Update Upstream

ed28089 Don't crash if fields are null in ChunkDeleter (1874)
f049d56 Revert "Use a Guava Cache instead of a ThreadLocal (1859)"
c5a4450 Internally use a negated mask class to prevent russian doll wrapping (1877)
1397ec7 Add Snow Smooth Tools (1580)

Fixes #955
Fixes #858

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

@@ -79,6 +79,7 @@ import com.sk89q.worldedit.command.tool.brush.HollowCylinderBrush;
 import com.sk89q.worldedit.command.tool.brush.HollowSphereBrush;
 import com.sk89q.worldedit.command.tool.brush.OperationFactoryBrush;
 import com.sk89q.worldedit.command.tool.brush.SmoothBrush;
+import com.sk89q.worldedit.command.tool.brush.SnowSmoothBrush;
 import com.sk89q.worldedit.command.tool.brush.SphereBrush;
 import com.sk89q.worldedit.command.util.CommandPermissions;
 import com.sk89q.worldedit.command.util.CommandPermissionsConditionGenerator;
@@ -1292,20 +1293,65 @@ public class BrushCommands {
     @CommandPermissions("worldedit.brush.smooth")
     public void smoothBrush(
             Player player, LocalSession session,
+            //FAWE start - Expression > double
             @Arg(desc = "The radius to sample for softening", def = "2")
                     Expression radius,
+            //FAWE end
             @Arg(desc = "The number of iterations to perform", def = "4")
                     int iterations,
             @Arg(desc = "The mask of blocks to use for the heightmap", def = "")
-                    Mask maskOpt,
+                    Mask mask,
             InjectedValueAccess context
     ) throws WorldEditException {
         worldEdit.checkMaxBrushRadius(radius);
 
+        //FAWE start
         FaweLimit limit = Settings.IMP.getLimit(player);
         iterations = Math.min(limit.MAX_ITERATIONS, iterations);
+        //FAWE end
 
-        set(context, new SmoothBrush(iterations, maskOpt)).setSize(radius);
+        set(context, new SmoothBrush(iterations, mask)).setSize(radius);
+        player.print(Caption.of(
+                "worldedit.brush.smooth.equip",
+                radius,
+                iterations,
+                Caption.of("worldedit.brush.smooth." + (mask == null ? "no" : "") + "filter")
+        ));
+    }
+
+    @Command(
+            name = "snowsmooth",
+            desc = "Choose the snow terrain softener brush",
+            descFooter = "Example: '/brush snowsmooth 5 1 -l 3'"
+    )
+    @CommandPermissions("worldedit.brush.snowsmooth")
+    public void snowSmoothBrush(
+            Player player, LocalSession session,
+            //FAWE start - Expression > double
+            @Arg(desc = "The radius to sample for softening", def = "2")
+                    Expression radius,
+            //FAWE end
+            @Arg(desc = "The number of iterations to perform", def = "4")
+                    int iterations,
+            @ArgFlag(name = 'l', desc = "The number of snow blocks under snow", def = "1")
+                    int snowBlockCount,
+            @ArgFlag(name = 'm', desc = "The mask of blocks to use for the heightmap")
+                    Mask mask, InjectedValueAccess context
+    ) throws WorldEditException {
+        worldEdit.checkMaxBrushRadius(radius);
+
+        //FAWE start
+        FaweLimit limit = Settings.IMP.getLimit(player);
+        iterations = Math.min(limit.MAX_ITERATIONS, iterations);
+        //FAWE end
+
+        set(context, new SnowSmoothBrush(iterations, mask)).setSize(radius);
+        player.print(Caption.of(
+                "worldedit.brush.smooth.equip",
+                radius,
+                iterations,
+                Caption.of("worldedit.brush.smooth." + (mask == null ? "no" : "") + "filter")
+        ));
     }
 
