--- a/hedgewars/uGearsUtils.pas	Thu Oct 05 18:26:08 2017 +0200
+++ b/hedgewars/uGearsUtils.pas	Fri Oct 06 14:03:13 2017 +0200
@@ -56,6 +56,7 @@
 function  GetUtility(Hedgehog: PHedgehog): TAmmoType;
 
 function WorldWrap(var Gear: PGear): boolean;
+function CalcWorldWrap(X, radius: LongInt): LongInt;
 
 function IsHogLocal(HH: PHedgehog): boolean;
 
@@ -1598,6 +1599,27 @@
     end;
 end;
 
+// Takes an X coordinate and corrects if according to the world edge rules
+// Wrap-around: X will be wrapped
+// Bouncy: X will be kept inside the legal land (taking radius into account)
+// Other world edges: Just returns X
+// radius is a radius (gear radius) tolerance for an appropriate distance from bouncy world edges.
+// Set radius to 0 if you don't care.
+function CalcWorldWrap(X, radius: LongInt): LongInt;
+begin
+    if WorldEdge = weWrap then
+        if X < LongInt(leftX) then
+             X:= X + (LongInt(rightX) - LongInt(leftX))
+        else if X > LongInt(rightX) then
+             X:= X - (LongInt(rightX) - LongInt(leftX))
+    else if WorldEdge = weBounce then
+        if X - radius < LongInt(leftX) then
+            X:= LongInt(leftX) + radius
+        else if X + radius > LongInt(rightX) then
+            X:= LongInt(rightX) - radius;
+    CalcWorldWrap:= X;
+end;
+
 procedure AddBounceEffectForGear(Gear: PGear);
 var boing: PVisualGear;
 begin