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#ifndef lint |
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static const char RCSid[] = "$Id: p_func.c,v 2.10 2023/11/17 20:02:07 greg Exp $"; |
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#endif |
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/* |
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* p_func.c - routine for procedural patterns. |
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*/ |
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|
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#include "copyright.h" |
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|
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#include "ray.h" |
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#include "func.h" |
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#include "random.h" |
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#include "rtotypes.h" |
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|
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/* |
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* A procedural pattern can either be a brightness or a |
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* color function. A brightness function is given as: |
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* |
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* modifier brightfunc name |
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* 2+ bvarname filename xf |
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* 0 |
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* n A1 A2 .. |
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* |
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* A color function is given as: |
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* |
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* modifier colorfunc name |
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* 4+ rvarname gvarname bvarname filename xf |
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* 0 |
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* n A1 A2 .. |
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* |
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* A spectral function is given as: |
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* |
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* modifier specfunc name |
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* 2+ sfunc filename xf |
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* 0 |
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* 2+ nmA nmB A3 .. |
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* |
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* Filename is the name of the file where the variable definitions |
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* can be found. The list of real arguments can be accessed by |
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* definitions in the file. The xf is a transformation |
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* to get from the original coordinates to the current coordinates. |
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* For the "specfunc" primitive, sfunc(nm) is a function of wavelength |
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* and must be defined from nmA to nmB, and should average to 1 over |
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* its range. |
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*/ |
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|
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|
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int |
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p_bfunc( /* compute brightness pattern */ |
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OBJREC *m, |
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RAY *r |
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) |
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{ |
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double bval; |
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MFUNC *mf; |
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|
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if (m->oargs.nsargs < 2) |
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objerror(m, USER, "bad # arguments"); |
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mf = getfunc(m, 1, 0x1, 0); |
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setfunc(m, r); |
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errno = 0; |
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bval = evalue(mf->ep[0]); |
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if ((errno == EDOM) | (errno == ERANGE)) { |
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objerror(m, WARNING, "compute error"); |
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return(0); |
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} |
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scalescolor(r->pcol, bval); |
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return(0); |
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} |
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|
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|
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int |
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p_cfunc( /* compute color pattern */ |
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OBJREC *m, |
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RAY *r |
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) |
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{ |
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SCOLOR scval; |
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MFUNC *mf; |
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|
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if (m->oargs.nsargs < 4) |
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objerror(m, USER, "bad # arguments"); |
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mf = getfunc(m, 3, 0x7, 0); |
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setfunc(m, r); |
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errno = 0; |
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setscolor(scval, evalue(mf->ep[0]), |
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evalue(mf->ep[1]), |
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evalue(mf->ep[2])); |
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if ((errno == EDOM) | (errno == ERANGE)) { |
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objerror(m, WARNING, "compute error"); |
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return(0); |
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} |
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smultscolor(r->pcol, scval); |
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return(0); |
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} |
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|
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|
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int |
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p_specfunc( /* compute spectral pattern */ |
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OBJREC *m, |
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RAY *r |
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) |
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{ |
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SCOLOR scsamp; |
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SCOLOR scval; |
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double wl, wlmin, wlmax, wlstep; |
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int ns, i; |
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MFUNC *mf; |
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|
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if ((m->oargs.nsargs < 2) | (m->oargs.nfargs < 2)) |
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objerror(m, USER, "bad # arguments"); |
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if (m->oargs.farg[0] < m->oargs.farg[1]) { |
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wlmin = m->oargs.farg[0]; |
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wlmax = m->oargs.farg[1]; |
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} else { |
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wlmin = m->oargs.farg[1]; |
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wlmax = m->oargs.farg[0]; |
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} |
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if (wlmin < WLPART[3]) wlmin = WLPART[3]; |
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if (wlmax > WLPART[0]) wlmax = WLPART[0]; |
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if (wlmin >= wlmax) { |
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objerror(m, WARNING, "incompatible wavelength sampling"); |
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return(0); |
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} |
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wlstep = (wlmax - wlmin)/(double)MAXCSAMP; |
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mf = getfunc(m, 1, 0, 0); |
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setfunc(m, r); |
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errno = 0; |
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ns = (wlmax - wlmin)/wlstep + .1; |
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wl = wlmax - .5*wlstep; |
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for (i = ns; i-- > 0; wl -= wlstep) { |
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double ws = wl + 0.9*(1.-frandom())*wlstep; |
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scsamp[i] = funvalue(m->oargs.sarg[0], 1, &ws); |
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if ((errno == EDOM) | (errno == ERANGE)) { |
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objerror(m, WARNING, "compute error"); |
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return(0); |
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} |
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} |
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convertscolor(scval, NCSAMP, WLPART[0], WLPART[3], |
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scsamp, ns, wlmin, wlmax); |
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smultscolor(r->pcol, scval); |
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return(0); |
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} |
