From dba5248a415d4ff57967b69207299310ca565c52 Mon Sep 17 00:00:00 2001
From: Steve <stephenjsweeney@battleforthesolarsystem.com>
Date: Thu, 22 Feb 2018 19:03:48 +0000
Subject: [PATCH] Fix segfault when freeing entities.

---
 src/world/entities.c |  9 +++++++--
 src/world/quadtree.c | 12 +++++++-----
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/src/world/entities.c b/src/world/entities.c
index 3279ad7..8c7f959 100644
--- a/src/world/entities.c
+++ b/src/world/entities.c
@@ -122,8 +122,12 @@ void doEntities(void)
 			
 			free(self);
 			
+			/* assign prev entity to self */
 			self = prev;
 			
+			/* assign prev as self, so that prev doesn't point at the now freed memory */
+			prev = self;
+			
 			continue;
 		}
 		
@@ -189,13 +193,14 @@ void doEntities(void)
 				{
 					self->touch(touched[i]);
 					
+					/* for objects that never move */
 					if (touched[i]->isStatic)
 					{
 						oldSelf = self;
 						
 						self = touched[i];
 						
-						touched[i]->touch(oldSelf); /* for objects that never move */
+						touched[i]->touch(oldSelf);
 						
 						self = oldSelf;
 					}
@@ -526,7 +531,7 @@ static int canWalkOnEntity(float x, float y)
 	SDL_Rect srcRect;
 	
 	srcRect.x = x;
-	srcRect.x = y;
+	srcRect.y = y;
 	srcRect.w = 8;
 	srcRect.h = MAP_TILE_SIZE * 4;
 
diff --git a/src/world/quadtree.c b/src/world/quadtree.c
index fd11986..6c415a5 100644
--- a/src/world/quadtree.c
+++ b/src/world/quadtree.c
@@ -143,12 +143,14 @@ static void resizeQTEntCapacity(Quadtree *root)
 
 static int getIndex(Quadtree *root, int x, int y, int w, int h)
 {
-	int index = -1;
+	int index, verticalMidpoint, horizontalMidpoint, topQuadrant, bottomQuadrant;
+	
+	index = -1;
 
-	int verticalMidpoint = root->x + (root->w / 2);
-	int horizontalMidpoint = root->y + (root->h / 2);
-	int topQuadrant = (y < horizontalMidpoint && y + h < horizontalMidpoint);
-	int bottomQuadrant = (y > horizontalMidpoint);
+	verticalMidpoint = root->x + (root->w / 2);
+	horizontalMidpoint = root->y + (root->h / 2);
+	topQuadrant = (y < horizontalMidpoint && y + h < horizontalMidpoint);
+	bottomQuadrant = (y > horizontalMidpoint);
 
 	if (x < verticalMidpoint && x + w < verticalMidpoint)
 	{