cv/mgflib/context.c

/* Copyright (c) 1997 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 curves */
static C_COLOR  cie_xf = { 1, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
                        {14,42,143,435,1344,2839,3483,3362,2908,1954,956,
                        320,49,93,633,1655,2904,4334,5945,7621,9163,10263,
                        10622,10026,8544,6424,4479,2835,1649,874,468,227,
                        114,58,29,14,7,3,2,1,0}, 106836L, .467, .368, 362.230
                        };
static C_COLOR  cie_yf = { 1, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
                        {0,1,4,12,40,116,230,380,600,910,1390,2080,3230,
                        5030,7100,8620,9540,9950,9950,9520,8700,7570,6310,
                        5030,3810,2650,1750,1070,610,320,170,82,41,21,10,
                        5,2,1,1,0,0}, 106856L, .398, .542, 493.525
                        };
static C_COLOR  cie_zf = { 1, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
                        {65,201,679,2074,6456,13856,17471,17721,16692,
                        12876,8130,4652,2720,1582,782,422,203,87,39,21,17,
                        11,8,3,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
                        106770L, .147, .077, 54.363
                        };
                                /* Derived CIE 1931 Primaries (imaginary) */
static C_COLOR  cie_xp = { 1, C_CDSPEC|C_CSSPEC|C_CSXY,
                        {-174,-198,-195,-197,-202,-213,-235,-272,-333,
                        -444,-688,-1232,-2393,-4497,-6876,-6758,-5256,
                        -3100,-815,1320,3200,4782,5998,6861,7408,7754,
                        7980,8120,8199,8240,8271,8292,8309,8283,8469,
                        8336,8336,8336,8336,8336,8336},
                        127424L, 1., .0,
                        };
static C_COLOR  cie_yp = { 1, C_CDSPEC|C_CSSPEC|C_CSXY,
                        {-451,-431,-431,-430,-427,-417,-399,-366,-312,
                        -204,57,691,2142,4990,8810,9871,9122,7321,5145,
                        3023,1123,-473,-1704,-2572,-3127,-3474,-3704,
                        -3846,-3927,-3968,-3999,-4021,-4038,-4012,-4201,
                        -4066,-4066,-4066,-4066,-4066,-4066},
                        -23035L, .0, 1.,
                        };
static C_COLOR  cie_zp = { 1, C_CDSPEC|C_CSSPEC|C_CSXY,
                        {4051,4054,4052,4053,4054,4056,4059,4064,4071,
                        4074,4056,3967,3677,2933,1492,313,-440,-795,
                        -904,-918,-898,-884,-869,-863,-855,-855,-851,
                        -848,-847,-846,-846,-846,-845,-846,-843,-845,
                        -845,-845,-845,-845,-845},
                        36057L, .0, .0,
                        };

static int      setspectrum();
static int      setbbtemp();
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);
                }
                if (!isname(av[1]))
                        return(MG_EILL);
                lp = lu_find(&clr_tab, av[1]);  /* lookup context */
                if (lp == NULL)
                        return(MG_EMEM);
                c_ccname = lp->key;
                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_ccname = lp->key;
                        c_ccolor = (C_COLOR *)lp->data;
                        c_ccolor->clock = 0;
                }
                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 (!isflt(av[1]) | !isflt(av[2]))
                        return(MG_ETYPE);
                return(setspectrum(c_ccolor, atof(av[1]), atof(av[2]),
                                ac-3, av+3));
        case MG_E_CCT:          /* assign black body spectrum */
                if (ac != 2)
                        return(MG_EARGC);
                if (!isflt(av[1]))
                        return(MG_ETYPE);
                return(setbbtemp(c_ccolor, atof(av[1])));
        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 ((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 ((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;
                }
                if (wsum <= 0.)
