有了地形接下來該生成結構和建築了，由於這部分代碼很長，本篇只研究生成洞穴
完整的provideChunk：
public Chunk provideChunk(int x, int z)
{
this.rand.setSeed((long)x * 341873128712L + (long)z * 132897987541L);
ChunkPrimer chunkprimer = new ChunkPrimer();
// 生成基本地形（沒有洞穴等建築）
this.setBlocksInChunk(x, z, chunkprimer);
// 生成16*16的生物羣系數組
this.biomesForGeneration = this.worldObj.getWorldChunkManager().loadBlockGeneratorData(this.biomesForGeneration, x * 16, z * 16, 16, 16);
// 把石頭替換成生物羣系相應的方塊
this.replaceBlocksForBiome(x, z, chunkprimer, this.biomesForGeneration);
// 生成洞穴、村莊、要塞等結構和建築
if (this.settings.useCaves)
{
this.caveGenerator.generate(this, this.worldObj, x, z, chunkprimer);
}
if (this.settings.useRavines)
{
this.ravineGenerator.generate(this, this.worldObj, x, z, chunkprimer);
}
if (this.settings.useMineShafts && this.mapFeaturesEnabled)
{
this.mineshaftGenerator.generate(this, this.worldObj, x, z, chunkprimer);
}
if (this.settings.useVillages && this.mapFeaturesEnabled)
{
this.villageGenerator.generate(this, this.worldObj, x, z, chunkprimer);
}
if (this.settings.useStrongholds && this.mapFeaturesEnabled)
{
this.strongholdGenerator.generate(this, this.worldObj, x, z, chunkprimer);
}
if (this.settings.useTemples && this.mapFeaturesEnabled)
{
this.scatteredFeatureGenerator.generate(this, this.worldObj, x, z, chunkprimer);
}
if (this.settings.useMonuments && this.mapFeaturesEnabled)
{
this.oceanMonumentGenerator.generate(this, this.worldObj, x, z, chunkprimer);
}
// 轉爲Chunk對象
Chunk chunk = new Chunk(this.worldObj, chunkprimer, x, z);
byte[] abyte = chunk.getBiomeArray();
// 設置生物羣系ID
for (int i = 0; i < abyte.length; ++i)
{
abyte[i] = (byte)this.biomesForGeneration[i].biomeID;
}
// 生成光照圖，這裏不討論
chunk.generateSkylightMap();
return chunk;
}生成洞穴
類名net.minecraft.world.gen.MapGenBase
public void generate(IChunkProvider chunkProviderIn, World worldIn, int chunkX, int chunkZ, ChunkPrimer chunkPrimerIn)
{
int range = this.range;
this.worldObj = worldIn;
this.rand.setSeed(worldIn.getSeed());
long rand1 = this.rand.nextLong();
long rand2 = this.rand.nextLong();
// 遍歷周圍(range*2+1)*(range*2+1)的區塊，默認range=8
for (int x = chunkX - range; x <= chunkX + range; ++x)
{
for (int z = chunkZ - range; z <= chunkZ + range; ++z)
{
long j1 = (long)x * rand1;
long k1 = (long)z * rand2;
this.rand.setSeed(j1 ^ k1 ^ worldIn.getSeed());
// 這個由子類實現
this.recursiveGenerate(worldIn, x, z, chunkX, chunkZ, chunkPrimerIn);
}
}
}類名net.minecraft.world.gen.MapGenCaves
public class MapGenCaves extends MapGenBase
{
// 挖洞，默認參數
protected void func_180703_a(long seed, int centerChunkX, int centerChunkZ, ChunkPrimer chunkPrimer, double seedPointX, double seedPointY, double seedPointZ)
{
this.func_180702_a(seed, centerChunkX, centerChunkZ, chunkPrimer, seedPointX, seedPointY, seedPointZ, 1.0F + this.rand.nextFloat() * 6.0F, 0.0F, 0.0F, -1, -1, 0.5D);
}
// 挖洞
protected void func_180702_a(long seed, int centerChunkX, int centerChunkZ, ChunkPrimer chunkPrimer, double seedPointX, double seedPointY, double seedPointZ, float rangeScale, float yawAngle, float pitchAngle, int smallRange, int bigRange, double heightScale)
{
double centerBlockX = (double)(centerChunkX * 16 + 8);
