The useful basiegaxorz sub topic

[jlf65]

One thing to keep in mind when using DMA... NOTHING else can use the 68000 bus while DMA is occurring. More than one commercial game stutters on the sound because they use long DMAs that prevent the Z80 from reading the rom for long enough to make the sound stutter. If you have a big block to DMA and use the Z80 (especially for PCM samples), consider breaking the block into several smaller blocks.

[Deleted]

Could someone explain what the LinkSprite command is doing? Is it something where you can specify a different set of tiles for your sprite?

[Tiido]

each sprite has a link attribute which specifies which sprite gets drawn next.

[Deleted]

Jul 15, 2011 9:54:12 GMT -5 Tiido said:

each sprite has a link attribute which specifies which sprite gets drawn next.

So it's not to change which set of tiles a sprite uses then? It just change the priority of the sprite?

LinkSPrite must only be useful for flicker management then. Maybe you would change which is the highest priority sprite to keep the last ones from always flickering. *shrugs*

[Deleted]

Priority is something else, the link field defines the order in which the sprites are rendered. Quoted from Charles ..

The VDP draws sprites in a front-to-back order, starting with sprite zero.
The 7-bit link field in each list entry is an index to the next entry of
the sprite that will be drawn. If the link field is zero, then no more
sprites will be drawn after the current sprite. Here's an example:

Sprite #00 has a link field of 2
Sprite #01 has a link field of 7
Sprite #02 has a link field of 4
Sprite #03 has a link field of 0
Sprite #04 has a link field of 3
Sprite #05 has a link field of 2

In this case, sprites #00, #02, #04, #03 will be drawn, in that order.

And flickering isn't caused by the hardware, it's a software "trick" in which you cycle the sprites that cause a scan-line overload in order to prevent one from being invisible all the time.

[Deleted]

LinkSprite would be useful for determining which sprite should be "in front" of the other - like in Streets of Rage when you walk up to an enemy, if you're closer to the bottom, your sprite should be "in front" of him, but if you're closer to the top, you should be "behind" him.