                        return(MG_EILL);
                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);
                }
                if (!isname(av[1]))
                        return(MG_EILL);
                lp = lu_find(&mat_tab, av[1]);  /* lookup context */
                if (lp == NULL)
                        return(MG_EMEM);
                c_cmname = lp->key;
                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_cmname = lp->key;
                        c_cmaterial = (C_MATERIAL *)lp->data;
                        c_cmaterial->clock = 0;
                }
                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_IR:           /* set index of refraction */
                if (ac != 3)
                        return(MG_EARGC);
                if (!isflt(av[1]) | !isflt(av[2]))
                        return(MG_ETYPE);
                c_cmaterial->nr = atof(av[1]);
                c_cmaterial->ni = atof(av[2]);
                if (c_cmaterial->nr <= FTINY)
                        return(MG_EILL);
                c_cmaterial->clock++;
                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);
        case MG_E_SIDES:        /* set number of sides */
                if (ac != 2)
                        return(MG_EARGC);
                if (!isint(av[1]))
                        return(MG_ETYPE);
                i = atoi(av[1]);
                if (i == 1)
                        c_cmaterial->sided = 1;
                else if (i == 2)
                        c_cmaterial->sided = 0;
                else
                        return(MG_EILL);
                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);
                }
                if (!isname(av[1]))
                        return(MG_EILL);
                lp = lu_find(&vtx_tab, av[1]);  /* lookup context */
                if (lp == NULL)
                        return(MG_EMEM);
                c_cvname = lp->key;
                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_cvname = lp->key;
                        c_cvertex = (C_VERTEX *)lp->data;
                }
                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;
        c_ccname = NULL;
        lu_done(&clr_tab);
        c_unmaterial = c_dfmaterial;
        c_cmaterial = &c_unmaterial;
        c_cmname = NULL;
        lu_done(&mat_tab);
        c_unvertex = c_dfvertex;
        c_cvertex = &c_unvertex;
        c_cvname = NULL;
        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;

        fl &= ~clr->flags;                      /* ignore what's done */
        if (!fl)                                /* everything's done! */
                return;
        if (!(clr->flags & (C_CSXY|C_CSSPEC)))  /* nothing set! */
                *clr = c_dfcolor;
        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];
                }
                x /= (double)cie_xf.ssum;
                y /= (double)cie_yf.ssum;
                z /= (double)cie_zf.ssum;
                z += x + y;
                clr->cx = x / z;
                clr->cy = y / z;
                clr->flags |= C_CSXY;
        } else if (fl & C_CSSPEC) {     /* cxy -> cspec */
                x = clr->cx;
                y = clr->cy;
                z = 1. - x - y;
                clr->ssum = 0;
                for (i = 0; i < C_CNSS; i++) {
                        clr->ssamp[i] = x*cie_xp.ssamp[i] + y*cie_yp.ssamp[i]
                                        + z*cie_zp.ssamp[i] + .5;
                        if (clr->ssamp[i] < 0)          /* out of gamut! */
                                clr->ssamp[i] = 0;
                        else
                                clr->ssum += clr->ssamp[i];
                }
                clr->flags |= C_CSSPEC;
        }
        if (fl & C_CSEFF) {             /* compute efficacy */
                if (clr->flags & C_CSSPEC) {            /* from spectrum */
                        y = 0.;
                        for (i = 0; i < C_CNSS; i++)
                                y += cie_yf.ssamp[i] * clr->ssamp[i];
                        clr->eff = C_CLPWM * y / clr->ssum;
                } else /* clr->flags & C_CSXY */ {      /* from (x,y) */
                        clr->eff = clr->cx*cie_xf.eff + clr->cy*cie_yf.eff +
                                        (1. - clr->cx - clr->cy)*cie_zf.eff;
                }
                clr->flags |= C_CSEFF;
        }
}


static int
setspectrum(clr, wlmin, wlmax, ac, av)  /* convert a spectrum */
register C_COLOR        *clr;
double  wlmin, wlmax;
int     ac;
char    **av;
{
        double  scale;
        float   va[C_CNSS];
        register int    i, pos;
        int     n, imax;
        int     wl;
        double  wl0, wlstep;
        double  boxpos, boxstep;
                                        /* check bounds */
        if (wlmax <= C_CMINWL | wlmax <= wlmin | wlmin >= C_CMAXWL)
                return(MG_EILL);
        wlstep = (wlmax - wlmin)/(ac-1);
        while (wlmin < C_CMINWL) {
                wlmin += wlstep;
                ac--; av++;
        }
        while (wlmax > C_CMAXWL) {
                wlmax -= wlstep;
                ac--;
        }
        imax = ac;                      /* box filter if necessary */
        boxpos = 0;
        boxstep = 1;
        if (wlstep < C_CWLI) {
                imax = (wlmax - wlmin)/C_CWLI + (1-FTINY);
                boxpos = (wlmin - C_CMINWL)/C_CWLI;
                boxstep = wlstep/C_CWLI;
                wlstep = C_CWLI;
        }
        scale = 0.;                     /* get values and maximum */
        pos = 0;
        for (i = 0; i < imax; i++) {
                va[i] = 0.; n = 0;
                while (boxpos < i+.5 && pos < ac) {
                        if (!isflt(av[pos]))
                                return(MG_ETYPE);
                        va[i] += atof(av[pos++]);
                        n++;
                        boxpos += boxstep;
                }
                if (n > 1)
                        va[i] /= (double)n;
                if (va[i] > scale)
                        scale = va[i];
                else if (va[i] < -scale)
                        scale = -va[i];
        }
        if (scale <= FTINY)
                return(MG_EILL);
        scale = C_CMAXV / scale;
        clr->ssum = 0;                  /* convert to our spacing */
        wl0 = wlmin;
        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] + .5;
                        else            /* interpolate if necessary */
                                clr->ssamp[i] = .5 + 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++;
        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_CSEFF);
                c_ccvt(c2, C_CSSPEC|C_CSEFF);
                w1 /= c1->eff*c1->ssum;
                w2 /= c2->eff*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 = w1/c1->cy + w2/c2->cy;
                if (scale == 0.)
                        return;
                scale = 1. / scale;
                cres->cx = (c1->cx*w1/c1->cy + c2->cx*w2/c2->cy) * scale;
                cres->cy = (w1 + w2) * scale;
                cres->flags = C_CDXY|C_CSXY;
        }
}


#define C1              3.741832e-16    /* W-m^2 */
#define C2              1.4388e-2       /* m-K */

#define bbsp(l,t)       (C1/((l)*(l)*(l)*(l)*(l)*(exp(C2/((t)*(l)))-1.)))
