1 files changed, 53 insertions, 34 deletions

diff --git a/src/map.cpp b/src/map.cpp
index 6eec4865..463a8c8e 100644
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -171,54 +171,73 @@ Map::drawOverlay(Graphics *graphics, float scrollX, float scrollY)
 {
     std::list<AmbientOverlay>::iterator i;
 
+    static int lastTick = tick_time;
+
+    // Avoid freaking out when tick_time overflows
+    if (tick_time < lastTick)
+    {
+        lastTick = tick_time;
+    }
+
     if (mLastScrollX == 0.0f && mLastScrollY == 0.0f)
     {
+        // first call - initialisation
         mLastScrollX = scrollX;
         mLastScrollY = scrollY;
     }
 
-    for (i = mOverlays.begin(); i != mOverlays.end(); i++)
+    //update Overlays
+    while (lastTick < tick_time)
     {
-
-        if ((*i).image != NULL)
+        for (i = mOverlays.begin(); i != mOverlays.end(); i++)
         {
-            //apply self scrolling
-            (*i).scrollX -= (*i).scrollSpeedX;
-            (*i).scrollY -= (*i).scrollSpeedY;
+            if ((*i).image != NULL)
+            {
+                //apply self scrolling
+                (*i).scrollX -= (*i).scrollSpeedX;
+                (*i).scrollY -= (*i).scrollSpeedY;
 
-            //apply parallaxing
-            (*i).scrollX += (scrollX - mLastScrollX) * (*i).parallax;
-            (*i).scrollY += (scrollY - mLastScrollY) * (*i).parallax;
+                //apply parallaxing
+                (*i).scrollX += (scrollX - mLastScrollX) * (*i).parallax;
+                (*i).scrollY += (scrollY - mLastScrollY) * (*i).parallax;
 
-            //keep the image pattern on the screen
-            while ((*i).scrollX > (*i).image->getWidth())
-            {
-                (*i).scrollX -= (*i).image->getWidth();
-            }
-            while ((*i).scrollY > (*i).image->getHeight())
-            {
-                (*i).scrollY -= (*i).image->getHeight();
-            }
-            while ((*i).scrollX < 0)
-            {
-                (*i).scrollX += (*i).image->getWidth();
-            }
-            while ((*i).scrollY < 0)
-            {
-                (*i).scrollY += (*i).image->getHeight();
+                //keep the image pattern on the screen
+                while ((*i).scrollX > (*i).image->getWidth())
+                {
+                    (*i).scrollX -= (*i).image->getWidth();
+                }
+                while ((*i).scrollY > (*i).image->getHeight())
+                {
+                    (*i).scrollY -= (*i).image->getHeight();
+                }
+                while ((*i).scrollX < 0)
+                {
+                    (*i).scrollX += (*i).image->getWidth();
+                }
+                while ((*i).scrollY < 0)
+                {
+                    (*i).scrollY += (*i).image->getHeight();
+                }
             }
-
-            graphics->drawImagePattern  (   (*i).image,
-                                            0 - (int)(*i).scrollX,
-                                            0 - (int)(*i).scrollY,
-                                            graphics->getWidth() + (int)(*i).scrollX,
-                                            graphics->getHeight() + (int)(*i).scrollY
-                                        );
         }
+        mLastScrollX = scrollX;
+        mLastScrollY = scrollY;
+        lastTick++;
     }
 
-    mLastScrollX = scrollX;
-    mLastScrollY = scrollY;
+    //draw overlays
+    for (i = mOverlays.begin(); i != mOverlays.end(); i++)
+    {
+        if ((*i).image != NULL)
+        {
+        graphics->drawImagePattern  (   (*i).image,
+                                        0 - (int)(*i).scrollX,
+                                        0 - (int)(*i).scrollY,
+                                        graphics->getWidth() + (int)(*i).scrollX,
+                                        graphics->getHeight() + (int)(*i).scrollY
+                                    );
+        };
+    };
 }
 
 void