Code review comment for lp:~vanvugt/mir/rotate-renderer

73 + glUniformMatrix4fv(display_transform_uniform_loc, 1, GL_TRUE, rot);

glUniform* functions need an active shader program. We should move glUseProgram() from render() to begin() (which makes sense anyway).

94 + mutable GLuint display_transform_uniform_loc;

No need for mutable.