cv/mgflib/context.c

/* Copyright (c) 1994 Regents of the University of California */

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

/*
 * Context handlers
 */

#include <stdio.h>
#include <math.h>
#include <string.h>
#include "parser.h"
#include "lookup.h"

                                /* default context values */
static C_COLOR          c_dfcolor = C_DEFCOLOR;
static C_MATERIAL       c_dfmaterial = C_DEFMATERIAL;
static C_VERTEX         c_dfvertex = C_DEFVERTEX;

                                /* the unnamed contexts */
static C_COLOR          c_uncolor = C_DEFCOLOR;
static C_MATERIAL       c_unmaterial = C_DEFMATERIAL;
static C_VERTEX         c_unvertex = C_DEFVERTEX;

                                /* the current contexts */
C_COLOR         *c_ccolor = &c_uncolor;
char            *c_ccname = NULL;
C_MATERIAL      *c_cmaterial = &c_unmaterial;
char            *c_cmname = NULL;
C_VERTEX        *c_cvertex = &c_unvertex;
char            *c_cvname = NULL;

static LUTAB    clr_tab = LU_SINIT(free,free);  /* color lookup table */
static LUTAB    mat_tab = LU_SINIT(free,free);  /* material lookup table */
static LUTAB    vtx_tab = LU_SINIT(free,free);  /* vertex lookup table */

                                /* CIE 1931 Standard Observer */
static C_COLOR  cie_xf = C_CIEX;
static C_COLOR  cie_yf = C_CIEY;
static C_COLOR  cie_zf = C_CIEZ;

static int      setspectrum();
static void     mixcolors();


int
c_hcolor(ac, av)                /* handle color entity */
int     ac;
register char   **av;
{
        double  w, wsum;
        register int    i;
        register LUENT  *lp;

        switch (mg_entity(av[0])) {
        case MG_E_COLOR:        /* get/set color context */
                if (ac > 4)
                        return(MG_EARGC);
                if (ac == 1) {          /* set unnamed color context */
                        c_uncolor = c_dfcolor;
                        c_ccolor = &c_uncolor;
                        c_ccname = NULL;
                        return(MG_OK);
                }
                lp = lu_find(&clr_tab, av[1]);  /* lookup context */
                if (lp == NULL)
                        return(MG_EMEM);
                c_ccolor = (C_COLOR *)lp->data;
                if (ac == 2) {          /* reestablish previous context */
                        if (c_ccolor == NULL)
                                return(MG_EUNDEF);
                        return(MG_OK);
                }
                if (av[2][0] != '=' || av[2][1])
                        return(MG_ETYPE);
                if (c_ccolor == NULL) { /* create new color context */
                        lp->key = (char *)malloc(strlen(av[1])+1);
                        if (lp->key == NULL)
                                return(MG_EMEM);
                        strcpy(lp->key, av[1]);
                        lp->data = (char *)malloc(sizeof(C_COLOR));
                        if (lp->data == NULL)
                                return(MG_EMEM);
                        c_ccolor = (C_COLOR *)lp->data;
                        c_ccolor->clock = 0;
                }
                c_ccname = lp->key;
                i = c_ccolor->clock;
                if (ac == 3) {          /* use default template */
                        *c_ccolor = c_dfcolor;
                        c_ccolor->clock = i + 1;
                        return(MG_OK);
                }
                lp = lu_find(&clr_tab, av[3]);  /* lookup template */
                if (lp == NULL)
                        return(MG_EMEM);
                if (lp->data == NULL)
                        return(MG_EUNDEF);
                *c_ccolor = *(C_COLOR *)lp->data;
                c_ccolor->clock = i + 1;
                return(MG_OK);
        case MG_E_CXY:          /* assign CIE XY value */
                if (ac != 3)
                        return(MG_EARGC);
                if (!isflt(av[1]) || !isflt(av[2]))
                        return(MG_ETYPE);
                c_ccolor->cx = atof(av[1]);
                c_ccolor->cy = atof(av[2]);
                c_ccolor->flags = C_CDXY|C_CSXY;
                if (c_ccolor->cx < 0. | c_ccolor->cy < 0. |
                                c_ccolor->cx + c_ccolor->cy > 1.)
                        return(MG_EILL);
                c_ccolor->clock++;
                return(MG_OK);
        case MG_E_CSPEC:        /* assign spectral values */
                if (ac < 5)
                        return(MG_EARGC);
                if (!isint(av[1]) || !isint(av[2]))
                        return(MG_ETYPE);
                return(setspectrum(c_ccolor, atoi(av[1]), atoi(av[2]),
                                ac-3, av+3));
        case MG_E_CMIX:         /* mix colors */
                if (ac < 5 || (ac-1)%2)
                        return(MG_EARGC);
                if (!isflt(av[1]))
                        return(MG_ETYPE);
                wsum = atof(av[1]);
                if (wsum < 0.)
                        return(MG_EILL);
                if ((lp = lu_find(&clr_tab, av[2])) == NULL)
                        return(MG_EMEM);
                if (lp->data == NULL)
                        return(MG_EUNDEF);
                *c_ccolor = *(C_COLOR *)lp->data;
                for (i = 3; i < ac; i += 2) {
                        if (!isflt(av[i]))
                                return(MG_ETYPE);
                        w = atof(av[i]);
                        if (w < 0.)
                                return(MG_EILL);
                        if ((lp = lu_find(&clr_tab, av[i+1])) == NULL)
                                return(MG_EMEM);
                        if (lp->data == NULL)
                                return(MG_EUNDEF);
                        mixcolors(c_ccolor, wsum, c_ccolor,
                                        w, (C_COLOR *)lp->data);
                        wsum += w;
                }
                c_ccolor->clock++;
                return(MG_OK);
        }
        return(MG_EUNK);
}


