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Old 03 January 2018, 23:50   #1
gazj82
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Blitz - Strange graphic problems

I have a really strange issue with a game I am currently developing.

When I compile the code on my real A1200 (68030) eveything works fine. I can even put my code (compiled) on disk boot from cold and everything works as it should.

Now the weird bit?!

If I load the same ADF in fs-uae even with a configuration as close to mine as I can get the colours come out wrong on bitmap 0. Bitmap 1 and Sprites are fine. This happens on any AGA configuration.

If I load the same ADF on any EGA machine any configuration the code runs but nothing is displayed on screen at all.

Some notes about the display. Dual playfield displaying two 16 colour bitmaps. Sprites are as far as I know in 16 colour mode. 4 sprites are displayed using the palette colours from bitmap 1.

Any ideas? I can post my code in "The Zone" if needed.
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Old 04 January 2018, 01:55   #2
idrougge
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Dual playfield has a maximum of 8 colours per playfield on ECS/OCS.
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Old 04 January 2018, 02:56   #3
Shatterhand
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But 16 colors per playfield on AGA, which is what he's using from what I understand.

I remember there are some registers to change what colors on the 256 color palette are used for sprites on AGA (which made my own game Quasarius show wrong colors on AGA machines on the 1st version, because change those registers had no effect on ECS), but I don't think there's something similar for dual playfield.
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Old 04 January 2018, 08:50   #4
gazj82
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Quote:
Originally Posted by idrougge View Post
Dual playfield has a maximum of 8 colours per playfield on ECS/OCS.
Well this will be why it doesn't work on a A500. I thought ECS was 16 per playfield. Oops! Does this mean only 8 colours available for sprites too?

It doesn't explain my A1200 troubles tho.
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Old 04 January 2018, 09:11   #5
idrougge
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Sprites are independent from the playfields and may use their own separate 16 colour palette.

What do your CopLists look like?
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Old 04 January 2018, 10:35   #6
Zener
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If it works in the real amiga, it must be emulator's fault. If you can, try it with WinUAE.

This game uses AGA dualplayfield with Blitz, you can try if results are the same: http://www.lemonamiga.com/games/details.php?id=3846
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Old 04 January 2018, 22:23   #7
gazj82
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Well, I got my game down to a single playfield with some work, and at least I know why my dual playfield wasn't working on an A500
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Old 04 January 2018, 22:46   #8
Shatterhand
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Quote:
Originally Posted by gazj82 View Post
Well this will be why it doesn't work on a A500. I thought ECS was 16 per playfield. Oops! Does this mean only 8 colours available for sprites too?

It doesn't explain my A1200 troubles tho.

Colors 16,17,18,19 for sprites 0 and 1
Colors 20,21,22,23 for sprites 2 and 3
Colors 24,25,26,27 for sprites 4 and 5
Colors 28,29,30,31 for sprites 6 and 7

colors 16,20,24 and 28 are transparent and won't show up when displayed on screen.

You can also use all colors from 16 to 31 in a single sprite (16 as transparency), but then the sprite will use 2 sprite channels.

Collision detection is also shared between sprites that use the same color registers. Very weird.
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