     @Command(

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

@@ -55,6 +55,7 @@ import com.sk89q.worldedit.math.Vector3;
 import com.sk89q.worldedit.math.convolution.GaussianKernel;
 import com.sk89q.worldedit.math.convolution.HeightMap;
 import com.sk89q.worldedit.math.convolution.HeightMapFilter;
+import com.sk89q.worldedit.math.convolution.SnowHeightMap;
 import com.sk89q.worldedit.math.noise.RandomNoise;
 import com.sk89q.worldedit.regions.ConvexPolyhedralRegion;
 import com.sk89q.worldedit.regions.CuboidRegion;
@@ -466,9 +467,7 @@ public class RegionCommands {
             @Arg(desc = "# of iterations to perform", def = "1")
                     int iterations,
             @Arg(desc = "The mask of blocks to use as the height map", def = "")
-                    Mask mask,
-            @Switch(name = 's', desc = "The flag makes it only consider snow")
-                    boolean snow
+                    Mask mask
     ) throws WorldEditException {
         //FAWE start > the mask will have been initialised with a WorldWrapper extent (very bad/slow)
         if (mask instanceof AbstractExtentMask) {
@@ -485,7 +484,7 @@ public class RegionCommands {
         }
         int affected;
         try {
-            HeightMap heightMap = new HeightMap(editSession, region, mask, snow);
+            HeightMap heightMap = new HeightMap(editSession, region, mask);
             HeightMapFilter filter = new HeightMapFilter(new GaussianKernel(5, 1.0));
             affected = heightMap.applyFilter(filter, iterations);
             actor.print(Caption.of("worldedit.smooth.changed", TextComponent.of(affected)));
@@ -527,6 +526,31 @@ public class RegionCommands {
         }
     }
 
+    @Command(
+            name = "/snowsmooth",
+            desc = "Smooth the elevation in the selection with snow layers",
+            descFooter = "Example: '//snowsmooth 1 -m snow_block,snow' would only smooth snow terrain."
+    )
+    @CommandPermissions("worldedit.region.snowsmooth")
+    @Logging(REGION)
+    @Preload(Preload.PreloadCheck.PRELOAD)
+    @Confirm(Confirm.Processor.REGION)
+    public int snowSmooth(
+            Actor actor, EditSession editSession, @Selection Region region,
+            @Arg(desc = "# of iterations to perform", def = "1")
+                    int iterations,
+            @ArgFlag(name = 'l', desc = "Set the amount of snow blocks under the snow", def = "1")
+                    int snowBlockCount,
+            @ArgFlag(name = 'm', desc = "The mask of blocks to use as the height map")
+                    Mask mask
+    ) throws WorldEditException {
+        SnowHeightMap heightMap = new SnowHeightMap(editSession, region, mask);
+        HeightMapFilter filter = new HeightMapFilter(new GaussianKernel(5, 1.0));
+        float[] changed = heightMap.applyFilter(filter, iterations);
+        int affected = heightMap.applyChanges(changed, snowBlockCount);
+        actor.printInfo(Caption.of("worldedit.snowsmooth.changed", TextComponent.of(affected)));
+        return affected;
+    }
 
     @Command(
             name = "/move",

worldedit-core/src/main/java/com/sk89q/worldedit/command/tool/brush/SnowSmoothBrush.java

@@ -0,0 +1,69 @@
+/*
+ * 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 <https://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.command.tool.brush;
+
+import com.sk89q.worldedit.EditSession;
+import com.sk89q.worldedit.MaxChangedBlocksException;
+import com.sk89q.worldedit.function.mask.Mask;
+import com.sk89q.worldedit.function.pattern.Pattern;
+import com.sk89q.worldedit.math.BlockVector3;
+import com.sk89q.worldedit.math.Vector3;
+import com.sk89q.worldedit.math.convolution.GaussianKernel;
+import com.sk89q.worldedit.math.convolution.HeightMapFilter;
+import com.sk89q.worldedit.math.convolution.SnowHeightMap;
+import com.sk89q.worldedit.regions.CuboidRegion;
+import com.sk89q.worldedit.regions.Region;
+
+import javax.annotation.Nullable;
+
+public class SnowSmoothBrush implements Brush {
+
+    private final Mask mask;
+    private final int iterations;
+    private final int snowBlockLayer;
+
+    public SnowSmoothBrush(int iterations) {
+        this(iterations, null);
+    }
+
+    public SnowSmoothBrush(int iterations, @Nullable Mask mask) {
+        this(iterations, 1, mask);
+    }
+
+    public SnowSmoothBrush(int iterations, int snowBlockLayer, @Nullable Mask mask) {
+        this.iterations = iterations;
+        this.mask = mask;
+        this.snowBlockLayer = snowBlockLayer;
+    }
+
+    @Override
+    public void build(EditSession editSession, BlockVector3 position, Pattern pattern, double size) throws
+            MaxChangedBlocksException {
+        Vector3 posDouble = position.toVector3();
+        BlockVector3 min = posDouble.subtract(size, size, size).toBlockPoint();
+        BlockVector3 max = posDouble.add(size, size + 10, size).toBlockPoint();
+        Region region = new CuboidRegion(editSession.getWorld(), min, max);
+        SnowHeightMap heightMap = new SnowHeightMap(editSession, region, mask);
+        HeightMapFilter filter = new HeightMapFilter(new GaussianKernel(10, 1.0));
+        float[] data = heightMap.applyFilter(filter, iterations);
+        heightMap.applyChanges(data, snowBlockLayer);
+    }
+
+}

