For example, i got 100 objects on the map and i want to apply those the sharp or contrast effect. Will this have an impact on the game performance? or the game will somewhat pre-render the effect and use the modified sprite in the game to avoid losing performance?
No, it'll do it in real-time, so it will hurt performance as you scale up. A good way to reduce the performance hit is to apply the effect to the entire layer, and then create layers just for the sprites you want to affect.
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Thanks, just the answer i was looking for, i was already planning to apply it to the layer. Good to know.