Method FillColumnMesa

src/Generating/DistortedHeightmap.cpp:832–905

void cDistortedHeightmap::FillColumnMesa(cChunkDesc & a_ChunkDesc, int a_RelX, int a_RelZ)
{
	// Frequencies for the clay floor noise:
	const NOISE_DATATYPE FrequencyX = 50;
	const NOISE_DATATYPE FrequencyZ = 50;

	int Top = a_ChunkDesc.GetHeight(a_RelX, a_RelZ);
	if (Top < m_SeaLevel)
	{
		// The terrain is below sealevel, handle as regular ocean:
		FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, patOFRedSand.Get());
		return;
	}

	NOISE_DATATYPE NoiseX = ((NOISE_DATATYPE)(m_CurChunkX * cChunkDef::Width + a_RelX)) / FrequencyX;
	NOISE_DATATYPE NoiseY = ((NOISE_DATATYPE)(m_CurChunkZ * cChunkDef::Width + a_RelZ)) / FrequencyZ;
	int ClayFloor = m_SeaLevel - 6 + (int)(4.f * m_MesaFloor.CubicNoise2D(NoiseX, NoiseY));
	if (ClayFloor >= Top)
	{
		ClayFloor = Top - 1;
	}
	
	if (Top - m_SeaLevel < 5)
	{
		// Simple case: top is red sand, then hardened clay down to ClayFloor, then stone:
		a_ChunkDesc.SetBlockTypeMeta(a_RelX, Top, a_RelZ, E_BLOCK_SAND, E_META_SAND_RED);
		for (int y = Top - 1; y >= ClayFloor; y--)
		{
			a_ChunkDesc.SetBlockType(a_RelX, y, a_RelZ, E_BLOCK_HARDENED_CLAY);
		}
		for (int y = ClayFloor - 1; y > 0; y--)
		{
			a_ChunkDesc.SetBlockType(a_RelX, y, a_RelZ, E_BLOCK_STONE);
		}
		a_ChunkDesc.SetBlockType(a_RelX, 0, a_RelZ, E_BLOCK_BEDROCK);
		return;
	}
	
	// Difficult case: use the mesa pattern and watch for overhangs:
	int NoiseArrayIdx = a_RelX + 17 * 257 * a_RelZ;
	int PatternIdx = cChunkDef::Height - (Top - ClayFloor);  // We want the block at index ClayFloor to be pattern's 256th block (first stone)
	const sBlockInfo * Pattern = m_MesaPattern;
	bool HasHadWater = false;
	for (int y = Top; y > 0; y--)
	{
		int HeightMapHeight = (int)m_DistortedHeightmap[NoiseArrayIdx + 17 * y];
		if (y < HeightMapHeight)
		{
			// "ground" part, use the pattern:
			a_ChunkDesc.SetBlockTypeMeta(a_RelX, y, a_RelZ, Pattern[PatternIdx].BlockType, Pattern[PatternIdx].BlockMeta);
			PatternIdx++;
			continue;
		}

		if (y >= m_SeaLevel)
		{
			// "air" part, do nothing
			continue;