Games/Quake/r_light.c

   1 /*
   2 Copyright (C) 1996-1997 Id Software, Inc.
   3
   4 This program is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU General Public License
   6 as published by the Free Software Foundation; either version 2
   7 of the License, or (at your option) any later version.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  12
  13 See the GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  18
  19 */
  20 // r_light.c
  21
  22 #include "quakedef.h"
  23 #include "r_local.h"
  24
  25 int     r_dlightframecount;
  26
  27
  28 /*
  29 ==================
  30 R_AnimateLight
  31 ==================
  32 */
  33 void R_AnimateLight (void)
  34 {
  35         int                     i,j,k;
  36
  37 //
  38 // light animations
  39 // 'm' is normal light, 'a' is no light, 'z' is double bright
  40         i = (int)(cl.time*10);
  41         for (j=0 ; j<MAX_LIGHTSTYLES ; j++)
  42         {
  43                 if (!cl_lightstyle[j].length)
  44                 {
  45                         d_lightstylevalue[j] = 256;
  46                         continue;
  47                 }
  48                 k = i % cl_lightstyle[j].length;
  49                 k = cl_lightstyle[j].map[k] - 'a';
  50                 k = k*22;
  51                 d_lightstylevalue[j] = k;
  52         }
  53 }
  54
  55
  56 /*
  57 =============================================================================
  58
  59 DYNAMIC LIGHTS
  60
  61 =============================================================================
  62 */
  63
  64 /*
  65 =============
  66 R_MarkLights
  67 =============
  68 */
  69 void R_MarkLights (dlight_t *light, int bit, mnode_t *node)
  70 {
  71         mplane_t        *splitplane;
  72         float           dist;
  73         msurface_t      *surf;
  74         int                     i;
  75
  76         if (node->contents < 0)
  77                 return;
  78
  79         splitplane = node->plane;
  80         dist = DotProduct (light->origin, splitplane->normal) - splitplane->dist;
  81
  82         if (dist > light->radius)
  83         {
  84                 R_MarkLights (light, bit, node->children[0]);
  85                 return;
  86         }
  87         if (dist < -light->radius)
  88         {
  89                 R_MarkLights (light, bit, node->children[1]);
  90                 return;
  91         }
  92
  93 // mark the polygons
  94         surf = cl.worldmodel->surfaces + node->firstsurface;
  95         for (i=0 ; i<node->numsurfaces ; i++, surf++)
  96         {
  97                 if (surf->dlightframe != r_dlightframecount)
  98                 {
  99                         surf->dlightbits = 0;
 100                         surf->dlightframe = r_dlightframecount;
 101                 }
 102                 surf->dlightbits |= bit;
 103         }
 104
 105         R_MarkLights (light, bit, node->children[0]);
 106         R_MarkLights (light, bit, node->children[1]);
 107 }
 108
 109
 110 /*
 111 =============
 112 R_PushDlights
 113 =============
 114 */
 115 void R_PushDlights (void)
 116 {
 117         int             i;
 118         dlight_t        *l;
 119
 120         r_dlightframecount = r_framecount + 1;  // because the count hasn't
 121                                                                                         //  advanced yet for this frame
 122         l = cl_dlights;
 123
 124         for (i=0 ; i<MAX_DLIGHTS ; i++, l++)
 125         {
 126                 if (l->die < cl.time || !l->radius)
 127                         continue;
 128                 R_MarkLights ( l, 1<<i, cl.worldmodel->nodes );
 129         }
 130 }
 131
 132
 133 /*
 134 =============================================================================
 135
 136 LIGHT SAMPLING
 137
 138 =============================================================================
 139 */
 140
 141 int RecursiveLightPoint (mnode_t *node, vec3_t start, vec3_t end)
 142 {
 143         int                     r;
 144         float           front, back, frac;
 145         int                     side;
 146         mplane_t        *plane;
 147         vec3_t          mid;
 148         msurface_t      *surf;
 149         int                     s, t, ds, dt;
 150         int                     i;
 151         mtexinfo_t      *tex;
 152         byte            *lightmap;
 153         unsigned        scale;
 154         int                     maps;
 155
 156         if (node->contents < 0)
 157                 return -1;              // didn't hit anything
 158
 159 // calculate mid point
 160
 161 // FIXME: optimize for axial
 162         plane = node->plane;
 163         front = DotProduct (start, plane->normal) - plane->dist;
 164         back = DotProduct (end, plane->normal) - plane->dist;
 165         side = front < 0;
 166
 167         if ( (back < 0) == side)
 168                 return RecursiveLightPoint (node->children[side], start, end);
 169
 170         frac = front / (front-back);
 171         mid[0] = start[0] + (end[0] - start[0])*frac;
 172         mid[1] = start[1] + (end[1] - start[1])*frac;
 173         mid[2] = start[2] + (end[2] - start[2])*frac;
 174
 175 // go down front side
 176         r = RecursiveLightPoint (node->children[side], start, mid);
 177         if (r >= 0)
 178                 return r;               // hit something
 179
 180         if ( (back < 0) == side )
 181                 return -1;              // didn't hit anuthing
 182
 183 // check for impact on this node
 184
 185         surf = cl.worldmodel->surfaces + node->firstsurface;
 186         for (i=0 ; i<node->numsurfaces ; i++, surf++)
 187         {
 188                 if (surf->flags & SURF_DRAWTILED)
 189                         continue;       // no lightmaps
 190
 191                 tex = surf->texinfo;
 192
 193                 s = DotProduct (mid, tex->vecs[0]) + tex->vecs[0][3];
 194                 t = DotProduct (mid, tex->vecs[1]) + tex->vecs[1][3];;
 195
 196                 if (s < surf->texturemins[0] ||
 197                 t < surf->texturemins[1])
 198                         continue;
 199
 200                 ds = s - surf->texturemins[0];
 201                 dt = t - surf->texturemins[1];
 202
 203                 if ( ds > surf->extents[0] || dt > surf->extents[1] )
 204                         continue;
 205
 206                 if (!surf->samples)
 207                         return 0;
 208
 209                 ds >>= 4;
 210                 dt >>= 4;
 211
 212                 lightmap = surf->samples;
 213                 r = 0;
 214                 if (lightmap)
 215                 {
 216
 217                         lightmap += dt * ((surf->extents[0]>>4)+1) + ds;
 218
 219                         for (maps = 0 ; maps < MAXLIGHTMAPS && surf->styles[maps] != 255 ;
 220                                         maps++)
 221                         {
 222                                 scale = d_lightstylevalue[surf->styles[maps]];
 223                                 r += *lightmap * scale;
 224                                 lightmap += ((surf->extents[0]>>4)+1) *
 225                                                 ((surf->extents[1]>>4)+1);
 226                         }
 227
 228                         r >>= 8;
 229                 }
 230
 231                 return r;
 232         }
 233
 234 // go down back side
 235         return RecursiveLightPoint (node->children[!side], mid, end);
 236 }
 237
 238 int R_LightPoint (vec3_t p)
 239 {
 240         vec3_t          end;
 241         int                     r;
 242
 243         if (!cl.worldmodel->lightdata)
 244                 return 255;
 245
 246         end[0] = p[0];
 247         end[1] = p[1];
 248         end[2] = p[2] - 2048;
 249
 250         r = RecursiveLightPoint (cl.worldmodel->nodes, p, end);
 251
 252         if (r == -1)
 253                 r = 0;
 254
 255         if (r < r_refdef.ambientlight)
 256                 r = r_refdef.ambientlight;
 257
 258         return r;
 259 }
 260