Games with Squeak

Mikael Kindborg mikael.kindborg at
Sun Nov 5 18:40:38 UTC 2006

On 11/5/06, Bert Freudenberg <bert at> wrote:
> Am 05.11.2006 um 12:27 schrieb Mikael Kindborg:
> > Have also been experimenting with Tweak which is
> > really nice, but as I understand it Tweak, like Morphic, uses standard
> > Squeak Forms and Display to render graphics.
> Tweak does not use Display directly. This allows for rendering to
> multiple display surfaces simultaneously, like when using Host
> Windows (a.k.a. Areithfa Ffenestri). Also, an experimental version of
> Tweak exists that uses Rome for rendering, although this also writes
> to Display in the end for now.

Ok, that sounds great. I will look at how Tweak does its rendering. I
was thinking it used Display since a Tweak Morphic window works
together with other Morphic windows, but that is perhaps a special
case, when running Tweak in Morphic, or perhaps I miss something about
how the rendering process works.

> > What concerns me is the blit speed of Form and Display. Have searched
> > the mailing list and the swiki and obviously there are lots of issues
> > that have been up for discussion previously, like conversion between
> > pixel formats, endianness, etc. Have seen mention of FXBlt,
> > ExternalForm, and ExternalScreen, which seems to be in the Balloon3D
> > package (which has been replaced by Croquet?).
> No, FXBlt has been rolled into regular BitBlt. You can use BitBlt to
> render to any surface registered via SurfacePlugin. Like, RomePlugin
> registers Cairo surfaces that can be used as source or destination of
> BitBlt.

I will look at the surface plugin, sounds promising!

> > I am confused about the current status of Squeak technologies for high
> > speed graphics. From what I understand, Croquet is the most recent
> > work in this area, based on OpenGL.
> Yes, which also is a severe limitation for general use as there is
> one important platform lacking good general OpenGL support.

What platform is that?

> > I have found SDL to be a very good library, have been working with SDL
> > in Python, using the Pygame library. It has good blitting performance
> > (will post some performance tests later on, comparing Pygame to
> > Squeak). Pygame/SDL uses bitmaps in the current format of the display
> > screen, and I would like to look at how this could be done in Squeak.
> >
> > As I understand it, there are two ways of using libraries like OpenGL
> > and SDL in Squeak:
> >
> > 1. As an "add on" that bypasses the Display, and renders "on top of"
> > Morphic/Tweak. This is how I understand that Croquet works. Drawback
> > is you cannot use Morphic/Tweak but have to do your own UI system
> > (like the one in Croquet).
> Actually, Tweak or Morphic run fine as an overlay inside an OpenGL
> window. That's how Plopp implements its UI, for example.

Well, that is extremely nice, does that boost performance of
Tweak/Morphic or is it mainly a way to integrate the UI with the 3D

> > 2. As an integrated part of the VM, making Display and Forms use the
> > native display format. Then you could use Morphic/Tweak with the best
> > performance.
> Actually I think Forms are outdated now, you really want a vector
> graphics API. So what would be best IMHO is opening a host window and
> a canvas on its surface, then using canvas commands to draw onto it.
> I think we have almost all needed bits in place (Host Window Plugin,
> Rome Plugin), they just need to be integrated.

Ok, great! I have to learn how this works. Why are forms outdated? Are
there other, better, options when working with bitmapped graphics?
Like rendering bitmaps in OpenGL? If I draw on the canvas (I assume
you mean a Squeak canvas) then it renders transparently onto the host
window surface?

Many thanks indeed for your pointers!

Best, Micke

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