worldedit-core/src/main/java/com/sk89q/worldedit/function/mask/Mask.java

@@ -86,6 +86,8 @@ public interface Mask {
             return Masks.ALWAYS_FALSE;
         } else if (this instanceof Masks.AlwaysFalse) {
             return Masks.ALWAYS_TRUE;
+        } else if (this instanceof Masks.NegatedMask) {
+            return ((Masks.NegatedMask) this).mask;
         }
         return new InverseMask(this);
     }

worldedit-core/src/main/java/com/sk89q/worldedit/function/mask/Masks.java

@@ -61,6 +61,7 @@ public final class Masks {
         return ALWAYS_TRUE;
     }
 
+    //FAWE start
     /**
      * Negate the given mask.
      *
@@ -70,6 +71,7 @@ public final class Masks {
     public static Mask negate(final Mask mask) {
         return mask.inverse();
     }
+    //FAWE end
 
     /**
      * Negate the given mask.
@@ -82,20 +84,12 @@ public final class Masks {
             return ALWAYS_FALSE;
         } else if (mask instanceof AlwaysFalse) {
             return ALWAYS_TRUE;
+        } else if (mask instanceof NegatedMask2D) {
+            return ((NegatedMask2D) mask).mask;
         }
 
         checkNotNull(mask);
-        return new AbstractMask2D() {
-            @Override
-            public boolean test(BlockVector2 vector) {
-                return !mask.test(vector);
-            }
-
-            @Override
-            public Mask2D copy2D() {
-                return Masks.negate(mask.copy2D());
-            }
-        };
+        return new NegatedMask2D(mask);
     }
 
     /**
@@ -216,4 +210,58 @@ public final class Masks {
 
     }
 
+    //FAWE start - protected > private
+    protected static class NegatedMask implements Mask {
+    //FAWE end
+        protected final Mask mask;
+
+        private NegatedMask(Mask mask) {
+            this.mask = mask;
+        }
+
+        @Override
+        public boolean test(BlockVector3 vector) {
+            return !mask.test(vector);
+        }
+
+        @Nullable
+        @Override
+        public Mask2D toMask2D() {
+            Mask2D mask2D = mask.toMask2D();
+            if (mask2D == null) {
+                return null;
+            }
+            return negate(mask2D);
+        }
+
+        //FAWE start
+        @Override
+        public Mask copy() {
+            return Masks.negate(mask.copy());
+        }
+        //FAWE end
+
+    }
+
+    private static class NegatedMask2D implements Mask2D {
+        private final Mask2D mask;
+
+        private NegatedMask2D(Mask2D mask) {
+            this.mask = mask;
+        }
+
+        @Override
+        public boolean test(BlockVector2 vector) {
+            return !mask.test(vector);
+        }
+
+        //FAWE start
+        @Override
+        public Mask2D copy2D() {
+            return Masks.negate(mask.copy2D());
+        }
+        //FAWE end
+
+    }
+
 }

worldedit-core/src/main/java/com/sk89q/worldedit/internal/anvil/ChunkDeleter.java

