#621: Add Block#getCollisionShape and associated API

By: konsolas <vincentyntang@gmail.com>

paper-api/src/main/java/org/bukkit/block/Block.java

@@ -15,6 +15,7 @@ import org.bukkit.metadata.Metadatable;
 import org.bukkit.util.BoundingBox;
 import org.bukkit.util.RayTraceResult;
 import org.bukkit.util.Vector;
+import org.bukkit.util.VoxelShape;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -501,4 +502,13 @@ public interface Block extends Metadatable {
      */
     @NotNull
     BoundingBox getBoundingBox();
+
+    /**
+     * Gets the collision shape of this block.
+     *
+     * @return a {@link VoxelShape} representing the collision shape of this
+     * block.
+     */
+    @NotNull
+    VoxelShape getCollisionShape();
 }

paper-api/src/main/java/org/bukkit/util/VoxelShape.java

@@ -0,0 +1,30 @@
+package org.bukkit.util;
+
+import java.util.Collection;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A shape made out of voxels.
+ *
+ * For example, used to represent the detailed collision shape of blocks.
+ */
+public interface VoxelShape {
+
+    /**
+     * Converts this shape into a collection of {@link BoundingBox} equivalent
+     * to the shape: a bounding box intersects with this block shape if it
+     * intersects with any of the shape's bounding boxes.
+     *
+     * @return shape converted to bounding boxes
+     */
+    @NotNull
+    public Collection<BoundingBox> getBoundingBoxes();
+
+    /**
+     * Checks if the given bounding box intersects this block shape.
+     *
+     * @param other bounding box to test
+     * @return true if other overlaps this, false otherwise
+     */
+    public boolean overlaps(@NotNull BoundingBox other);
+}