int
c_hmaterial(ac, av)             /* handle material entity */
int     ac;
register char   **av;
{
        int     i;
        register LUENT  *lp;

        switch (mg_entity(av[0])) {
        case MG_E_MATERIAL:     /* get/set material context */
                if (ac > 4)
                        return(MG_EARGC);
                if (ac == 1) {          /* set unnamed material context */
                        c_unmaterial = c_dfmaterial;
                        c_cmaterial = &c_unmaterial;
                        c_cmname = NULL;
                        return(MG_OK);
                }
                lp = lu_find(&mat_tab, av[1]);  /* lookup context */
                if (lp == NULL)
                        return(MG_EMEM);
                c_cmaterial = (C_MATERIAL *)lp->data;
                if (ac == 2) {          /* reestablish previous context */
                        if (c_cmaterial == NULL)
                                return(MG_EUNDEF);
                        return(MG_OK);
                }
                if (av[2][0] != '=' || av[2][1])
                        return(MG_ETYPE);
                if (c_cmaterial == NULL) {      /* create new material */
                        lp->key = (char *)malloc(strlen(av[1])+1);
                        if (lp->key == NULL)
                                return(MG_EMEM);
                        strcpy(lp->key, av[1]);
                        lp->data = (char *)malloc(sizeof(C_MATERIAL));
                        if (lp->data == NULL)
                                return(MG_EMEM);
                        c_cmaterial = (C_MATERIAL *)lp->data;
                        c_cmaterial->clock = 0;
                }
                c_cmname = lp->key;
                i = c_cmaterial->clock;
                if (ac == 3) {          /* use default template */
                        *c_cmaterial = c_dfmaterial;
                        c_cmaterial->clock = i + 1;
                        return(MG_OK);
                }
                lp = lu_find(&mat_tab, av[3]);  /* lookup template */
                if (lp == NULL)
                        return(MG_EMEM);
                if (lp->data == NULL)
                        return(MG_EUNDEF);
                *c_cmaterial = *(C_MATERIAL *)lp->data;
                c_cmaterial->clock = i + 1;
                return(MG_OK);
        case MG_E_RD:           /* set diffuse reflectance */
                if (ac != 2)
                        return(MG_EARGC);
                if (!isflt(av[1]))
                        return(MG_ETYPE);
                c_cmaterial->rd = atof(av[1]);
                if (c_cmaterial->rd < 0. | c_cmaterial->rd > 1.)
                        return(MG_EILL);
                c_cmaterial->rd_c = *c_ccolor;
                c_cmaterial->clock++;
                return(MG_OK);
        case MG_E_ED:           /* set diffuse emittance */
                if (ac != 2)
                        return(MG_EARGC);
                if (!isflt(av[1]))
                        return(MG_ETYPE);
                c_cmaterial->ed = atof(av[1]);
                if (c_cmaterial->ed < 0.)
                        return(MG_EILL);
                c_cmaterial->ed_c = *c_ccolor;
                c_cmaterial->clock++;
                return(MG_OK);
        case MG_E_TD:           /* set diffuse transmittance */
                if (ac != 2)
                        return(MG_EARGC);
                if (!isflt(av[1]))
                        return(MG_ETYPE);
                c_cmaterial->td = atof(av[1]);
                if (c_cmaterial->td < 0. | c_cmaterial->td > 1.)
                        return(MG_EILL);
                c_cmaterial->td_c = *c_ccolor;
                c_cmaterial->clock++;
                return(MG_OK);
        case MG_E_RS:           /* set specular reflectance */
                if (ac != 3)
                        return(MG_EARGC);
                if (!isflt(av[1]) || !isflt(av[2]))
                        return(MG_ETYPE);
                c_cmaterial->rs = atof(av[1]);
                c_cmaterial->rs_a = atof(av[2]);
                if (c_cmaterial->rs < 0. | c_cmaterial->rs > 1. |
                                c_cmaterial->rs_a < 0.)
                        return(MG_EILL);
                c_cmaterial->rs_c = *c_ccolor;
                c_cmaterial->clock++;
                return(MG_OK);
        case MG_E_TS:           /* set specular transmittance */
                if (ac != 3)
                        return(MG_EARGC);
                if (!isflt(av[1]) || !isflt(av[2]))
                        return(MG_ETYPE);
                c_cmaterial->ts = atof(av[1]);
                c_cmaterial->ts_a = atof(av[2]);
                if (c_cmaterial->ts < 0. | c_cmaterial->ts > 1. |
                                c_cmaterial->ts_a < 0.)
                        return(MG_EILL);
                c_cmaterial->ts_c = *c_ccolor;
                c_cmaterial->clock++;
                return(MG_OK);
        }
        return(MG_EUNK);
}


int
c_hvertex(ac, av)               /* handle a vertex entity */
int     ac;
register char   **av;
{
        int     i;
        register LUENT  *lp;

