gfx/povray/ray.c

   1 /****************************************************************************
   2 *                ray.c
   3 *
   4 *  This module implements the code pertaining to rays.
   5 *
   6 *  from Persistence of Vision(tm) Ray Tracer
   7 *  Copyright 1996,1999 Persistence of Vision Team
   8 *---------------------------------------------------------------------------
   9 *  NOTICE: This source code file is provided so that users may experiment
  10 *  with enhancements to POV-Ray and to port the software to platforms other
  11 *  than those supported by the POV-Ray Team.  There are strict rules under
  12 *  which you are permitted to use this file.  The rules are in the file
  13 *  named POVLEGAL.DOC which should be distributed with this file.
  14 *  If POVLEGAL.DOC is not available or for more info please contact the POV-Ray
  15 *  Team Coordinator by email to team-coord@povray.org or visit us on the web at
  16 *  http://www.povray.org. The latest version of POV-Ray may be found at this site.
  17 *
  18 * This program is based on the popular DKB raytracer version 2.12.
  19 * DKBTrace was originally written by David K. Buck.
  20 * DKBTrace Ver 2.0-2.12 were written by David K. Buck & Aaron A. Collins.
  21 *
  22 *****************************************************************************/
  23
  24 #include "frame.h"
  25 #include "vector.h"
  26 #include "povproto.h"
  27 #include "povray.h"
  28 #include "interior.h"
  29 #include "ray.h"
  30 #include "texture.h"
  31
  32
  33
  34 /*****************************************************************************
  35 * Local preprocessor defines
  36 ******************************************************************************/
  37
  38
  39
  40 /*****************************************************************************
  41 * Local typedefs
  42 ******************************************************************************/
  43
  44
  45
  46 /*****************************************************************************
  47 * Local variables
  48 ******************************************************************************/
  49
  50
  51
  52 /*****************************************************************************
  53 * Static functions
  54 ******************************************************************************/
  55
  56
  57
  58 /*****************************************************************************
  59 *
  60 * FUNCTION
  61 *
  62 *   Initialize_Ray_Containers
  63 *
  64 * INPUT
  65 *
  66 * OUTPUT
  67 *
  68 * RETURNS
  69 *
  70 * AUTHOR
  71 *
  72 *   POV-Ray Team
  73 *
  74 * DESCRIPTION
  75 *
  76 *   -
  77 *
  78 * CHANGES
  79 *
  80 *   -
  81 *
  82 ******************************************************************************/
  83
  84 void Initialize_Ray_Containers(RAY *Ray)
  85 {
  86   Ray->Index = - 1;
  87 }
  88
  89
  90
  91 /*****************************************************************************
  92 *
  93 * FUNCTION
  94 *
  95 *   Copy_Ray_Containers
  96 *
  97 * INPUT
  98 *
  99 * OUTPUT
 100 *
 101 * RETURNS
 102 *
 103 * AUTHOR
 104 *
 105 *   POV-Ray Team
 106 *
 107 * DESCRIPTION
 108 *
 109 *   -
 110 *
 111 * CHANGES
 112 *
 113 *   -
 114 *
 115 ******************************************************************************/
 116
 117 void Copy_Ray_Containers(RAY *Dest_Ray, RAY  *Source_Ray)
 118 {
 119   register int i;
 120
 121   if ((Dest_Ray->Index = Source_Ray->Index) >= MAX_CONTAINING_OBJECTS)
 122   {
 123     Error("ERROR - Containing Index too high.\n");
 124   }
 125
 126   for (i = 0 ; i <= Source_Ray->Index; i++)
 127   {
 128     Dest_Ray->Interiors[i] = Source_Ray->Interiors[i];
 129   }
 130 }
 131
 132
 133
 134 /*****************************************************************************
 135 *
 136 * FUNCTION
 137 *
 138 *   Ray_Enter
 139 *
 140 * INPUT
 141 *
 142 * OUTPUT
 143 *
 144 * RETURNS
 145 *
 146 * AUTHOR
 147 *
 148 *   POV-Ray Team
 149 *
 150 * DESCRIPTION
 151 *
 152 *   -
 153 *
 154 * CHANGES
 155 *
 156 *   Oct 1995 : Fixed bug with IOR assignment (only valid for plain textures) [DB]
 157 *
 158 ******************************************************************************/
 159
 160 void Ray_Enter(RAY *Ray, INTERIOR *interior)
 161 {
 162   int index;
 163
 164   if ((index = ++(Ray->Index)) >= MAX_CONTAINING_OBJECTS)
 165   {
 166     Error("Too many nested refracting objects.");
 167   }
 168
 169   Ray->Interiors[index] = interior;
 170 }
 171
 172
 173
 174 /*****************************************************************************
 175 *
 176 * FUNCTION
 177 *
 178 *   Ray_Exit
 179 *
 180 * INPUT
 181 *
 182 * OUTPUT
 183 *
 184 * RETURNS
 185 *
 186 * AUTHOR
 187 *
 188 *   POV-Ray Team
 189 *
 190 * DESCRIPTION
 191 *
 192 *   Remove given entry from given ray's container.
 193 *
 194 * CHANGES
 195 *
 196 *   -
 197 *
 198 ******************************************************************************/
 199
 200 void Ray_Exit(RAY *Ray, int nr)
 201 {
 202   int i;
 203
 204   for (i = nr; i < Ray->Index; i++)
 205   {
 206     Ray->Interiors[i] = Ray->Interiors[i+1];
 207   }
 208
 209   if (--(Ray->Index) < - 1)
 210   {
 211     Error("Too many exits from refractions.");
 212   }
 213 }
 214
 215
 216
 217 /*****************************************************************************
 218 *
 219 * FUNCTION
 220 *
 221 *   Interior_In_Ray_Container
 222 *
 223 * INPUT
 224 *
 225 * OUTPUT
 226 *
 227 * RETURNS
 228 *
 229 * AUTHOR
 230 *
 231 *   Dieter Bayer
 232 *
 233 * DESCRIPTION
 234 *
 235 *   Test if a given interior is in the container of a given ray.
 236 *
 237 * CHANGES
 238 *
 239 *   Mar 1996 : Creation.
 240 *
 241 ******************************************************************************/
 242
 243 int Interior_In_Ray_Container(RAY *ray, INTERIOR *interior)
 244 {
 245   int i, found = -1;
 246
 247   if (ray->Index > -1)
 248   {
 249     for (i = 0; i <= ray->Index; i++)
 250     {
 251       if (interior == ray->Interiors[i])
 252       {
 253         found = i;
 254
 255         break;
 256       }
 257     }
 258   }
 259
 260   return(found);
 261 }
 262
 263
 264