#define bblm(t)         (C2/5./(t))

static int
setbbtemp(clr, tk)              /* set black body spectrum */
register C_COLOR        *clr;
double  tk;
{
        double  sf, wl;
        register int    i;

        if (tk < 1000)
                return(MG_EILL);
        wl = bblm(tk);                  /* scalefactor based on peak */
        if (wl < C_CMINWL*1e-9)
                wl = C_CMINWL*1e-9;
        else if (wl > C_CMAXWL*1e-9)
                wl = C_CMAXWL*1e-9;
        sf = C_CMAXV/bbsp(wl,tk);
        clr->ssum = 0;
        for (i = 0; i < C_CNSS; i++) {
                wl = (C_CMINWL + i*C_CWLI)*1e-9;
                clr->ssum += clr->ssamp[i] = sf*bbsp(wl,tk) + .5;
        }
        clr->flags = C_CDSPEC|C_CSSPEC;
        clr->clock++;
        return(MG_OK);
}

#undef  C1
#undef  C2
#undef  bbsp
#undef  bblm
Revision:	1.24
Committed:	Wed Feb 12 11:38:52 1997 UTC (28 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.23:	+7 -6 lines
Log Message:	allow negative weights in cmix entity
#	User	Rev	Content
1	greg	1.24	/* Copyright (c) 1997 Regents of the University of California */
2	greg	1.1
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	1.19	/* CIE 1931 Standard Observer curves */
40			static C_COLOR cie_xf = { 1, C_CDSPEC\|C_CSSPEC\|C_CSXY\|C_CSEFF,
41			{14,42,143,435,1344,2839,3483,3362,2908,1954,956,
42			320,49,93,633,1655,2904,4334,5945,7621,9163,10263,
43			10622,10026,8544,6424,4479,2835,1649,874,468,227,
44			114,58,29,14,7,3,2,1,0}, 106836L, .467, .368, 362.230
45			};
46			static C_COLOR cie_yf = { 1, C_CDSPEC\|C_CSSPEC\|C_CSXY\|C_CSEFF,
47			{0,1,4,12,40,116,230,380,600,910,1390,2080,3230,
48			5030,7100,8620,9540,9950,9950,9520,8700,7570,6310,
49			5030,3810,2650,1750,1070,610,320,170,82,41,21,10,
50			5,2,1,1,0,0}, 106856L, .398, .542, 493.525
51			};
52			static C_COLOR cie_zf = { 1, C_CDSPEC\|C_CSSPEC\|C_CSXY\|C_CSEFF,
53			{65,201,679,2074,6456,13856,17471,17721,16692,
54			12876,8130,4652,2720,1582,782,422,203,87,39,21,17,
55			11,8,3,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
56			106770L, .147, .077, 54.363
57			};
58			/* Derived CIE 1931 Primaries (imaginary) */
59			static C_COLOR cie_xp = { 1, C_CDSPEC\|C_CSSPEC\|C_CSXY,
60			{-174,-198,-195,-197,-202,-213,-235,-272,-333,
61			-444,-688,-1232,-2393,-4497,-6876,-6758,-5256,
62			-3100,-815,1320,3200,4782,5998,6861,7408,7754,
63			7980,8120,8199,8240,8271,8292,8309,8283,8469,
64			8336,8336,8336,8336,8336,8336},
65			127424L, 1., .0,
66			};
67			static C_COLOR cie_yp = { 1, C_CDSPEC\|C_CSSPEC\|C_CSXY,
68			{-451,-431,-431,-430,-427,-417,-399,-366,-312,
69			-204,57,691,2142,4990,8810,9871,9122,7321,5145,
70			3023,1123,-473,-1704,-2572,-3127,-3474,-3704,
71			-3846,-3927,-3968,-3999,-4021,-4038,-4012,-4201,
72			-4066,-4066,-4066,-4066,-4066,-4066},
73			-23035L, .0, 1.,
74			};
75			static C_COLOR cie_zp = { 1, C_CDSPEC\|C_CSSPEC\|C_CSXY,
76			{4051,4054,4052,4053,4054,4056,4059,4064,4071,
77			4074,4056,3967,3677,2933,1492,313,-440,-795,
78			-904,-918,-898,-884,-869,-863,-855,-855,-851,
79			-848,-847,-846,-846,-846,-845,-846,-843,-845,
80			-845,-845,-845,-845,-845},
81			36057L, .0, .0,
82			};
83	greg	1.1
84	greg	1.5	static int setspectrum();
85	greg	1.18	static int setbbtemp();
86	greg	1.5	static void mixcolors();
87
88
89	greg	1.1	int
90			c_hcolor(ac, av) /* handle color entity */
91			int ac;
92			register char **av;
93			{
