Made GroundScatterFunction use a NoiseGenerator.

src/main/java/com/sk89q/worldedit/EditSession.java

@@ -2662,12 +2662,16 @@ public class EditSession {
             throws WorldEditException {
 
         ForestGenerator generator = new ForestGenerator(this, treeGenerator);
-        generator.setRange(lowerY, upperY);
-        generator.setDensity(density);
+
+        // And we want to scatter them
+        GroundScatterFunction scatter = new GroundScatterFunction(this, generator);
+        scatter.setDensity(density);
+        scatter.setRange(lowerY, upperY);
+
         int affected = 0;
 
         for (Vector2D pt : it) {
-            if (generator.apply(pt)) {
+            if (scatter.apply(pt)) {
                 affected++;
             }
         }

src/main/java/com/sk89q/worldedit/commands/RegionCommands.java

@@ -543,11 +543,16 @@ public class RegionCommands {
 
         Region region = session.getSelection(player.getWorld());
 
-        ForestGenerator function = new ForestGenerator(editSession, new TreeGenerator(type));
-        function.setRange(region);
-        function.setDensity(density);
+        // We want to generate trees
+        ForestGenerator generator = new ForestGenerator(editSession, new TreeGenerator(type));
 
-        FlatRegionApplicator operation = new FlatRegionApplicator(region, function);
+        // And we want to scatter them
+        GroundScatterFunction scatter = new GroundScatterFunction(editSession, generator);
+        scatter.setDensity(density);
+        scatter.setRange(region);
+
+        // Generate that forest
+        FlatRegionApplicator operation = new FlatRegionApplicator(region, scatter);
         OperationHelper.complete(operation);
 
         player.print(operation.getAffected() + " trees created.");

src/main/java/com/sk89q/worldedit/generator/ForestGenerator.java

@@ -20,17 +20,18 @@
 package com.sk89q.worldedit.generator;
 
 import com.sk89q.worldedit.EditSession;
-import com.sk89q.worldedit.MaxChangedBlocksException;
 import com.sk89q.worldedit.Vector;
+import com.sk89q.worldedit.WorldEditException;
 import com.sk89q.worldedit.blocks.BaseBlock;
 import com.sk89q.worldedit.blocks.BlockID;
+import com.sk89q.worldedit.operation.RegionFunction;
 import com.sk89q.worldedit.util.TreeGenerator;
 
 /**
  * Generates forests by searching for the ground starting from the given upper Y
  * coordinate for every column given.
  */
-public class ForestGenerator extends GroundGenerator {
+public class ForestGenerator implements RegionFunction {
 
     private final TreeGenerator treeGenerator;
     private final EditSession editSession;
@@ -42,25 +43,23 @@ public class ForestGenerator extends GroundGenerator {
      * @param treeGenerator a tree generator
      */
     public ForestGenerator(EditSession editSession, TreeGenerator treeGenerator) {
-        super(editSession);
         this.editSession = editSession;
         this.treeGenerator = treeGenerator;
     }
 
     @Override
-    protected boolean apply(Vector pt, BaseBlock block) throws MaxChangedBlocksException {
+    public boolean apply(Vector position) throws WorldEditException {
+        BaseBlock block = editSession.getBlock(position);
         int t = block.getType();
 
         if (t == BlockID.GRASS || t == BlockID.DIRT) {
-            treeGenerator.generate(editSession, pt.add(0, 1, 0));
+            treeGenerator.generate(editSession, position.add(0, 1, 0));
             return true;
         } else if (t == BlockID.SNOW) {
-            editSession.setBlock(pt, new BaseBlock(BlockID.AIR));
+            editSession.setBlock(position, new BaseBlock(BlockID.AIR));
             return false;
         } else { // Trees won't grow on this!
             return false;
         }
     }
-
-
 }

src/main/java/com/sk89q/worldedit/generator/GroundGenerator.java

@@ -1,67 +0,0 @@
-/*
- * WorldEdit, a Minecraft world manipulation toolkit
- * Copyright (C) sk89q <http://www.sk89q.com>
- * Copyright (C) WorldEdit team and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-package com.sk89q.worldedit.generator;
-
-import com.sk89q.worldedit.EditSession;
-import com.sk89q.worldedit.Vector2D;
-import com.sk89q.worldedit.operation.GroundFindingFunction;
-
-/**
- * An abstract implementation for generators.
- */
-public abstract class GroundGenerator extends GroundFindingFunction {
-
-    private double density;
-
-    /**
-     * Create a new instance.
-     *
-     * @param editSession the edit session
-     */
-    protected GroundGenerator(EditSession editSession) {
-        super(editSession);
-    }
-
-    /**
-     * Set the density (0 <= density <= 1) which indicates the percentage chance
-     * that an object will spawn in each column.
-     *
-     * @return the density
-     */
-    public double getDensity() {
-        return density;
-    }
-
-    /**
-     * Get the density (0 <= density <= 1) which indicates the percentage chance
-     * that an object will spawn in each column.
-     *
-     * @param density the density
-     */
-    public void setDensity(double density) {
-        this.density = density;
-    }
-
-    @Override
-    protected boolean shouldContinue(Vector2D pt) {
-        return Math.random() < density;
-    }
-
-}

