Function UpdateTerrainLightmaps

Descent3/terrain.cpp:1053–1123

Generates lightmaps based on the info given by the .light field of each Terrain_seg

// Generates lightmaps based on the info given by the .light field of each Terrain_seg
void UpdateTerrainLightmaps() {
  int i, t;

  // First make the wraparounds work right

  // lower-left strip
  for (i = 0; i < 128; i++) {
    Terrain_seg[i * TERRAIN_WIDTH].r = Terrain_seg[i * TERRAIN_WIDTH + 128].r;
    Terrain_seg[i * TERRAIN_WIDTH].g = Terrain_seg[i * TERRAIN_WIDTH + 128].g;
    Terrain_seg[i * TERRAIN_WIDTH].b = Terrain_seg[i * TERRAIN_WIDTH + 128].b;

    Terrain_seg[i].r = Terrain_seg[128 * TERRAIN_WIDTH + i].r;
    Terrain_seg[i].g = Terrain_seg[128 * TERRAIN_WIDTH + i].g;
    Terrain_seg[i].b = Terrain_seg[128 * TERRAIN_WIDTH + i].b;
  }

  // lower-right strip
  for (i = 0; i < 128; i++) {
    Terrain_seg[i * TERRAIN_WIDTH + 255].r = Terrain_seg[i * TERRAIN_WIDTH + 127].r;
    Terrain_seg[i * TERRAIN_WIDTH + 255].g = Terrain_seg[i * TERRAIN_WIDTH + 127].g;
    Terrain_seg[i * TERRAIN_WIDTH + 255].b = Terrain_seg[i * TERRAIN_WIDTH + 127].b;

    Terrain_seg[i + 128].r = Terrain_seg[128 * TERRAIN_WIDTH + i + 128].r;
    Terrain_seg[i + 128].g = Terrain_seg[128 * TERRAIN_WIDTH + i + 128].g;
    Terrain_seg[i + 128].b = Terrain_seg[128 * TERRAIN_WIDTH + i + 128].b;
  }

  // upper-left strip
  for (i = 0; i < 128; i++) {
    Terrain_seg[(i + 128) * TERRAIN_WIDTH].r = Terrain_seg[(i + 128) * TERRAIN_WIDTH + 128].r;
    Terrain_seg[(i + 128) * TERRAIN_WIDTH].g = Terrain_seg[(i + 128) * TERRAIN_WIDTH + 128].g;
    Terrain_seg[(i + 128) * TERRAIN_WIDTH].b = Terrain_seg[(i + 128) * TERRAIN_WIDTH + 128].b;

    Terrain_seg[255 * TERRAIN_WIDTH + i].r = Terrain_seg[127 * TERRAIN_WIDTH + i].r;
    Terrain_seg[255 * TERRAIN_WIDTH + i].g = Terrain_seg[127 * TERRAIN_WIDTH + i].g;
    Terrain_seg[255 * TERRAIN_WIDTH + i].b = Terrain_seg[127 * TERRAIN_WIDTH + i].b;
  }

  // upper-right strip
  for (i = 0; i < 128; i++) {
    Terrain_seg[(i + 128) * TERRAIN_WIDTH + 255].r = Terrain_seg[(i + 128) * TERRAIN_WIDTH + 127].r;
    Terrain_seg[(i + 128) * TERRAIN_WIDTH + 255].g = Terrain_seg[(i + 128) * TERRAIN_WIDTH + 127].g;
    Terrain_seg[(i + 128) * TERRAIN_WIDTH + 255].b = Terrain_seg[(i + 128) * TERRAIN_WIDTH + 127].b;

    Terrain_seg[255 * TERRAIN_WIDTH + i + 128].r = Terrain_seg[127 * TERRAIN_WIDTH + i + 128].r;
    Terrain_seg[255 * TERRAIN_WIDTH + i + 128].g = Terrain_seg[127 * TERRAIN_WIDTH + i + 128].g;
    Terrain_seg[255 * TERRAIN_WIDTH + i + 128].b = Terrain_seg[127 * TERRAIN_WIDTH + i + 128].b;
  }

  int w = lm_w(TerrainLightmaps[0]);

  for (i = 0; i < TERRAIN_DEPTH; i++) {
    for (t = 0; t < TERRAIN_WIDTH; t++) {
      int tseg = i * TERRAIN_WIDTH + t;
      terrain_segment *tp = &Terrain_seg[tseg];
      int x = t % 128;
      int y = 127 - (i % 128);
      int which = ((i / 128) * 2) + (t / 128);