94	greg	1.5	double w, wsum;
95			register int i;
96	greg	1.1	register LUENT *lp;
97
98			switch (mg_entity(av[0])) {
99			case MG_E_COLOR: /* get/set color context */
100	greg	1.4	if (ac > 4)
101			return(MG_EARGC);
102	greg	1.1	if (ac == 1) { /* set unnamed color context */
103			c_uncolor = c_dfcolor;
104			c_ccolor = &c_uncolor;
105	greg	1.12	c_ccname = NULL;
106	greg	1.1	return(MG_OK);
107			}
108	greg	1.22	if (!isname(av[1]))
109			return(MG_EILL);
110	greg	1.1	lp = lu_find(&clr_tab, av[1]); /* lookup context */
111			if (lp == NULL)
112			return(MG_EMEM);
113	greg	1.14	c_ccname = lp->key;
114	greg	1.9	c_ccolor = (C_COLOR *)lp->data;
115	greg	1.1	if (ac == 2) { /* reestablish previous context */
116	greg	1.9	if (c_ccolor == NULL)
117	greg	1.1	return(MG_EUNDEF);
118			return(MG_OK);
119			}
120			if (av[2][0] != '=' \|\| av[2][1])
121			return(MG_ETYPE);
122	greg	1.9	if (c_ccolor == NULL) { /* create new color context */
123	greg	1.1	lp->key = (char *)malloc(strlen(av[1])+1);
124			if (lp->key == NULL)
125			return(MG_EMEM);
126			strcpy(lp->key, av[1]);
127			lp->data = (char *)malloc(sizeof(C_COLOR));
128			if (lp->data == NULL)
129			return(MG_EMEM);
130	greg	1.14	c_ccname = lp->key;
131	greg	1.9	c_ccolor = (C_COLOR *)lp->data;
132			c_ccolor->clock = 0;
133	greg	1.1	}
134	greg	1.10	i = c_ccolor->clock;
135	greg	1.1	if (ac == 3) { /* use default template */
136			*c_ccolor = c_dfcolor;
137	greg	1.9	c_ccolor->clock = i + 1;
138	greg	1.1	return(MG_OK);
139			}
140			lp = lu_find(&clr_tab, av[3]); /* lookup template */
141			if (lp == NULL)
142			return(MG_EMEM);
143			if (lp->data == NULL)
144			return(MG_EUNDEF);
145			c_ccolor = (C_COLOR *)lp->data;
146	greg	1.9	c_ccolor->clock = i + 1;
147	greg	1.1	return(MG_OK);
148			case MG_E_CXY: /* assign CIE XY value */
149			if (ac != 3)
150			return(MG_EARGC);
151	greg	1.18	if (!isflt(av[1]) \| !isflt(av[2]))
152	greg	1.1	return(MG_ETYPE);
153			c_ccolor->cx = atof(av[1]);
154			c_ccolor->cy = atof(av[2]);
155	greg	1.5	c_ccolor->flags = C_CDXY\|C_CSXY;
156	greg	1.1	if (c_ccolor->cx < 0. \| c_ccolor->cy < 0. \|
157			c_ccolor->cx + c_ccolor->cy > 1.)
158			return(MG_EILL);
159	greg	1.8	c_ccolor->clock++;
160	greg	1.1	return(MG_OK);
161	greg	1.5	case MG_E_CSPEC: /* assign spectral values */
162			if (ac < 5)
163			return(MG_EARGC);
164	greg	1.18	if (!isflt(av[1]) \| !isflt(av[2]))
165	greg	1.5	return(MG_ETYPE);
166	greg	1.17	return(setspectrum(c_ccolor, atof(av[1]), atof(av[2]),
167	greg	1.5	ac-3, av+3));
168	greg	1.18	case MG_E_CCT: /* assign black body spectrum */
169			if (ac != 2)
170			return(MG_EARGC);
171			if (!isflt(av[1]))
172			return(MG_ETYPE);
173			return(setbbtemp(c_ccolor, atof(av[1])));
174	greg	1.5	case MG_E_CMIX: /* mix colors */
175			if (ac < 5 \|\| (ac-1)%2)
176			return(MG_EARGC);
177			if (!isflt(av[1]))
178			return(MG_ETYPE);
179			wsum = atof(av[1]);
180			if ((lp = lu_find(&clr_tab, av[2])) == NULL)
181			return(MG_EMEM);
182			if (lp->data == NULL)
183			return(MG_EUNDEF);
184			c_ccolor = (C_COLOR *)lp->data;
185			for (i = 3; i < ac; i += 2) {
186			if (!isflt(av[i]))
187			return(MG_ETYPE);
188			w = atof(av[i]);
189			if ((lp = lu_find(&clr_tab, av[i+1])) == NULL)
190			return(MG_EMEM);
191			if (lp->data == NULL)
192			return(MG_EUNDEF);
193			mixcolors(c_ccolor, wsum, c_ccolor,
194			w, (C_COLOR *)lp->data);
195			wsum += w;
196			}
197	greg	1.24	if (wsum <= 0.)
