animating textures

Hi there -

this is probably a very simple problem but I've not stumbled over the answer yet. My Art Monkey has just sent me a model with an animated gif file attached. XNA complains about this texture so presumably gifs are not yet supported. Is there a way round this For instance a simple way to apply a texture to a model, or change the UV coordinates a model is using, so I could have a big bitmap with the necessary graphics on it and just change the UV Or even some way to load a bitmap into another structure, perhaps a Texture3D, which I've just noticed, and apply it to a model.

Apologies if this is painfully simple or has been covered elsewhere.

Cheers

Robin.

Hi Jubber!

I have almost the same problem and wakka told me about the Texture2D.Getdata( ) and Texture2D.Setdata( ) methods, one of their overloads have a sourcerectangle that we can use to get just part of our texture inside an array that can feed another "temporary" texture. So after build the sprite map we can try update the texturing with just some texture sectors. I did not have tested this yet to tell you about performance but I bet that have everything to work fine.

Best!

Hi chaps - thanks for the responses. I've not yet even touched vertex shaders, so that might have to wait - but the various suggestions you've all posted make me think just loading up some bitmaps as textures and using effect.texture = textures[anim_number] will do the trick. I'll also have a look at matrix calculations on textures as suggested by Jon (not sure what that is yet, but sounds interesting). If I need only one texture in a model animated I can always get my Art Monkey to export two models, one with just the polys that need texture animation. Bit laborious, but will work, which is the main thing. Creasso and Waka - thanks for the tips about texture2D - another avenue to explore. Will report back if all works like clockwork.

Cheers,

Jubber

P.S. as an aside - anyone have trouble getting effect.alpha = n to do anything to a model Perhaps the associated texture needs an alpha channel or something else in the pipeline needs to be turned on. Bear in mind I don't know diddly about effects yet and am using the basic one.

The correct and most efficient method for animating a texture is to compile the frames of animation into a larger 2D texture, and modify the texture matrix depending on the frame of animation you would like to display. Attempting copy texture data using Texture2D.Getdata() and Texture2D.SetData() is horrendously inefficient because of the huge amount of memory that it would require to copy to video memory each time the frame of animation changes. Furthermore, with the problem would become compounded when dealing with more than 1 object sharing the animated texture with a different current frame in it's animation.

As far as getting blending to 'do something' goes, the texture doesn't necessarily need an alpha channel for certain kinds of blending, but for others, you will. See this post to learn a little about how blending works:

http://forums.microsoft.com/MSDN/ShowPost.aspx PostID=1068970&SiteID=1

Aki pl wrote:

Do You have some programs to make that sprote sheet I made 5 png pics from animated gif. Now i want to put all of them on one big png and then change coordinates. But program that makes rows will help me much. Must this rows be the same Because I have standing fighter and kicking. And second one is bigger. (wide)

For simplicity's sake when generating the source rectangle used for drawing your sprite, you may want to use uniformly sized and spaced frames in your large texture, but nothing is preventing you from using non-uniformly spaced or sized frames. You just need to store the information somewhere (I would do this in a seperate xml file per sprite) that represents the source rectangle for each frame. It's probably just easier to use uniformly sized and spaced frames.