wined3d: Do not free regularily locked surfaces.

dlls/wined3d/surface.c

@@ -824,6 +824,19 @@ static HRESULT WINAPI IWineD3DSurfaceImpl_LockRect(IWineD3DSurface *iface, WINED
         }
     }
 
+    /* Performance optimization: Count how often a surface is locked, if it is locked regularly do not throw away the system memory copy.
+     * This avoids the need to download the surface from opengl all the time. The surface is still downloaded if the opengl texture is
+     * changed
+     */
+    if(!(This->Flags & SFLAG_DYNLOCK)) {
+        This->lockCount++;
+        /* MAXLOCKCOUNT is defined in wined3d_private.h */
+        if(This->lockCount > MAXLOCKCOUNT) {
+            TRACE("Surface is locked regularily, not freeing the system memory copy any more\n");
+            This->Flags |= SFLAG_DYNLOCK;
+        }
+    }
+
     TRACE("returning memory@%p, pitch(%d) dirtyfied(%d)\n", pLockedRect->pBits, pLockedRect->Pitch, This->Flags & SFLAG_DIRTY ? 0 : 1);
 
     This->Flags |= SFLAG_LOCKED;

dlls/wined3d/wined3d_private.h

@@ -984,6 +984,8 @@ struct IWineD3DSurfaceImpl
 
     RECT                      lockedRect;
     RECT                      dirtyRect;
+    int                       lockCount;
+#define MAXLOCKCOUNT          50 /* After this amount of locks do not free the sysmem copy */
 
     glDescriptor              glDescription;