Add API to get the collision shape of a block before it's placed (#9821)

* Add API to get the collision shape of a block before it's placed

* Tweak API documentation

* Clarify behavior

* Rebase

* Rebase

2 files changed, 63 insertions, 0 deletions

diff --git a/patches/api/0443-Add-API-to-get-the-collision-shape-of-a-block-before.patch b/patches/api/0443-Add-API-to-get-the-collision-shape-of-a-block-before.patch
new file mode 100644
index 0000000000..8c93339e29
--- /dev/null
+++ b/patches/api/0443-Add-API-to-get-the-collision-shape-of-a-block-before.patch
@@ -0,0 +1,31 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: TrollyLoki <[email protected]>
+Date: Wed, 11 Oct 2023 00:45:54 -0400
+Subject: [PATCH] Add API to get the collision shape of a block before it's
+ placed
+
+
+diff --git a/src/main/java/org/bukkit/block/data/BlockData.java b/src/main/java/org/bukkit/block/data/BlockData.java
+index 31111cea5ffd018c3c011c1f3b8befbbd33db5e5..66903e0fa65052ede789a163dad723ba05a2cc8c 100644
+--- a/src/main/java/org/bukkit/block/data/BlockData.java
++++ b/src/main/java/org/bukkit/block/data/BlockData.java
+@@ -204,6 +204,19 @@ public interface BlockData extends Cloneable {
+      */
+     boolean isFaceSturdy(@NotNull BlockFace face, @NotNull BlockSupport support);
+ 
++    // Paper start
++    /**
++     * Calculates the collision shape this block data would have at a particular location.
++     * <p>
++     * This does not take into account any block updates that may occur if the block was to be actually placed in the world.
++     *
++     * @param location the location to calculate the collision shape at
++     *
++     * @return a {@link org.bukkit.util.VoxelShape} representing the collision shape of this block data.
++     */
++    @NotNull org.bukkit.util.VoxelShape getCollisionShape(@NotNull Location location);
++    // Paper end
++
+     /**
+      * Gets the material that a player would use to place this block.
+      * <p>
diff --git a/patches/server/1041-Add-API-to-get-the-collision-shape-of-a-block-before.patch b/patches/server/1041-Add-API-to-get-the-collision-shape-of-a-block-before.patch
new file mode 100644
index 0000000000..1db7a2132f
--- /dev/null
+++ b/patches/server/1041-Add-API-to-get-the-collision-shape-of-a-block-before.patch
@@ -0,0 +1,32 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: TrollyLoki <[email protected]>
+Date: Wed, 11 Oct 2023 00:45:53 -0400
+Subject: [PATCH] Add API to get the collision shape of a block before it's
+ placed
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/block/data/CraftBlockData.java b/src/main/java/org/bukkit/craftbukkit/block/data/CraftBlockData.java
+index 0bf863f597f3657a0f158756a2a91bda7eb453f6..2a9dba6d4a94f1488ef9d86ee4f60b7fd06419fb 100644
+--- a/src/main/java/org/bukkit/craftbukkit/block/data/CraftBlockData.java
++++ b/src/main/java/org/bukkit/craftbukkit/block/data/CraftBlockData.java
+@@ -669,6 +669,20 @@ public class CraftBlockData implements BlockData {
+         return this.state.isFaceSturdy(EmptyBlockGetter.INSTANCE, BlockPos.ZERO, CraftBlock.blockFaceToNotch(face), CraftBlockSupport.toNMS(support));
+     }
+ 
++    // Paper start
++    @Override
++    public org.bukkit.util.VoxelShape getCollisionShape(Location location) {
++        Preconditions.checkArgument(location != null, "location must not be null");
++
++        CraftWorld world = (CraftWorld) location.getWorld();
++        Preconditions.checkArgument(world != null, "location must not have a null world");
++
++        BlockPos position = CraftLocation.toBlockPosition(location);
++        net.minecraft.world.phys.shapes.VoxelShape shape = this.state.getCollisionShape(world.getHandle(), position);
++        return new org.bukkit.craftbukkit.util.CraftVoxelShape(shape);
++    }
++    // Paper end
++
+     @Override
+     public Material getPlacementMaterial() {
+         return CraftMagicNumbers.getMaterial(this.state.getBlock().asItem());