16 replies to this topic

[in8regs]

Hi! First time posting.

I thought of this forum/contest when I saw this on youtube: http://www.youtube.c...U7D7l7U_I#t=22s

Here's the BBC Micro version:

It looks to be well within the TI's capabilities, very simple, yet has a spark of fun to it. If there was a TI-99/4a version, I haven't run across it, anyone?

Edited by in8regs, Fri Mar 19, 2010 7:05 PM.

[sometimes99er]

Much the same sound chip in BBC as TI.

http://en.wikipedia.org/wiki/BBC_Micro
http://en.wikipedia....ruments_SN76489

Looks like a good choice for conversion !

[retroclouds]

I'm not aware of a TI version of this game and it looks doable

Checked the mentioned wikipedia link and the BBC micro even has a TMS5220 speech synthesizer
Makes me wonder if some of the games actually used it ?

same sound chip + speech chip = good candidate for TI conversion ?

[in8regs]

With the Electron and BBC Micro, resolution is 160 x 256, while the TI is 256 x 192, I was wondering if the TI was able to flip the x & y, else would have to sit the TV on it's side(or add a switch to the video cable to cross x & y)/use the rotate screen option under MESS, for 1:1 graphics.

Edited by in8regs, Sun Mar 21, 2010 6:10 PM.

[GroovyBee]

Just scale the graphics to the TI screen accordingly. All you really need are the game play aspects for your conversion.

Its a pity the TI99 isn't 6502 based. I'm working on a Beeb to Atari 7800 adaptation (using the original Beeb executable binary). I'm displaying the lower 192 scan lines of the display (and emulating the OS functionality used by the game). Its much more fun that I originally thought it would be.

[sometimes99er]

in8regs, on Sun Mar 21, 2010 6:07 PM, said:

With the Electron and BBC Micro, resolution is 160 x 256, while the TI is 256 x 192, I was wondering if the TI was able to flip the x & y, else would have to sit the TV on it's side(or add a switch to the video cable to cross x & y)/use the rotate screen option under MESS, for 1:1 graphics.

Hehe, rotate under MESS. You would have to care especially for that, but I like the idea.

[sometimes99er]

GroovyBee, on Sun Mar 21, 2010 6:17 PM, said:

Just scale the graphics to the TI screen accordingly. All you really need are the game play aspects for your conversion.

Well, I would rather generally keep the 8x8 pattern characters and rearrange the screen layout a bit.

GroovyBee, on Sun Mar 21, 2010 6:17 PM, said:

Its a pity the TI99 isn't 6502 based. I'm working on a Beeb to Atari 7800 adaptation (using the original Beeb executable binary). I'm displaying the lower 192 scan lines of the display (and emulating the OS functionality used by the game). Its much more fun that I originally thought it would be.

It's hard to change old habits. Have you ever done 68000 programming ?

Edited by sometimes99er, Sun Mar 21, 2010 11:58 PM.

[in8regs]

Anyone know anything about BBC Micros? The emulators, the ones I've gotten to work at least(I swear, disk/etc images never work with MESS, it's like they one offed everything,) the screen capture options and displays do 320x256 or multiples thereof, not 160x256. Did the machines double render x for 320 displayed, 160 addressed?

Found the answer, akin to what I thought: http://www.acornelec.../67/a-diys.html

gunsmoke looks to use eight colors, which according to this: http://nvg.org/bbc/history.php3 makes it mode 2, which contradicts the first link and a gunsmoke review I had run across, but whatever.

Here's a useful cheat to see the whole game: http://www.acornelec.../11/a-elke.html Except I have no idea where to put this. I used a bbc utility called bas2txt, after extracting the game files from the disk image with bbcexplorer 2.01, that converted two of the games files(smoke$ & smoke2$) to basic, but nothing in them matches up with the basic listed in the cheat. The two bigger game files look to be assembled or compiled code that bas2txt doesn't generate meaningful output for. MESS has it's debugger, but no disk files work with MESS.

BTW, the BBC has some nice ideas for utilities that the TI could benefit from: http://www.acornelec...and/r-imag.html Of course, I can't find it to download it. They were doing this back in 2007, and the links have gone stale.

Edited by in8regs, Mon Mar 22, 2010 5:03 AM.

[GroovyBee]

sometimes99er, on Sun Mar 21, 2010 11:57 PM, said:

Have you ever done 68000 programming ?

Back in the day I used 68000 on my ST. With Devpac it was by far the fastest development solution.

in8regs, on Mon Mar 22, 2010 12:48 AM, said:

Anyone know anything about BBC Micros? The emulators, the ones I've gotten to work at least(I swear, disk/etc images never work with MESS, it's like they one offed everything,) the screen capture options and displays do 320x256 or multiples thereof, not 160x256. Did the machines double render x for 320 displayed, 160 addressed?

