Tightened clamping.

src/engine/InterestManagement/HeightMap.java

@@ -306,11 +306,17 @@ public class HeightMap {
 
         Vector2f gridSquare;
 
-        if (zoneLoc.x < 0 || zoneLoc.x > this.fullExtentsX)
-            return -1;
+        if (zoneLoc.x < 0)
+            zoneLoc.x = 0;
 
-        if (zoneLoc.y < 0 || zoneLoc.y > this.fullExtentsY)
-            return -1;
+        if (zoneLoc.y < 0)
+            zoneLoc.y = 0;
+
+        if (zoneLoc.x > this.fullExtentsX)
+            zoneLoc.x = this.fullExtentsX;
+
+        if (zoneLoc.y > this.fullExtentsY)
+            zoneLoc.y = this.fullExtentsY;
 
         int maxX = (int) (this.fullExtentsX / this.bucketWidthX);
         int maxY = (int) (this.fullExtentsY / this.bucketWidthY);
@@ -320,10 +326,15 @@ public class HeightMap {
         int gridX = (int) gridSquare.x;
         int gridY = (int) gridSquare.y;
 
+        if (gridX < 0)
+            gridX = 0;
+        if (gridY < 0)
+            gridY = 0;
+
         if (gridX > maxX)
-            gridX = maxX;
+            gridX = maxX - 1;
         if (gridY > maxY)
-            gridY = maxY;
+            gridY = maxY - 1;
 
         float offsetX = (gridSquare.x - gridX);
         float offsetY = gridSquare.y - gridY;