so @TomF talked me into making it so blending colors on the #Mega68k console is true blending rather than resolving back to one of the 64 palette colors (so that the output is always 64 color)
i made a utility that takes an image and converts it into a tile layer with only 16 base colors with the framebuffer overlaid using all 64 colors with alpha blending and i can't help but wonder if this isn't too powerful
grabbed a background from opengameart.org (https://opengameart.org/content/backgrounds-3) processed it and slotted it into the battle scene i've been working on and
yeah, i'd say that works pretty well?
@eniko @sinbad @TomF So you get all 4096 colours at once, but it can take up to 3 pixels to get the right colour (each pixel in a row only changes one channel).
That results in colour fringing and made it hard to animate.
There was also Extra Half Bright. You get a palette of 32 colours, but 6 bits per pixel. There's an extra 32 colours that are all half as bright as the colours you set. Since the display was planar, one bit plane could work as a shadow layer.
Dang! Looks good to me... Really good!
@eniko
is this blending between multiple tile layers, or a tile layer and sprite layers?
could it also work with moving objects that stay aligned to the tile grid? (i.e. board games, tetris blocks)
@clyde it's blending between one tile layer and the framebuffer (which sort of acts like a layer as well)
the trick is that the console's framebuffer uses 1 byte per pixel, allowing you to use all 64 colors plus all 4 blend factors (25%, 50%, 75%, and 100%) so even though the tiles are restricted to a 16 color palette the framebuffer can blend over that to create 16 * 256 = 4096 theoretical colors
it would be very hard to do with anything non-static because you have to figure out for each pixel which of those 4096 combinations is closest to your source pixel
you can however layer the 2nd tile layer on top of this, as well as sprites
@eniko with the 2nd tile layer and sprites it might make a good background for a shmup if it can be scrolled
wrt whether it's too powerful it seems like exactly the kind of neat trick that makes retro systems and fantasy console development fun!
@glairedaggers well the secret sauce here is that the framebuffer allows you full use of all 64 available colors in order to blend them into the base 16. not sure you can do that on the SNES?
looking at it mode 3 has a 256 color plane and a 16 color plane so maybe? though i think the blending could only do 50% blend, not 25%, 50% and 75%
@eniko The second image is just the FB, right? Already looks pretty nice to me! The final has a little bit less dithering in places, but you have to look pretty hard.
This is easily as annoying to use as Amiga HAM mode, with similar end results. I don't think it's too much :-)
@TomF the 2nd one is the reduced color one yeah. it uses both a 16 color tile layer plus the framebuffer with blending, so once you set both of those up its set and forget
and i guess you do have to roll your own utility to do the conversion which is not exactly trivial >_>
Attached: 1 image in case its not clear you overlay the 4th image in the original post on the 3rd and you get the result. like this:
@eniko @TomF it's weird but effectively you can think of it as just tripling the available colors, with the restriction that the two additionals are shades of the normal 15 colors per sprite limit, combine that with compositing multiple sprites, ntsc trickery, and even mid-frame palette updates you could do a LOT of onscreen colors. (though in practice around 100 is what the most "colorful" games used)
I really love tricks like that with color, lets you do cool things with not much to work with
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