@@ -58,7 +58,7 @@ public final class ChunkDeleter {
     );
 
     private static final Gson chunkDeleterGson = new GsonBuilder()
-            .registerTypeAdapter(BlockVector2.class, new BlockVector2Adapter())
+            .registerTypeAdapter(BlockVector2.class, new BlockVector2Adapter().nullSafe())
             .setPrettyPrinting()
             .create();
 

worldedit-core/src/main/java/com/sk89q/worldedit/math/convolution/HeightMap.java

@@ -180,7 +180,7 @@ public class HeightMap {
         System.arraycopy(data, 0, newData, 0, data.length);
 
         for (int i = 0; i < iterations; ++i) {
-            newData = filter.filter(newData, width, height);
+            newData = filter.filter(newData, width, height, 0.5F);
         }
 
         //FAWE start - check layers
@@ -229,7 +229,7 @@ public class HeightMap {
                     BlockStateHolder<BlockState> existing = session.getBlock(xr, curBlock, zr);
 
                     // Skip water/lava
-                    if (existing.getBlockType().getMaterial().isMovementBlocker()) {
+                    if (!existing.getBlockType().getMaterial().isLiquid()) {
                         // Grow -- start from 1 below top replacing airblocks
                         for (int setY = newBlock - 1, getY = curBlock; setY >= curBlock; --setY, getY--) {
                             BlockStateHolder<BlockState> get = session.getBlock(xr, getY, zr);

worldedit-core/src/main/java/com/sk89q/worldedit/math/convolution/HeightMapFilter.java

@@ -79,50 +79,107 @@ public class HeightMapFilter {
      * @return the modified height map
      */
     public int[] filter(int[] inData, int width, int height) {
+        return filter(inData, width, height, 0.5F);
+    }
+
+    /**
+     * Filter with a 2D kernel.
+     *
+     * @param inData the data
+     * @param width  the width
+     * @param height the height
+     * @param offset the offset added to the height
+     * @return the modified height map
+     */
+    public int[] filter(int[] inData, int width, int height, float offset) {
         checkNotNull(inData);
 
+        float[] inDataFloat = new float[inData.length];
+        for (int i = 0; i < inData.length; i++) {
+            inDataFloat[i] = inData[i];
+        }
+
         int index = 0;
         float[] matrix = kernel.getKernelData(null);
         int[] outData = new int[inData.length];
 
-        int kh = kernel.getHeight();
-        int kw = kernel.getWidth();
-        int kox = kernel.getXOrigin();
-        int koy = kernel.getYOrigin();
-
         for (int y = 0; y < height; ++y) {
             for (int x = 0; x < width; ++x) {
-                float z = 0;
-
-                for (int ky = 0; ky < kh; ++ky) {
-                    int offsetY = y + ky - koy;
-                    // Clamp coordinates inside data
-                    if (offsetY < 0 || offsetY >= height) {
-                        offsetY = y;
-                    }
-
-                    offsetY *= width;
-
-                    int matrixOffset = ky * kw;
-                    for (int kx = 0; kx < kw; ++kx) {
-                        float f = matrix[matrixOffset + kx];
-                        if (f == 0) {
-                            continue;
-                        }
-
-                        int offsetX = x + kx - kox;
-                        // Clamp coordinates inside data
-                        if (offsetX < 0 || offsetX >= width) {
-                            offsetX = x;
-                        }
-
-                        z += f * inData[offsetY + offsetX];
-                    }
-                }
-                outData[index++] = (int) (z + 0.5);
+                outData[index++] = (int) calculateHeight(inDataFloat, width, height, offset, matrix, x, y);
             }
         }
         return outData;
     }
 
