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?
Attributes are values passed into a vertex shader. Transform feedback records the outputs from a shader. Recording attributes makes zero sense; you already have these values because you gave them to the shader.
So you're asking for how to capture vertex shader outputs.