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Resource Library: Graphics
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graphics-16000.iso
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msdos
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raytrace
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rayshade
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src
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atmosphe.c
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1992-05-04
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/*
* atmosphere.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: atmosphere.c,v 4.0 91/07/17 14:40:02 kolb Exp Locker: kolb $
*
* $Log: atmosphere.c,v $
* Revision 4.0 91/07/17 14:40:02 kolb
* Initial version.
*
*/
#include "atmosphere.h"
Atmosphere *
AtmosCreate(data, method)
char *data;
void (*method)();
{
Atmosphere *ef;
ef = (Atmosphere *)RayMalloc(sizeof(Atmosphere));
ef->data = data;
ef->method = method;
ef->next = (Atmosphere *)0;
return ef;
}
Atmosphere *
AtmosphereCopy(atmos)
Atmosphere *atmos;
{
Atmosphere *res;
if (atmos == (Atmosphere *)NULL)
return (Atmosphere *)NULL;
res = AtmosCreate(atmos->data, atmos->method);
res->next = AtmosphereCopy(atmos->next);
return res;
}
Medium *
MediumPush(index, statten, media)
Float index, statten;
Medium *media;
{
Medium *new;
new = (Medium *)RayMalloc(sizeof(Medium));
new->index = index;
new->statten = statten;
new->next = media;
return new;
}
void
Atmospherics(effects, ray, dist, pos, color)
Atmosphere *effects;
Ray *ray;
Float dist;
Vector *pos;
Color *color;
{
Atmosphere *etmp;
for (etmp = effects; etmp; etmp = etmp->next)
(*etmp->method)(etmp->data, ray, pos, dist, color);
}
Float
ExpAtten(dist, trans)
Float dist, trans;
{
Float atten;
if (trans < EPSILON)
return 0.;
#ifdef __WATCOMC__
dist = dist > 1.0e20 ? 1.0e20 : dist;
#endif
atten = LNHALF * dist / trans;
return (atten < -10. ? 0. : exp(atten));
return -1.0;
}