PalRGB not working on OCS/Kick1.3?

[carrion]

Hi Guys.
I've encountered interesting issues with PalRGB function.

As we know Palette object can have 256 colors (indexes). PalRGB, as we know is used to set RGB colors for each of them.
Palette IMO is independent of the Display so I can have a Palette with 256 colors on OCS for example to use for Rainbows. Right?

Now...
What I've found is that
On OCS PalRGB crashes when I try to set color for index 32 and above. Even so when Palette I'm doing it for is 256 colors big.
On AGA machines I can set the colors without problems.
But what's more interesting is that when on OCS machine with kick 3.0 I can setup colors for full 256 Palette.

For me it looks like a bug on 1.3 OCS machines, but maybe I'm doing something wrong? Or misunderstand the use of Palettes and PalRGB?

[Thomas Richter]

While I do not know Bliz, the v33 graphics library does not allow to set a color index beyond index 32, not matter which size the color map was allocated.

Note the OCS chipset only supports 32 color registers, and thus the Os truncates indices to 32. The Os, however, does not crash upon illegal entries, it just returns -1.

[Honitos]

I guess you are testing your code without the debugger, right?
As what I can see in the code of the palettelib, it checks the exec version to be at least 39. In this case it is assumed that aga chipset is available.
If exec version is less than 39, there will be done some boundary checks for example if colour registers are in the range 0-31.


As the system works with processor traps that are catched by the debugger, the program will crash if the debugger is switched off.

[Asman]

I guess that assumption about chipset aga (exec version to be at least 39) is wrong, right ?

[carrion]

Guys
What I understand so far is that PalRGB is using some kickstart function to build palette that on non AGA machines can be max of 32 colors.
If that's true then on OCS the DisplayRainbow is limited only to have 32 colors in the rainbow - Which IMO is very limiting.

Looks like on OCS the way to do rainbows is by using DisplayRGB. Correct?

[Honitos]

I am not very familiar with graphics at all, so I cannot help choosing the propor commands here.

I could remove the checking that you could modify colours above 31 with PalRGB, but I don't know if this would result in any other side effects....

[Thomas Richter]

Originally Posted by carrion

If that's true then on OCS the DisplayRainbow is limited only to have 32 colors in the rainbow - Which IMO is very limiting.

I'm not sure what you want to attempt, but the 32 colors is a limitation of the chipset as well, thus you need to use other techniques to get more colors on the screen. HAM or user copper lists are two prime techniques to get more colors than there are color registers, and both are supported by the Os.

[carrion]

Well what I want to achieve is to use DisplayRainbow to do a nice copper rainbow. To define colors for the rainbow I am supposed to use PalRGB to define colors for the rainbow but on OCS kick 1.3 I can do it only for 32 colors.

Of course I can think of some workarounds (like mentioned DisplayRGB) but I was just wondering and wanted to confirm that PalRGB command is limited on kick 1.3 - and looks like it is limited to 32 colors in palette.
Thants it