        switch (mg_entity(av[0])) {
        case MG_E_VERTEX:       /* get/set vertex context */
                if (ac > 4)
                        return(MG_EARGC);
                if (ac == 1) {          /* set unnamed vertex context */
                        c_unvertex = c_dfvertex;
                        c_cvertex = &c_unvertex;
                        c_cvname = NULL;
                        return(MG_OK);
                }
                lp = lu_find(&vtx_tab, av[1]);  /* lookup context */
                if (lp == NULL)
                        return(MG_EMEM);
                c_cvertex = (C_VERTEX *)lp->data;
                if (ac == 2) {          /* reestablish previous context */
                        if (c_cvertex == NULL)
                                return(MG_EUNDEF);
                        return(MG_OK);
                }
                if (av[2][0] != '=' || av[2][1])
                        return(MG_ETYPE);
                if (c_cvertex == NULL) {        /* create new vertex context */
                        lp->key = (char *)malloc(strlen(av[1])+1);
                        if (lp->key == NULL)
                                return(MG_EMEM);
                        strcpy(lp->key, av[1]);
                        lp->data = (char *)malloc(sizeof(C_VERTEX));
                        if (lp->data == NULL)
                                return(MG_EMEM);
                        c_cvertex = (C_VERTEX *)lp->data;
                }
                c_cvname = lp->key;
                i = c_cvertex->clock;
                if (ac == 3) {          /* use default template */
                        *c_cvertex = c_dfvertex;
                        c_cvertex->clock = i + 1;
                        return(MG_OK);
                }
                lp = lu_find(&vtx_tab, av[3]);  /* lookup template */
                if (lp == NULL)
                        return(MG_EMEM);
                if (lp->data == NULL)
                        return(MG_EUNDEF);
                *c_cvertex = *(C_VERTEX *)lp->data;
                c_cvertex->clock = i + 1;
                return(MG_OK);
        case MG_E_POINT:        /* set point */
                if (ac != 4)
                        return(MG_EARGC);
                if (!isflt(av[1]) || !isflt(av[2]) || !isflt(av[3]))
                        return(MG_ETYPE);
                c_cvertex->p[0] = atof(av[1]);
                c_cvertex->p[1] = atof(av[2]);
                c_cvertex->p[2] = atof(av[3]);
                c_cvertex->clock++;
                return(MG_OK);
        case MG_E_NORMAL:       /* set normal */
                if (ac != 4)
                        return(MG_EARGC);
                if (!isflt(av[1]) || !isflt(av[2]) || !isflt(av[3]))
                        return(MG_ETYPE);
                c_cvertex->n[0] = atof(av[1]);
                c_cvertex->n[1] = atof(av[2]);
                c_cvertex->n[2] = atof(av[3]);
                (void)normalize(c_cvertex->n);
                c_cvertex->clock++;
                return(MG_OK);
        }
        return(MG_EUNK);
}


void
c_clearall()                    /* empty context tables */
{
        c_uncolor = c_dfcolor;
        c_ccolor = &c_uncolor;
        lu_done(&clr_tab);
        c_unmaterial = c_dfmaterial;
        c_cmaterial = &c_unmaterial;
        lu_done(&mat_tab);
        c_unvertex = c_dfvertex;
        c_cvertex = &c_unvertex;
        lu_done(&vtx_tab);
}


C_MATERIAL *
c_getmaterial(name)             /* get a named material */
char    *name;
{
        register LUENT  *lp;

        if ((lp = lu_find(&mat_tab, name)) == NULL)
                return(NULL);
        return((C_MATERIAL *)lp->data);
}


C_VERTEX *
c_getvert(name)                 /* get a named vertex */
char    *name;
{
        register LUENT  *lp;

        if ((lp = lu_find(&vtx_tab, name)) == NULL)
                return(NULL);
        return((C_VERTEX *)lp->data);
}


C_COLOR *
c_getcolor(name)                /* get a named color */
char    *name;
{
        register LUENT  *lp;

        if ((lp = lu_find(&clr_tab, name)) == NULL)
                return(NULL);
        return((C_COLOR *)lp->data);
}


int
c_isgrey(clr)                   /* check if color is grey */
register C_COLOR        *clr;
{
        if (!(clr->flags & (C_CSXY|C_CSSPEC)))
                return(1);              /* no settings == grey */
        c_ccvt(clr, C_CSXY);
        return(clr->cx >= .323 && clr->cx <= .343 &&
                        clr->cy >= .323 && clr->cy <= .343);
}


void
c_ccvt(clr, fl)                 /* convert color representations */
register C_COLOR        *clr;
int     fl;
{
        double  x, y, z;
        register int    i;

        if (clr->flags & fl)            /* already done */
                return;
        if (!(clr->flags & (C_CSXY|C_CSSPEC)))  /* nothing set! */
                *clr = c_dfcolor;
        else if (fl & C_CSXY) {         /* cspec -> cxy */
                x = y = z = 0.;
                for (i = 0; i < C_CNSS; i++) {
                        x += cie_xf.ssamp[i] * clr->ssamp[i];
                        y += cie_yf.ssamp[i] * clr->ssamp[i];
                        z += cie_zf.ssamp[i] * clr->ssamp[i];
                }
                z += x + y;
                clr->cx = x / z;
                clr->cy = y / z;
                clr->flags |= C_CSXY;
        } else {                        /* cxy -> cspec */
                z = (cie_xf.ssum + cie_yf.ssum + cie_zf.ssum) / 3.;
                x = clr->cx * z / cie_xf.ssum;
                y = clr->cy * z / cie_yf.ssum;
                z = (1. - clr->cx - clr->cy) * z / cie_zf.ssum;
                clr->ssum = 0;
                for (i = 0; i < C_CNSS; i++)
                        clr->ssum += clr->ssamp[i] =
                                        x * cie_xf.ssamp[i] +
                                        y * cie_yf.ssamp[i] +
                                        z * cie_zf.ssamp[i] ;
                clr->flags |= C_CSSPEC;
        }
}


