Maybe this question relates maths rather than jitter... I am following the bump mapping example of the Orange book, and in order to transform the vertex position, normal and light position into tangent space, I need to calculate tangent on every vertex. There seems to be no "gl_Tangent" or built-in variable which allows the application to pass these values to the shader. Also, jit.gl.gridshape does not allow the message "auto_tangents 1"...
So, how do I calculate tangents? See .zip file for the patch, the initial vertices are generated by a jit.gl.gridshape into the shader.