+    /**
+     * Filter with a 2D kernel for float values.
+     *
+     * @param inData the data
+     * @param width  the width
+     * @param height the height
+     * @return the modified height map
+     */
+    public float[] filter(float[] inData, int width, int height, float offset) {
+        checkNotNull(inData);
+
+        int index = 0;
+        float[] matrix = kernel.getKernelData(null);
+        float[] outData = new float[inData.length];
+
+        for (int y = 0; y < height; ++y) {
+            for (int x = 0; x < width; ++x) {
+                outData[index++] = calculateHeight(inData, width, height, offset, matrix, x, y);
+            }
+        }
+        return outData;
+    }
+
+    /**
+     * Calculate the height based on the existing data and the kernel data.
+     *
+     * @param inData the existing height data
+     * @param width  the width
+     * @param height the height
+     * @param offset the offset to add to the height
+     * @param matrix the matrix with the kernel's data
+     * @param x      the current x coordinate
+     * @param y      the current y coordinate
+     * @return the calculated height for that block
+     */
+    private float calculateHeight(float[] inData, int width, int height, float offset, float[] matrix, int x, int y) {
+        int kh = kernel.getHeight();
+        int kw = kernel.getWidth();
+        int kox = kernel.getXOrigin();
+        int koy = kernel.getYOrigin();
+
+        float z = 0;
+
+        for (int ky = 0; ky < kh; ++ky) {
+            int offsetY = y + ky - koy;
+            // Clamp coordinates inside data
+            if (offsetY < 0 || offsetY >= height) {
+                offsetY = y;
+            }
+
+            offsetY *= width;
+
+            int matrixOffset = ky * kw;
+            for (int kx = 0; kx < kw; ++kx) {
+                float f = matrix[matrixOffset + kx];
+                if (f == 0) {
+                    continue;
+                }
+
+                int offsetX = x + kx - kox;
+                // Clamp coordinates inside data
+                if (offsetX < 0 || offsetX >= width) {
+                    offsetX = x;
+                }
+
+                z += f * inData[offsetY + offsetX];
+            }
+        }
+        return z + offset;
+    }
+
 }

worldedit-core/src/main/java/com/sk89q/worldedit/math/convolution/SnowHeightMap.java

