About guys and Players changing positions and priorities

[José Pereira]

In traditional Arcade beat'em'ups where, for example, you have 'our guy' and the enemys... like this taken from C64 version of Double Dragon 2:

According to their yPos vs the others they would be in front or behind.

In C64 where all Players are Hardware sprites, probably they would change Hardware sprite number according to yPos to get the needed priority.

 

If on A8, for example, I have 4PMs overlays 4soft sprites, in each PM/soft sprite is a guy, but in PRIOR stuff I need rigid PMs number to get the guys colour... like 'our guy' be PM2 and 3Enemys would be PM0,PM1andPM3.

 

All that constantly changing yPos would need constant Bitmap Masking between:

-> 1st: each (PM&soft sprite=one guy) Bitmap Masking with the screen Gfxs.

-> 2nd: (PM&soft sprite=one guy) Bitmap Masking with the other (PM&soft sprite=other guy) and this to all the 4guys.

 

The 1st would be only PFs. Bitmap Masking, right?

But using the (PMs. overlays soft sprites) you also need on the 2nd doing another Bitmap Masking and this time between the PMs.

Like, for example, PM2 on 'our guy' is in front of Enemy using PM0 then:

-> Enemy PM0 pixels that are 'behind' our guy must be erased.

 

How this sort of Bitmap Masking between PMs can be called?

The idea is having always same guys=same PMs numbers... This is possible, but is this really hard?

And will it takes many, many cycles wasting?

 

 

And a 4guys on screen with this size and this way, would or not be difficult to achieve in a 40bytes wide screen (even with ANTIC needing 48byte) ?

Edited September 28, 2011 by José Pereira

[emkay]

Not sure , if it answers your questions.

But, nothin easier to change the priority of software sprites than to change the drawing priority.

The last drawn object simply has the highest priority.

Same with Players. As you want to change the priority, just change the used player(s) and colour.

On the A8 you have to redraw the gfx content anyways, so caring of limited hardware features is the real wasting of cpu cycles.