198			return(MG_EILL);
199	greg	1.10	c_ccolor->clock++;
200	greg	1.5	return(MG_OK);
201	greg	1.1	}
202			return(MG_EUNK);
203			}
204
205
206			int
207			c_hmaterial(ac, av) /* handle material entity */
208			int ac;
209			register char **av;
210			{
211	greg	1.9	int i;
212	greg	1.1	register LUENT *lp;
213
214			switch (mg_entity(av[0])) {
215			case MG_E_MATERIAL: /* get/set material context */
216	greg	1.4	if (ac > 4)
217			return(MG_EARGC);
218	greg	1.1	if (ac == 1) { /* set unnamed material context */
219			c_unmaterial = c_dfmaterial;
220			c_cmaterial = &c_unmaterial;
221	greg	1.12	c_cmname = NULL;
222	greg	1.1	return(MG_OK);
223			}
224	greg	1.22	if (!isname(av[1]))
225			return(MG_EILL);
226	greg	1.1	lp = lu_find(&mat_tab, av[1]); /* lookup context */
227			if (lp == NULL)
228			return(MG_EMEM);
229	greg	1.14	c_cmname = lp->key;
230	greg	1.9	c_cmaterial = (C_MATERIAL *)lp->data;
231	greg	1.1	if (ac == 2) { /* reestablish previous context */
232	greg	1.9	if (c_cmaterial == NULL)
233	greg	1.1	return(MG_EUNDEF);
234			return(MG_OK);
235			}
236			if (av[2][0] != '=' \|\| av[2][1])
237			return(MG_ETYPE);
238	greg	1.9	if (c_cmaterial == NULL) { /* create new material */
239	greg	1.1	lp->key = (char *)malloc(strlen(av[1])+1);
240			if (lp->key == NULL)
241			return(MG_EMEM);
242			strcpy(lp->key, av[1]);
243			lp->data = (char *)malloc(sizeof(C_MATERIAL));
244			if (lp->data == NULL)
245			return(MG_EMEM);
246	greg	1.14	c_cmname = lp->key;
247	greg	1.9	c_cmaterial = (C_MATERIAL *)lp->data;
248			c_cmaterial->clock = 0;
249	greg	1.1	}
250	greg	1.10	i = c_cmaterial->clock;
251	greg	1.1	if (ac == 3) { /* use default template */
252			*c_cmaterial = c_dfmaterial;
253	greg	1.9	c_cmaterial->clock = i + 1;
254	greg	1.1	return(MG_OK);
255			}
256			lp = lu_find(&mat_tab, av[3]); /* lookup template */
257			if (lp == NULL)
258			return(MG_EMEM);
259			if (lp->data == NULL)
260			return(MG_EUNDEF);
261			c_cmaterial = (C_MATERIAL *)lp->data;
262	greg	1.9	c_cmaterial->clock = i + 1;
263	greg	1.1	return(MG_OK);
264	greg	1.21	case MG_E_IR: /* set index of refraction */
265			if (ac != 3)
266			return(MG_EARGC);
267			if (!isflt(av[1]) \| !isflt(av[2]))
268			return(MG_ETYPE);
269			c_cmaterial->nr = atof(av[1]);
270			c_cmaterial->ni = atof(av[2]);
271			if (c_cmaterial->nr <= FTINY)
272			return(MG_EILL);
273			c_cmaterial->clock++;
274			return(MG_OK);
275	greg	1.1	case MG_E_RD: /* set diffuse reflectance */
276			if (ac != 2)
277			return(MG_EARGC);
278			if (!isflt(av[1]))
279			return(MG_ETYPE);
280			c_cmaterial->rd = atof(av[1]);
281			if (c_cmaterial->rd < 0. \| c_cmaterial->rd > 1.)
282			return(MG_EILL);
283			c_cmaterial->rd_c = *c_ccolor;
284	greg	1.2	c_cmaterial->clock++;
285	greg	1.1	return(MG_OK);
286			case MG_E_ED: /* set diffuse emittance */
287			if (ac != 2)
288			return(MG_EARGC);
289			if (!isflt(av[1]))
290			return(MG_ETYPE);
291			c_cmaterial->ed = atof(av[1]);
292			if (c_cmaterial->ed < 0.)
293			return(MG_EILL);
294			c_cmaterial->ed_c = *c_ccolor;
295	greg	1.2	c_cmaterial->clock++;
296	greg	1.1	return(MG_OK);
297			case MG_E_TD: /* set diffuse transmittance */
298			if (ac != 2)
299			return(MG_EARGC);
300			if (!isflt(av[1]))
301			return(MG_ETYPE);
302			c_cmaterial->td = atof(av[1]);
303			if (c_cmaterial->td < 0. \| c_cmaterial->td > 1.)
304			return(MG_EILL);
305			c_cmaterial->td_c = *c_ccolor;
306	greg	1.8	c_cmaterial->clock++;
307	greg	1.1	return(MG_OK);
308			case MG_E_RS: /* set specular reflectance */
309			if (ac != 3)
310			return(MG_EARGC);
311	greg	1.18	if (!isflt(av[1]) \| !isflt(av[2]))
312	greg	1.1	return(MG_ETYPE);
313			c_cmaterial->rs = atof(av[1]);
314			c_cmaterial->rs_a = atof(av[2]);
315			if (c_cmaterial->rs < 0. \| c_cmaterial->rs > 1. \|
316			c_cmaterial->rs_a < 0.)
317			return(MG_EILL);
318			c_cmaterial->rs_c = *c_ccolor;
319	greg	1.2	c_cmaterial->clock++;
320	greg	1.1	return(MG_OK);
321			case MG_E_TS: /* set specular transmittance */
322			if (ac != 3)
323			return(MG_EARGC);
324	greg	1.18	if (!isflt(av[1]) \| !isflt(av[2]))
325	greg	1.1	return(MG_ETYPE);
326			c_cmaterial->ts = atof(av[1]);
327			c_cmaterial->ts_a = atof(av[2]);
328			if (c_cmaterial->ts < 0. \| c_cmaterial->ts > 1. \|
329			c_cmaterial->ts_a < 0.)
