From 351ce1525f570a52d571d1da720ae4f6a5815a22 Mon Sep 17 00:00:00 2001
From: Simon Robertshaw <simon@hardwired.org.uk>
Date: Sun, 5 Aug 2012 14:03:54 +0100
Subject: [PATCH] Update gravity walls, fixes issue #52

---
 src/simulation/Simulation.cpp | 15 +++++++++++++--
 src/simulation/Simulation.h   |  2 +-
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/simulation/Simulation.cpp b/src/simulation/Simulation.cpp
index 59ff5d11c..8717faa54 100644
--- a/src/simulation/Simulation.cpp
+++ b/src/simulation/Simulation.cpp
@@ -114,7 +114,7 @@ int Simulation::Load(int fullX, int fullY, GameSave * save)
 		}
 	}
 
-	grav->gravity_mask();
+	gravWallChanged = true;
 
 	return 0;
 }
@@ -232,6 +232,8 @@ void Simulation::clear_area(int area_x, int area_y, int area_w, int area_h)
 	{
 		for (cx=0; cx<area_w; cx++)
 		{
+			if(bmap[(cy+area_y)/CELL][(cx+area_x)/CELL] == WL_GRAV)
+				gravWallChanged = true;
 			bmap[(cy+area_y)/CELL][(cx+area_x)/CELL] = 0;
 			delete_part(cx+area_x, cy+area_y, 0);
 		}
@@ -1240,6 +1242,10 @@ int Simulation::CreateWalls(int x, int y, int rx, int ry, int c, int flags, Brus
 					fvx[j][i] = 0.0f;
 					fvy[j][i] = 0.0f;
 				}
+				if (b==WL_GRAV || bmap[j][i]==WL_GRAV)
+				{
+					gravWallChanged = true;
+				}
 				if (b==WL_STREAM)
 				{
 					i = x + rx/2;
@@ -1253,7 +1259,6 @@ int Simulation::CreateWalls(int x, int y, int rx, int ry, int c, int flags, Brus
 					bmap[j][i] = WL_STREAM;
 					continue;
 				}
-				if (b==0 && bmap[j][i]==WL_GRAV) gravwl_timeout = 60;
 				bmap[j][i] = b;
 			}
 		}
@@ -4341,6 +4346,12 @@ void Simulation::update_particles()//doesn't update the particles themselves, bu
 			gravy = grav->gravy;
 			gravp = grav->gravp;
 			gravmap = grav->gravmap;
+
+			if(gravWallChanged)
+			{
+				grav->gravity_mask();
+				gravWallChanged = false;
+			}
 		}
 	}
 
diff --git a/src/simulation/Simulation.h b/src/simulation/Simulation.h
index 31a0a075b..e4f43111d 100644
--- a/src/simulation/Simulation.h
+++ b/src/simulation/Simulation.h
@@ -62,7 +62,7 @@ public:
 	playerst fighters[256]; //255 is the maximum number of fighters
 	unsigned char fighcount; //Contains the number of fighters
 	int lighting_recreate;
-	int gravwl_timeout;
+	bool gravWallChanged;
 	Particle portalp[CHANNELS][8][80];
 	Particle emptyparticle;
 	int portal_rx[8];