static int
setspectrum(clr, wlmin, wlmax, ac, av)  /* convert a spectrum */
register C_COLOR        *clr;
int     wlmin, wlmax;
int     ac;
char    **av;
{
        double  scale;
        float   *va;
        register int    i;
        int     wl, pos;
        double  wl0, wlstep;

        if (wlmin < C_CMINWL || wlmin >= wlmax || wlmax > C_CMAXWL)
                return(MG_EILL);
        if ((va = (float *)malloc(ac*sizeof(float))) == NULL)
                return(MG_EMEM);
        scale = 0.;                     /* get values and maximum */
        for (i = 0; i < ac; i++) {
                if (!isflt(av[i]))
                        return(MG_ETYPE);
                va[i] = atof(av[i]);
                if (va[i] < 0.)
                        return(MG_EILL);
                if (va[i] > scale)
                        scale = va[i];
        }
        if (scale == 0.)
                return(MG_EILL);
        scale = C_CMAXV / scale;
        clr->ssum = 0;                  /* convert to our spacing */
        wl0 = wlmin;
        wlstep = (double)(wlmax - wlmin)/(ac-1);
        pos = 0;
        for (i = 0, wl = C_CMINWL; i < C_CNSS; i++, wl += C_CWLI)
                if (wl < wlmin || wl > wlmax)
                        clr->ssamp[i] = 0;
                else {
                        while (wl0 + wlstep < wl+FTINY) {
                                wl0 += wlstep;
                                pos++;
                        }
                        if (wl+FTINY >= wl0 && wl-FTINY <= wl0)
                                clr->ssamp[i] = scale*va[pos];
                        else            /* interpolate if necessary */
                                clr->ssamp[i] = scale / wlstep *
                                                ( va[pos]*(wl0+wlstep - wl) +
                                                        va[pos+1]*(wl - wl0) );
                        clr->ssum += clr->ssamp[i];
                }
        clr->flags = C_CDSPEC|C_CSSPEC;
        clr->clock++;
        free((MEM_PTR)va);
        return(MG_OK);
}


static void
mixcolors(cres, w1, c1, w2, c2) /* mix two colors according to weights given */
register C_COLOR        *cres, *c1, *c2;
double  w1, w2;
{
        double  scale;
        float   cmix[C_CNSS];
        register int    i;

