[Development] Adding new third party component three.js to Qt?

Fri Jan 9 16:01:09 CET 2015

On Fri, Jan 9, 2015 at 3:39 PM, Keränen Pasi <pasi.keranen at theqtcompany.com>
wrote:

> Hi Louai,
>
> The changes required to the library were originally quite large. But
> thanks to the bug fixes in V4VM, maturing of Canvas3D and writing of some
> wrapper classes to make e.g. Image loading look and smell like in HTML
> land, the delta has been getting smaller and smaller. Here is a pretty
> complete list based on quick compare between the R69 original three.js and
> the Canvas3D port of the R69 release of three.js. There might be something
> I’m forgetting to mention here. But as I said the delta has been getting
> smaller and should get even smaller in Qt 5.5 and 5.6. But there will be
> some delta always as QtQuick is not HTML.
>
> * We don’t have performance timers in Qt Quick JS, so the Clock class must
> be modified to not use those.
>
> * In some files the class is declared with syntax of ( function (THREE) {
> blahblabh }( THREE ) ); that V4VM seems to dislike and in some cases self
> executing functions don’t seem to work, V4VM just refuses to load the
> file. I haven’t been able to replicate this behaviour with a small
> example, so probably it’s relates to some complex situation arising when
> loading a large JavaScript file OR then there is some minute detail in
> that self executing function that I can’t spot.
>
> * Resizing of images has to be modified as that is usually done with HTML
> trickery that doesn’t work at the moment with Canvas3D.
>
> * Accessor functions defined in prototypes with:
> get x() { return this._x },
> set x(value)  { this._x = value; this.onChangeCallback(); }
>
> * Must be rewritten with the (older?) syntax of:
> this.__defineGetter__("x", function(){return this._x;});
>     this.__defineSetter__("x", function(value){this._x =
> value;this.onChangeCallback();});
>
> * Canvas3DRenderer is new code, ported from WebGL. Main differences are to
> do with initialization differences between Canvas3D and WebGL. Handling of
> some Canvas3D Tech Preview quirks like the handling of TypedArray wrappers
> (should be ok to remove in 5.5 when we have proper V4VM TypedArrays in
> place and function overloading should work). And I’ve wanted to support
> the logging features of Canvas3D objects, by setting the .name attribute
> of some objects so that when you turn on logging you can see what
> UniformAttribute, what Shader3D object you are looking at in the logs..
> Plus a couple of workarounds for weird behavior (e.g. boolean as attribute
> name in the renderer causes V4VM not to load the file, but again a minimal
> example of this doesn’t have this problem so can’t replicate it). Again,
> the delta should get smaller with WebGLRenderer, but I’d expect there to
> always be some delta.
>
> That is all the delta I can list quickly, if you are interested in details
> just get the R69 release from three.js git and the stable branch of
> QtCanvas3D port and do a detailed compare of those.
>
> Reagrding this delta I’ve thought a bit how to reorganise the delta so
> that it could live in a separate folder inside three.js. If I can make
> that happen, then maybe it would be possible to get these few changes in
> to three.js upstream and make it possible to always use the latest from
> there as well if one so wishes. But that will require a bit more work on
> V4VM I think before we’re there. E.g. Add support for binary file loading
> with XMLHttpRequest and track down why those few anomalies occur when
> loading self executing functions declared in the manner they are in
> three.js so that the upstream code should run as much as possible
> unmodified on top of Canvas3D with just the few changes we need in place.
>
> Regards,
> Pasi
>
>
>
> On 08/01/15 12:54, "Al-Khanji Louai" <louai.al-khanji at theqtcompany.com>
> wrote:
>
> >> On Wednesday 7. January 2015 06.03.14 Keränen Pasi wrote:
> >> > Hi,
> >> >
> >> > I¹d like to open the discussion on including the three library as
> >>part of
> >> > Qt 5.6 and onwards. Mainly because this would give our users a better
> >> > experience if we¹d bundle the right, tested version of Three.js
> >>together
> >> > with the Qt version it was tested on.
> >> >
> >> > I¹ve been pushing the Qt Canvas3D component onwards and timewise it
> >> should
> >> > be landing to Qt 5.5 release. The WebGL-like API (non-conformance
> >>tested)
> >> > it offers is very low level and most users will not like to work on
> >>that
> >> > level. To that end I¹ve ported the WebGL based Three.js scenegraph
> >>library
> >> > available at http://threejs.org on top of Canvas3D. You can find the
> >> > latest version from master branch at
> >>https://github.com/tronlec/three.js
> >> >
> >> > The reason for picking this particular library over others are:
> >> > * It¹s one of the most active WebGL scene graph projects out there.
> >> > * It¹s well done, with examples, API documentation etc.
> >> > * It has excellent support form community in the form of tutorials,
> >> > websites, discussion forums etc.
> >> > * It is available under permissive MIT license:
> >> > https://github.com/mrdoob/three.js/blob/master/LICENSE
> >> >
> >> > In Qt 5.5 we¹ll include a few examples that will have this library as
> >>part
> >> > of the examples.
> >> >
> >> > The library will for now at least need some porting effort to make it
> >>run
> >> > on top of Canvas3D as there are some HTML depencencies that need to be
> >> > handled, plus V4VM has a few quirks that need to be accounted for.
> >> > Hopefully some of the V4VM quirks are bugs and will be fixed in due
> >>time,
> >> > but the HTML dependencies do remain. And my current experience with
> >> > graphics APIs is that you want to test the whole stack together. If we
> >> > e.g. add support for new extensions in Canvas3D, that can activate new
> >> > codepaths in Three.js that again need testing and possibly new Qt
> >>specific
> >> > delta must be added to the three.js for those parts.
> >> >
> >> >
> >> > Comments? Thoughts?
> >>
> >> Sounds like a good idea to me. What's the size (lines of code) that we
> >>are
> >> talking about here? Is it just one big "minified" .js file?
> >>
> >>
> >> Simon
> >
> >Out of curiosity, how large are the changes that were required to port
> >the library?
> >
> >-- Louai
> >
> >
> >
> >_______________________________________________
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> >Development at qt-project.org
> >http://lists.qt-project.org/mailman/listinfo/development
>
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Just wondering for Canvas3D. Where is the documentation? I can't find any
link to it from http://doc.qt.io/ or http://doc.qt.io/qt-5/index.html I can
find it via google though. Then it's placed under "Qt Documentation
(Technology Preview)" which is again nowhere to be found on qt.io.

So i'm just a bit puzzled how to get tot the Canvas3D documentation
(without google).
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