Fireball and ghast improvements (#1469)

* Fireball and ghast improvements

- Ghasts now visually show if they're charging a fireball
- Fireballs are now vastly better and will update better

* Add gravity and drag to projectiles

* Add check for session close and improve fireball

* Remove motion stuff from fireball

* Make fireball hittable

* Add wither skull entity

* Small changes

* Add note about laggy fireballs

Co-authored-by: David Choo <davchoo3@gmail.com>

connector/src/main/java/org/geysermc/connector/entity/ItemedFireballEntity.java

@@ -27,10 +27,24 @@ package org.geysermc.connector.entity;
 
 import com.nukkitx.math.vector.Vector3f;
 import org.geysermc.connector.entity.type.EntityType;
+import org.geysermc.connector.network.session.GeyserSession;
 
-public class ItemedFireballEntity extends Entity {
+public class ItemedFireballEntity extends ThrowableEntity {
+    private final Vector3f acceleration;
 
     public ItemedFireballEntity(long entityId, long geyserId, EntityType entityType, Vector3f position, Vector3f motion, Vector3f rotation) {
-        super(entityId, geyserId, entityType, position, motion, rotation);
+        super(entityId, geyserId, entityType, position, Vector3f.ZERO, rotation);
+        acceleration = motion;
+    }
+
+    @Override
+    protected void updatePosition(GeyserSession session) {
+        position = position.add(motion);
+        // TODO: While this reduces latency in position updating (needed for better fireball reflecting),
+        // TODO: movement is incredibly stiff. See if the MoveEntityDeltaPacket in 1.16.100 fixes this, and if not,
+        // TODO: only use this laggy movement for fireballs that be reflected
+        moveAbsoluteImmediate(session, position, rotation, false, true);
+        float drag = getDrag(session);
+        motion = motion.add(acceleration).mul(drag);
     }
 }

connector/src/main/java/org/geysermc/connector/entity/ThrowableEntity.java

@@ -31,14 +31,23 @@ import com.nukkitx.protocol.bedrock.data.entity.EntityFlag;
 import com.nukkitx.protocol.bedrock.packet.LevelEventPacket;
 import org.geysermc.connector.entity.type.EntityType;
 import org.geysermc.connector.network.session.GeyserSession;
+import org.geysermc.connector.network.translators.world.block.BlockTranslator;
 
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 
+/**
+ * Used as a class for any object-like entity that moves as a projectile
+ */
 public class ThrowableEntity extends Entity {
 
     private Vector3f lastPosition;
-    private ScheduledFuture<?> positionUpdater;
+    /**
+     * Updates the position for the Bedrock client.
+     *
+     * Java clients assume the next positions of moving items. Bedrock needs to be explicitly told positions
+     */
+    protected ScheduledFuture<?> positionUpdater;
 
     public ThrowableEntity(long entityId, long geyserId, EntityType entityType, Vector3f position, Vector3f motion, Vector3f rotation) {
         super(entityId, geyserId, entityType, position, motion, rotation);
@@ -49,20 +58,86 @@ public class ThrowableEntity extends Entity {
     public void spawnEntity(GeyserSession session) {
         super.spawnEntity(session);
         positionUpdater = session.getConnector().getGeneralThreadPool().scheduleAtFixedRate(() -> {
-            super.moveRelative(session, motion.getX(), motion.getY(), motion.getZ(), rotation, onGround);
+            if (session.isClosed()) {
-
+                positionUpdater.cancel(true);
-            if (metadata.getFlags().getFlag(EntityFlag.HAS_GRAVITY)) {
+                return;
-                float gravity = 0.03f; // Snowball, Egg, and Ender Pearl
-                if (entityType == EntityType.THROWN_POTION || entityType == EntityType.LINGERING_POTION) {
-                    gravity = 0.05f;
-                } else if (entityType == EntityType.THROWN_EXP_BOTTLE) {
-                    gravity = 0.07f;
-                }
-                motion = motion.down(gravity);
             }
+            updatePosition(session);
         }, 0, 50, TimeUnit.MILLISECONDS);
     }
 
+    protected void moveAbsoluteImmediate(GeyserSession session, Vector3f position, Vector3f rotation, boolean isOnGround, boolean teleported) {
+        super.moveAbsolute(session, position, rotation, isOnGround, teleported);
+    }
+
+    protected void updatePosition(GeyserSession session) {
+        super.moveRelative(session, motion.getX(), motion.getY(), motion.getZ(), rotation, onGround);
+        float drag = getDrag(session);
+        float gravity = getGravity();
+        motion = motion.mul(drag).down(gravity);
+    }
+
+    /**
+     * Get the gravity of this entity type. Used for applying gravity while the entity is in motion.
+     *
+     * @return the amount of gravity to apply to this entity while in motion.
+     */
+    protected float getGravity() {
+        if (metadata.getFlags().getFlag(EntityFlag.HAS_GRAVITY)) {
+            switch (entityType) {
+                case THROWN_POTION:
+                case LINGERING_POTION:
+                    return 0.05f;
+                case THROWN_EXP_BOTTLE:
+                    return 0.07f;
+                case FIREBALL:
+                    return 0;
+                case SNOWBALL:
+                case THROWN_EGG:
+                case THROWN_ENDERPEARL:
+                    return 0.03f;
+            }
+        }
+        return 0;
+    }
+
+    /**
+     * @param session the session of the Bedrock client.
+     * @return the drag that should be multiplied to the entity's motion
+     */
+    protected float getDrag(GeyserSession session) {
+        if (isInWater(session)) {
+            return 0.8f;
+        } else {
+            switch (entityType) {
+                case THROWN_POTION:
+                case LINGERING_POTION:
+                case THROWN_EXP_BOTTLE:
+                case SNOWBALL:
+                case THROWN_EGG:
+                case THROWN_ENDERPEARL:
+                    return 0.99f;
+                case FIREBALL:
+                case SMALL_FIREBALL:
+                case DRAGON_FIREBALL:
+                    return 0.95f;
+            }
+        }
+        return 1;
+    }
+
+    /**
+     * @param session the session of the Bedrock client.
+     * @return true if this entity is currently in water.
+     */
+    protected boolean isInWater(GeyserSession session) {
+        if (session.getConnector().getConfig().isCacheChunks()) {
+            int block = session.getConnector().getWorldManager().getBlockAt(session, position.toInt());
+            return block == BlockTranslator.BEDROCK_WATER_ID;
+        }
+        return false;
+    }
+
     @Override
     public boolean despawnEntity(GeyserSession session) {
         positionUpdater.cancel(true);

