builder stuff, fixes #1059

src/api/java/baritone/api/Settings.java

@@ -184,6 +184,20 @@ public final class Settings {
             Blocks.WALL_SIGN
     )));
 
+    /**
+     * A list of blocks to be treated as if they're air.
+     * <p>
+     * If a schematic asks for air at a certain position, and that position currently contains a block on this list, it will be treated as correct.
+     */
+    public final Setting<List<Block>> buildIgnoreBlocks = new Setting<>(new ArrayList<>(Arrays.asList(
+
+    )));
+
+    /**
+     * If this is true, the builder will treat all non-air blocks as correct. It will only place new blocks.
+     */
+    public final Setting<Boolean> buildIgnoreExisting = new Setting<>(true);
+
     /**
      * If this setting is true, Baritone will never break a block that is adjacent to an unsupported falling block.
      * <p>

src/main/java/baritone/process/BuilderProcess.java

@@ -764,11 +764,20 @@ public final class BuilderProcess extends BaritoneProcessHelper implements IBuil
     }
 
     private boolean valid(IBlockState current, IBlockState desired) {
+        if (desired == null) {
+            return true;
+        }
         // TODO more complicated comparison logic I guess
         if (current.getBlock() instanceof BlockLiquid && Baritone.settings().okIfWater.value) {
             return true;
         }
-        return desired == null || current.equals(desired);
+        if (desired.getBlock() instanceof BlockAir && Baritone.settings().buildIgnoreBlocks.value.contains(current.getBlock())) {
+            return true;
+        }
+        if (!(current.getBlock() instanceof BlockAir) && Baritone.settings().buildIgnoreExisting.value) {
+            return true;
+        }
+        return current.equals(desired);
     }
 
     public class BuilderCalculationContext extends CalculationContext {