transform feedback using attribute locations
I'm finding it very hard to find out whether or not it's possible to record vertex transformations using the TransformFeedback family of OpenGL calls using the generic attributes provided by the application. "Normally" you'd define glTransformFeedbackVaryings() with strings that match the ones in the shader. The thing is, I'm using CGFX and I really want to use the generic vertex attributes (ATTR0, ATTR1, etc...).
When drawing, you'd use glEnableVertexAttribArray. Is there an analogue for reading?