double centerBlockZ = (double)(centerChunkZ * 16 + 8);
float yawAngleOffset = 0.0F;
float pitchAngleOffset = 0.0F;
Random random = new Random(seed);
if (bigRange <= 0)
{
int tmp = (range - 1) * 16;
bigRange = tmp - random.nextInt(tmp / 4);
}
boolean smallRangeIsNull = false;
if (smallRange == -1)
{
smallRange = bigRange / 2;
smallRangeIsNull = true;
}
// 可能的擴展點
int keyPoint = random.nextInt(bigRange / 2) + bigRange / 4;
boolean flag = random.nextInt(6) == 0;
// 循環挖出一條道路
for (; smallRange < bigRange; ++smallRange)
{
// 用sin從1到0過渡
double xzRange = 1.5D + (double)(MathHelper.sin((float)smallRange * (float)Math.PI / (float)bigRange) * rangeScale);
double yRange = xzRange * heightScale;
// 向yawAngle、pitchAngle方向偏移一個單位
float cos = MathHelper.cos(pitchAngle);
float sin = MathHelper.sin(pitchAngle);
seedPointX += (double)(MathHelper.cos(yawAngle) * cos);
seedPointY += (double)sin;
seedPointZ += (double)(MathHelper.sin(yawAngle) * cos);
if (flag) // 1/6概率俯仰角衰減較慢
{
pitchAngle *= 0.92F;
}
else
{
pitchAngle *= 0.7F;
}
pitchAngle += pitchAngleOffset * 0.1F;
yawAngle += yawAngleOffset * 0.1F;
pitchAngleOffset *= 0.9F;
yawAngleOffset *= 0.75F;
pitchAngleOffset += (random.nextFloat() - random.nextFloat()) * random.nextFloat() * 2.0F;
yawAngleOffset += (random.nextFloat() - random.nextFloat()) * random.nextFloat() * 4.0F;
if ( !smallRangeIsNull
&& smallRange == keyPoint
&& rangeScale > 1.0F
&& bigRange > 0)
{
// 向左右兩邊擴展
this.func_180702_a(random.nextLong(), centerChunkX, centerChunkZ, chunkPrimer, seedPointX, seedPointY, seedPointZ, random.nextFloat() * 0.5F + 0.5F, yawAngle - ((float)Math.PI / 2F), pitchAngle / 3.0F, smallRange, bigRange, 1.0D);
this.func_180702_a(random.nextLong(), centerChunkX, centerChunkZ, chunkPrimer, seedPointX, seedPointY, seedPointZ, random.nextFloat() * 0.5F + 0.5F, yawAngle + ((float)Math.PI / 2F), pitchAngle / 3.0F, smallRange, bigRange, 1.0D);
return;
}
if (smallRangeIsNull || random.nextInt(4) != 0)
{
double _xDist = seedPointX - centerBlockX;
double _zDist = seedPointZ - centerBlockZ;
double restRange = (double)(bigRange - smallRange);
double range = (double)(rangeScale + 2.0F + 16.0F);
if (_xDist * _xDist + _zDist * _zDist - restRange * restRange > range * range)
{
return;
}
// 種子點在中心方塊附近（不在的話說明不在這個區塊內不用管）
if ( seedPointX >= centerBlockX - 16.0D - xzRange * 2.0D
&& seedPointZ >= centerBlockZ - 16.0D - xzRange * 2.0D
&& seedPointX <= centerBlockX + 16.0D + xzRange * 2.0D
&& seedPointZ <= centerBlockZ + 16.0D + xzRange * 2.0D)
{
int startX = MathHelper.floor_double(seedPointX - xzRange) - centerChunkX * 16 - 1;
int endX = MathHelper.floor_double(seedPointX + xzRange) - centerChunkX * 16 + 1;
int endY = MathHelper.floor_double(seedPointY - yRange) - 1;
int startY = MathHelper.floor_double(seedPointY + yRange) + 1;
int startZ = MathHelper.floor_double(seedPointZ - xzRange) - centerChunkZ * 16 - 1;
int endZ = MathHelper.floor_double(seedPointZ + xzRange) - centerChunkZ * 16 + 1;
// 限制座標範圍
if (startX < 0)
{
startX = 0;
}
if (endX > 16)
{
endX = 16;
}
if (endY < 1)
{
endY = 1;
}
if (startY > 248)
{
startY = 248;
}
if (startZ < 0)
{
startZ = 0;
}
if (endZ > 16)
{
endZ = 16;
}
// 判斷是不是海洋，如果在海洋則不生成洞穴