        if ((c1->flags|c2->flags) & C_CDSPEC) {         /* spectral mixing */
                c_ccvt(c1, C_CSSPEC);
                c_ccvt(c2, C_CSSPEC);
                w1 /= (double)c1->ssum;
                w2 /= (double)c2->ssum;
                scale = 0.;
                for (i = 0; i < C_CNSS; i++) {
                        cmix[i] = w1*c1->ssamp[i] + w2*c2->ssamp[i];
                        if (cmix[i] > scale)
                                scale = cmix[i];
                }
                scale = C_CMAXV / scale;
                cres->ssum = 0;
                for (i = 0; i < C_CNSS; i++)
                        cres->ssum += cres->ssamp[i] = scale*cmix[i] + .5;
                cres->flags = C_CDSPEC|C_CSSPEC;
        } else {                                        /* CIE xy mixing */
                c_ccvt(c1, C_CSXY);
                c_ccvt(c2, C_CSXY);
                scale = 1. / (w1/c1->cy + w2/c2->cy);
                cres->cx = (c1->cx*w1/c1->cy + c2->cx*w2/c2->cy) * scale;
                cres->cy = (w1 + w2) * scale;
                cres->flags = C_CDXY|C_CSXY;
        }
}
Revision:	1.12
Committed:	Fri Jul 1 10:18:38 1994 UTC (29 years, 10 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.11:	+9 -12 lines
Log Message:	changed context names from struct members to extern variables
#	User	Rev	Content
1	greg	1.1	/* Copyright (c) 1994 Regents of the University of California */
2
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* Context handlers
9			*/
10
11			#include <stdio.h>
12	greg	1.2	#include <math.h>
13	greg	1.1	#include <string.h>
14			#include "parser.h"
15			#include "lookup.h"
16
17			/* default context values */
18			static C_COLOR c_dfcolor = C_DEFCOLOR;
19			static C_MATERIAL c_dfmaterial = C_DEFMATERIAL;
20			static C_VERTEX c_dfvertex = C_DEFVERTEX;
21
22			/* the unnamed contexts */
23			static C_COLOR c_uncolor = C_DEFCOLOR;
24			static C_MATERIAL c_unmaterial = C_DEFMATERIAL;
25			static C_VERTEX c_unvertex = C_DEFVERTEX;
26
27			/* the current contexts */
28			C_COLOR *c_ccolor = &c_uncolor;
29	greg	1.12	char *c_ccname = NULL;
30	greg	1.1	C_MATERIAL *c_cmaterial = &c_unmaterial;
31	greg	1.12	char *c_cmname = NULL;
32	greg	1.1	C_VERTEX *c_cvertex = &c_unvertex;
33	greg	1.12	char *c_cvname = NULL;
34	greg	1.1
35	greg	1.3	static LUTAB clr_tab = LU_SINIT(free,free); /* color lookup table */
36			static LUTAB mat_tab = LU_SINIT(free,free); /* material lookup table */
37			static LUTAB vtx_tab = LU_SINIT(free,free); /* vertex lookup table */
38	greg	1.1
39	greg	1.5	/* CIE 1931 Standard Observer */
40			static C_COLOR cie_xf = C_CIEX;
41			static C_COLOR cie_yf = C_CIEY;
42			static C_COLOR cie_zf = C_CIEZ;
43	greg	1.1
44	greg	1.5	static int setspectrum();
45			static void mixcolors();
46
47
48	greg	1.1	int
49			c_hcolor(ac, av) /* handle color entity */
50			int ac;
51			register char **av;
52			{
53	greg	1.5	double w, wsum;
54			register int i;
55	greg	1.1	register LUENT *lp;
56
57			switch (mg_entity(av[0])) {
58			case MG_E_COLOR: /* get/set color context */
59	greg	1.4	if (ac > 4)
60			return(MG_EARGC);
61	greg	1.1	if (ac == 1) { /* set unnamed color context */
62			c_uncolor = c_dfcolor;
63			c_ccolor = &c_uncolor;
64	greg	1.12	c_ccname = NULL;
65	greg	1.1	return(MG_OK);
66			}
67			lp = lu_find(&clr_tab, av[1]); /* lookup context */
68			if (lp == NULL)
69			return(MG_EMEM);
70	greg	1.9	c_ccolor = (C_COLOR *)lp->data;
71	greg	1.1	if (ac == 2) { /* reestablish previous context */
72	greg	1.9	if (c_ccolor == NULL)
73	greg	1.1	return(MG_EUNDEF);
74			return(MG_OK);
75			}
76			if (av[2][0] != '=' \|\| av[2][1])
77			return(MG_ETYPE);
78	greg	1.9	if (c_ccolor == NULL) { /* create new color context */
79	greg	1.1	lp->key = (char *)malloc(strlen(av[1])+1);
80			if (lp->key == NULL)
81			return(MG_EMEM);
82			strcpy(lp->key, av[1]);
83			lp->data = (char *)malloc(sizeof(C_COLOR));
84			if (lp->data == NULL)
85			return(MG_EMEM);
86	greg	1.9	c_ccolor = (C_COLOR *)lp->data;
87			c_ccolor->clock = 0;
88	greg	1.1	}
89	greg	1.12	c_ccname = lp->key;
90	greg	1.10	i = c_ccolor->clock;
91	greg	1.1	if (ac == 3) { /* use default template */
92			*c_ccolor = c_dfcolor;
93	greg	1.9	c_ccolor->clock = i + 1;
94	greg	1.1	return(MG_OK);
95			}
96			lp = lu_find(&clr_tab, av[3]); /* lookup template */
97			if (lp == NULL)
98			return(MG_EMEM);
99			if (lp->data == NULL)
100			return(MG_EUNDEF);