330			return(MG_EILL);
331			c_cmaterial->ts_c = *c_ccolor;
332	greg	1.2	c_cmaterial->clock++;
333	greg	1.1	return(MG_OK);
334	greg	1.13	case MG_E_SIDES: /* set number of sides */
335			if (ac != 2)
336			return(MG_EARGC);
337			if (!isint(av[1]))
338			return(MG_ETYPE);
339			i = atoi(av[1]);
340			if (i == 1)
341			c_cmaterial->sided = 1;
342			else if (i == 2)
343			c_cmaterial->sided = 0;
344			else
345			return(MG_EILL);
346			c_cmaterial->clock++;
347			return(MG_OK);
348	greg	1.1	}
349			return(MG_EUNK);
350			}
351
352
353			int
354			c_hvertex(ac, av) /* handle a vertex entity */
355			int ac;
356			register char **av;
357			{
358	greg	1.9	int i;
359	greg	1.1	register LUENT *lp;
360
361			switch (mg_entity(av[0])) {
362			case MG_E_VERTEX: /* get/set vertex context */
363	greg	1.4	if (ac > 4)
364			return(MG_EARGC);
365	greg	1.1	if (ac == 1) { /* set unnamed vertex context */
366			c_unvertex = c_dfvertex;
367			c_cvertex = &c_unvertex;
368	greg	1.12	c_cvname = NULL;
369	greg	1.1	return(MG_OK);
370			}
371	greg	1.22	if (!isname(av[1]))
372			return(MG_EILL);
373	greg	1.1	lp = lu_find(&vtx_tab, av[1]); /* lookup context */
374			if (lp == NULL)
375			return(MG_EMEM);
376	greg	1.14	c_cvname = lp->key;
377	greg	1.9	c_cvertex = (C_VERTEX *)lp->data;
378	greg	1.1	if (ac == 2) { /* reestablish previous context */
379	greg	1.9	if (c_cvertex == NULL)
380	greg	1.1	return(MG_EUNDEF);
381			return(MG_OK);
382			}
383			if (av[2][0] != '=' \|\| av[2][1])
384			return(MG_ETYPE);
385	greg	1.9	if (c_cvertex == NULL) { /* create new vertex context */
386	greg	1.1	lp->key = (char *)malloc(strlen(av[1])+1);
387			if (lp->key == NULL)
388			return(MG_EMEM);
389			strcpy(lp->key, av[1]);
390			lp->data = (char *)malloc(sizeof(C_VERTEX));
391			if (lp->data == NULL)
392			return(MG_EMEM);
393	greg	1.14	c_cvname = lp->key;
394	greg	1.9	c_cvertex = (C_VERTEX *)lp->data;
395	greg	1.1	}
396	greg	1.10	i = c_cvertex->clock;
397	greg	1.1	if (ac == 3) { /* use default template */
398			*c_cvertex = c_dfvertex;
399	greg	1.9	c_cvertex->clock = i + 1;
400	greg	1.1	return(MG_OK);
401			}
402			lp = lu_find(&vtx_tab, av[3]); /* lookup template */
403			if (lp == NULL)
404			return(MG_EMEM);
405			if (lp->data == NULL)
406			return(MG_EUNDEF);
407			c_cvertex = (C_VERTEX *)lp->data;
408	greg	1.9	c_cvertex->clock = i + 1;
409	greg	1.1	return(MG_OK);
410			case MG_E_POINT: /* set point */
411			if (ac != 4)
412			return(MG_EARGC);
413	greg	1.18	if (!isflt(av[1]) \| !isflt(av[2]) \| !isflt(av[3]))
414	greg	1.1	return(MG_ETYPE);
415			c_cvertex->p[0] = atof(av[1]);
416			c_cvertex->p[1] = atof(av[2]);
417			c_cvertex->p[2] = atof(av[3]);
418	greg	1.8	c_cvertex->clock++;
419	greg	1.1	return(MG_OK);
420			case MG_E_NORMAL: /* set normal */
421			if (ac != 4)
422			return(MG_EARGC);
423	greg	1.18	if (!isflt(av[1]) \| !isflt(av[2]) \| !isflt(av[3]))
424	greg	1.1	return(MG_ETYPE);
425			c_cvertex->n[0] = atof(av[1]);
426			c_cvertex->n[1] = atof(av[2]);
427			c_cvertex->n[2] = atof(av[3]);
428			(void)normalize(c_cvertex->n);
429	greg	1.8	c_cvertex->clock++;
430	greg	1.1	return(MG_OK);
431			}
432			return(MG_EUNK);
433			}
434
435
436			void
437			c_clearall() /* empty context tables */
438			{
439			c_uncolor = c_dfcolor;
440			c_ccolor = &c_uncolor;
441	greg	1.15	c_ccname = NULL;
442	greg	1.3	lu_done(&clr_tab);
443	greg	1.1	c_unmaterial = c_dfmaterial;
444			c_cmaterial = &c_unmaterial;
445	greg	1.15	c_cmname = NULL;
446	greg	1.3	lu_done(&mat_tab);
447	greg	1.1	c_unvertex = c_dfvertex;
448			c_cvertex = &c_unvertex;
449	greg	1.15	c_cvname = NULL;
450	greg	1.3	lu_done(&vtx_tab);
451	greg	1.1	}
452
453
454	greg	1.11	C_MATERIAL *
