Self Wright

Tag: sdl

Baktoo: Taking baby steps with generative art

Continuing (or stumbling) along a path to using Common Lisp for stuff I consider fun, I came up with this.

As mentioned in the `README`, I need to work on making this more efficient.

Stuff I learned along the way:

  • I love how I can focus on “making it work” _before_ worrying about “making it fast”
  • Utilities exist for a reason. _Use them_ (I’ve decided to stick with `:rutils`)
  • Don’t be afraid of using libraries. I found `:cl-log`, which is amazingly well-written and I will never use all of it, but just the basic use case of toggling levels of verbosity is good enough for me, and something that would normally be hard to do.
  • Building up the system works really well. This is the first time I’ve had an experience of writing stuff that sort of _just worked_, since it felt like I was **directly translating my thoughts into code**.
  • It’s easy to rapidly create and modify functions, stubs, what not, while keeping them all in view, in the same 100 or so lines of vertical space (contrast with switching between (say) multiple `.java` files)

Anyway, here are a couple of samples I made with this (click to see detailed image):
Baktoo - 2

Baktoo - 1


(ql:quickload 'lispbuilder-sdl) worked right away on an ubuntu box, but failed (couldn’t find `cocoahelper) when I tried the sam on my Macbook.

The fix is to install SDL, then go to ~/quicklisp/dists/quicklisp/software/lispbuilder-20140113-svn/lispbuilder-sdl/cocoahelper and type make. After this, the ql:quickload form succeeds.

However, the same dummy blank screen test program that worked fine on the linux box doesn’t seem to work anymore:

(defpackage :simple-sdl
  (:use :common-lisp

(in-package :simple-sdl)

(defun main-screen ()
  (sdl:with-init ()
    (sdl:window 300 300
        :title-caption "Simple SDL"
        :icon-caption "Simple SDL")
    (sdl:with-events ()
      (:quit-event () t)
      (:key-down-event ()

It fails with this backtrace:

  0: ("bogus stack frame")
  1: ("foreign function: CGSScanconverterRenderRGBMask")
  2: ("foreign function: create_rgb_bitmap")
  3: ("foreign function: CGGlyphBitmapCreateWithPath_32")
  4: ("foreign function: CGFontCreateGlyphBitmap")
  5: ("foreign function: _ZN14CGGlyphBuilder22create_missing_bitmapsEPK17CGGlyphIdentifiermPPK13CGGlyphBitmap")
  6: ("foreign function: render_glyphs")
  7: ("foreign function: draw_glyph_bitmaps")
  8: ("foreign function: ripc_DrawGlyphs")
  9: ("foreign function: draw_glyphs")
 10: ("foreign function: CTFontDrawGlyphsAtPositions")
 11: ("foreign function: -[CUITextEffectStack drawGlyphs:inContext:usingFont:atPositions:count:lineHeight:inBounds:atScale:]")
 12: ("foreign function: -[CUICatalog drawGlyphs:atPositions:inContext:withFont:count:stylePresetName:styleConfiguration:foregroundColor:]")
 13: ("foreign function: -[NSLineFragmentRenderingContext drawAtPoint:inContext:]")
 14: ("foreign function: _NSStringDrawingCore")
 15: ("foreign function: _NSDrawTextCell")
 16: ("foreign function: -[NSTitledFrame _drawTitleStringIn:withColor:]")
 17: ("foreign function: -[NSThemeFrame _drawTitleStringInClip:]")
 18: ("foreign function: -[NSThemeFrame drawFrame:]")

Just when I was getting excited about it … so what other platform-independent Lisp GUI should I use 🙁 ?

BTW, while we’re knocking this (unfairly, of course), I should point out it doesn’t support SDL 2.x

I then stumbled on this library which seemed better maintained, and modified my example:

(defun main-screen ()
  (sdl2:with-init (:everything)
    (sdl2:with-window (win :w 300 :h 300
               :title "Simple SDL")
    (sdl2:with-event-loop (:method :poll)
      (:quit () t)
      (:keydown ()

Now a window did get created, but it didn’t play well with OSX (it wasn’t a “window” so much as a blank square of real estate on the screen, with a spinning beachball and no response).

So … the search for a basic simple drawing facility continues 🙁

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