megatronx my genre is top-down space shooter.. unbound layout. So I have pretty big background graphics.. nebulas, star, planets etc.. the nebulas are the most worrisome because there needs to be a lot to give the levels some "life" (color), otherwise it's all bland black and white stars...I'll be posting the trailer this week.. here's my parallax test vid.
https://vimeo.com/137027609
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> keep all assets hd first, but then gradually lower their resolution, starting with the obvious assets of lowest priority of importance.
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Do you mean make my current graphics lowres, by Shift-click dragging the corner of the sprite in the Layout view? or are you saying to scale them down in PS?
I was originally thinking of doing exactly what you are saying as a way to test performance - like who cares what the graphics look like, just make all my current assets tiny and run the game. But I have so many things on my plate I decided to come to the boards to see if anyone was ever wondering the same thing. i.e. is it a worth while test?
You can still make it look like a blast!
Optimize in PS, not in c2 and not by shift-drag. This doesn't do anything if you are using high quality scaling -it will still load full res image and then it will shrink it. But it works in reverse too: if you have sprite 16x16 and game running in 430x270 and high resolution scaling, and you are outputting this in full hd, that 16x16 sprite becomes 4 times the size when rendered, it becomes 64x64, and takes as much memory, even thought it is still looking like 16x16. But now imagine something different: that your sprite is 64x64 but shrank down in c2 layout editor to 16x16 and the game is still 430x270. In high quality scaling and in full screen and in full hd it again becomes 64x64. But now it is not upscaled 16x16 sprite - it is that original 64x64! Now check this: if the pc is not strong enough to output assets in full hd, you switch renderer to low quality scalling, and now this 16x16 is rendered as 16x16 but upscaled to fit the screen.
So what you need to do, is to set your games resolution to half hd i wrote above, make all sprites in the editor half the size, but load original hd assets, and those will render now differently depending on the type of scaling.
And now going back to your question about optimising the graphics: you do this in photoshop. For example that nebula could be done differently: instead of having interlaced 16-bit or higher png, you can set its saturation and levels in ps, and also replace transparency with black colour, then export as 8-bit png, and in c2 editor set it's blending mode, making black background becoming transparent.
Also, exactly on images like nebula, you could try lowering their resolution in PS, because when rendered in high quality, the outline might not be perfectly smooth, but if you work it out, it being lower resolution might be barely visible.
Stars in the background you can easily slash by half of their resolution, and in c2 use sharpener and maybe some polishing one to give more brightness ( thought here I can't remember if the shaders will also render in full hd if high quality scaling is on, or not )