v1.2.0: fixed a bug with purity and adjusted some blob logic

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/actors/blobs/Blob.java

@@ -219,6 +219,10 @@ public class Blob extends Actor {
 		off = new int[Dungeon.level.length()];
 	}
 
+	public void onBuildFlagMaps( Level l ){
+		//do nothing by default, only some blobs affect flags
+	}
+	
 	public String tileDesc() {
 		return null;
 	}

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/actors/blobs/Web.java

@@ -91,6 +91,16 @@ public class Web extends Blob {
 		Dungeon.level.buildFlagMaps();
 	}
 
+	@Override
+	public void onBuildFlagMaps(Level l) {
+		if (volume > 0){
+			for (int i=0; i < l.length(); i++) {
+				l.solid[i] = l.solid[i] || cur[i] > 0;
+				l.flamable[i] = l.flamable[i] || cur[i] > 0;
+			}
+		}
+	}
+
 	@Override
 	public String tileDesc() {
 		return Messages.get(this, "desc");

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/items/potions/PotionOfPurity.java

@@ -67,16 +67,7 @@ public class PotionOfPurity extends Potion {
 			if (PathFinder.distance[i] < Integer.MAX_VALUE) {
 				
 				for (Blob blob : blobs) {
-					
-					int value = blob.cur[i];
-					if (value > 0) {
-						
 					blob.clear(i);
-						blob.cur[i] = 0;
-						blob.volume -= value;
-						
-					}
-					
 				}
 				
 				if (Dungeon.level.heroFOV[i]) {

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/levels/Level.java

@@ -657,12 +657,8 @@ public abstract class Level implements Bundlable {
 			pit[i]			= (flags & Terrain.PIT) != 0;
 		}
 
-		Web w = (Web) blobs.get(Web.class);
-		if (w != null && w.volume > 0){
-			for (int i=0; i < length(); i++) {
-				solid[i] = solid[i] || w.cur[i] > 0;
-				flamable[i] = flamable[i] || w.cur[i] > 0;
-			}
+		for (Blob b : blobs.values()){
+			b.onBuildFlagMaps(this);
 		}
 		
 		int lastRow = length() - width();
@@ -680,7 +676,7 @@ public abstract class Level implements Bundlable {
 		}
 
 		//an open space is large enough to fit large mobs. A space is open when it is not solid
-		// and there is and open corner with both adjacent cells opens
+		// and there is an open corner with both adjacent cells opens
 		for (int i=0; i < length(); i++) {
 			if (solid[i]){
 				openSpace[i] = false;