src/main/java/com/sk89q/worldedit/noise/NoiseGenerator.java

@@ -0,0 +1,46 @@
+/*
+ * WorldEdit, a Minecraft world manipulation toolkit
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldEdit team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.noise;
+
+import com.sk89q.worldedit.Vector;
+import com.sk89q.worldedit.Vector2D;
+
+/**
+ * Generates noise in a deterministic or non-deterministic manner.
+ */
+public interface NoiseGenerator {
+
+    /**
+     * Get the noise for the given position.
+     *
+     * @param position the position
+     * @return a noise value between 0 (inclusive) and 1 (inclusive)
+     */
+    float noise(Vector2D position);
+
+    /**
+     * Get the noise for the given position.
+     *
+     * @param position the position
+     * @return a noise value between 0 (inclusive) and 1 (inclusive)
+     */
+    float noise(Vector position);
+
+}

src/main/java/com/sk89q/worldedit/noise/RandomNoise.java

@@ -0,0 +1,61 @@
+/*
+ * WorldEdit, a Minecraft world manipulation toolkit
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldEdit team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.noise;
+
+import com.sk89q.worldedit.Vector;
+import com.sk89q.worldedit.Vector2D;
+
+import java.util.Random;
+
+/**
+ * Generates noise non-deterministically using {@link java.util.Random}.
+ */
+public class RandomNoise implements NoiseGenerator {
+
+    private final Random random;
+
+    /**
+     * Create a new noise generator using the given <code>Random</code>.
+     *
+     * @param random the random instance
+     */
+    public RandomNoise(Random random) {
+        this.random = random;
+    }
+
+    /**
+     * Create a new noise generator with a newly constructed <code>Random</code>
+     * instance.
+     */
+    public RandomNoise() {
+        this(new Random());
+    }
+
+    @Override
+    public float noise(Vector2D position) {
+        return random.nextFloat();
+    }
+
+    @Override
+    public float noise(Vector position) {
+        return random.nextFloat();
+    }
+
+}

src/main/java/com/sk89q/worldedit/operation/GroundScatterFunction.java

@@ -21,18 +21,32 @@ package com.sk89q.worldedit.operation;
 
 import com.sk89q.worldedit.EditSession;
 import com.sk89q.worldedit.Vector;
+import com.sk89q.worldedit.Vector2D;
 import com.sk89q.worldedit.WorldEditException;
 import com.sk89q.worldedit.blocks.BaseBlock;
-import com.sk89q.worldedit.generator.GroundGenerator;
+import com.sk89q.worldedit.noise.NoiseGenerator;
+import com.sk89q.worldedit.noise.RandomNoise;
 
 /**
  * Randomly applies the given {@link RegionFunction} onto random ground blocks.
  * <p>
  * This class can be used to generate a structure randomly over an area.
  */
-public class GroundScatterFunction extends GroundGenerator {
+public class GroundScatterFunction extends GroundFindingFunction {
 
+    private NoiseGenerator noiseGenerator;
     private RegionFunction function;
+    private double density;
+
+    /**
+     * Create a new instance using a {@link RandomNoise} as the noise generator.
+     *
+     * @param editSession the edit session
+     * @param function the function
+     */
+    public GroundScatterFunction(EditSession editSession, RegionFunction function) {
+        this(editSession, function, new RandomNoise());
+    }
 
     /**
      * Create a new instance.
@@ -40,9 +54,48 @@ public class GroundScatterFunction extends GroundGenerator {
      * @param editSession the edit session
      * @param function the function
      */
-    public GroundScatterFunction(EditSession editSession, RegionFunction function) {
+    public GroundScatterFunction(EditSession editSession, RegionFunction function, NoiseGenerator noiseGenerator) {
         super(editSession);
         this.function = function;
+        this.noiseGenerator = noiseGenerator;
+    }
+
+    /**
+     * Get the density (0 <= density <= 1) which indicates the threshold that
+     * must be met for the function to be applied to a column.
+     *
+     * @return the density
+     */
+    public double getDensity() {
+        return density;
+    }
+
+    /**
+     * Set the density (0 <= density <= 1) which indicates the threshold that
+     * must be met for the function to be applied to a column.
+     *
+     * @param density the density
+     */
+    public void setDensity(double density) {
+        this.density = density;
+    }
+
+    /**
+     * Get the noise generator.
+     *
+     * @return the noise generator
+     */
+    public NoiseGenerator getNoiseGenerator() {
+        return noiseGenerator;
+    }
+
+    /**
+     * Set the noise generator.
+     *
+     * @param noiseGenerator the noise generator
+     */
+    public void setNoiseGenerator(NoiseGenerator noiseGenerator) {
+        this.noiseGenerator = noiseGenerator;
     }
 
     /**
@@ -63,6 +116,11 @@ public class GroundScatterFunction extends GroundGenerator {
         this.function = function;
     }
 
+    @Override
+    protected boolean shouldContinue(Vector2D pt) {
+        return noiseGenerator.noise(pt) <= density;
+    }
+
     @Override
     protected boolean apply(Vector position, BaseBlock block) throws WorldEditException {
         return function.apply(position);