455			c_getmaterial(name) /* get a named material */
456			char *name;
457			{
458			register LUENT *lp;
459
460			if ((lp = lu_find(&mat_tab, name)) == NULL)
461			return(NULL);
462			return((C_MATERIAL *)lp->data);
463			}
464
465
466	greg	1.1	C_VERTEX *
467			c_getvert(name) /* get a named vertex */
468			char *name;
469			{
470			register LUENT *lp;
471
472			if ((lp = lu_find(&vtx_tab, name)) == NULL)
473			return(NULL);
474			return((C_VERTEX *)lp->data);
475	greg	1.5	}
476
477
478	greg	1.7	C_COLOR *
479			c_getcolor(name) /* get a named color */
480			char *name;
481			{
482			register LUENT *lp;
483
484			if ((lp = lu_find(&clr_tab, name)) == NULL)
485			return(NULL);
486			return((C_COLOR *)lp->data);
487			}
488
489
490	greg	1.5	int
491			c_isgrey(clr) /* check if color is grey */
492			register C_COLOR *clr;
493			{
494	greg	1.8	if (!(clr->flags & (C_CSXY\|C_CSSPEC)))
495	greg	1.5	return(1); /* no settings == grey */
496			c_ccvt(clr, C_CSXY);
497			return(clr->cx >= .323 && clr->cx <= .343 &&
498			clr->cy >= .323 && clr->cy <= .343);
499			}
500
501
502			void
503			c_ccvt(clr, fl) /* convert color representations */
504			register C_COLOR *clr;
505			int fl;
506			{
507			double x, y, z;
508			register int i;
509
510	greg	1.16	fl &= ~clr->flags; /* ignore what's done */
511			if (!fl) /* everything's done! */
512	greg	1.5	return;
513	greg	1.8	if (!(clr->flags & (C_CSXY\|C_CSSPEC))) /* nothing set! */
514	greg	1.5	*clr = c_dfcolor;
515	greg	1.16	if (fl & C_CSXY) { /* cspec -> cxy */
516	greg	1.5	x = y = z = 0.;
517			for (i = 0; i < C_CNSS; i++) {
518			x += cie_xf.ssamp[i] * clr->ssamp[i];
519			y += cie_yf.ssamp[i] * clr->ssamp[i];
520			z += cie_zf.ssamp[i] * clr->ssamp[i];
521			}
522	greg	1.17	x /= (double)cie_xf.ssum;
523			y /= (double)cie_yf.ssum;
524			z /= (double)cie_zf.ssum;
525	greg	1.5	z += x + y;
526			clr->cx = x / z;
527			clr->cy = y / z;
528			clr->flags \|= C_CSXY;
529	greg	1.16	} else if (fl & C_CSSPEC) { /* cxy -> cspec */
530	greg	1.19	x = clr->cx;
531			y = clr->cy;
532			z = 1. - x - y;
533	greg	1.5	clr->ssum = 0;
534	greg	1.19	for (i = 0; i < C_CNSS; i++) {
535			clr->ssamp[i] = xcie_xp.ssamp[i] + ycie_yp.ssamp[i]
536			+ z*cie_zp.ssamp[i] + .5;
537			if (clr->ssamp[i] < 0) /* out of gamut! */
538			clr->ssamp[i] = 0;
539			else
540			clr->ssum += clr->ssamp[i];
541			}
542	greg	1.5	clr->flags \|= C_CSSPEC;
543			}
544	greg	1.16	if (fl & C_CSEFF) { /* compute efficacy */
545	greg	1.19	if (clr->flags & C_CSSPEC) { /* from spectrum */
546	greg	1.16	y = 0.;
547			for (i = 0; i < C_CNSS; i++)
548			y += cie_yf.ssamp[i] * clr->ssamp[i];
549			clr->eff = C_CLPWM * y / clr->ssum;
550	greg	1.19	} else /* clr->flags & C_CSXY / { / from (x,y) */
551	greg	1.16	clr->eff = clr->cxcie_xf.eff + clr->cycie_yf.eff +
552			(1. - clr->cx - clr->cy)*cie_zf.eff;
553			}
554			clr->flags \|= C_CSEFF;
555			}
556	greg	1.5	}
557
558
559			static int
560			setspectrum(clr, wlmin, wlmax, ac, av) /* convert a spectrum */
561			register C_COLOR *clr;
562	greg	1.17	double wlmin, wlmax;
563	greg	1.5	int ac;
564			char **av;
565			{
566			double scale;
567	greg	1.17	float va[C_CNSS];
568			register int i, pos;
569			int n, imax;
570			int wl;
571	greg	1.5	double wl0, wlstep;
572	greg	1.20	double boxpos, boxstep;
573	greg	1.17	/* check bounds */
574			if (wlmax <= C_CMINWL \| wlmax <= wlmin \| wlmin >= C_CMAXWL)
575	greg	1.5	return(MG_EILL);
576	greg	1.17	wlstep = (wlmax - wlmin)/(ac-1);
577			while (wlmin < C_CMINWL) {
578			wlmin += wlstep;
579			ac--; av++;
580			}
581			while (wlmax > C_CMAXWL) {
582			wlmax -= wlstep;
583			ac--;
584			}
585			imax = ac; /* box filter if necessary */
586	greg	1.20	boxpos = 0;
587			boxstep = 1;
