feat: implement basic liquid functions

api/src/main/java/org/allaymc/api/block/component/BlockBaseComponent.java

@@ -311,6 +311,20 @@ default double calculateBreakTime(BlockState blockState, ItemStack usedItem, Ent
         return 1d / speed;
     }
 
+    /**
+     * Check if a position on the side of the block placed in the world at a specific position is
+     * closed. When this returns true (for example, when the side is below the position and the block is a
+     * slab), liquid inside the block won't flow from pos into side.
+     *
+     * @param blockState the block to check.
+     * @param blockFace  the side of the block to check.
+     *
+     * @return {@code true} if the side is closed, {@code false} otherwise.
+     */
+    default boolean canLiquidFlowIntoSide(BlockState blockState, BlockFace blockFace) {
+        return true;
+    }
+
     private double speedBonusByEfficiency(int efficiencyLevel) {
         if (efficiencyLevel == 0) return 0;
         return efficiencyLevel * efficiencyLevel + 1;

api/src/main/java/org/allaymc/api/block/component/BlockLiquidBaseComponent.java

@@ -2,6 +2,7 @@
 
 import org.allaymc.api.block.property.type.BlockPropertyTypes;
 import org.allaymc.api.block.type.BlockState;
+import org.allaymc.api.block.type.BlockType;
 import org.allaymc.api.world.DimensionInfo;
 
 /**
@@ -11,41 +12,32 @@
  */
 public interface BlockLiquidBaseComponent extends BlockBaseComponent {
     /**
-     * Check if the liquid is flowing down.
+     * Check if the liquid is falling.
      *
      * @param blockState the block state to check.
      *
      * @return {@code true} if the liquid is flowing down, {@code false} otherwise.
      */
-    default boolean isFlowingDown(BlockState blockState) {
-        // The first bit of the liquid depth property is set to 1 if the liquid is flowing down.
+    static boolean isFalling(BlockState blockState) {
+        // The first bit of the liquid depth property is set to 1 if the liquid is falling
         return (blockState.getPropertyValue(BlockPropertyTypes.LIQUID_DEPTH) & 0b1000) == 0b1000;
     }
 
     /**
-     * Get the block state of the flowing down block.
-     *
-     * @return the block state of the flowing down block.
-     */
-    default BlockState getFlowingDownBlockState() {
-        return getBlockType().ofState(BlockPropertyTypes.LIQUID_DEPTH.createValue(0b1111));
-    }
-
-    /**
-     * Get the liquid level of the block.
+     * Get the liquid depth of the block.
      * <p>
-     * Flowing down blocks and source blocks have a liquid level of 8.
-     * Other blocks have a liquid level between 1 and 7.
+     * Falling blocks and source blocks have a liquid depth of 8.
+     * Other blocks have a liquid depth between 1 and 7.
      *
-     * @param blockState the block state to get the liquid level from.
+     * @param blockState the block state to get the liquid depth from.
      *
-     * @return the liquid level of the block.
+     * @return the liquid depth of the block.
      */
-    default int getLevel(BlockState blockState) {
-        if (isFlowingDown(blockState) || isSource(blockState)) {
+    static int getDepth(BlockState blockState) {
+        if (isFalling(blockState) || isSource(blockState)) {
             return 8;
         }
-        return blockState.getPropertyValue(BlockPropertyTypes.LIQUID_DEPTH) & 0b0111;
+        return 8 - blockState.getPropertyValue(BlockPropertyTypes.LIQUID_DEPTH) & 0b0111;
     }
 
     /**
@@ -55,10 +47,31 @@ default int getLevel(BlockState blockState) {
      *
      * @return {@code true} if the block state represents a liquid source, {@code false} otherwise.
      */
-    default boolean isSource(BlockState blockState) {
+    static boolean isSource(BlockState blockState) {
         return blockState.getPropertyValue(BlockPropertyTypes.LIQUID_DEPTH) == 0;
     }
 
+    /**
+     * Get the block state of the liquid block with given depth and falling state.
+     *
+     * @param depth   the depth of the liquid.
+     * @param falling {@code true} if the liquid is falling, {@code false} otherwise.
+     *
+     * @return the block state of the liquid block with given depth and falling state.
+     */
+    default BlockState getLiquidBlockState(int depth, boolean falling) {
+        return getBlockType().ofState(BlockPropertyTypes.LIQUID_DEPTH.createValue(falling ? 0b1000 | 8 - depth : 8 - depth));
+    }
+
+    /**
+     * Get the block state of the falling block.
+     *
+     * @return the block state of the falling block.
+     */
+    default BlockState getFallingBlockState() {
+        return getBlockType().ofState(BlockPropertyTypes.LIQUID_DEPTH.createValue(0b1000));
+    }
+
     /**
      * Get the block state of the source block.
      *
@@ -94,4 +107,13 @@ default BlockState getSourceBlockState() {
      * @return {@code true} if the block can become a source block, {@code false} otherwise.
      */
     boolean canFormSource();
+
+    /**
+     * Check if the given block type is the same liquid type as this block type.
+     *
+     * @param blockType the block type to check.
+     *
+     * @return {@code true} if the given block type is the same liquid type as this block type, {@code false} otherwise.
+     */
+    boolean isSameLiquidType(BlockType<?> blockType);
 }

api/src/main/java/org/allaymc/api/block/component/data/BlockStateData.java

@@ -16,6 +16,8 @@
 
 import java.awt.*;
 
