Set the texture format to RGBA and when you bind a RGB image a default alpha channel will be added.
_____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Glenn Waldron Sent: 04 December 2007 20:21 To: OpenSceneGraph Users Subject: [osg-users] Adding an alpha channel to a texture? I want to set up a geometry such that when I apply a texture, it renders, but when no texture is applied it is invisible. I created the geometry with color (1,1,1,0) and I'm using the TexEnv::GL_REPLACE mode. This works perfectly on 4-channel RGBA textures (because texture alpha replaces fragment alpha), but on a 3-channel RGB texture the GL_REPLACE mode uses the fragment's alpha color (which makes sense) and thus the geometry remains invisible. Is there either a) an easy way to add an alpha channel to an existing osg::Image, or b) a better way to solve this problem? (I know I can use node masks etc., but I would prefer to do it simply by setting or removing the texture attribute.) Thanks in advance! -gw -- Glenn Waldron : Pelican Mapping : http://pelicanmapping.com : 703-652-4791
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