Graphics over code in Impromptu

Andrew Sorensen posted some code in the Impromptu mailing list showing how to add graphics (and various other things) on top of a code 'image'.

Quick tests

As usual I regret not having a whole free day to play with this, but just by messing around a bit with some parameters it's easy to achieve some interesting effects...

Here's the source code from Andrew:


(define canvas (gfx:make-canvas 640 480))

(define gl (gl:make-opengl))
(gl:open-opengl gl '(0 0 640 480))

;; draw code behind a rotating cube
;; if you wanted you could now call gfx:start-movie-capture
;; and pass the gl context where canvas usually goes.

(define loop-gl
    (lambda (beat)
       (let* ((code (gfx:get-code-image))
              (flipped (gfx:flip-image code))
              (width (car (gfx:get-image-size code)))
              (height (cdr (gfx:get-image-size code))))
          (gl:clear gl (+ *gl:color-buffer-bit* *gl:depth-buffer-bit*))
          (gl:window-pos gl 0 0 .99)
          (gl:draw-pixels gl width height *gl:rgba* *gl:unsigned-byte* flipped)
          (gl:load-identity gl)
          (gl:translate gl 0 0 .5)
          (gl:rotate gl (* beat 10) 1 1 1)
          (gl:color gl 1 1 1 1)
          (glut:wire-cube gl 0.5)
          (gl:flush gl)
          (gl:update-backing-image gl)
          (objc:release (+ (now) 5000) code flipped)
          (callback (*metro* (+ beat (* .5 1/6))) 'loop-gl (+ beat 1/6)))))

(loop-gl (*metro* 'get-beat 4))8

;; define an image to use as layer3

(define layer3 (gfx:make-image 640 480))

;; draw paths to layer3
(define draw-on-layer3
    (lambda (beat)
       (gfx:clear-image layer3)
       (dotimes (i 10)
          (gfx:path2image (gfx:make-circle (cosr 320 200 (/ i 100))
                                           (sinr 240 200 (/ i 100))
                          '() (list (/ i 5) 0 1 1)))
       (callback (*metro* (+ beat (* .5 1/6))) 'draw-on-layer3 (+ beat 1/6))))

(draw-on-layer3 (*metro* 'get-beat 4))

;; draw video and layer3 transparently into the opengl bitmap
;; then render the opengl bitmap to the canvas
;; You could easily replace
;; (gl:get-image-from-opengl gl) with (gfx:get-code-image)
;; if you didn't want to use any opengl

(define capture-code
    (lambda (time)
       (let ((video (gfx:get-live-frame))
             (opengl (gl:get-image-from-opengl gl)))
          (gfx:image2image video opengl .3)
          (gfx:image2image layer3 opengl 1)
          (gfx:draw-image time canvas opengl .9)
          (objc:release (+ time 5000) opengl video))
       (callback (+ time 2000) 'capture-code (+ time 5000))))

(capture-code (now))

;; start-movie-capture takes a canvas OR an opengl context
;; so you could call (gfx:start-movie-capture gl ...
;; as long as your gl code calls gl:update-backing-image

(gfx:start-movie-capture canvas "~/tmp/" #t)
;(gfx:stop-movie-capture canvas)

Cite this blog post:

Michele Pasin. Graphics over code in Impromptu. Blog post on Published on Nov. 4, 2009.

Comments via Github:

See also:


paper  Interlinking SciGraph and DBpedia datasets using Link Discovery and Named Entity Recognition Techniques

Second biennial conference on Language, Data and Knowledge (LDK 2019), Leipzig, Germany, May 2019.


paper  Linked data experience at Macmillan: Building discovery services for scientific and scholarly content on top of a semantic data model

International Semantic Web Conference (ISWC-14), Riva del Garda, Italy, Oct 2014.