Help with Polyvector animation

[AlienMenace]

Going through the forum, I think I have the hang of drawing sprites using polyvector but I am having difficulty figuring out how to draw animated sprites.
I am looking at replacing this:

LOADANIM "explosions.png",150,50,50
DRAWANIM 150, anim_frame, x, y

With a method that uses polyvector.
Thanks

[Ian Price]

Here's a simple routine that displays an animated polyvector (32x32pixels) at position X,Y. You can load the image in with LOADSPRITE OR LOADANIM.

Code (glbasic) Select Expand

SETCURRENTDIR("Media") // go to media files

LOADSPRITE "anim.png",1

LOCAL dlay,anim,x,y

x=300
y=200

WHILE TRUE

INC dlay // Animation speed

IF dlay>7
INC anim // Animation frame
dlay=0
ENDIF

IF anim>5 THEN anim=0

STARTPOLY 1
POLYVECTOR 0+x,0+y,0+anim*32,0
POLYVECTOR 32+x,0+y,32+anim*32,0
POLYVECTOR 32+x,32+y,32+anim*32,32
POLYVECTOR 0+x,32+y,0+anim*32,32
ENDPOLY

SHOWSCREEN

WEND

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[AlienMenace]

Cool, thanks! Is there anyway to retrieve the frame size info dynamically from an image loaded with Loadanim?

Cheers.
Steve

[Ian Price]

Ummm... If you've loaded an image (or set of images) with LOADANIM you already know the framesize of each image, as you need to put that into the command for it to work - LOADANIM "image.PNG", ID#, SIZEX, SIZEY. Just save the info into an array if you need it later.

[AlienMenace]

Yeah, well I was hoping to get away from a lookup array and let a routine handle the sizing issue on it's own. Anyhow, not a big deal.

Thanks

[Wampus]

AlienMenace you might find useful some functions I wrote that mimic the default GLBasic sprite commands with POLYVECTOR equivalents, including rotation and resizing. The basic code is in this thread here. It uses a predefined lookup array for sprite co-ordinates but you could change that for your purposes.

PNG files contain the size of the image at offset 16 (width) and 20 (height). There are also custom fields in a PNG file that you could use to specify the x-width of an animation. Your app could use this information to read any PNG file as a potential animation.