boolean isOcean = false;
for (int x = startX; !isOcean && x < endX; ++x)
{
for (int z = startZ; !isOcean && z < endZ; ++z)
{
for (int y = startY + 1; !isOcean && y >= endY - 1; --y)
{
if (y >= 0 && y < 256)
{
if (isOceanBlock(chunkPrimer, x, y, z, centerChunkX, centerChunkZ))
{
isOcean = true;
}
// 只判斷邊界
if ( y != endY - 1
&& x != startX
&& x != endX - 1
&& z != startZ
&& z != endZ - 1)
{
y = endY;
}
}
}
}
}
if (!isOcean)
{
// 挖掉一個橢球內的方塊
for (int x = startX; x < endX; ++x)
{
// （歸一化的距離）
double xDist = ((double)(x + centerChunkX * 16) + 0.5D - seedPointX) / xzRange;
for (int z = startZ; z < endZ; ++z)
{
double zDist = ((double)(z + centerChunkZ * 16) + 0.5D - seedPointZ) / xzRange;
boolean _isTopBlock = false;
// 平面上平方距離<1
if (xDist * xDist + zDist * zDist < 1.0D)
{
for (int y = startY; y > endY; --y)
{
double yDist = ((double)(y - 1) + 0.5D - seedPointY) / yRange;
// 空間平方距離<1
if (yDist > -0.7D && xDist * xDist + yDist * yDist + zDist * zDist < 1.0D)
{
IBlockState curBlock = chunkPrimer.getBlockState(x, y, z);
IBlockState upBlock = (IBlockState)Objects.firstNonNull(chunkPrimer.getBlockState(x, y + 1, z), Blocks.air.getDefaultState());
if (isTopBlock(chunkPrimer, x, y, z, centerChunkX, centerChunkZ))
{
_isTopBlock = true;
}
// 把這個方塊替換爲空氣或岩漿
digBlock(chunkPrimer, x, y, z, centerChunkX, centerChunkZ, _isTopBlock, curBlock, upBlock);
}
}
}
}
}
if (smallRangeIsNull)
{
break;
}
}
}
}
}
}
// 判斷是否可以挖開這個方塊
protected boolean func_175793_a(IBlockState curBlock, IBlockState upBlock)
{
return curBlock.getBlock() == Blocks.stone ? true :
(curBlock.getBlock() == Blocks.dirt ? true :
(curBlock.getBlock() == Blocks.grass ? true :
(curBlock.getBlock() == Blocks.hardened_clay ? true :
(curBlock.getBlock() == Blocks.stained_hardened_clay ? true :
(curBlock.getBlock() == Blocks.sandstone ? true :
(curBlock.getBlock() == Blocks.red_sandstone ? true :
(curBlock.getBlock() == Blocks.mycelium ? true :
(curBlock.getBlock() == Blocks.snow_layer ? true :
( curBlock.getBlock() == Blocks.sand
|| curBlock.getBlock() == Blocks.gravel)
&& upBlock.getBlock().getMaterial() != Material.water
))))))));
}
/**
* Recursively called by generate()
*/
protected void recursiveGenerate(World worldIn, int chunkX, int chunkZ, int centerChunkX, int centerChunkZ, ChunkPrimer chunkPrimerIn)
{
// 之前根據chunkXZ設置種子了
int seedPointCount = this.rand.nextInt(this.rand.nextInt(this.rand.nextInt(15) + 1) + 1);
// 1/7概率不生成洞穴
if (this.rand.nextInt(7) != 0)
{
seedPointCount = 0;
}
for (int i = 0; i < seedPointCount; ++i)
{
// 在chunk內y=8~127隨機選種子點
double seedPointX = (double)(chunkX * 16 + this.rand.nextInt(16));
double seedPointX = (double)this.rand.nextInt(this.rand.nextInt(120) + 8);
double seedPointZ = (double)(chunkZ * 16 + this.rand.nextInt(16));
int directionCount = 1;
if (this.rand.nextInt(4) == 0)
{
// 挖洞，默認參數
this.func_180703_a(this.rand.nextLong(), centerChunkX, centerChunkZ, chunkPrimerIn, seedPointX, seedPointX, seedPointZ);
directionCount += this.rand.nextInt(4);
}
// 向幾個方向挖洞
for (int j = 0; j < directionCount; ++j)
{
float yawAngle = this.rand.nextFloat() * (float)Math.PI * 2.0F;
float pitchAngle = (this.rand.nextFloat() - 0.5F) * 2.0F / 8.0F;
