Games in bitmap mode and multicolor mode

[Sergioz82]

Hello.

 

What are the TI-99 games that use bitmap mode and those that use multicolor mode?

 

I'd like to start messing with assembler and I'd like to see what could be achieved with such modes.

 

Now I'm looking at games try to figure out how they did that.

 

In particular I'm interested in moving terrain like in Moonsweeper and Buck Rogers.

Is such effect obtainable in standard graphic mode? 

 

Speaking of Moonsweeper, what mode do you think it uses? The background planet doesn't look standard graphic mode, but maybe it's a trick (two contiguous character with different colors that give the illusion of multicolor, for example the green moon that has a shade of lighter green). Also, the enemy UFO while on the moon has 3 colors(2 + transparent). Maybe it's two overlapped sprites?

 

Another thing I don't understand: can sprites be multicolor? 

 

 

[+Lee Stewart]

1 hour ago, Sergioz82 said:

Another thing I don't understand: can sprites be multicolor? 

 

No.  Sprites can have only one color in each mode they are allowed. They are allowed in all modes except text mode. The on bits in the sprite pattern take the sprite color and the off bits are transparent.

 

...lee

[ti99iuc]

Hello Sergio,
I do not know if you have already seen it but there are some pages on ti99iuc's website that could be of your interest maybe.

 

this is the Back Rogers XB routine:

https://www.ti99iuc.it/web/index.php?pageid=database_cerca&archivioid=920

 

for the Multicolor Assembler routine, I do not know if it also can help you, it is a program in MM but on the magazine scanned you can find the source listing... maybe is this the multicolor mode you mean?

https://www.ti99iuc.it/web/index.php?pageid=database_cerca&archivioid=1002

 

I also suggest to look here in AtariAge there are some of the @Asmusr demos that using multicolor mode.
some of them you can also find <<here>> including the sources he realeased with.


 

 

[Asmusr]

You can see in an emulator if a game is using bitmap mode by checking in the debugger if VDP register 0 is 2. Parsec and the Atarisoft title are examples.

Sprites with more than one color can be obtained by stacking sprites (Ms. Pac-Man, Flappy Bird), or by adding a 'soft sprite' made of characters behind the sprite (ghosts' eyes in Ms. Pac-Man). With the former method you quickly run out of sprites per line, and the latter is expensive for performance and requires that the background is otherwise empty.

Edited March 27 by Asmusr

[Asmusr]

To see if something is made of sprites or characters, run the game in Classic 99 where you can disable the sprite layer.

[Sergioz82]

@ti99iuc

 

thank you, I didn't think it was possible to have that terrain effect in XB. I'm downloading that routine. About multicolor, it doesn't seem a viable option for games, am I right?

 

@Asmusr

 

thank you very much for this suggestion, I'm definitely going to try it.

For sprites I suspected there was some kind of trick, now I've got the confirmation.

I imagined the one can make multicolor sprites by stacking them but I've never imagined the sprite + character combination, interesting idea 

[+pixelpedant]

 

3 hours ago, Sergioz82 said:

About multicolor, it doesn't seem a viable option for games, am I right?

 

It's entirely possible to create a multicolor game, especially given that you still have sprites to work with.  Your background is just very low-res, and somewhat annoyingly difficult to work with itself, for all the simplicity of the result. 

 

Full-fledged multicolor mode games have been created on MSX (with the same graphics architecture).  Consider, for example, Spade Carrier - a Space Harrier clone:

 

 

There have been text mode Space Harrier clones for earlier Japanese computers, so a 64 by 48 clone isn't all that crazy, at the end of the day. 

 

[Elia Spallanzani fdt]