Sprite loading/access

[to90zeroblue]

I'm loading a sprite sheet and splitting it into its 16 individual sprites. I would like to know if there is a way to save each part (which will be a sprite animation) in one variable so i can just PUT sprite(1),sprite(2), sprite(3) for animation or something like
INKEY$=FIRE then PUT sprite(5). Or if there is a better way, I would be glad to know as well !

thanks
adam

[ophelius]

You basicly want to create an index array where each subscript gives you the coresponding position withing the images array. For example:
Index(1) = 0
Index(2) = 45
Index(3) = 115
etc...
Then, when you take the segment and offset, you use it like this:

Segment% = varseg(Images(0))
Offset% = varptr(Images(Index(1))) -> Image 1
Offset% = varptr(Images(Index(2))) -> Image 2
Offset% = varptr(Images(Index(3))) -> Image 3
blah...
Check out PP256 for routines that automatically create an index and image array.

[adosorken]

Or you could save memory by skipping the extra array if your sprites are all the same size by using a simple offset variable. To calculate the offset for 13h, the formula's easy:

offset = SpriteHeight * SpriteWidth / 2 + 2

assuming integer sprite arrays. Then, for GET and PUT, you do something like this:

GET(0,0)-(15,15),sprite(offset *spritenumber)
PUT(20,50),sprite(offset * spritenumber)

Far more effective for fixed-size sprites. Of course, for sprites of varying size in the same array, adding the second array is the most effective way to do it.

[to90zeroblue]

My sprites are all going to be the same size, and I think it will be a lot easier that way, but I'll save both code examples just in case. This is for my megaman game. The first guy I did had a different array for each sprite and I ended up with around 100 arrays. This isn't practical for one character, forget five. This way will be much easier. Thanks to you both!

adam

[Plasma]

An even easier way is to actually use a 2-dimensional array (instead of simulating one by multiplying with an offset)

Code:

DIM Sprites(SpriteSizeX * SpriteSizeY \ 2 + 1, 1 TO NumSprites)

and then to GET/PUT use:

Code:

GET (x1, y1)-(x2, y2), Sprites(0, n)
PUT (x, y), Sprites(0, n), PSET

where n is from 1 to NumSprites