@@ -0,0 +1,218 @@
+/*
+ * 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 <https://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.math.convolution;
+
+import com.google.common.collect.ImmutableMap;
+import com.sk89q.worldedit.EditSession;
+import com.sk89q.worldedit.MaxChangedBlocksException;
+import com.sk89q.worldedit.function.mask.Mask;
+import com.sk89q.worldedit.math.BlockVector3;
+import com.sk89q.worldedit.regions.Region;
+import com.sk89q.worldedit.registry.state.Property;
+import com.sk89q.worldedit.world.block.BlockState;
+import com.sk89q.worldedit.world.block.BlockTypes;
+
+import javax.annotation.Nullable;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Allows applications of Kernels onto the region's height map for snow layers
+ *
+ * <p>Currently only used for snow layer smoothing (with a GaussianKernel)</p>.
+ */
+public class SnowHeightMap {
+
+    private final float[] data;
+    private final int width;
+    private final int height;
+
+    private final Region region;
+    private final EditSession session;
+
+    private final Property<Integer> layers;
+
+    /**
+     * Constructs the SnowHeightMap.
+     *
+     * @param session an edit session
+     * @param region  the region
+     * @param mask    optional mask for the height map
+     */
+    public SnowHeightMap(EditSession session, Region region, @Nullable Mask mask) {
+        checkNotNull(session);
+        checkNotNull(region);
+
+        this.session = session;
+        this.region = region;
+
+        this.width = region.getWidth();
+        this.height = region.getLength();
+
+        this.layers = BlockTypes.SNOW.getProperty("layers");
+
+        int minX = region.getMinimumPoint().getBlockX();
+        int minY = region.getMinimumPoint().getBlockY();
+        int minZ = region.getMinimumPoint().getBlockZ();
+        int maxY = region.getMaximumPoint().getBlockY();
+
+        // Store current heightmap data
+        data = new float[width * height];
+        for (int z = 0; z < height; ++z) {
+            for (int x = 0; x < width; ++x) {
+                int highestBlockY = session.getHighestTerrainBlock(x + minX, z + minZ, minY, maxY, mask);
+                BlockState upper = session.getBlock(BlockVector3.at(x + minX, highestBlockY + 1, z + minZ));
+                if (upper.getBlockType() == BlockTypes.SNOW) {
+                    Integer amountLayers = upper.getState(layers);
+                    data[z * width + x] = (highestBlockY + 1 + (((float) amountLayers - 1) / 8));
+                } else {
+                    BlockState block = session.getBlock(BlockVector3.at(x + minX, highestBlockY, z + minZ));
+                    if (block.getBlockType().getMaterial().isAir()) {
+                        data[z * width + x] = highestBlockY;
+                    } else {
+                        data[z * width + x] = highestBlockY + 1;
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Compute the new heightmap with the filter 'iterations' amount times.
+     *
+     * @param filter     the filter
+     * @param iterations the number of iterations
+     * @return new generated heightmap of the terrain
+     */
+    public float[] applyFilter(HeightMapFilter filter, int iterations) {
+        checkNotNull(filter);
+
+        float[] newData = data.clone();
+
+        for (int i = 0; i < iterations; ++i) {
+            // add an offset from 0.0625F to the values (snowlayer half)
+            newData = filter.filter(newData, width, height, 0.0625F);
+        }
+        return newData;
+    }
+
+    /**
+     * Apply a raw heightmap to a region. Use snow layers.
+     *
+     * @param data        the data
+     * @param layerBlocks amount of blocks with type SNOW_BLOCK
+     * @return number of blocks affected
+     * @throws MaxChangedBlocksException if the maximum block change limit is exceeded
+     */
+    public int applyChanges(float[] data, int layerBlocks) throws MaxChangedBlocksException {
+        checkNotNull(data);
+
+        BlockVector3 minY = region.getMinimumPoint();
+        int originX = minY.getBlockX();
+        int originY = minY.getBlockY();
+        int originZ = minY.getBlockZ();
+
+        int maxY = region.getMaximumPoint().getBlockY();
+
+        BlockState fillerAir = BlockTypes.AIR.getDefaultState();
+        BlockState fillerSnow = BlockTypes.SNOW_BLOCK.getDefaultState();
+
+        int blocksChanged = 0;
+
+        // Apply heightmap
+        for (int z = 0; z < height; ++z) {
+            for (int x = 0; x < width; ++x) {
+                int index = z * width + x;
+                float curHeight = this.data[index];
+
+                if (curHeight == originY) {
+                    continue;
+                }
+
+                // Clamp newHeight within the selection area
+                float newHeight = Math.min(maxY, data[index]);
+
+                // Offset x,z to be 'real' coordinates
+                int xr = x + originX;
+                int zr = z + originZ;
+
+                // We are keeping the topmost blocks so take that in account for the scale
+                double scale = (double) (curHeight - originY) / (double) (newHeight - originY);
+
+                // Depending on growing or shrinking we need to start at the bottom or top
+                if (newHeight >= curHeight) {
+                    // Set the top block of the column to be the same type (this might go wrong with rounding)
+                    BlockState existing = session.getBlock(BlockVector3.at(xr, curHeight, zr));
+
+                    // Skip water/lava
+                    if (!existing.getBlockType().getMaterial().isLiquid()) {
+                        setSnowLayer(xr, zr, newHeight);
+                        ++blocksChanged;
+
+                        // Grow -- start from 1 below top replacing airblocks
+                        for (int y = (int) newHeight - 1 - originY; y >= 0; --y) {
+                            if (y >= newHeight - 1 - originY - layerBlocks) {
+                                session.setBlock(BlockVector3.at(xr, originY + y, zr), fillerSnow);
+                            } else {
+                                int copyFrom = (int) (y * scale);
+                                BlockState block = session.getBlock(BlockVector3.at(xr, originY + copyFrom, zr));
+                                session.setBlock(BlockVector3.at(xr, originY + y, zr), block);
+                            }
+                            ++blocksChanged;
+                        }
+                    }
+                } else {
+                    // Shrink -- start from bottom
+                    for (int y = 0; y < (int) newHeight - originY; ++y) {
+                        if (y >= (int) newHeight - originY - layerBlocks) {
+                            session.setBlock(BlockVector3.at(xr, originY + y, zr), fillerSnow);
+                        } else {
+                            int copyFrom = (int) (y * scale);
+                            BlockState block = session.getBlock(BlockVector3.at(xr, originY + copyFrom, zr));
+                            session.setBlock(BlockVector3.at(xr, originY + y, zr), block);
+                        }
+                        ++blocksChanged;
+                    }
+
+                    setSnowLayer(xr, zr, newHeight);
+                    ++blocksChanged;
+
+                    // Fill rest with air
+                    for (int y = (int) newHeight + 1; y <= curHeight; ++y) {
+                        session.setBlock(BlockVector3.at(xr, y, zr), fillerAir);
+                        ++blocksChanged;
+                    }
+                }
+            }
+        }
+
+        // Drop trees to the floor -- TODO
+        return blocksChanged;
+    }
+
+    private void setSnowLayer(int x, int z, float newHeight) throws MaxChangedBlocksException {
+        int numOfLayers = (int) ((newHeight % 1) * 8) + 1;
+        session.setBlock(
+                BlockVector3.at(x, (int) newHeight, z),
+                BlockTypes.SNOW.getState(ImmutableMap.of(this.layers, numOfLayers))
+        );
+    }
+
+}

worldedit-core/src/main/java/com/sk89q/worldedit/session/request/Request.java

@@ -19,9 +19,6 @@
 
 package com.sk89q.worldedit.session.request;
 
