Difference between revisions of "Sprites Multiplexing"

Revision as of 10:52, 8 October 2009

Sprites Multiplexing is a technic often used on other achines with Hardware Sprite Capability.

It was often used on the C64.

On the Amstrad PLUS range, it couldn't be used as well. But some possibilities exist.

It allows to Multiplex the same Sprite at different rasters lines.

The technic impose some specifications :

• The same Sprite is simply copied as it is.
• No multiplexed sprites can be at the same Line.

This can then be used for games like Shoot'emups... as the spriutes don't always need to be well animated (just moved) and as enemies waves are often pre-determined (R-Type is the typical exemple).

So it fit well for Vertical Waves of enemies.

Also for vertical or even diagonal special effects.

Multiplexing on the PLUS is much more difficult than on the C64. The reason is that the location for the graphics are fixed on the PLUS. e.g. Sprite 0 always looks at &4000 in the ASIC sprite RAM. This can't be changed.

On the PLUS however you can freely change the X,Y position so it is possible to perform some multiplexing of the sprites.

Another way to multiplex sprites is to use screen rupture, because the sprite X,Y coordinate is based on the CRTC's Raster and Line Counter.

Sprites Multiplexing on an Amstrad Plus

• maybe the Synergy synergy demo.

Other Sources

[Sprite Multiplexing Article for C64]