H4plo

Thanks for the clarification, and sorry about the elementary questions. I'm not at my development machine, otherwise I would have just played around with it. So every horizontal pixel is drawn twice in mode 2, meaning if I have a simple sprite which is a solid 8x8 block, at normal width it will appear as a solid 16x8 block.

Thanks. So in other words, if I have understood correctly, in mode 2, the *absolute* horizontal position of Player 0 is (HPOSP0 * 2), meaning it can travel over the whole visible screen. Is this right? Let's say my sprite is only 8 pixels tall. If I want the sprite to overlap the character on the 38th column (column 37), what should the HPOSP0 value be? 48 + ((37 * 8)/2)?

Thanks. So when in mode 2, if the X position is set to 90 for example, does it appear at position 90 on the screen, or 180? I'm trying to understand if the sprites can be positioned on the right side of the screen, when it is 320-pixels wide.

Hi all I have been trying to get my head around how the sprites work on the Atari 8-bit series. They are sure weird. I mean Amiga-grade weird. For obvious reasons. One thing I still don't have clear is the horizontal positions. I understand that they can be set using the registers HPOSPx. They are one-byte registers and I read somewhere that the visible range is actually 48-207 (160 pixels). But the screen is 320 pixels wide. Does this mean that the sprites can only be positioned on even X values? I'm surprised that all the sites I've seen so far simply brush over this. Thanks!

Thanks! Try Tenebra 2 as well.

Well the ST version took a while, but it is finally ready! https://www.atari-forum.com/viewtopic.php?t=43563

Hi all, I am pleased to announce that Tenebra 2 is ready! Get it from: https://h4plo.itch.io/tenebra-2 Although Tenebra 2 looks similar to Tenebra, it is a much more versatile game. Its adds many exciting new game play elements, including a portal gun! While the focus of Tenebra was precise positioning of lights, Tenebra 2 is more about using portals to pave your path to the exit. The first for levels are go over the existing elements from Tenebra, and the portals are introduced from level 5. Just like its prequel, Tenebra 2 is an atmospheric puzzle game with rogue-like aesthetics. Guide the hapless protagonist to the exit. Poor guy is afraid of darkness and refuses to walk in the dark areas. The game contains 35 levels and works on both PAL and NTSC machines. I hope you will enjoy it!

Thanks everyone. With some optimisations I was able to bring the end address back to $9E99. This is a port of one of my C64 games; I had a couple of big loops unrolled in the light rendering path for performance reasons, but Atari runs almost twice as fast as C64 and there was no need to keep those loops unrolled (actually it turned out it wasn't even necessary on C64, but I kept it that way anyway). I'll keep your advice in mind for my next game.

Thanks. Should I worry about this? Or is it normal/accepted for games not to run on those old variants?

Thanks. So if I understand correctly there is RAM available at $A000-$BFFF, but if a cartridge gets inserted it will be bank-switched to ROM.

Hi all, I read somewhere that the available RAM is from $2000 to $A000. My game (.XEX) uses $2000-$B3FF, however, it works fine on the emulator (Altirra) on all the configurations I have tried. Is it OK to leave it like this, or some additional steps are required? Just want to make sure that the emulator is not playing nice and giving me RAM where there is none. Thanks.

That's one platform I'm really keen on porting the game to. I know almost nothing about its architecture and will need to learn a lot, but the novel concept of the CPU's workspace registers intrigues me.

Thanks every one for your support! I'll try to port Tenebra 2 before the end of the year.

Watched this live, very entertaining! Thanks. It was cool to see people playing my game in real time. By the way, "Johnson's Cave" was a homage to Cave Johnson of Portal 2, which was a source of inspiration for Tenebra (and even more on Tenebra 2, which gives you a portal gun!). Finsternis was the original name of the game, but when I realised I couldn't fit it nicely on the title screen I switched from German to Latin and changed it to Tenebra.

¡Muchas gracias por eso!