There are a lot of ways to do it but I won’t detail it here, it’s not the right thread.
I could explain it in 20 pages like in 1000.
Vblank,scanline change, palette cycles, rendering and many other techniques for that.
Metal Slug 3 on the Neo Geo also makes heavy use of animation-based transparency. On the big alien boss, when he’s still covered in his brain, the energy balls he generates are transparent, but when they start moving towards you, they become solid. The reason they are transparent at first is because they are all pre-rendered.
Or maybe that too. Are you telling me that composite is useful for displaying transparency?
I suggest you read the link I provided. Everything I site comes from there.and the answer to your question is also there I think…
It’s always a problem of semantic argument. Is the shaking of the checkerboard transparency? Is blinking an image every odd frame transparency? Both accomplish a similar effect to transparency, as does S/H.
It’s very different for me, dithering only works in the case of bad video output, and the flashing image is easily broken just by pausing the game, so anyone can see that it’s fake!
Very different from S/H mode, which works great on any video output and looks great even today.
https://www.sega-16.com/forum/showthread.php?28972-Mega-Drive-Genesis-Transparency
In depth
https://www.sega-16.com/forum/showthread.php?9179-Highlight-and-Shadow
https://www.sega-16.com/forum/showthread.php?25837-Games-that-use-Shadow-Highlight
Discussion between users of the good and not so good
https://www.sega-16.com/forum/showthread.php?42-Genesis-VS-SNES-VS-TG-16&p=32485&viewfull=1#post32485
For example in the link highlight and shadow I can see interesting things like this…
Quote Originally Posted by Jasper061992 View Post
Oh. If it’s a scan line change, how come every time I have slowdowns underwater, the color stays solid (no flicker)? I can tell the difference between the water in Sonic 1 (the water in the maze which has a real clean hue and the water in act 1 of the aqua planet area in Sonic 2 which has a dotted look every other pixel. Is this the effect of changing the scan line?
Are these two Sonic you are talking about the SMS or Genesis versions? The Genesis version of Sonic 1 does mid-screen palette updates (it may even do mid-screen tile changes too, but I doubt it since it already does palette block updates).
This leaves artifacts of corrupted pixels on the screen, mostly evenly spaced (it’s either 16 or 32 pixels apart, I forget from memory). So they put glittery/alternating sprites at the edge to help hide that. And that really makes it imperceptible. Also, when you change the position of a palette or mosaic in the middle of the screen, the rest of the screen is now drawn with these new updates. So you don’t need to do this effect on every scan line. Just at this point.
Actually, when i pause the game on Sonic 1-3 that flickering water waves can disappear at one side. The sprite colour neatly changes colour when one half is outside and the other inside along with any other graphics thats half out.
I’m not sure what you’re asking though? Not every transparency trick uses 60hz “flicker”, obviously. And what the game does when you pause it, is up to the developers. There’s nothing to prevent the sprites from alternating on the waters edge, other than the programmer decided the pause function was also going to pause that routine as well. There are a lot of tricks you can do be it the SMS or the Genesis, and not all of them are necessarily the same. Hell, SMS games are known to do software sprites because it has 4bit tiles. You’ll 99.999% never see this on the NES because if its lower color count/restrictions on tiles. If I were going to do such method on the SMS, it would a tilemap method like I mentioned earlier on and interrupt, and manually update the Sonic sprite with different colors depending on which point he entered the water (mainly, because I’m not sure what the effects or possibility of updating palette ram mid screen on the SMS), which is a very simple task given the 4bit color limit of sprites.
lol, i meant if Sonic loses rings underwater, the game framerate slows down to 25-30fps and yet the water colour is still solid, no flicker.
Why would that make any difference though? And interrupt is an interrupt. It’s going to happen whether the game codes falls behind or not, on a frame. It’s regardless if this is done via palette reg updates or tilemap method, or both. The color shouldn’t flicker because the game slowed down. You might be confusing this with some else (or some other broken/borked game engine) or maybe flicker style transparency. Dunno.