CRT Unit

Posted by ALB42 on 29. Dezember 2019No Comments

Most Tutorials about Pascal use the CRT unit in a very early Lesson. They use it only for ReadKey() to wait for a key at end of Program. It would be of course the same to just use a ReadLn and wait for an Enter.

I tried already to implement CRT before using an old implementation, but exactly this ReadKey implementation does not work at all when KingCON or other console replacements is used.

Now I got a hint in MorphOS Forum (always a very good Source for Implementation hints) to set the console in RAW: mode (using SetMode()) and then just read from the console the pressed keys. If console in raw mode, one can read cursor keys and F keys from the console.

I tried that and on MorphOS and AmigaOS3 it works well, Read blocks until a Button is pressed. But AROS of course is different again 😉 it always returns a Value sometimes 185, sometimes 184, not really know what that means. I thought about some kind of timer event but this should look different.

But finally it works, mapped some keys like F-keys and cursor. Also worked on the output gotoxy and colors, the colors are a little bit tricky, because the Amiga console only supports the first 8 pens (as far as I see it) so I cannot just ObtainBestPen, and the first 8 Pens are usually fixed and not the colors I need. I try to change them with ObtainPen but when they are already taken I just try to find one which has a close color, which does not work very well. Solution unknown.

I compile the example of ReadKey as example3.pas and compiled a little RPG-Game I found which is console based, which is a good testcase for colors and GotoXY. Of course looks not the same as in the DOS console but it is usable.

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