Colors on the Amiga

[Thomas]

I gave you an answer on The Amiga Forums: http://www.amigaforums.org/forums/viewtopic.php?t=1404

Bye,
Thomas

[Thomas]

HAM is 4096 color. 16 colors can be choosen directly and the others need three pixels to be set (one for changing red, one for changing green and one to change blue).

And yes, theoretically the Copper is able to change the colors every line. But every copper instruction needs as much time as the graphics needs to display four pixels. Changing all 32 color registers needs more time than the horizontal sync signal (the time the beam needs from the right end of one row to return to the outer left in order to start the next row). But it is easily possible to create a color fade from the top to the bottom of the screen with only one color register. For example for creating a sunset sky and the corresponding horizon and ground as a background. No graphics data is needed for this apart from the Copper's command list. The foreground can be painted using the remaining 31 colors (or 4096 colors in HAM).

Bye,
Thomas

[Thomas]

Startup code is ok, but I don't like the exit code. Usually you want to return to the assembler without reboot after the test.

Something like

mouseloop:
   btst #6,$bfe001
   beq.s mouseloop
;
;  restore system copper list here
   rts

is much more convenient.

Bye,
Thomas

[Thomas]

Well, some school friends of mine were members of a scene group. Alpha Flight, IIRC. They [d]provided me with cracked games and[/d] encouraged me to start coding intros and demos. I think I finished two or three works which were really published, but I never advanved as far as the "real" demo coders. If memory servers correctly just before end of school (must be 1989 or '90) we joined a group called Catwalk. But then I lost contact to the people and to the scene shortly after that.

One of my friends coded a translator which created 68k assembler code from Rob Hubbard C64 songs, just around the time when (or shortly before) PlaySID was developed.

Bye,
Thomas

[Thomas]

evil_nerd wrote:
ok I wanna give it a try! Using C, I wanna make some graphics But whats a good tutorial (never programmed on an Amiga before, is it much different from x86?

Before you start coding for the Amiga you have to learn about the structure of AmigaOS and its coding rules. #include will not work on the Amiga.

A big big recommendation is to buy the Amiga Developer CD. It is not too expensive, especially in its older versions which all cover the 1.3 NDK (Native Developer Kit).

It also covers the RKRMs (ROM Kernel Reference Manuals) which are essential readings.

Bye,
Thomas

[Thomas]

But before I buy the CD

Why It is essential. And it is cheap. And it has a C/C++ compiler with GUI on it (which requires Amiga OS 3.x though, and a CD-ROM drive of course).

However you might have a look at the programming part of http://www.amigau.com/

Bye,
Thomas