beginTextureFill() from atlas texture behaves wierd

[hardcoremore]

When I do this:

var texture:Texture = Assets.atlas.getTexture( "SimpleCrate" );

displayObject.graphics.beginTextureFill( texture ); displayObject.graphics.moveTo( 0, 0 );

displayObject.graphics.lineTo( 150, 0 ); displayObject.graphics.lineTo( 150, 150 ); displayObject.graphics.lineTo( 0, 150 ); displayObject.graphics.endFill();

And that draws fine except that it draws entire game atlas png scaled into 150x150 pixel box instead of just normal crate image texture.

Thanks, Caslav

[ekeeper]

A little solution:

        var sh:Shape = new Shape();
        var m:Matrix = new Matrix();

        var texS:SubTexture = tex as SubTexture;
        var clip:Rectangle = texS.clipping;
        var widthScale:Number = texS.parent.width/texS.root.width;
        var heightScale:Number = texS.parent.height/tex.root.height;

        m.scale(clip.width * widthScale, clip.height * heightScale);
        m.translate(clip.x * widthScale, clip.y * heightScale);

        sh.graphics.beginTextureFill( tex, m );
        sh.graphics.lineStyle( 1, 0xffffff );
        sh.graphics.drawRect(0,0,tex.width,tex.height);
        sh.graphics.drawRect(0,0,tex.width * 1.5,tex.height * 1.5);
        sh.x = 200;
        sh.y = 50;
        addChild( sh );

But we have another issue here if drawing will have width/height larger than width/height of a texture - shape will filled of another part of the atlas :(

[HoecusPocus]

Hi there, any luck with getting this to work so it repeats the texture from an atlas? Like if you were to draw ground from part of a texture atlas...?

Do you think it's possible to fill a RenderTexture like this from a source subTexture?

[jonathanrpace]

I don't think it's possible to repeat a sub-texture, no. As far as the GPU is concerned, it's still dealing with a single texture (the full atlas), and there's no way for a shader to 'repeat just this bit'.

If you want repeating textures you'll either have to stop using an atlas, or break apart your geometry into multiple quads - with each quad's uv's setup to only reference a particular part of the atlas (which you could achieve with the 'matrix' property on the beginFill() call).

[makc]

there's no way for a shader to 'repeat just this bit'.

I'd disagree. I don't have ready code at hand but frc agal opcodes might help.

[HoecusPocus]

I'm a complete novice as far as shader stuff goes. There's no way I can afford to extract loads of textures into single items. There would be too many state changes I'm sure... I'd like to keep all my background / level items in one textureAtlas, then draw arbitrary polygons of shapes, using a segment of the textureAtlas for each shape.

I wonder how using this atlas is made possible?

http://www.google.co.uk/imgres?imgurl=http://www.gamerendering.com/wp-content/uploads/textureatlas.jpg&imgrefurl=http://www.gamerendering.com/2009/12/08/texture-atlas/&h=400&w=400&sz=67&tbnid=zjReuNHL54qnzM:&tbnh=90&tbnw=90&zoom=1&usg=__dU8Mdt2PcL0KZiyk3nohnKONQFk=&docid=Ea8N2zguAQkkUM&sa=X&ei=qGebUfn-C-TC0QXooIGwDQ&ved=0CEQQ9QEwAg&dur=508

[HoecusPocus]

Page 10 of this article discusses the repeating of a subtexture, and says that it is possible using ddx and ddy shader methods... http://http.download.nvidia.com/developer/NVTextureSuite/Atlas_Tools/Texture_Atlas_Whitepaper.pdf

However I've no idea how to implement this.

[jonathanrpace]

makc - good point. You could divide the uv by whatever repeat interval you want, then take the fractional part and add a bit of offsetting to get a value that only repeats in a sub-section of the 0-1 uv space. Didn't think of that.

Hoecus - Afraid I've got no plans to implement this feature into the library (at least not in the near future - work is killer ATM), however the material system is open enough to allow for custom shaders to get plugged in (you'd need to start using 'beginMaterialFill' for this to work).