101			c_ccolor = (C_COLOR *)lp->data;
102	greg	1.9	c_ccolor->clock = i + 1;
103	greg	1.1	return(MG_OK);
104			case MG_E_CXY: /* assign CIE XY value */
105			if (ac != 3)
106			return(MG_EARGC);
107			if (!isflt(av[1]) \|\| !isflt(av[2]))
108			return(MG_ETYPE);
109			c_ccolor->cx = atof(av[1]);
110			c_ccolor->cy = atof(av[2]);
111	greg	1.5	c_ccolor->flags = C_CDXY\|C_CSXY;
112	greg	1.1	if (c_ccolor->cx < 0. \| c_ccolor->cy < 0. \|
113			c_ccolor->cx + c_ccolor->cy > 1.)
114			return(MG_EILL);
115	greg	1.8	c_ccolor->clock++;
116	greg	1.1	return(MG_OK);
117	greg	1.5	case MG_E_CSPEC: /* assign spectral values */
118			if (ac < 5)
119			return(MG_EARGC);
120			if (!isint(av[1]) \|\| !isint(av[2]))
121			return(MG_ETYPE);
122			return(setspectrum(c_ccolor, atoi(av[1]), atoi(av[2]),
123			ac-3, av+3));
124			case MG_E_CMIX: /* mix colors */
125			if (ac < 5 \|\| (ac-1)%2)
126			return(MG_EARGC);
127			if (!isflt(av[1]))
128			return(MG_ETYPE);
129			wsum = atof(av[1]);
130			if (wsum < 0.)
131			return(MG_EILL);
132			if ((lp = lu_find(&clr_tab, av[2])) == NULL)
133			return(MG_EMEM);
134			if (lp->data == NULL)
135			return(MG_EUNDEF);
136			c_ccolor = (C_COLOR *)lp->data;
137			for (i = 3; i < ac; i += 2) {
138			if (!isflt(av[i]))
139			return(MG_ETYPE);
140			w = atof(av[i]);
141			if (w < 0.)
142			return(MG_EILL);
143			if ((lp = lu_find(&clr_tab, av[i+1])) == NULL)
144			return(MG_EMEM);
145			if (lp->data == NULL)
146			return(MG_EUNDEF);
147			mixcolors(c_ccolor, wsum, c_ccolor,
148			w, (C_COLOR *)lp->data);
149			wsum += w;
150			}
151	greg	1.10	c_ccolor->clock++;
152	greg	1.5	return(MG_OK);
153	greg	1.1	}
154			return(MG_EUNK);
155			}
156
157
158			int
159			c_hmaterial(ac, av) /* handle material entity */
160			int ac;
161			register char **av;
162			{
163	greg	1.9	int i;
164	greg	1.1	register LUENT *lp;
165
166			switch (mg_entity(av[0])) {
167			case MG_E_MATERIAL: /* get/set material context */
168	greg	1.4	if (ac > 4)
169			return(MG_EARGC);
170	greg	1.1	if (ac == 1) { /* set unnamed material context */
171			c_unmaterial = c_dfmaterial;
172			c_cmaterial = &c_unmaterial;
173	greg	1.12	c_cmname = NULL;
174	greg	1.1	return(MG_OK);
175			}
176			lp = lu_find(&mat_tab, av[1]); /* lookup context */
177			if (lp == NULL)
178			return(MG_EMEM);
179	greg	1.9	c_cmaterial = (C_MATERIAL *)lp->data;
180	greg	1.1	if (ac == 2) { /* reestablish previous context */
181	greg	1.9	if (c_cmaterial == NULL)
182	greg	1.1	return(MG_EUNDEF);
183			return(MG_OK);
184			}
185			if (av[2][0] != '=' \|\| av[2][1])
186			return(MG_ETYPE);
187	greg	1.9	if (c_cmaterial == NULL) { /* create new material */
188	greg	1.1	lp->key = (char *)malloc(strlen(av[1])+1);
189			if (lp->key == NULL)
190			return(MG_EMEM);
191			strcpy(lp->key, av[1]);
192			lp->data = (char *)malloc(sizeof(C_MATERIAL));
193			if (lp->data == NULL)
194			return(MG_EMEM);
195	greg	1.9	c_cmaterial = (C_MATERIAL *)lp->data;
196			c_cmaterial->clock = 0;
197	greg	1.1	}
198	greg	1.12	c_cmname = lp->key;
199	greg	1.10	i = c_cmaterial->clock;
200	greg	1.1	if (ac == 3) { /* use default template */
201			*c_cmaterial = c_dfmaterial;
202	greg	1.9	c_cmaterial->clock = i + 1;
203	greg	1.1	return(MG_OK);
204			}
205			lp = lu_find(&mat_tab, av[3]); /* lookup template */
206			if (lp == NULL)
207			return(MG_EMEM);
208			if (lp->data == NULL)
209			return(MG_EUNDEF);
210			c_cmaterial = (C_MATERIAL *)lp->data;
211	greg	1.9	c_cmaterial->clock = i + 1;
212	greg	1.1	return(MG_OK);
213			case MG_E_RD: /* set diffuse reflectance */
214			if (ac != 2)
215			return(MG_EARGC);
216			if (!isflt(av[1]))
217			return(MG_ETYPE);
218			c_cmaterial->rd = atof(av[1]);
219			if (c_cmaterial->rd < 0. \| c_cmaterial->rd > 1.)
220			return(MG_EILL);
221			c_cmaterial->rd_c = *c_ccolor;
222	greg	1.2	c_cmaterial->clock++;
223	greg	1.1	return(MG_OK);
224			case MG_E_ED: /* set diffuse emittance */
225			if (ac != 2)
226			return(MG_EARGC);
227			if (!isflt(av[1]))
228			return(MG_ETYPE);
229			c_cmaterial->ed = atof(av[1]);
230			if (c_cmaterial->ed < 0.)
231			return(MG_EILL);
232			c_cmaterial->ed_c = *c_ccolor;
233	greg	1.2	c_cmaterial->clock++;
234	greg	1.1	return(MG_OK);
235			case MG_E_TD: /* set diffuse transmittance */
236			if (ac != 2)
237			return(MG_EARGC);
238			if (!isflt(av[1]))
239			return(MG_ETYPE);
240			c_cmaterial->td = atof(av[1]);
241			if (c_cmaterial->td < 0. \| c_cmaterial->td > 1.)
