Bukkit has an event which can be used to modify the result of mixing lava and water. I'm wondering if Forge has something similar. I don't see anything in net.minecraft,block.BlockLiquid.checkForMixing, but I thought I'd double check here before I try anything too complex.

 

My intention is to modify minecraft's behavior such that you can get granite etc. from a cobblestone generator.

 

Would this not be possible (but ugly) with an IWorldEventListener & overriding IWorldEventListener::notifyBlockUpdate? Would require some guess-work to make sure it was indeed placed by BlockLiquid::checkForMixing, but should be viable.

Edited December 25, 20177 yr by Matryoshika

It is possible; I've confirmed that this code has the desired effect:

public void notifyBlockUpdate(World worldIn, BlockPos pos, IBlockState oldState, IBlockState newState, int flags){
    if (oldState.getBlock() != Blocks.FLOWING_LAVA) return;
    if (newState.getBlock() != Blocks.COBBLESTONE) return;

    boolean adjacentToWater = false;
    if (worldIn.getBlockState(pos.north()).getMaterial() == Material.WATER) adjacentToWater = true;
    if (worldIn.getBlockState(pos.south()).getMaterial() == Material.WATER) adjacentToWater = true;
    if (worldIn.getBlockState(pos.east() ).getMaterial() == Material.WATER) adjacentToWater = true;
    if (worldIn.getBlockState(pos.west() ).getMaterial() == Material.WATER) adjacentToWater = true;
    if (worldIn.getBlockState(pos.down() ).getMaterial() == Material.WATER) adjacentToWater = true;
    if (worldIn.getBlockState(pos.up()   ).getMaterial() == Material.WATER) adjacentToWater = true;
    if(!adjacentToWater) return;

    worldIn.setBlockState(pos, Blocks.DIAMOND_BLOCK.getDefaultState());
}

But like you said, I'm using guess-work.

 

I would still be interested in submitting a PR - if my technical knowledge extended to all that "@@ -452,4 +452,29 @@" stuff in BlockLiquid.java.patch. I don't suppose anyone has suggestions for topics to google?

 

You don't write the patches yourself, you set up a Forge workspace, make your changes to the appropriate Vanilla classes and then run the genPatches Gradle task to re-generate the patches with your changes.

 

Forge's documentation explains how to contribute to Forge here and here.