Added new predictive flight protection

src/pocketmine/Player.php

@@ -147,6 +147,9 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 	protected $moveToSend = [];
 	protected $motionToSend = [];
 
+	/** @var Vector3 */
+	public $speed = null;
+
 	public $blocked = false;
 	public $achievements = [];
 	public $lastCorrect;
@@ -1164,6 +1167,10 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 					}
 				}
 			}
+
+			$this->speed = $to->subtract($from);
+		}elseif($distanceSquared == 0){
+			$this->speed = new Vector3(0, 0, 0);
 		}
 
 		if($revert){
@@ -1186,13 +1193,14 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 			$pk->teleport = true;
 			$this->directDataPacket($pk);
 			$this->forceMovement = new Vector3($from->x, $from->y, $from->z);
-			$this->newPosition = null;
 		}else{
 			$this->forceMovement = null;
 			if($distanceSquared != 0 and $this->nextChunkOrderRun > 20){
 				$this->nextChunkOrderRun = 20;
 			}
 		}
+
+		$this->newPosition = null;
 	}
 
 	public function updateMovement(){
@@ -1224,8 +1232,13 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 			if($this->onGround){
 				$this->inAirTicks = 0;
 			}else{
-				if($this->inAirTicks > 100 and $this->isSurvival() and !$this->isSleeping() and $this->spawned and !$this->server->getAllowFlight()){
+				if($this->inAirTicks > 20 and $this->isSurvival() and !$this->isSleeping() and $this->spawned and !$this->server->getAllowFlight()){
+					$expectedVelocity = (-$this->gravity) / $this->drag - ((-$this->gravity) / $this->drag) * exp(-$this->drag * ($this->inAirTicks - 2));
+					$diff = ($this->speed->y - $expectedVelocity) ** 2;
+
+					if($diff > 0.6 and $expectedVelocity < $this->speed->y){
 						$this->kick("Flying is not enabled on this server");
+					}
 					return false;
 				}else{
 					++$this->inAirTicks;

src/pocketmine/block/Block.php

@@ -1039,7 +1039,7 @@ class Block extends Position implements Metadatable{
 	 */
 	public function collidesWithBB(AxisAlignedBB $bb, &$list = []){
 		$bb2 = $this->getBoundingBox();
-		if($bb2 !== null and $bb2->intersectsWith($bb)){
+		if($bb2 !== null and $bb->intersectsWith($bb2)){
 			$list[] = $bb2;
 		}
 	}
@@ -1055,11 +1055,10 @@ class Block extends Position implements Metadatable{
 	 * @return AxisAlignedBB
 	 */
 	public function getBoundingBox(){
-		if($this->boundingBox !== null){
+		if($this->boundingBox === null){
-			return $this->boundingBox;
+			$this->boundingBox = $this->recalculateBoundingBox();
-		}else{
-			return ($this->boundingBox = $this->recalculateBoundingBox());
 		}
+		return $this->boundingBox;
 	}
 
 	/**

src/pocketmine/entity/Entity.php

@@ -1004,7 +1004,7 @@ abstract class Entity extends Location implements Metadatable{
 					if(!$this->onGround or $movY != 0){
 						$bb = clone $this->boundingBox;
 						$bb->minY -= 1;
-						if(count($this->level->getCollisionBlocks($bb->expand(0.01, 0.01, 0.01))) > 0){
+						if(count($this->level->getCollisionBlocks($bb)) > 0){
 							$this->onGround = true;
 						}else{
 							$this->onGround = false;