Function ApplyLightingToTerrain

Descent3/lighting.cpp:1466–1603

Changes the terrain shading to approximate lighting

// Changes the terrain shading to approximate lighting
void ApplyLightingToTerrain(vector *pos, int cellnum, float light_dist, float red_scale, float green_scale,
                            float blue_scale, vector *light_direction, float dot_range) {
  int celllist[MAX_DYNAMIC_CELLS];
  int num_cells, i;

  if (Dedicated_server)
    return;

  ApplyLightingToObjects(pos, MAKE_ROOMNUM(cellnum), light_dist, red_scale, green_scale, blue_scale, light_direction,
                         dot_range);

  num_cells = fvi_QuickDistCellList(cellnum, pos, light_dist, celllist, MAX_DYNAMIC_CELLS);

  if (num_cells < 1)
    return;

  if (num_cells == MAX_DYNAMIC_CELLS) {
    mprintf(0, "One object has hit %d terrain cells in lighting!\n", MAX_DYNAMIC_CELLS);
  }

  int red_limit = 255;
  int green_limit = 255;
  int blue_limit = 255;

  for (i = 0; i < num_cells; i++) {
    int cellnum = celllist[i];
    terrain_segment *tseg = &Terrain_seg[cellnum];

    int seg_x = cellnum % TERRAIN_WIDTH;
    int seg_z = cellnum / TERRAIN_WIDTH;

    int subx = seg_x % 128;
    int subz = 127 - (seg_z % 128);

    int whichmap = ((seg_z / 128) * 2) + (seg_x / 128);
    whichmap = TerrainLightmaps[whichmap];

    // Make sure face was rendered
    // if (tseg->renderframe!=((FrameCount-1)%256))
    //	continue;

    if (Num_dynamic_cells >= MAX_DYNAMIC_CELLS) {
      mprintf(0, "Too many dynamic cells!\n");
      return;
    }

    // Check for backfaces
    vector tpos;

    tpos.x = (seg_x * TERRAIN_SIZE) + (TERRAIN_SIZE / 2);
    tpos.z = (seg_z * TERRAIN_SIZE) + (TERRAIN_SIZE / 2);
    tpos.y = tseg->y;

    vector subvec = *pos - tpos;

    float dist = vm_GetMagnitudeFast(&subvec);
    float scalar = 1.0 - (dist / light_dist);