588	greg	1.17	if (wlstep < C_CWLI) {
589	greg	1.20	imax = (wlmax - wlmin)/C_CWLI + (1-FTINY);
590			boxpos = (wlmin - C_CMINWL)/C_CWLI;
591			boxstep = wlstep/C_CWLI;
592	greg	1.17	wlstep = C_CWLI;
593			}
594	greg	1.5	scale = 0.; /* get values and maximum */
595	greg	1.17	pos = 0;
596			for (i = 0; i < imax; i++) {
597			va[i] = 0.; n = 0;
598	greg	1.20	while (boxpos < i+.5 && pos < ac) {
599	greg	1.17	if (!isflt(av[pos]))
600			return(MG_ETYPE);
601			va[i] += atof(av[pos++]);
602			n++;
603	greg	1.20	boxpos += boxstep;
604	greg	1.17	}
605			if (n > 1)
606			va[i] /= (double)n;
607	greg	1.5	if (va[i] > scale)
608			scale = va[i];
609	greg	1.23	else if (va[i] < -scale)
610			scale = -va[i];
611	greg	1.5	}
612	greg	1.20	if (scale <= FTINY)
613	greg	1.5	return(MG_EILL);
614			scale = C_CMAXV / scale;
615			clr->ssum = 0; /* convert to our spacing */
616			wl0 = wlmin;
617			pos = 0;
618			for (i = 0, wl = C_CMINWL; i < C_CNSS; i++, wl += C_CWLI)
619	greg	1.17	if (wl < wlmin \| wl > wlmax)
620	greg	1.5	clr->ssamp[i] = 0;
621			else {
622			while (wl0 + wlstep < wl+FTINY) {
623			wl0 += wlstep;
624			pos++;
625			}
626	greg	1.17	if (wl+FTINY >= wl0 & wl-FTINY <= wl0)
627	greg	1.18	clr->ssamp[i] = scale*va[pos] + .5;
628	greg	1.5	else /* interpolate if necessary */
629	greg	1.18	clr->ssamp[i] = .5 + scale / wlstep *
630	greg	1.5	( va[pos]*(wl0+wlstep - wl) +
631			va[pos+1]*(wl - wl0) );
632			clr->ssum += clr->ssamp[i];
633			}
634			clr->flags = C_CDSPEC\|C_CSSPEC;
635	greg	1.8	clr->clock++;
636	greg	1.5	return(MG_OK);
637			}
638
639
640			static void
641			mixcolors(cres, w1, c1, w2, c2) /* mix two colors according to weights given */
642			register C_COLOR cres, c1, *c2;
643			double w1, w2;
644			{
645			double scale;
646			float cmix[C_CNSS];
647			register int i;
648
649			if ((c1->flags\|c2->flags) & C_CDSPEC) { /* spectral mixing */
650	greg	1.16	c_ccvt(c1, C_CSSPEC\|C_CSEFF);
651			c_ccvt(c2, C_CSSPEC\|C_CSEFF);
652			w1 /= c1->eff*c1->ssum;
653	greg	1.17	w2 /= c2->eff*c2->ssum;
654	greg	1.5	scale = 0.;
655			for (i = 0; i < C_CNSS; i++) {
656			cmix[i] = w1c1->ssamp[i] + w2c2->ssamp[i];
657			if (cmix[i] > scale)
658			scale = cmix[i];
659			}
660			scale = C_CMAXV / scale;
661			cres->ssum = 0;
662			for (i = 0; i < C_CNSS; i++)
663			cres->ssum += cres->ssamp[i] = scale*cmix[i] + .5;
664			cres->flags = C_CDSPEC\|C_CSSPEC;
665			} else { /* CIE xy mixing */
666			c_ccvt(c1, C_CSXY);
667			c_ccvt(c2, C_CSXY);
668	greg	1.24	scale = w1/c1->cy + w2/c2->cy;
669			if (scale == 0.)
670			return;
671			scale = 1. / scale;
672	greg	1.5	cres->cx = (c1->cxw1/c1->cy + c2->cxw2/c2->cy) * scale;
673			cres->cy = (w1 + w2) * scale;
674			cres->flags = C_CDXY\|C_CSXY;
675			}
676	greg	1.1	}
677	greg	1.18
678
679			#define C1 3.741832e-16 /* W-m^2 */
680			#define C2 1.4388e-2 /* m-K */
681
682			#define bbsp(l,t) (C1/((l)(l)(l)(l)(l)(exp(C2/((t)(l)))-1.)))
683			#define bblm(t) (C2/5./(t))
684
685			static int
686			setbbtemp(clr, tk) /* set black body spectrum */
687			register C_COLOR *clr;
688			double tk;
689			{
690			double sf, wl;
691			register int i;
692
693			if (tk < 1000)
694			return(MG_EILL);
695			wl = bblm(tk); /* scalefactor based on peak */
696			if (wl < C_CMINWL*1e-9)
697			wl = C_CMINWL*1e-9;
698			else if (wl > C_CMAXWL*1e-9)
699			wl = C_CMAXWL*1e-9;
700			sf = C_CMAXV/bbsp(wl,tk);
701			clr->ssum = 0;
702			for (i = 0; i < C_CNSS; i++) {
703			wl = (C_CMINWL + iC_CWLI)1e-9;
704			clr->ssum += clr->ssamp[i] = sf*bbsp(wl,tk) + .5;
705			}
706			clr->flags = C_CDSPEC\|C_CSSPEC;
707			clr->clock++;
708			return(MG_OK);
709			}
710
711			#undef C1
712			#undef C2
713			#undef bbsp
714			#undef bblm