-import com.google.common.cache.CacheBuilder;
-import com.google.common.cache.CacheLoader;
-import com.google.common.cache.LoadingCache;
 import com.sk89q.worldedit.EditSession;
 import com.sk89q.worldedit.LocalSession;
 import com.sk89q.worldedit.extension.platform.Actor;
@@ -30,15 +27,19 @@ import com.sk89q.worldedit.world.World;
 
 import javax.annotation.Nullable;
 import java.util.Collection;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
- * Describes the current request
+ * Describes the current request using a {@link ThreadLocal}.
  */
 public final class Request {
 
-    private static final LoadingCache<Thread, Request> THREAD_TO_REQUEST = CacheBuilder.newBuilder()
-            .weakKeys()
-            .build(CacheLoader.from(Request::new));
+    private static final ThreadLocal<Request> threadLocal = ThreadLocal.withInitial(Request::new);
+    //FAWE start
+    // TODO any better way to deal with this?
+    private static final Map<Thread, Request> requests = new ConcurrentHashMap<>();
+    //FAWE end
 
     @Nullable
     private World world;
@@ -55,11 +56,14 @@ public final class Request {
     //FAWE end
 
     private Request() {
+        //FAWE start
+        requests.put(Thread.currentThread(), this);
+        //FAWE end
     }
 
     //FAWE start
     public static Collection<Request> getAll() {
-        return THREAD_TO_REQUEST.asMap().values();
+        return requests.values();
     }
     //FAWE end
 
@@ -158,7 +162,7 @@ public final class Request {
      * @return the current request
      */
     public static Request request() {
-        return THREAD_TO_REQUEST.getUnchecked(Thread.currentThread());
+        return threadLocal.get();
     }
 
     /**
@@ -166,7 +170,10 @@ public final class Request {
      */
     public static void reset() {
         request().invalidate();
-        THREAD_TO_REQUEST.invalidate(Thread.currentThread());
+        threadLocal.remove();
+        //FAWE start
+        requests.remove(Thread.currentThread());
+        //FAWE end
     }
 
     /**

worldedit-core/src/main/resources/lang/strings.json

@@ -283,6 +283,11 @@
     "worldedit.brush.cylinder.equip": "Cylinder brush shape equipped ({0} by {1}).",
     "worldedit.brush.clipboard.equip": "Clipboard brush shape equipped.",
     "worldedit.brush.smooth.equip": "Smooth brush equipped ({0} x {1}x using {2}).",
+    "worldedit.brush.smooth.nofilter": "any block",
+    "worldedit.brush.smooth.filter": "filter",
+    "worldedit.brush.snowsmooth.equip": "SnowSmooth brush equipped ({0} x {1}x using {2}), {3} snow blocks.",
+    "worldedit.brush.snowsmooth.nofilter": "any block",
+    "worldedit.brush.snowsmooth.filter": "filter",
     "worldedit.brush.extinguish.equip": "Extinguisher equipped ({0}).",
     "worldedit.brush.gravity.equip": "Gravity brush equipped ({0}).",
     "worldedit.brush.butcher.equip": "Butcher brush equipped ({0}).",
@@ -482,6 +487,7 @@
     "worldedit.naturalize.naturalized": "{0} block(s) have been made to look more natural.",
     "worldedit.center.changed": "Center set. ({0} blocks changed)",
     "worldedit.smooth.changed": "Terrain's height map smoothed. {0} blocks changed.",
+    "worldedit.snowsmooth.changed": "Snow's height map smoothed. {0} blocks changed.",
     "worldedit.move.moved": "{0} blocks moved.",
     "worldedit.deform.deformed": "{0} blocks have been deformed.",
     "worldedit.hollow.changed": "{0} blocks have been changed.",