Function GetSpruceTreeImage

src/Generating/Trees.cpp:458–549

void GetSpruceTreeImage(int a_BlockX, int a_BlockY, int a_BlockZ, cNoise & a_Noise, int a_Seq, sSetBlockVector & a_LogBlocks, sSetBlockVector & a_OtherBlocks)
{
	// Spruces have a top section with layer sizes of (0, 1, 0) or only (1, 0),
	// then 1 - 3 sections of ascending sizes (1, 2) [most often], (1, 3) or (1, 2, 3)
	// and an optional bottom section of size 1, followed by 1 - 3 clear trunk blocks
	
	// We'll use bits from this number as partial random numbers; but the noise function has mod8 irregularities
	// (each of the mod8 remainders has a very different chance of occurrence) - that's why we divide by 8
	int MyRandom = a_Noise.IntNoise3DInt(a_BlockX + 32 * a_Seq, a_BlockY + 32 * a_Seq, a_BlockZ) / 8;
	
	static const int  sHeights[] = {1, 2, 2, 3};
	int Height = sHeights[MyRandom & 3];
	MyRandom >>= 2;

	// Prealloc, so that we don't realloc too often later:
	a_LogBlocks.reserve(Height);
	a_OtherBlocks.reserve(180);
	
	// Clear trunk blocks:
	for (int i = 0; i < Height; i++)
	{
		a_LogBlocks.push_back(sSetBlock(a_BlockX, a_BlockY + i, a_BlockZ, E_BLOCK_LOG, E_META_LOG_CONIFER));
	}
	Height += a_BlockY;
	
	// Optional size-1 bottom leaves layer:
	if ((MyRandom & 1) == 0)
	{
		PushCoordBlocks(a_BlockX, Height, a_BlockZ, a_OtherBlocks, BigO1, ARRAYCOUNT(BigO1), E_BLOCK_LEAVES, E_META_LEAVES_CONIFER);
		a_OtherBlocks.push_back(sSetBlock(a_BlockX, Height, a_BlockZ, E_BLOCK_LOG, E_META_LOG_CONIFER));
		Height++;
	}
	MyRandom >>= 1;
	
	// 1 to 3 sections of leaves layers:
	static const int sNumSections[] = {1, 2, 2, 3};
	int NumSections = sNumSections[MyRandom & 3];
	MyRandom >>= 2;
	for (int i = 0; i < NumSections; i++)
	{
		switch (MyRandom & 3)  // SectionType; (1, 2) twice as often as the other two
		{
			case 0:
			case 1:
			{
				PushCoordBlocks(a_BlockX, Height,     a_BlockZ, a_OtherBlocks, BigO2, ARRAYCOUNT(BigO2), E_BLOCK_LEAVES, E_META_LEAVES_CONIFER);
				PushCoordBlocks(a_BlockX, Height + 1, a_BlockZ, a_OtherBlocks, BigO1, ARRAYCOUNT(BigO1), E_BLOCK_LEAVES, E_META_LEAVES_CONIFER);
				a_LogBlocks.push_back(sSetBlock(a_BlockX, Height,     a_BlockZ, E_BLOCK_LOG, E_META_LOG_CONIFER));
				a_LogBlocks.push_back(sSetBlock(a_BlockX, Height + 1, a_BlockZ, E_BLOCK_LOG, E_META_LOG_CONIFER));
				Height += 2;
				break;
			}
			case 2:
			{
				PushCoordBlocks(a_BlockX, Height,     a_BlockZ, a_OtherBlocks, BigO3, ARRAYCOUNT(BigO3), E_BLOCK_LEAVES, E_META_LEAVES_CONIFER);
				PushCoordBlocks(a_BlockX, Height + 1, a_BlockZ, a_OtherBlocks, BigO1, ARRAYCOUNT(BigO1), E_BLOCK_LEAVES, E_META_LEAVES_CONIFER);
				a_LogBlocks.push_back(sSetBlock(a_BlockX, Height,     a_BlockZ, E_BLOCK_LOG, E_META_LOG_CONIFER));
				a_LogBlocks.push_back(sSetBlock(a_BlockX, Height + 1, a_BlockZ, E_BLOCK_LOG, E_META_LOG_CONIFER));