connector/src/main/java/org/geysermc/connector/entity/WitherSkullEntity.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2019-2020 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Geyser
+ */
+
+package org.geysermc.connector.entity;
+
+import com.github.steveice10.mc.protocol.data.game.entity.metadata.EntityMetadata;
+import com.nukkitx.math.vector.Vector3f;
+import org.geysermc.connector.entity.type.EntityType;
+import org.geysermc.connector.network.session.GeyserSession;
+
+public class WitherSkullEntity extends ItemedFireballEntity {
+    private boolean isCharged;
+
+    public WitherSkullEntity(long entityId, long geyserId, EntityType entityType, Vector3f position, Vector3f motion, Vector3f rotation) {
+        super(entityId, geyserId, entityType, position, motion, rotation);
+    }
+
+    @Override
+    protected float getDrag(GeyserSession session) {
+        return isCharged ? 0.73f : super.getDrag(session);
+    }
+
+    @Override
+    public void updateBedrockMetadata(EntityMetadata entityMetadata, GeyserSession session) {
+        if (entityMetadata.getId() == 7) {
+            boolean newIsCharged = (boolean) entityMetadata.getValue();
+            if (newIsCharged != isCharged) {
+                isCharged = newIsCharged;
+                entityType = isCharged ? EntityType.WITHER_SKULL_DANGEROUS : EntityType.WITHER_SKULL;
+                despawnEntity(session);
+                spawnEntity(session);
+            }
+        }
+        super.updateBedrockMetadata(entityMetadata, session);
+    }
+}

connector/src/main/java/org/geysermc/connector/entity/living/monster/GhastEntity.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2019-2020 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Geyser
+ */
+
+package org.geysermc.connector.entity.living.monster;
+
+import com.github.steveice10.mc.protocol.data.game.entity.metadata.EntityMetadata;
+import com.nukkitx.math.vector.Vector3f;
+import com.nukkitx.protocol.bedrock.data.entity.EntityData;
+import org.geysermc.connector.entity.living.FlyingEntity;
+import org.geysermc.connector.entity.type.EntityType;
+import org.geysermc.connector.network.session.GeyserSession;
+
+public class GhastEntity extends FlyingEntity {
+
+    public GhastEntity(long entityId, long geyserId, EntityType entityType, Vector3f position, Vector3f motion, Vector3f rotation) {
+        super(entityId, geyserId, entityType, position, motion, rotation);
+    }
+
+    @Override
+    public void updateBedrockMetadata(EntityMetadata entityMetadata, GeyserSession session) {
+        if (entityMetadata.getId() == 15) {
+            // If the ghast is attacking
+            metadata.put(EntityData.CHARGE_AMOUNT, (byte) ((boolean) entityMetadata.getValue() ? 1 : 0));
+        }
+        super.updateBedrockMetadata(entityMetadata, session);
+    }
+}

connector/src/main/java/org/geysermc/connector/entity/type/EntityType.java

@@ -74,7 +74,7 @@ public enum EntityType {
     ENDERMAN(EndermanEntity.class, 38, 2.9f, 0.6f),
     SILVERFISH(MonsterEntity.class, 39, 0.3f, 0.4f),
     CAVE_SPIDER(MonsterEntity.class, 40, 0.5f, 0.7f),
-    GHAST(FlyingEntity.class, 41, 4.0f),
+    GHAST(GhastEntity.class, 41, 4.0f),
     MAGMA_CUBE(MagmaCubeEntity.class, 42, 0.51f),
     BLAZE(BlazeEntity.class, 43, 1.8f, 0.6f),
     ZOMBIE_VILLAGER(ZombieEntity.class, 44, 1.8f, 0.6f, 0.6f, 1.62f),
@@ -125,9 +125,9 @@ public enum EntityType {
     THROWN_POTION(ThrowableEntity.class, 86, 0.25f, 0.25f, 0.25f, 0f, "minecraft:splash_potion"),
     THROWN_ENDERPEARL(ThrowableEntity.class, 87, 0.25f, 0.25f, 0.25f, 0f, "minecraft:ender_pearl"),
     LEASH_KNOT(LeashKnotEntity.class, 88, 0.5f, 0.375f),
-    WITHER_SKULL(Entity.class, 89, 0.3125f),
+    WITHER_SKULL(WitherSkullEntity.class, 89, 0.3125f),
     BOAT(BoatEntity.class, 90, 0.7f, 1.6f, 1.6f, 0.35f),
-    WITHER_SKULL_DANGEROUS(Entity.class, 91, 0f),
+    WITHER_SKULL_DANGEROUS(WitherSkullEntity.class, 91, 0f),
     LIGHTNING_BOLT(Entity.class, 93, 0f),
     SMALL_FIREBALL(ItemedFireballEntity.class, 94, 0.3125f),
     AREA_EFFECT_CLOUD(AreaEffectCloudEntity.class, 95, 0.5f, 1.0f),