Function BuildMinMaxTerrain

Descent3/terrain.cpp:307–382

Builds the min max quadtree data for terrain VSD

// Builds the min max quadtree data for terrain VSD
void BuildMinMaxTerrain() {
  int i, w, h, start, x, y, cell;
  int row_width, xoffset, yoffset, total_rows;
  int minheight, maxheight, cellheight;

  mprintf(0, "Building min/max terrain table.\n");

  // Calculate our integer y positions (0-255)
  for (i = 0; i < TERRAIN_WIDTH * TERRAIN_DEPTH; i++) {
    float fl;

#if (!defined(RELEASE) || defined(NEWEDITOR))
    Terrain_seg_render_objs[i] = -1;
#endif

    fl = Terrain_seg[i].ypos * TERRAIN_HEIGHT_INCREMENT;

    Terrain_seg[i].y = fl;
  }

  int check = GetTerrainGeometryChecksum();

  if (check == Terrain_checksum)
    return;

  Terrain_checksum = check;

  // Generate level of detail deltas
  if (!Dedicated_server)
    GenerateLODDeltas();

  for (i = 0; i < 7; i++) {
    row_width = 1 << i;
    total_rows = 1 << i;
    int yspeed_offset = 0;

    for (yoffset = 0; yoffset < total_rows; yoffset++, yspeed_offset += row_width) {
      for (xoffset = 0; xoffset < row_width; xoffset++) {
        w = TERRAIN_WIDTH >> i;
        h = TERRAIN_WIDTH >> i;

        start = ((yoffset * (TERRAIN_WIDTH >> i)) * TERRAIN_WIDTH);
        start += (xoffset * (TERRAIN_WIDTH >> i));

        minheight = 999;
        maxheight = 0;

        if (h < TERRAIN_DEPTH)
          h++;
        if (w < TERRAIN_DEPTH)
          w++;

        int terrain_offset = 0;
        for (y = 0; y < h; y++, terrain_offset += TERRAIN_WIDTH) {
          for (x = 0; x < w; x++) {
            cell = start + (terrain_offset) + x;
            cellheight = Terrain_seg[cell].ypos;