gl_render   xtlang

;; a trivial opengl draw loop
(bind-func gl_render
  (let ((fbo:E_fbo* null)
        (size 0.01)
        (lights:i32 3)
        (i:i32 0)
        (eye:float* (alloc 4))
        (target:float* (alloc 4))
        (up:float* (alloc 4))
        (tmp_matrix:float* (alloc 16))
        (model_matrix:float* (alloc 16))
        (view_matrix:float* (alloc 16))
        (projection_matrix:float* (alloc 16))
        (mata:float* (alloc 4))
        (matd:float* (alloc 4))
        (mats:float* (alloc 4))
        (_angle:float* (alloc 10))
        (_power:float* (alloc 10))
        (_spotpos:float* (alloc (* lights 4)))
        (spotpos:float* null)
        (_spottgt:float* (alloc (* lights 4)))
        (spottgt:float* null)
        (_light_view_matrix:float* (alloc (* lights 16)))
        (light_view_matrix:float* null)
        (_diffuse_light:float* (alloc (* lights 4)))
        (_specular_light:float* (alloc (* lights 4)))
        (_ambient_light:float* (alloc (* lights 4))))
    ;; warm for light 1!
    (pfill! (pref-ptr _ambient_light 0) 1.0 0.8 0.5 1.0)
    (pfill! (pref-ptr _specular_light 0) 1.0 1.0 1.0 1.0)
    (pfill! (pref-ptr _diffuse_light 0) 1.0 0.8 0.5 1.0)
    ;; red for light 2!
    (pfill! (pref-ptr _ambient_light 4) 0.0 0.0 0.0 1.0)
    (pfill! (pref-ptr _specular_light 4) 1.0 0.0 0.0 1.0)
    (pfill! (pref-ptr _diffuse_light 4) 1.0 0.1 0.0 1.0)
    ;; green for light 3!
    (pfill! (pref-ptr _ambient_light 8) 0.0 0.0 0.0 1.0)
    (pfill! (pref-ptr _specular_light 8) 0.0 1.0 0.0 1.0)
    (pfill! (pref-ptr _diffuse_light 8) 0.1 1.0 0.0 1.0)
    ;; camera always up and pointing to centre
    (pfill! target 0.0 0.0 0.0 1.0) ;; position vector gets w==1.0
    (pfill! up 0.0 1.0 0.0 0.0) ;; direction vector gets w==0.0
    (lambda (model1:xtm_node* model2:xtm_node* model3:xtm_node* degree:double)
      ;; setup rotating spot light
      (pfill! (pref-ptr _spottgt 0)
              (dtof (* 5.0 (cos (* degree .05))))
              -1.7
              (+ 11.0 (dtof (* 5.0 (sin (* degree .05)))))
              1.0)
      (pfill! (pref-ptr _spotpos 0) 0.0 -2.8 11.0 1.0)
      ;; (pfill! (pref-ptr _spotpos 0) (+ .5 (dtof (* 8.0 (cos (* degree 0.05))))) 1.0 20.0 1.0)
      ;; setup second light as fixed
      ;; (pfill! (pref-ptr _spottgt 4) (+ .5 (dtof (* 10.0 (cos (* degree 0.05))))) 0.0 -1.0 1.0)
      ;; (pfill! (pref-ptr _spotpos 4) (+ .5 (dtof (* 10.0 (cos (* degree 0.05))))) 2.0 20.0 1.0)
      (pfill! (pref-ptr _spottgt 4) -3.0 0.0 0.0 1.0)
      (pfill! (pref-ptr _spotpos 4) 8.0 4.0 -2.0 1.0)
      (pfill! (pref-ptr _spottgt 8) -1.0 0.0 -1.0 1.0)
      (pfill! (pref-ptr _spotpos 8) -15.0 4.0 7.0 1.0)
      ;; (pfill! (pref-ptr _spottgt 8) 2.0 0.0 -5.0 1.0)
      ;; (pfill! (pref-ptr _spotpos 8) -3.0 1.0 10.0 1.0)
      ;; set eye position (looking at target)
      (pfill! eye
              (dtof (* 5.0 (cos (* .01 degree))))
              (dtof (+ 5.0 (* 5.0 (cos (* .005 degree)))))
              (dtof (+ 15.0 (* 10.0 (cos (* .025 degree)))))
              1.0) ;; position
      ;; setup projection matrix
      (fill_projection_matrix projection_matrix 35.0 (/ width height) 0.1 100.0)
      (set! lights (i64toi32 3))
      ;; make sure a few opengl settings are enabled
      (glShadeModel GL_SMOOTH)
      (glEnable GL_DEPTH_TEST)
      (glEnable GL_TEXTURE_2D)
      ;;
      ;; Now we render the Scene into An FBO
      ;; this first pass is from the lights
      ;; perspective (i.e. Light provides ViewMatrix)
      ;; We really only care about the depth buffer here
      ;;
      (set! fbo (get-fbo))
      ;; bind framebuffer to write depth info into
      (glBindFramebuffer GL_FRAMEBUFFER (tref fbo 0))
      (glUseProgram simpleshader)
      ;; clear fbo
      (glClearColor 0.0 0.0 0.0 1.0)
      (glClear (+ GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT))