(bind-func gl_draw
(lambda ()
(glClear GL_COLOR_BUFFER_BIT)
;; draw the world
(let ((texloc (glGetUniformLocation sp "tex")))
(glUseProgram sp)
(glUniform1i texloc 0))
(VAO_bind_and_draw_arrays vao GL_TRIANGLE_STRIP 0 4)
(glfwSwapBuffers window)
void))