.5-frandom())wlstep;
132	greg	2.10	scsamp[i] = funvalue(m->oargs.sarg[0], 1, &ws);
133	greg	2.9	if ((errno == EDOM) \| (errno == ERANGE)) {
134			objerror(m, WARNING, "compute error");
135			return(0);
136			}
137			}
138			convertscolor(scval, NCSAMP, WLPART[0], WLPART[3],
139			scsamp, ns, wlmin, wlmax);
140			smultscolor(r->pcol, scval);
141	greg	2.3	return(0);
142	greg	1.1	}