242			return(MG_EILL);
243			c_cmaterial->td_c = *c_ccolor;
244	greg	1.8	c_cmaterial->clock++;
245	greg	1.1	return(MG_OK);
246			case MG_E_RS: /* set specular reflectance */
247			if (ac != 3)
248			return(MG_EARGC);
249			if (!isflt(av[1]) \|\| !isflt(av[2]))
250			return(MG_ETYPE);
251			c_cmaterial->rs = atof(av[1]);
252			c_cmaterial->rs_a = atof(av[2]);
253			if (c_cmaterial->rs < 0. \| c_cmaterial->rs > 1. \|
254			c_cmaterial->rs_a < 0.)
255			return(MG_EILL);
256			c_cmaterial->rs_c = *c_ccolor;
257	greg	1.2	c_cmaterial->clock++;
258	greg	1.1	return(MG_OK);
259			case MG_E_TS: /* set specular transmittance */
260			if (ac != 3)
261			return(MG_EARGC);
262			if (!isflt(av[1]) \|\| !isflt(av[2]))
263			return(MG_ETYPE);
264			c_cmaterial->ts = atof(av[1]);
265			c_cmaterial->ts_a = atof(av[2]);
266			if (c_cmaterial->ts < 0. \| c_cmaterial->ts > 1. \|
267			c_cmaterial->ts_a < 0.)
268			return(MG_EILL);
269			c_cmaterial->ts_c = *c_ccolor;
270	greg	1.2	c_cmaterial->clock++;
271	greg	1.1	return(MG_OK);
272			}
273			return(MG_EUNK);
274			}
275
276
277			int
278			c_hvertex(ac, av) /* handle a vertex entity */
279			int ac;
280			register char **av;
281			{
282	greg	1.9	int i;
283	greg	1.1	register LUENT *lp;
284
285			switch (mg_entity(av[0])) {
286			case MG_E_VERTEX: /* get/set vertex context */
287	greg	1.4	if (ac > 4)
288			return(MG_EARGC);
289	greg	1.1	if (ac == 1) { /* set unnamed vertex context */
290			c_unvertex = c_dfvertex;
291			c_cvertex = &c_unvertex;
292	greg	1.12	c_cvname = NULL;
293	greg	1.1	return(MG_OK);
294			}
295			lp = lu_find(&vtx_tab, av[1]); /* lookup context */
296			if (lp == NULL)
297			return(MG_EMEM);
298	greg	1.9	c_cvertex = (C_VERTEX *)lp->data;
299	greg	1.1	if (ac == 2) { /* reestablish previous context */
300	greg	1.9	if (c_cvertex == NULL)
301	greg	1.1	return(MG_EUNDEF);
302			return(MG_OK);
303			}
304			if (av[2][0] != '=' \|\| av[2][1])
305			return(MG_ETYPE);
306	greg	1.9	if (c_cvertex == NULL) { /* create new vertex context */
307	greg	1.1	lp->key = (char *)malloc(strlen(av[1])+1);
308			if (lp->key == NULL)
309			return(MG_EMEM);
310			strcpy(lp->key, av[1]);
311			lp->data = (char *)malloc(sizeof(C_VERTEX));
312			if (lp->data == NULL)
313			return(MG_EMEM);
314	greg	1.9	c_cvertex = (C_VERTEX *)lp->data;
315	greg	1.1	}
316	greg	1.12	c_cvname = lp->key;
317	greg	1.10	i = c_cvertex->clock;
318	greg	1.1	if (ac == 3) { /* use default template */
319			*c_cvertex = c_dfvertex;
320	greg	1.9	c_cvertex->clock = i + 1;
321	greg	1.1	return(MG_OK);
322			}
323			lp = lu_find(&vtx_tab, av[3]); /* lookup template */
324			if (lp == NULL)
325			return(MG_EMEM);
326			if (lp->data == NULL)
327			return(MG_EUNDEF);
328			c_cvertex = (C_VERTEX *)lp->data;
329	greg	1.9	c_cvertex->clock = i + 1;
330	greg	1.1	return(MG_OK);
331			case MG_E_POINT: /* set point */
332			if (ac != 4)
333			return(MG_EARGC);
334			if (!isflt(av[1]) \|\| !isflt(av[2]) \|\| !isflt(av[3]))
335			return(MG_ETYPE);
336			c_cvertex->p[0] = atof(av[1]);
337			c_cvertex->p[1] = atof(av[2]);
338			c_cvertex->p[2] = atof(av[3]);
339	greg	1.8	c_cvertex->clock++;
340	greg	1.1	return(MG_OK);
341			case MG_E_NORMAL: /* set normal */
342			if (ac != 4)
343			return(MG_EARGC);
344			if (!isflt(av[1]) \|\| !isflt(av[2]) \|\| !isflt(av[3]))
345			return(MG_ETYPE);
346			c_cvertex->n[0] = atof(av[1]);
347			c_cvertex->n[1] = atof(av[2]);
348			c_cvertex->n[2] = atof(av[3]);
349			(void)normalize(c_cvertex->n);
350	greg	1.8	c_cvertex->clock++;
351	greg	1.1	return(MG_OK);
352			}
353			return(MG_EUNK);
354			}
355
356
357			void
358			c_clearall() /* empty context tables */
359			{
360			c_uncolor = c_dfcolor;
361			c_ccolor = &c_uncolor;
362	greg	1.3	lu_done(&clr_tab);
363	greg	1.1	c_unmaterial = c_dfmaterial;
364			c_cmaterial = &c_unmaterial;
365	greg	1.3	lu_done(&mat_tab);
366	greg	1.1	c_unvertex = c_dfvertex;
367			c_cvertex = &c_unvertex;
368	greg	1.3	lu_done(&vtx_tab);
369	greg	1.1	}
370
371
372	greg	1.11	C_MATERIAL *
373			c_getmaterial(name) /* get a named material */
374			char *name;
375			{
376			register LUENT *lp;
377
378			if ((lp = lu_find(&mat_tab, name)) == NULL)
379			return(NULL);
380			return((C_MATERIAL *)lp->data);
381			}
382
383
384	greg	1.1	C_VERTEX *
385			c_getvert(name) /* get a named vertex */
386			char *name;
387			{
388			register LUENT *lp;
389
390			if ((lp = lu_find(&vtx_tab, name)) == NULL)
