Okay.
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One simple idea is to create tiles of the night graphic place them on a layer above(use the "snap to grid" option) the player and you have the same overlay without the engine having to worry about the movement and tracking of the sprite. this will eliminate the need for the engine to scroll, track and update the position of the very large sprite.
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However if you're intent is to animate the night, ie;
simulate daybreak,
time lapse photography,
cloud cover
freaky spell efx
then i offer this bit of information:
I have experimented with over 96, 32x32, animationFiles.
With 16 frames of contantly looping animation.
Each all with a frame delay of 5...i have noticed no delay.
On a map that's approximately 832x624 that means i've covered 20% of the map with animating tiles.
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The DemoGame's map is about 3,000+ pixels large, you might want to use larger tiles; 96x96, 128x128,256x256.
that wway you use fewer tiles and cover a larger area without overwhelming the engine.
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You're unlikely to see this case of slowdown improve...no matter how much RAM you alot, that's just a really large(LxW)png.
Its just big and awkward...
and if you've noticed the engine is slow at animating png graphics in the editor.
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Random note:
for simple transparencies(meaning single/consistent level of transparency) using a pict files might be best.
use appleworks and use a pattern fill...save as a pict...the white areas will be knocked out andd the transparency effet will be akin to loking through fine knit fabric(Pict) as opposed to a film(PNG).
Useful if you don't have graphicConvertor, PhotoShop (full or element), or care to learn about the PNG format.
This solution's usefulness varies by case.
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