+import static org.allaymc.api.block.component.data.LiquidReactionOnTouch.NOREACTION;
+
 /**
  * @author daoge_cmd | CoolLoong
  */
@@ -69,10 +71,10 @@ public class BlockStateData {
     @Builder.Default
     protected int burnOdds = 0;
     /**
-     * Whether the block state can contain liquid.
+     * Whether the block state can contain liquid source.
      */
     @Builder.Default
-    protected boolean canContainLiquid = false;
+    protected boolean canContainLiquidSource = false;
     /**
      * The reaction of this block state when liquid flow into.
      */
@@ -194,4 +196,13 @@ public VoxelShape computeOffsetShape(Vector3ic vector) {
     public boolean isTransparent() {
         return translucency() != 1.0f;
     }
+
+    /**
+     * Check if the block state can contain liquid, no matter it is liquid source or not.
+     *
+     * @return {@code true} if the block state can contain liquid, otherwise {@code false}.
+     */
+    public boolean canContainLiquid() {
+        return canContainLiquidSource || liquidReactionOnTouch == NOREACTION;
+    }
 }

api/src/main/java/org/allaymc/api/block/component/data/LiquidReactionOnTouch.java

@@ -14,10 +14,22 @@ public enum LiquidReactionOnTouch {
     POPPED,
     /**
      * The block will prevent the liquid from flowing into.
+     * Compared to {@link BlockStateData#canContainLiquidSource}, this only
+     * affects flowing liquid, not source liquid. That's mean the block
+     * may still can contain source liquid block.
      */
     BLOCKING,
     /**
      * The block won't have any reaction, also won't have any impact on the liquid just like air.
      */
-    NOREACTION
+    NOREACTION;
+
+    /**
+     * Check if the block should be removed when touched by liquid.
+     *
+     * @return true if the block should be removed when touched by liquid.
+     */
+    public boolean removedOnTouch() {
+        return this == BROKEN || this == POPPED;
+    }
 }

api/src/main/java/org/allaymc/api/math/voxelshape/VoxelShapes.java

@@ -9,8 +9,6 @@
 import java.util.EnumMap;
 import java.util.Map;
 
-import static org.allaymc.api.block.data.BlockFace.getBlockFaceByStairDirectionValue;
-
 /**
  * VoxelShapes contains some useful voxel shapes.
  *
@@ -41,7 +39,7 @@ public final class VoxelShapes {
 
     public static VoxelShape buildStairShape(BlockState stairBlockState) {
         var isDownwards = stairBlockState.getPropertyValue(BlockPropertyTypes.UPSIDE_DOWN_BIT);
-        var face = getBlockFaceByStairDirectionValue(stairBlockState.getPropertyValue(BlockPropertyTypes.WEIRDO_DIRECTION));
+        var face = BlockFace.getBlockFaceByStairDirectionValue(stairBlockState.getPropertyValue(BlockPropertyTypes.WEIRDO_DIRECTION));
         return isDownwards ? DOWNWARDS_STAIR_SHAPES.get(face) : UPWARDS_STAIR_SHAPES.get(face);
     }
 
@@ -50,7 +48,7 @@ public static VoxelShape buildLiquidShape(BlockState liquidBlockState) {
             throw new IllegalArgumentException("The liquidBlockState must implement BlockLiquidBaseComponent!");
         }
         return VoxelShape.builder()
-                .solid(0, 0, 0, 1, 0.125f * liquidBaseComponent.getLevel(liquidBlockState), 1)
+                .solid(0, 0, 0, 1, 0.125f * BlockLiquidBaseComponent.getDepth(liquidBlockState), 1)
                 .build();
     }
 }

data/src/main/java/org/allaymc/data/BlockStateDataProcessor.java

@@ -32,7 +32,7 @@ public static void main(String[] args) {
 
     public static class RawBlockStateData {
         public int burnOdds = 0;
-        public boolean canContainLiquid = false;
+        public boolean canContainLiquidSource;
         public String liquidReactionOnTouch;
         public float[] collisionShape;
         public float[] liquidClipShape;
@@ -57,7 +57,7 @@ public static class RawBlockStateData {
 
     public static class NewBlockStateData {
         public int burnOdds = 0;
-        public boolean canContainLiquid = false;
+        public boolean canContainLiquidSource;
         public String liquidReactionOnTouch;
         public float[] collisionShape;
         public float[] shape;
@@ -79,7 +79,7 @@ public static class NewBlockStateData {
         public static NewBlockStateData fromRaw(RawBlockStateData raw) {
             var data = new NewBlockStateData();
             data.burnOdds = raw.burnOdds;
-            data.canContainLiquid = raw.canContainLiquid;
+            data.canContainLiquidSource = raw.canContainLiquidSource;
             data.liquidReactionOnTouch = raw.liquidReactionOnTouch;
             data.collisionShape = clampShape(raw.collisionShape);
             data.hardness = raw.hardness;

server/src/main/java/org/allaymc/server/block/component/BlockLavaBaseComponentImpl.java

@@ -30,6 +30,11 @@ public BlockLavaBaseComponentImpl(BlockType<? extends BlockBehavior> blockType)
         super(blockType);
     }
 
+    @Override
+    public boolean isSameLiquidType(BlockType<?> blockType) {
+        return blockType == BlockTypes.LAVA || blockType == BlockTypes.FLOWING_LAVA;
+    }
+
     @Override
     public void onCollideWithEntity(BlockStateWithPos blockStateWithPos, Entity entity) {
         if (!(entity instanceof EntityDamageComponent damageComponent)) {