Have you tried BeebEm?

http://en.wikipedia.org/wiki/BeebEm

Its what I've been using for my stuff. However the debugger is very basic . The emulator hasn't had any problems with any of the games I've thrown at it .

160x256 is mode 2 or mode 5 depending on the number of colours. There is a better description of the Beeb's video modes at the wiki for it.

http://en.wikipedia.org/wiki/BBC_Micro

For acquiring games I've been using :-

http://www.stairwaytohell.com

If you have any other Beeb problems just ask. I'm learning more about the Beeb every day.

[in8regs]

The wiki doesn't go into details.

160 x 256 is the logical representation of the mode while the actual display is scaled:

http://www.stairwayt...cro-CToday.html

"The first clever thing about the graphics is that no matter what Mode you are in, the graphics screen is made to appear 1280 pixels wide by 1024 pixels high."

If you were to try to match the logical, your port wouldn't look the same as the BBC output. The ratio for 1280x1024 is 1.25, which is the equivalent to 320x256.

Edited by in8regs, Mon Mar 22, 2010 9:39 AM.

[GroovyBee]

in8regs, on Mon Mar 22, 2010 9:34 AM, said:

160 x 256 is the logical representation of the mode while the actual display is scaled:

Yep! I have to divide X and Y to get the 160x256 that I need to display.

Quote

If you were to try to match the logical, your port wouldn't look the same as the BBC output. The ratio for 1280x1024 is 1.25, which is the equivalent of 320x256 scaled down.

Nope! The display looks like it does on the Beeb. You are assuming that for each video mode X and Y are scaled equally but they aren't.

[in8regs]

GroovyBee, on Mon Mar 22, 2010 9:40 AM, said:

in8regs, on Mon Mar 22, 2010 9:34 AM, said:

160 x 256 is the logical representation of the mode while the actual display is scaled:

Yep! I have to divide X and Y to get the 160x256 that I need to display.

Quote

If you were to try to match the logical, your port wouldn't look the same as the BBC output. The ratio for 1280x1024 is 1.25, which is the equivalent of 320x256 scaled down.

Nope! The display looks like it does on the Beeb. You are assuming that for each video mode X and Y are scaled equally but they aren't.

X & Y aren't scaled equally at 320x256. X is 2x the logical while Y is 1:1. If you're saying the display renders the logical resolution of 160x256, then all the BBC emulator authors have written their emulators incorrectly, as their virtual screens are 320x256. If you want to see the difference, do screen capture then scale the picture to 160x256, the result is narrower than what emulators display.

Edited by in8regs, Mon Mar 22, 2010 9:50 AM.

[GroovyBee]

in8regs, on Mon Mar 22, 2010 9:43 AM, said:

X & Y aren't scaled equally at 320x256. X is 2x the logical while Y is 1:1. If you're saying the display renders the logical resolution of 160x256, then all the BBC emulator authors have written their emulators incorrectly, as their virtual screens are 320x256. If you want to see the difference, do screen capture then scale the picture to 160x256, the result is narrower than what emulators display.

I'm not familiar with how the BBC generates its video display down to the pixel clock. However it is pretty common not to have square pixels under emulation because the aspect ratio doesn't look right.

[sometimes99er]

GroovyBee, on Mon Mar 22, 2010 8:39 AM, said:

sometimes99er, on Sun Mar 21, 2010 11:57 PM, said:

GroovyBee, on Sun Mar 21, 2010 6:17 PM, said:

Its a pity the TI99 isn't 6502 based.

Have you ever done 68000 programming ?

Back in the day I used 68000 on my ST. With Devpac it was by far the fastest development solution.

Oh yes, Devpac. Anyways, personally I think 9900 is more like 68000 than 6502. The bare TI console only has 256 bytes of RAM. The 16K RAM is allocated to the VDP accessible thru a port (write address and the read of write bytes with auto increment). The Coleco and MSX uses Z80A and has 1K and 16K CPU RAM respectively.

[in8regs]

Attached is a cleaned up 256x192 resolution of gunsmoke. His leg and arm/gun animation and then inverse for going both directions are all that's left to do graphics, aside from the dot representing the bullet, palette flashing from getting hit, nighttime color scheme, and regular character fonts.

Attached Files

•  gunsmoke.bmp   49.05K   12 downloads

Edited by in8regs, Mon Mar 22, 2010 10:46 PM.

[retroclouds]

very nice

[in8regs]

And the walking and aiming frames.

Attached Files

•  gunsmoke.bmp   49.05K   8 downloads