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rupy
Registered: Mar 2020
Posts: 45 |
3 Color high res with char + multiplexed sprites 192x192 res.
Has any game made a fullscreen multicolor highres rendering engine?
How expensive would that be in terms of cycles?
Edit: Wait now that I think about it... sprites would cover 3 chars in width... that would only allow one overlay color.
I guess it kind of works with black background, white highlight color and char custom color.
Dithering to the rescue? |
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cobbpg
Registered: Jan 2022
Posts: 50 |
Just to give some examples of games that use a sprite layer to add more colours or increase resolution:
BrainBreak: hires sprites over hires bitmap (160x160)
Welltris: static hires sprites over multicolour bitmap (168x160, I think)
Kye: X expanded hires sprites under hires text (240x160 due to the level sizes, but could be full screen)
As for cycles used, it’s not too bad: you lose roughly 2 cycles per sprite per scanline due to sprite DMA, plus you have to multiplex them every 21 lines, which costs two scanlines worth of cycles each time: one to update Y coordinates, and another to change the sprite pointers (you likely need to sacrifice another line if you want to involve all 8 sprites in this). And you have to be mindful of badlines, of course. Altogether this eats up roughly 33% of the cycles within the affected area assuming 7 sprites.
Using only 7 sprites makes the timing easier, since you can just e.g. increment all sprite pointers within a single line without having to save any registers first, because you can set a timer to fire during sprite DMA for a free raster stable timing. |
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Krill
Registered: Apr 2002
Posts: 3097 |
Quoting cobbpgAnd you have to be mindful of badlines, of course. Actually no.
Can likely also use this Maniac-Mansion-like lazy multiplex scheme which exchanges exact register updates with some more memory for partially redundant sprite patterns. =) |
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cobbpg
Registered: Jan 2022
Posts: 50 |
Fair enough! When it comes to games, you certainly can’t go as crazy with memory layouts as in demos, but it’s true that there can be a lot of flexibility depending on your needs.
In the case of Kye I only have to update 5 sprites thanks to only needing to cover 30 characters horizontally, so I could get away with just plain non-stable raster interrupts and starting the whole process from a specific Y coordinate that makes it easy. :P |
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rupy
Registered: Mar 2020
Posts: 45 |
Thx, now I just have to solve the network! |
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oziphantom
Registered: Oct 2014
Posts: 502 |
for "rouge" graphics, ECBM would probably do just fine as well. |
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rupy
Registered: Mar 2020
Posts: 45 |
The difference between 2 and 3 colors is huge in terms of not looking like YASG (speccy)...
This makes C64 almost compete with NES.
Also I already have gfx in 3 colors... just need to adapt them to C64 palette. |
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ChristopherJam
Registered: Aug 2004
Posts: 1423 |
Archon - Super Hires is 320x200 with three colours - there is just an slight restriction left and right of the middle six character columns.
(basically for the outer 34 columns each character has to make a choice as to whether it is black or white that can share 2x1 pixel areas with grey inside that 8x8 block. Black paired with white is always legal.) |
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rupy
Registered: Mar 2020
Posts: 45 |
Cool, what is the difference between "super hires" and "hires + sprites" when you search here?
nm, I think I figured it out, super hires is the one I'm looking for (only 20 pictures ever!?) and + sprites just fills the border.
Nice one: Untitled |
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ChristopherJam
Registered: Aug 2004
Posts: 1423 |
Yeah there are various ways of using sprite underlays or overlays to get more colours in hires, often by doing interesting things with priorities. What works best depends a lot on the style of graphics you want to produce. |
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Fungus
Registered: Sep 2002
Posts: 749 |
DeeKay and Crossbow made quite a few parts with these ideas and also with FLI. |
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