VoxelExporter.cs

/**
 *           DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
 *                   Version 2, December 2004
 *
 * Everyone is permitted to copy and distribute verbatim or modified
 * copies of this license document, and changing it is allowed as long
 * as the name is changed.
 * 
 *           DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
 *  TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
 *
 * 0. You just DO WHAT THE FUCK YOU WANT TO.
 **/
public static class VoxelExporter
{
    public static void ExportToVoxFile(NativeList<VoxelBlock> voxelBlocks, NativeArray<PlanetBodySettings.BiomeColourSettings.Material> materials, string filePath)
    {
      if (File.Exists(filePath))
        File.Delete(filePath);

      Debug.Log($"Starting export with {voxelBlocks.Length} blocks");

      var minPos = new float3(float.MaxValue);
      var maxPos = new float3(float.MinValue);

      // Find our actual bounds
      foreach (VoxelBlock block in voxelBlocks)
      {
        minPos = math.min(minPos, block.position);
        maxPos = math.max(maxPos, block.position);
      }

      // Ensure we include the final column block in the bounds.
      maxPos += new float3(1);

      using var writer = new BinaryWriter(File.Open(filePath, FileMode.Create));
      writer.Write("VOX ".ToCharArray());
      writer.Write(150);

      writer.Write("MAIN".ToCharArray());
      writer.Write(0);
      long childrenSizePosition = writer.BaseStream.Position;
      writer.Write(0);

      var size = new int3(
        (int)((maxPos.x - minPos.x + 1)),
        (int)((maxPos.y - minPos.y + 1)),
        (int)((maxPos.z - minPos.z + 1))
      );

      writer.Write("SIZE".ToCharArray());
      writer.Write(12);
      writer.Write(0);
      writer.Write(size.x);
      writer.Write(size.y);
      writer.Write(size.z);

      writer.Write("XYZI".ToCharArray());
      writer.Write(4 + voxelBlocks.Length * 4);
      writer.Write(0);
      writer.Write(voxelBlocks.Length);

      foreach (VoxelBlock block in voxelBlocks)
      {
        var blockPos = new int3(
          (int)(block.position.x - minPos.x),
          (int)(block.position.y - minPos.y),
          (int)(block.position.z - minPos.z)
        );

        writer.Write((byte)blockPos.x);
        writer.Write((byte)blockPos.y);
        writer.Write((byte)blockPos.z);
        writer.Write((byte)block.material);
      }

      // Simple palette
      writer.Write("RGBA".ToCharArray());
      writer.Write(256 * 4); // RGBA chunk content size
      writer.Write(0);

      // Write the palette
      for (var i = 0; i < 256; i++)
      {
        if (i < materials.Length)
        {
          PlanetBodySettings.BiomeColourSettings.Material material = materials[i];
          writer.Write((byte)(material.material.color.r * 255)); // R
          writer.Write((byte)(material.material.color.g * 255)); // G
          writer.Write((byte)(material.material.color.b * 255)); // B
          writer.Write((byte)(material.material.color.a * 255)); // A
        }
        else
        {
          writer.Write(0); // R
          writer.Write(0); // G
          writer.Write(0); // B
          writer.Write(0); // A
        }
      }

      writer.Write("MATL");
      writer.Write(materials.Length);
      writer.Write(0);

      for (var i = 0; i < materials.Length; i++)
      {
        writer.Write(i + 1);
        writer.Write(0);
      }

      long endPosition = writer.BaseStream.Position;
      writer.BaseStream.Position = childrenSizePosition;
      writer.Write((int)(endPosition - childrenSizePosition - 4));
    }
}