From cc7f12739dbe92a0c3fecfe1f702ab2b40378b7d Mon Sep 17 00:00:00 2001
From: Shoghi Cervantes <shoghicp@gmail.com>
Date: Tue, 4 Nov 2014 12:23:42 +0100
Subject: [PATCH] Added vertical and horizontal collision detection to Entities

---
 src/pocketmine/entity/Entity.php     | 14 ++++++++------
 src/pocketmine/entity/Projectile.php | 12 ++++++++++--
 src/pocketmine/entity/Snowball.php   |  2 +-
 3 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/src/pocketmine/entity/Entity.php b/src/pocketmine/entity/Entity.php
index 5583e0259..49fc6eec7 100644
--- a/src/pocketmine/entity/Entity.php
+++ b/src/pocketmine/entity/Entity.php
@@ -140,7 +140,10 @@ abstract class Entity extends Location implements Metadatable{
 	public $canCollide = true;
 
 	protected $isStatic = false;
-	protected $isColliding = false;
+
+	public $isCollided = false;
+	public $isCollidedHorizontally = false;
+	public $isCollidedVertically = false;
 
 	public $noDamageTicks;
 	private $justCreated;
@@ -811,11 +814,6 @@ abstract class Entity extends Location implements Metadatable{
 		return false;
 	}
 
-	public function collision(){
-		$this->isColliding = true;
-		$this->fallDistance = 0;
-	}
-
 	public function move($dx, $dy, $dz){
 
 		if($dx == 0 and $dz == 0 and $dy == 0){
@@ -1009,7 +1007,11 @@ abstract class Entity extends Location implements Metadatable{
 							$this->onGround = false;
 						}
 					}
+					$this->isCollided = $this->onGround;
 				}else{
+					$this->isCollidedVertically = $movY != $dy;
+					$this->isCollidedHorizontally = ($movX != $dx or $movZ != $dz);
+					$this->isCollided = ($this->isCollidedHorizontally or $this->isCollidedVertically);
 					$this->onGround = ($movY != $dy and $movY < 0);
 				}
 				$this->updateFallState($dy, $this->onGround);
diff --git a/src/pocketmine/entity/Projectile.php b/src/pocketmine/entity/Projectile.php
index f926afdad..33a4872b1 100644
--- a/src/pocketmine/entity/Projectile.php
+++ b/src/pocketmine/entity/Projectile.php
@@ -37,6 +37,8 @@ abstract class Projectile extends Entity{
 	public $shootingEntity = null;
 	protected $damage = 0;
 
+	private $hadCollision = false;
+
 	protected function initEntity(){
 		$this->setMaxHealth(1);
 		$this->setHealth(1);
@@ -90,7 +92,9 @@ abstract class Projectile extends Entity{
 
 			$movingObjectPosition = null;
 
-			$this->motionY -= $this->gravity;
+			if(!$this->isCollided){
+				$this->motionY -= $this->gravity;
+			}
 
 			$this->keepMovement = $this->checkObstruction($this->x, ($this->boundingBox->minY + $this->boundingBox->maxY) / 2, $this->z);
 
@@ -159,12 +163,16 @@ abstract class Projectile extends Entity{
 
 			$this->move($this->motionX, $this->motionY, $this->motionZ);
 
-			if($this->onGround and ($this->motionX != 0 or $this->motionY != 0 or $this->motionZ != 0)){
+			if($this->isCollided and !$this->hadCollision){
+				$this->hadCollision = true;
+
 				$this->motionX = 0;
 				$this->motionY = 0;
 				$this->motionZ = 0;
 
 				$this->server->getPluginManager()->callEvent(new ProjectileHitEvent($this));
+			}elseif(!$this->isCollided and !$this->hadCollision){
+				$this->hadCollision = false;
 			}
 
 			if(!$this->onGround or $this->motionX != 0 or $this->motionY != 0 or $this->motionZ != 0){
diff --git a/src/pocketmine/entity/Snowball.php b/src/pocketmine/entity/Snowball.php
index 3248b8c7b..db1daba4f 100644
--- a/src/pocketmine/entity/Snowball.php
+++ b/src/pocketmine/entity/Snowball.php
@@ -52,7 +52,7 @@ class Snowball extends Projectile{
 
 		$hasUpdate = parent::onUpdate($currentTick);
 
-		if($this->age > 1200 or $this->onGround){
+		if($this->age > 1200 or $this->isCollided){
 			$this->kill();
 			$hasUpdate = true;
 		}