Loading/Unloading Backgrounds and Sprite Dominance

[sylus101]

Greetings everyone!!

Things are moving along well, and I've got some quick questions.

When loading a new background, is there a way to "free" the previous one like a sprite is freed with Sprite.Free()? Currently I just run all the same commands pointing to a different map pal and raw file and that seems to work but I wonder if I have a memory leak there. 

Also, I'm trying to see what causes one sprite to be drawn on top of another. I've played with order of loading and palette number with varying results. Is there a tried and true way to control this?

[Jeremysr]

I was wondering this too since I'm making a game with lots of different background maps. So I remembered CPU_Smarts' point-and-click game, which has a lot of backgrounds. (This is probably the only place you can download it anymore: http://gchack.free.fr/DS/homebrew/SunsetResort/SunsetResort.zip .) What he did was load his new background into the same variable as his old one. An example:

Code:

-- Load Bottom Screen

BGBottomMap:LoadPalette( "DS-bottom.bmp.pal" )

BGBottomMap:LoadTiles( "DS-bottom.raw", 256 )

BGBottomMap:LoadMap( "DS-bottom.map", ( 256 / 8 ), ( 192 / 8 ))

Screen.Initialize( SCREEN_BOTTOM, BGBottomMap )

-- (touch the screen to continue)
while not Stylus.Down() do end


-- Load new background to bottom screen
BGBottomMap:LoadPalette( "DS-bottom2.bmp.pal" )
BGBottomMap:LoadTiles( "DS-bottom2.raw", 256 )
BGBottomMap:LoadMap( "DS-bottom2.map", ( 256 / 8 ), ( 192 / 8 ))
Screen.Initialize( SCREEN_BOTTOM, BGBottomMap )

He has over 30 background maps in the game, and when I played it there didn't appear to be any problems.

And the sprites, for now, will be on top of each other in the order that they are created. Eventually DSLua should let you choose which ones will go on top of each other.

[TOAST]

And the sprites, for now, will be on top of each other in the order that they are created. Eventually DSLua should let you choose which ones will go on top of each other.

You already can, it depends on which order you create them in.
Or did you mean something like swapping depth later in game?? So far there's no faster way than freeing the sprite and creating it again with Sprite.Create().

[sylus101]

Will do on the Backgrounds.

I'll run a few more test with the sprites, it seemed to be erratic but I could have been freeing and creating in some kind of off order.

Thanks again everyone!

[daltonlaffs]

Sylus, TOAST, and jeremy:

Note about the Backgrounds: I found that and tried to create a video player (each frame was in a seperate map file), and noticed that that does NOT replace the background, it just appears OVER it. After about 70 frames, the program crashed with an allocation error. 

Edit: And jeremy, your Skydiver 3 crashes after you play so many times for the same reason @.@

[TOAST]

Ouch, then you'll have to free and recreate?? Also clear screen.

[Jeremysr]

I don't think there's a Free function for backgrounds in DSLua yet... but according to PAlib you may not need one. There's a PAlib function to delete backgrounds from memory but it says that when you load a new background the old one will be automatically deleted. ( http://www.palib.info/Doc/PAlibDoc%20Eng/group___bg_tiles.html#ga6 )

[sylus101]

Note about the Backgrounds: I found that and tried to create a video player (each frame was in a seperate map file), and noticed that that does NOT replace the background, it just appears OVER it. After about 70 frames, the program crashed with an allocation error. 

Was this with or without defining a different variable each time? I can't say I know if it'd make a difference, but I was just curious.

[daltonlaffs]

It didn't seem to matter wether it was a different variable or not. It crashed at the exact same frame both ways.

And btw, this post made on Linux Ubuntu 6.06! I haven't given up Windows YET (I'm running Ubuntu off a CD), but I might just do it if it keeps this up!

[jester]

Yes i had found this out the hard way

Also sometimes the next background and the one it is replacing may muddle up the screen!

[sylus101]

OOoookay. I'm stuck.

chimera.zip

I can't figure out why the sword is always appearing behind the chimera. Just use A and B to use sword and Start to close.
(The attack grid is working, but just clutters up the test so I omitted it for now).

HELP!

*Edit - Well it appears I've got it figured out. I guess first loaded is most dominant (on top) and so on down. I found I could load the sword first on frame 0, leave that blank, and then just cycle frames after that.
I'm sure I'll have to play with Sprite.Create and Free to save memory when the need arises.

[suloku]

Is the background limit still there? I mean, backgrounds are still in memory with no known way to unload/replace them?

I don't need anything like 70 backgrounds, but it may be very interesting to solve this.

[daltonlaffs]

Well, if you're using DSLua 0.7, you can load raw BMP, JPG, or GIF images as 16-bit backgrounds, and use the :Clear() subfunction to free it.

[Jeremysr]

Well, if you're using DSLua 0.7, you can load raw BMP, JPG, or GIF images as 16-bit backgrounds, and use the :Clear() subfunction to free it.

That doesn't really free any memory, you just have to set your variable holding the image to imagevariable = ""

[suloku]

Well, if you're using DSLua 0.7, you can load raw BMP, JPG, or GIF images as 16-bit backgrounds, and use the :Clear() subfunction to free it.

That doesn't really free any memory, you just have to set your variable holding the image to imagevariable = ""

I think this doesn't apply to maps right? Just for the new iamge files that can be opened by 0.7 version, which anyway is good to know how to free them.

BTW, Jeremysr, I added you to msn two days ago because I saw that you have your adress for "contact". I wanted to ask you something, but I forgot (I must already figured out or something :S)