391			return(NULL);
392			return((C_VERTEX *)lp->data);
393	greg	1.5	}
394
395
396	greg	1.7	C_COLOR *
397			c_getcolor(name) /* get a named color */
398			char *name;
399			{
400			register LUENT *lp;
401
402			if ((lp = lu_find(&clr_tab, name)) == NULL)
403			return(NULL);
404			return((C_COLOR *)lp->data);
405			}
406
407
408	greg	1.5	int
409			c_isgrey(clr) /* check if color is grey */
410			register C_COLOR *clr;
411			{
412	greg	1.8	if (!(clr->flags & (C_CSXY\|C_CSSPEC)))
413	greg	1.5	return(1); /* no settings == grey */
414			c_ccvt(clr, C_CSXY);
415			return(clr->cx >= .323 && clr->cx <= .343 &&
416			clr->cy >= .323 && clr->cy <= .343);
417			}
418
419
420			void
421			c_ccvt(clr, fl) /* convert color representations */
422			register C_COLOR *clr;
423			int fl;
424			{
425			double x, y, z;
426			register int i;
427
428			if (clr->flags & fl) /* already done */
429			return;
430	greg	1.8	if (!(clr->flags & (C_CSXY\|C_CSSPEC))) /* nothing set! */
431	greg	1.5	*clr = c_dfcolor;
432			else if (fl & C_CSXY) { /* cspec -> cxy */
433			x = y = z = 0.;
434			for (i = 0; i < C_CNSS; i++) {
435			x += cie_xf.ssamp[i] * clr->ssamp[i];
436			y += cie_yf.ssamp[i] * clr->ssamp[i];
437			z += cie_zf.ssamp[i] * clr->ssamp[i];
438			}
439			z += x + y;
440			clr->cx = x / z;
441			clr->cy = y / z;
442			clr->flags \|= C_CSXY;
443			} else { /* cxy -> cspec */
444			z = (cie_xf.ssum + cie_yf.ssum + cie_zf.ssum) / 3.;
445			x = clr->cx * z / cie_xf.ssum;
446			y = clr->cy * z / cie_yf.ssum;
447			z = (1. - clr->cx - clr->cy) * z / cie_zf.ssum;
448			clr->ssum = 0;
449			for (i = 0; i < C_CNSS; i++)
450			clr->ssum += clr->ssamp[i] =
451			x * cie_xf.ssamp[i] +
452			y * cie_yf.ssamp[i] +
453			z * cie_zf.ssamp[i] ;
454			clr->flags \|= C_CSSPEC;
455			}
456			}
457
458
459			static int
460			setspectrum(clr, wlmin, wlmax, ac, av) /* convert a spectrum */
461			register C_COLOR *clr;
462			int wlmin, wlmax;
463			int ac;
464			char **av;
465			{
466			double scale;
467			float *va;
468			register int i;
469			int wl, pos;
470			double wl0, wlstep;
471
472			if (wlmin < C_CMINWL \|\| wlmin >= wlmax \|\| wlmax > C_CMAXWL)
473			return(MG_EILL);
474			if ((va = (float )malloc(acsizeof(float))) == NULL)
475			return(MG_EMEM);
476			scale = 0.; /* get values and maximum */
477			for (i = 0; i < ac; i++) {
478			if (!isflt(av[i]))
479			return(MG_ETYPE);
480			va[i] = atof(av[i]);
481			if (va[i] < 0.)
482			return(MG_EILL);
483			if (va[i] > scale)
484			scale = va[i];
485			}
486			if (scale == 0.)
487			return(MG_EILL);
488			scale = C_CMAXV / scale;
489			clr->ssum = 0; /* convert to our spacing */
490			wl0 = wlmin;
491			wlstep = (double)(wlmax - wlmin)/(ac-1);
492			pos = 0;
493			for (i = 0, wl = C_CMINWL; i < C_CNSS; i++, wl += C_CWLI)
494			if (wl < wlmin \|\| wl > wlmax)
495			clr->ssamp[i] = 0;
496			else {
497			while (wl0 + wlstep < wl+FTINY) {
498			wl0 += wlstep;
499			pos++;
500			}
501			if (wl+FTINY >= wl0 && wl-FTINY <= wl0)
502			clr->ssamp[i] = scale*va[pos];
503			else /* interpolate if necessary */
504			clr->ssamp[i] = scale / wlstep *
505			( va[pos]*(wl0+wlstep - wl) +
506			va[pos+1]*(wl - wl0) );
507			clr->ssum += clr->ssamp[i];
508			}
509			clr->flags = C_CDSPEC\|C_CSSPEC;
510	greg	1.8	clr->clock++;
511	greg	1.5	free((MEM_PTR)va);
512			return(MG_OK);
513			}
514
515
516			static void
517			mixcolors(cres, w1, c1, w2, c2) /* mix two colors according to weights given */
518			register C_COLOR cres, c1, *c2;
519			double w1, w2;
520			{
521			double scale;
522			float cmix[C_CNSS];
523			register int i;
524
525			if ((c1->flags\|c2->flags) & C_CDSPEC) { /* spectral mixing */
526			c_ccvt(c1, C_CSSPEC);
527			c_ccvt(c2, C_CSSPEC);
528			w1 /= (double)c1->ssum;
529			w2 /= (double)c2->ssum;
530			scale = 0.;
531			for (i = 0; i < C_CNSS; i++) {
532			cmix[i] = w1c1->ssamp[i] + w2c2->ssamp[i];
533			if (cmix[i] > scale)
534			scale = cmix[i];
535			}
536			scale = C_CMAXV / scale;
537			cres->ssum = 0;
538			for (i = 0; i < C_CNSS; i++)
539			cres->ssum += cres->ssamp[i] = scale*cmix[i] + .5;
540			cres->flags = C_CDSPEC\|C_CSSPEC;
541			} else { /* CIE xy mixing */
542			c_ccvt(c1, C_CSXY);
543			c_ccvt(c2, C_CSXY);
544			scale = 1. / (w1/c1->cy + w2/c2->cy);
545			cres->cx = (c1->cxw1/c1->cy + c2->cxw2/c2->cy) * scale;
546			cres->cy = (w1 + w2) * scale;
547			cres->flags = C_CDXY\|C_CSXY;
548			}
549	greg	1.1	}