BBC Micro conversions

[GroovyBee]

You guys aren't the only ones having some fun. Its my first one for the 7800 .

[PeteD]

I've GOT to go back and finish Arcadians especially now the sound stuff is working a lot better. I keep playing around with other games instead.

 

So far, things "running" (ie, working, just about playable but a percentage of the graphics display needs fixing) are Arcadians, Alien 8, Exploding Fist, Last Ninja 1 and 2, Starship Command, some "others"

 

I've also done a quick app to find graphics in beeb files.

 

 

It'll let you chnage video mode, width of the display, a byte offset and tell you where in "ram" your mouse is pointing. I'm adding a RAM/HEX display window and a thing to "tag" the start addresses of sprites etc then a hunt option that will look through data to see if it can find any sensible indexes or offsets based on the difference between the start addresses of different graphics.

 

*edit*

GB, you've arsed that url, it's got http://http:// or something odd in it.

 

 

Pete

Edited March 16, 2010 by PeteD

[GroovyBee]

I've GOT to go back and finish Arcadians especially now the sound stuff is working a lot better. I keep playing around with other games instead.

 

Yep! I know the feeling. Gotta keep at it.

 

So far, things "running" (ie, working, just about playable but a percentage of the graphics display needs fixing) are Arcadians, Alien 8, Exploding Fist, Last Ninja 1 and 2, Starship Command, some "others"

 

You're a busy man. I'm looking forward to seeing how they turn out.

 

I've also done a quick app to find graphics in beeb files.

 

This should make Beeb conversion life much easier. If you need beta testers just let me know.

[GroovyBee]

GB, you've arsed that url, it's got http://http:// or something odd in it.

 

Fixed! Still half asleep this morning .

[PeteD]

Will the lack of RAM on 7800 make doing any graphics intensive stuff impossible? I suppose it depends if the graphics are in a format that's easily pointed to for drawing, ie not like the sprites in last ninja which are runlengthed.

 

 

Pete

[GroovyBee]

Will the lack of RAM on 7800 make doing any graphics intensive stuff impossible? I suppose it depends if the graphics are in a format that's easily pointed to for drawing, ie not like the sprites in last ninja which are runlengthed.

 

For Tempest I create a frame buffer in cart RAM using MARIA 160B mode (4BPP). The only thing likely to slow things down is MARIA DMA. If its a really intense graphics game I can see things slowing down. It also depends on how much self modifying code is the original game too. I have to work around that when its in ROM.

[PeteD]

ahh so you can have a full screen buffer I thought you were doing something crazy like making a y bucket/point list as the VDU PLOT function was called then drawing pixels as sprites I've found (as I think you have) that stuff tends to run at an ok speed as no doubt our ROM functions are a little more specific than the beeb ones and don't trudge through a pile of superfluous code to actually do THE thing it's been called to do

 

 

Pete

[GroovyBee]

ahh so you can have a full screen buffer I thought you were doing something crazy like making a y bucket/point list as the VDU PLOT function was called then drawing pixels as sprites

 

Nah! I went for the simple option of a frame buffer. When you have 4K of RAM that needs to hold the Display Lists, the self modifying code and the variables needed for the game its probably going to be a tight squeeze in most cases.

 

I've found (as I think you have) that stuff tends to run at an ok speed as no doubt our ROM functions are a little more specific than the beeb ones and don't trudge through a pile of superfluous code to actually do THE thing it's been called to do

 

The Tempest line drawing routines could easily be optimised. I just wanted something to get me going ASAP. As soon as I've got rid of the game glitches they'll be first on the hit list.