Path: chuka.playstation.co.uk!scea!peter_alau@playstation.sony.com
From: Elliott Lee <tenchi@jps.net>
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: Re: Combining multiple images in TIMs for frame animation
Date: Wed, 22 Jul 1998 18:26:21 -0700
Organization: Cisco Systems
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Message-ID: <35B6913D.308CB2B@jps.net>
References: <35B67C25.42A6@cadgraphics.com.au>
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At least to get the one big TIM, just use your favourite 2D editor
(e.g. Photoshop) and make each of your frames of animation the
same size (e.g. 32x48).  Now create one very large new image and just
cut/paste the images side by side.  Crop that strip afterwards.  So,
for example, if you had 10 images at 20x40 resolution, you'd end up
with a strip that is 200x40.  So, when you load your TIM into memory,
you just bump the u member up by 20.  If you wanted to make it a little
more readable (albeit slower), you could make an array of offsets:

	#define	PIX_PER_BYTE 1
	#define	NUM_FRAMES 10
	#define FRAME_WIDTH 20
	int	FrameOfs[NUM_FRAMES;
	int	CurFrame=0,OrigUOffset;
	GsSPRITE MyTim;

	// ... other stuff in between ...

	for( i=0; i<NUM_FRAMES; i++ )
          FrameOfs[i]=i*(FRAME_WIDTH/PIX_PER_BYTE);

	// ... other stuff in between ...
	MyTim.u = FrameOfs[CurFrame]+OrigUOffset;
	CurFrame = (CurFrame+1)%NUM_FRAMES;

That should do the simple animation for you.  Now, there's one thing
more: this example assumed you were using a 16-bit TIM, one byte per
pixel.  If you had an 8-bit image, you need to divide your u coords
by 2, 4-bit then by 4.  There's a #define above (PIX_PER_BYTE) and
you could set it accordingly:

	if 16-bit: PIX_PER_BYTE = 1.
	if 8-bit:  PIX_PER_BYTE = 2.
	if 4-bit:  PIX_PER_BYTE = 4.

Oops.  One more thing: remember to save your original u offset.  :)
If you don't, you'll cycle through the animation in possibly another
part of VRAM.

This animation method works decently well, and is applicable other
other things like custom fonts and animated textures.

- e!

David "DM" Treay wrote:
> 
> I'm trying to get some sprites up that animate nicely when you control
> them with the pad (ie. say a stick figure - press right and his legs
> move, etc.). My initial idea of loading all the frames into memory and
> then switching between them when needed was clunky and hard to program,
> now having looked at some tutorials on Yaroze pages, I've discovered
> that you can combine multiple frames into one .TIM file (and then
> combine all the necessary .TIMs into one big .PAK file or something for
> easier downloads), and then use the GsSPRITE members u and v to change
> between frames on the fly. Unfortunately, none of the tutorials I've
> found actually tell you how to set up this big .TIM. Can somebody please
> answer a confused newbie's cries and give me a quick rundown on how to
> achieve the said animation?
> 
> --
> - David "DM" Treay (the tribe that hides from Man)
>         dmtreay@cadgraphics.com.au

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