fix: fluid flow using incorrect direction in bfs

#526
CaffeineMC · Jun 19, 2024 · dad1367 · dad1367
1 parent 1f97499
commit dad1367
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Showing 2 changed files with 9 additions and 2 deletions.
diff --git a/src/main/java/me/jellysquid/mods/lithium/common/util/DirectionConstants.java b/src/main/java/me/jellysquid/mods/lithium/common/util/DirectionConstants.java
@@ -11,4 +11,5 @@ private DirectionConstants() {}
     public static final Direction[] ALL = Direction.values();
     public static final Direction[] VERTICAL = {Direction.DOWN, Direction.UP};
     public static final Direction[] HORIZONTAL = {Direction.WEST, Direction.EAST, Direction.NORTH, Direction.SOUTH};
+    public static final byte[] HORIZONTAL_OPPOSITE_INDICES = {1, 0, 3, 2};
 }
diff --git a/src/main/java/me/jellysquid/mods/lithium/mixin/block/fluid/flow/FlowableFluidMixin.java b/src/main/java/me/jellysquid/mods/lithium/mixin/block/fluid/flow/FlowableFluidMixin.java
@@ -19,6 +19,7 @@
 import net.minecraft.util.math.Direction;
 import net.minecraft.world.BlockView;
 import net.minecraft.world.World;
+import net.minecraft.world.WorldAccess;
 import net.minecraft.world.WorldView;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Overwrite;
@@ -68,6 +69,9 @@ public abstract class FlowableFluidMixin {
     protected abstract boolean receivesFlow(Direction face, BlockView world, BlockPos pos, BlockState state, BlockPos fromPos, BlockState fromState);
 
 
+    @Shadow
+    protected abstract void flow(WorldAccess world, BlockPos pos, BlockState state, Direction direction, FluidState fluidState);
+
     @Unique
     private static int getNumIndicesFromRadius(int radius) {
         return (radius + 1) * (2 * radius + 1);
@@ -218,8 +222,10 @@ private void calculateComplexFluidFlowDirections(World world, BlockPos startPos,
 
                 for (int j = 0; j < DirectionConstants.HORIZONTAL.length; j++) {
                     Direction flowDirection = DirectionConstants.HORIZONTAL[j];
-                    if (((currentInfo >> 4) & (1 << ((j + 2) % 4))) != (byte) 0) {
-                        //In this direction is one of the disallowed directions, +2%4 to get opposite direction index
+                    int oppositeDirection = DirectionConstants.HORIZONTAL_OPPOSITE_INDICES[j];
+
+                    if (((currentInfo >> 4) & (1 << oppositeDirection)) != (byte) 0) {
+                        //In this direction is one of the disallowed directions
                         continue;
                     }
                     BlockPos flowTargetPos = currentPos.offset(flowDirection);