From 950cffcb4ff1692216df249c76d8e290c3cd33a1 Mon Sep 17 00:00:00 2001
From: Steve <stephenjsweeney@battleforthesolarsystem.com>
Date: Mon, 2 Nov 2015 13:19:31 +0000
Subject: [PATCH] Use grid to determine drawn entities.

---
 src/battle/entities.c | 13 +++++++++++--
 src/battle/entities.h |  1 +
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/battle/entities.c b/src/battle/entities.c
index 48830aa..f8a9109 100644
--- a/src/battle/entities.c
+++ b/src/battle/entities.c
@@ -160,9 +160,14 @@ static void doEntity(void)
 
 void drawEntities(void)
 {
-	Entity *e;
+	Entity *e, **candidates;
+	int i;
 	
-	for (e = battle.entityHead.next ; e != NULL ; e = e->next)
+	candidates = getAllEntsWithin(battle.camera.x, battle.camera.y, SCREEN_WIDTH, SCREEN_HEIGHT, NULL);
+	i = 0;
+	e = candidates[i];
+	
+	while (e)
 	{
 		if (e->active)
 		{
@@ -177,6 +182,10 @@ void drawEntities(void)
 					break;
 			}
 		}
+		
+		i++;
+		
+		e = (i < MAX_GRID_CANDIDATES) ? candidates[i] : NULL;
 	}
 }
 
diff --git a/src/battle/entities.h b/src/battle/entities.h
index d52aa5f..8431755 100644
--- a/src/battle/entities.h
+++ b/src/battle/entities.h
@@ -28,6 +28,7 @@ extern void drawFighter(Entity *e);
 extern void doFighter(void);
 extern void addToGrid(Entity *e);
 extern void removeFromGrid(Entity *e);
+extern Entity **getAllEntsWithin(int x, int y, int w, int h, Entity *ignore);
 
 extern Battle battle;
 extern Entity *self;