render tetrahedron without vertex buffers

tet.csp

; shader
(compile-program tet-pg
    (glsl-string
        (#version 150)
        
        (#include "lib/ext.glsl")
        (#include "lib/projection.glsl")
        (#include "lib/hslhsv.glsl")
        
        (#escape ubo_decls)
        
        (const (vec3 (: data 4)) ((: vec3)
            (vec3 -1 -1 -1)
            (vec3  1 -1  1)
            (vec3  1  1 -1)
            (vec3 -1  1  1)
        ))
        
        (out (vec3 col))
        
        (define-proc nil (main)
            (var (
                    ((vec3 p) (: data (% gl_VertexID (#n 4))))
                )
                (= p (* (- p camera_origin) camera_aim))
                (= gl_Position (projection_transform mtx_proj.xy mtx_proj.z 
                    (vec4 p 1)
                ))
                (= col (hue2rgb (/ (float gl_VertexID) 4)))
            )
        )
    )
    (glsl-string
        (#version 150)
        
        (in (vec3 col))
        (out (vec4 color))
        
        (define-proc nil (main)
            (= color (vec4 col 1))
        )
    )
)

; render 
(glUseProgram tet-pg)
; bogus vao that contains nothing
(glBindVertexArray null-vao)
; presto
(glDrawArrays GL_TRIANGLE_STRIP 0 6)