float rangeScale = this.rand.nextFloat() * 2.0F + this.rand.nextFloat();
if (this.rand.nextInt(10) == 0)
{
// 擴大到1~3倍
rangeScale *= this.rand.nextFloat() * this.rand.nextFloat() * 3.0F + 1.0F;
}
this.func_180702_a(this.rand.nextLong(), centerChunkX, centerChunkZ, chunkPrimerIn, seedPointX, seedPointX, seedPointZ, rangeScale, yawAngle, pitchAngle, 0, 0, 1.0D);
}
}
}
protected boolean isOceanBlock(ChunkPrimer data, int x, int y, int z, int chunkX, int chunkZ)
{
net.minecraft.block.Block block = data.getBlockState(x, y, z).getBlock();
return block== Blocks.flowing_water || block == Blocks.water;
}
//Exception biomes to make sure we generate like vanilla
private boolean isExceptionBiome(net.minecraft.world.biome.BiomeGenBase biome)
{
if (biome == net.minecraft.world.biome.BiomeGenBase.beach) return true;
if (biome == net.minecraft.world.biome.BiomeGenBase.desert) return true;
return false;
}
//Determine if the block at the specified location is the top block for the biome, we take into account
//Vanilla bugs to make sure that we generate the map the same way vanilla does.
private boolean isTopBlock(ChunkPrimer data, int x, int y, int z, int chunkX, int chunkZ)
{
net.minecraft.world.biome.BiomeGenBase biome = worldObj.getBiomeGenForCoords(new BlockPos(x + chunkX * 16, 0, z + chunkZ * 16));
IBlockState state = data.getBlockState(x, y, z);
return (isExceptionBiome(biome) ? state.getBlock() == Blocks.grass : state.getBlock() == biome.topBlock);
}
/**
* Digs out the current block, default implementation removes stone, filler, and top block
* Sets the block to lava if y is less then 10, and air other wise.
* If setting to air, it also checks to see if we've broken the surface and if so
* tries to make the floor the biome's top block
*
* @param data Block data array
* @param index Pre-calculated index into block data
* @param x local X position
* @param y local Y position
* @param z local Z position
* @param chunkX Chunk X position
* @param chunkZ Chunk Y position
* @param foundTop True if we've encountered the biome's top block. Ideally if we've broken the surface.
*/
protected void digBlock(ChunkPrimer data, int x, int y, int z, int chunkX, int chunkZ, boolean foundTop, IBlockState state, IBlockState up)
{
net.minecraft.world.biome.BiomeGenBase biome = worldObj.getBiomeGenForCoords(new BlockPos(x + chunkX * 16, 0, z + chunkZ * 16));
IBlockState top = biome.topBlock;
IBlockState filler = biome.fillerBlock;
if ( this.func_175793_a(state, up)
|| state.getBlock() == top.getBlock()
|| state.getBlock() == filler.getBlock())
{
if (y < 10) // y<10岩漿多應該是這個造成的
{
// 設置爲岩漿
data.setBlockState(x, y, z, Blocks.lava.getDefaultState());
}
else
{
// 設置爲空氣
data.setBlockState(x, y, z, Blocks.air.getDefaultState());
if (up.getBlock() == Blocks.sand)
{
// 如果上面的方塊是沙子則替換爲沙石
data.setBlockState(x, y + 1, z, up.getValue(BlockSand.VARIANT) == BlockSand.EnumType.RED_SAND ? Blocks.red_sandstone.getDefaultState() : Blocks.sandstone.getDefaultState());
}
if (foundTop && data.getBlockState(x, y - 1, z).getBlock() == filler.getBlock())
{
// 如果挖開了頂層方塊則把下面的方塊設置爲頂層方塊
data.setBlockState(x, y - 1, z, top.getBlock().getDefaultState());
}
}
}
}
}