parallax scrolling

I know a somewhat-evil way of doing parallax scrolling if you are using DD. I don''t know if there is a better way to do this that is hardwear accelerated, but just make a surface for each layer, blt your background to it or your tiles and then blt the layer. Repeat this for all the layers, going back to front, etc. Make sure to leave some transparent space in your layers to see the one''s behind. Blt your foreground objects (player, items, bad guys) last. Set up some kind of proportion that relates player movement to the speed of the background. Try this for starters, you may need/want to tweak it.

LayerSpeed = PlayerSpeed / Layer;

Make sure that Layer 1 is the one closest to the foreground and you don''t have a layer 0 . Use the LayerSpeed value to tell how much you need to offset the background layer. If you are using tiles instead of a giant bitmap you will probably need to re-render them.

I forgot to mention that the foreground objects and Layer 1 should move at the same speed, although you could change it for some rather weird effects (it reminds me of being dizzy).

If you want to have parallax scrolling for up and down as well as side to side, you can use the same formula! Just apply it to the Y coordinate instead of the X. I hope this helps you...

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