Move tower background update code to logic functions

Otherwise it'll go really really quickly, which is not good.

desktop_version/src/Graphics.cpp

@@ -2348,6 +2348,11 @@ void Graphics::drawtowerspikes()
 }
 
 void Graphics::drawtowerbackground()
+{
+    SDL_BlitSurface(towerbuffer,NULL, backBuffer,NULL);
+}
+
+void Graphics::updatetowerbackground()
 {
     int temp;
 
@@ -2366,8 +2371,6 @@ void Graphics::drawtowerbackground()
             }
         }
 
-        SDL_BlitSurface(towerbuffer,NULL, backBuffer,NULL);
-
         map.tdrawback = false;
     }
     else
@@ -2394,8 +2397,6 @@ void Graphics::drawtowerbackground()
                 drawtowertile3(i * 8, 31*8 - (map.bypos % 8) - map.bscroll, temp, map.colstate);
             }
         }
-
-        SDL_BlitSurface(towerbuffer,NULL, backBuffer,NULL);
     }
 }
 

desktop_version/src/Graphics.h

@@ -197,6 +197,7 @@ public:
 	void menuoffrender();
 
 	void drawtowerbackground();
+	void updatetowerbackground();
 
 	void setcol(int t);
 	void drawfinalmap();

desktop_version/src/Logic.cpp

@@ -12,6 +12,11 @@ void titlelogic()
     map.bypos -= 2;
     map.bscroll = -2;
 
+    if (!game.colourblindmode)
+    {
+        graphics.updatetowerbackground();
+    }
+
     if (game.menucountdown > 0)
     {
         game.menucountdown--;
@@ -96,6 +101,11 @@ void gamecompletelogic()
         map.bscroll = +1;
     }
 
+    if (!game.colourblindmode)
+    {
+        graphics.updatetowerbackground();
+    }
+
     if (graphics.fademode == 1)
     {
         //Fix some graphical things
@@ -1542,7 +1552,14 @@ void gamelogic()
 
     if (!game.colourblindmode)
     {
-        graphics.updatebackground(map.background);
+        if (map.towermode)
+        {
+            graphics.updatetowerbackground();
+        }
+        else
+        {
+            graphics.updatebackground(map.background);
+        }
     }
 
     if (!game.blackout)

desktop_version/src/editor.cpp

@@ -3622,6 +3622,10 @@ void editorlogic()
             break;
         }
     }
+    else if (!game.colourblindmode)
+    {
+        graphics.updatetowerbackground();
+    }
 
     if (graphics.fademode == 1)
     {