feat: add structure void placeholders when loading structure file and add option to ignore structure void blocks on paste

Author: PierreSchwang

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/clipboard/io/schematic/MinecraftStructure.java

@@ -103,6 +103,9 @@ public Clipboard read(UUID clipboardId) throws IOException {
                 size.get(0).valueAsInt(), size.get(1).valueAsInt(), size.get(2).value()
         ).subtract(BlockVector3.ONE));
         final Clipboard clipboard = new BlockArrayClipboard(region, clipboardId);
+        // fill clipboard with structure void blocks to represent empty entries.
+        // known block data will be overridden with palette data.
+        clipboard.setBlocks((Region) region, BlockTypes.STRUCTURE_VOID.getDefaultState());
 
         // Palette
         final List<LinCompoundTag> paletteEntry = parent.getListTag("palette", LinTagType.compoundTag()).value();
@@ -204,6 +207,7 @@ public void write(Clipboard clipboard) throws IOException {
         Int2ObjectMap<BlockState> paletteIndexes = new Int2ObjectArrayMap<>();
         for (final BlockVector3 pos : clipboard) {
             final BlockState block = clipboard.getBlock(pos);
+            // Structure Void Blocks are not part of the structure file and therefor not part of the palette
             if (block.getBlockType() == BlockTypes.STRUCTURE_VOID || ordinals.containsKey(block.getOrdinalChar())) {
                 continue;
             }
@@ -226,6 +230,7 @@ public void write(Clipboard clipboard) throws IOException {
         LinListTag.Builder<@org.jetbrains.annotations.NotNull LinCompoundTag> blocks = LinListTag.builder(LinTagType.compoundTag());
         for (final BlockVector3 pos : clipboard) {
             final BaseBlock block = clipboard.getFullBlock(pos);
+            // Structure Void Blocks are not part of the structure file
             if (block.getBlockType() == BlockTypes.STRUCTURE_VOID) {
                 continue;
             }

worldedit-core/src/main/java/com/sk89q/worldedit/command/ClipboardCommands.java

@@ -58,6 +58,7 @@
 import com.sk89q.worldedit.extent.clipboard.io.ClipboardFormats;
 import com.sk89q.worldedit.extent.clipboard.io.ClipboardWriter;
 import com.sk89q.worldedit.function.block.BlockReplace;
+import com.sk89q.worldedit.function.mask.InverseSingleBlockTypeMask;
 import com.sk89q.worldedit.function.mask.Mask;
 import com.sk89q.worldedit.function.mask.MaskIntersection;
 import com.sk89q.worldedit.function.mask.Masks;
@@ -85,6 +86,7 @@
 import com.sk89q.worldedit.util.formatting.text.TextComponent;
 import com.sk89q.worldedit.util.formatting.text.event.ClickEvent;
 import com.sk89q.worldedit.world.World;
+import com.sk89q.worldedit.world.block.BlockTypes;
 import org.enginehub.piston.annotation.Command;
 import org.enginehub.piston.annotation.CommandContainer;
 import org.enginehub.piston.annotation.param.Arg;
@@ -526,14 +528,15 @@ public void paste(
                     Mask sourceMask,
             //FAWE start - entity removal
             @Switch(name = 'x', desc = "Remove existing entities in the affected region")
-                    boolean removeEntities
+                    boolean removeEntities,
+            @Switch(name = 'v', desc = "Don't paste structure void blocks and keep the target block state")
+                    boolean ignoreStructureVoidBlocks
             //FAWE end
-
     ) throws WorldEditException {
 
         ClipboardHolder holder = session.getClipboard();
         //FAWE start - use place
-        if (holder.getTransform().isIdentity() && sourceMask == null) {
+        if (holder.getTransform().isIdentity() && sourceMask == null && !ignoreStructureVoidBlocks) {
             place(actor, world, session, editSession, ignoreAirBlocks, atOrigin, selectPasted, onlySelect,
                     pasteEntities, pasteBiomes, removeEntities
             );
@@ -550,13 +553,16 @@ public void paste(
         //FAWE end
 
         if (!onlySelect) {
+            final Mask finalSourceMask = ignoreStructureVoidBlocks ?
+                    MaskIntersection.of(sourceMask, new InverseSingleBlockTypeMask(clipboard, BlockTypes.STRUCTURE_VOID)) :
+                    sourceMask;
             Operation operation = holder
                     .createPaste(editSession)
                     .to(to)
                     .ignoreAirBlocks(ignoreAirBlocks)
                     .copyBiomes(pasteBiomes)
                     .copyEntities(pasteEntities)
-                    .maskSource(sourceMask)
+                    .maskSource(finalSourceMask)
                     .build();
             Operations.completeLegacy(operation);
             messages.addAll(Lists.newArrayList(operation.getStatusMessages()));