About sprites priorities?

[youki]

Hi,

 

I would need to code a sprite multiplexer for my game.

 

the idea (and i think the commun way to do that on Coleco/MSx) is to rotate the sprite priority smartly.

 

But how can you change the sprite priority?? I didn't see any attribute or even a notion of changing sprite priority in VDP docs.

 

Do you have to do that by switching sprites (with all their attributes)?

 

Thanks

[newcoleco]

I think the developpers of the Coleco bios did something about it, I just simply not use it... never have to actually.

 

But basically, you identify a part of the ram in the header to be the sprites table with the order reorganized by the routine... but because I've never tried, I don't know exactly. But, it may be time and space saving for your projects if you can figure out how it works.

 

The priority for sprites is very simple to understand, sprite 0 is the one on the front, and so on... up to sprite 31 which is the behind all the other sprites, but also just above the tiles (characters) in the priorities. This information can be find in the coding guide, there is also a picture that explain it in the document.

[youki]

I think the developpers of the Coleco bios did something about it, I just simply not use it... never have to actually.

 

But basically, you identify a part of the ram in the header to be the sprites table with the order reorganized by the routine... but because I've never tried, I don't know exactly. But, it may be time and space saving for your projects if you can figure out how it works.

 

The priority for sprites is very simple to understand, sprite 0 is the one on the front, and so on... up to sprite 31 which is the behind all the other sprites, but also just above the tiles (characters) in the priorities. This information can be find in the coding guide, there is also a picture that explain it in the document.

 

Thanks Daniel,

 

Yes, It is what i have figured out about the sprite priority. But as in lot of forums and article about programing MSX and Coleco they spoke about rotate sprite priority i thought i missed something.... In fact you don't change priority , you change sprite organization at each frame.

[newcoleco]

Thanks Daniel,

 

Yes, It is what i have figured out about the sprite priority. But as in lot of forums and article about programing MSX and Coleco they spoke about rotate sprite priority i thought i missed something.... In fact you don't change priority , you change sprite organization at each frame.

I suppose, a smart way to deal with is : well, if reading the video chip gives me a sprite number for the first 5th sprite (not show because limit 4-in-a-row), then next time I should start showing sprites with this one. But the problem with this idea is when multiple sprites are used to be a single object on screen and the pattern of the sprite under can mask patially or totally the sprite over if their priority are somehow switched... so, you have two choices : to make the graphics with that in mind or don't take that possible situation as an issue.