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17 Bit Software 6: Level 6
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libshade
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lightdef.c
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C/C++ Source or Header
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1991-08-08
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4KB
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147 lines
/*
* lightdef.c
*
* Copyright (C) 1989, 1991, Craig E. Kolb
* All rights reserved.
*
* This software may be freely copied, modified, and redistributed
* provided that this copyright notice is preserved on all copies.
*
* You may not distribute this software, in whole or in part, as part of
* any commercial product without the express consent of the authors.
*
* There is no warranty or other guarantee of fitness of this software
* for any purpose. It is provided solely "as is".
*
* $Id: lightdef.c,v 4.0 91/07/17 14:46:25 kolb Exp Locker: kolb $
*
* $Log: lightdef.c,v $
* Revision 4.0 91/07/17 14:46:25 kolb
* Initial version.
*
*/
#include "rayshade.h"
#include "options.h"
#include "liblight/light.h"
#include "liblight/infinite.h" /* to create default infinite light */
#include "liblight/jittered.h" /* to create jittered light sources */
Light *Lights = NULL; /* Linked list of defined lights */
void
LightAddToDefined(light)
Light *light;
{
if (light) {
light->next = Lights;
Lights = light;
}
}
void
LightSetup()
{
long shadowopts;
Light *ltmp;
/*
* Set shadowing options.
*/
shadowopts = 0;
if (Options.no_shadows)
shadowopts |= SHADOW_NONE;
if (Options.shadowtransp)
shadowopts |= SHADOW_TRANSP;
if (Options.csg)
shadowopts |= SHADOW_CSG;
if (Options.cache)
shadowopts |= SHADOW_CACHE;
if (Options.shutterspeed > 0.)
shadowopts |= SHADOW_BLUR;
ShadowSetOptions(shadowopts);
/*
* If no light sources were defined, add a default.
*/
if (Lights == (Light *)NULL) {
Color ctmp;
Vector vtmp;
vtmp.x = vtmp.z = 1.;
vtmp.y = -1;
ctmp.r = ctmp.g = ctmp.b = 1.;
LightAddToDefined(LightInfiniteCreate(&ctmp, &vtmp));
}
/*
* Now that we've parsed the input file, we know what
* maxlevel is, and we can allocate the correct amount of
* space for each light source's cache.
*/
for (ltmp = Lights; ltmp; ltmp = ltmp->next) {
ltmp->cache = (ShadowCache *)Calloc(
(unsigned)Options.maxdepth + 1, sizeof(ShadowCache));
}
}
void
AreaLightCreate(color, corner, u, usamp, v, vsamp, shadow)
Color *color;
Vector *corner, *u, *v;
int usamp, vsamp, shadow;
{
Vector vpos, curpos;
int i, j, numlight;
Float ulen, vlen;
Color intens;
Light *ltmp;
if (usamp < 1 || vsamp < 1)
RLerror(RL_ABORT, "Invalid area light specification.\n");
numlight = usamp * vsamp; /* Total number of jittered sources */
/*
* Sum of all intensities is equal to specified intensity.
*/
intens.r = color->r / (Float)numlight;
intens.g = color->g / (Float)numlight;
intens.b = color->b / (Float)numlight;
VecSub(*u, *corner, u);
VecSub(*v, *corner, v);
/*
* Make sure that u and v are not degenerate.
*/
ulen = VecNormalize(u);
vlen = VecNormalize(v);
if (ulen < EPSILON || vlen < EPSILON)
RLerror(RL_ABORT, "Degenerate area light source.\n");
/*
* Scale u and v such that they define the area covered by a
* single sample.
*/
VecScale(ulen / (Float)usamp, *u, u);
VecScale(vlen / (Float)vsamp, *v, v);
/*
* For each sample...
*/
vpos = *corner;
for (i = 0; i < vsamp; i++) {
curpos = vpos;
for (j = 0; j < usamp; j++) {
/*
* current pos is the "corner" of a new light
* source. A jittered position based on
* the "corner" and the two edge vectors
* is used as the position for the
* light source in lighting calculations.
*/
ltmp = LightJitteredCreate(&intens, &curpos, u, v);
ltmp->shadow = shadow;
LightAddToDefined(ltmp);
VecAdd(curpos, *u, &curpos);
}
VecAdd(vpos, *v, &vpos);
}
}