DeleD Community Edition

LIONCode · Posted: Thu Mar 08, 2007 8:16 am Post subject: Redo

It would be nice if there would be a redo as well as an undo. Sometimes i go back to much steps and want to the last step back in. Should not be a big item to add Smile

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Dennis Taapken

http://www.lioncode.com

Nocturn · DeleD PRO user Joined: 08 Aug 2004 Posts: 635

Well, Redo are very complex to implement. It isn't that easy.

LIONCode · Posted: Thu Mar 08, 2007 12:20 pm Post subject:

Actually it is not that complex. There is even a nice design pattern for it, which makes the job very easy Smile

I am a fulltime software developer and have implemented this type of thing several times. It is really not that big of a deal.

Anyway if it is not easy to add i am fine with it, but i see it as a nice feature which makes DeleD more conform standards.
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Dennis Taapken

http://www.lioncode.com

Jeroen · Posted: Thu Mar 08, 2007 1:30 pm Post subject:

LIONCode · Posted: Thu Mar 08, 2007 1:41 pm Post subject:

OK. I will make a nice doc explaining a great way of doing undo/redo and send it to you. Because of my planning i will probably not come around to this, until the weekend.
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Dennis Taapken

http://www.lioncode.com

Daaark · Posted: Thu Mar 08, 2007 1:45 pm Post subject:

Don't you just step through an array of changes? Everytime you make a change, you save the scene state to the array (and knock out an old entry)... then redo is moving forward, and undo is moving backwards?

Clueless, just wondering... Laughing

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LIONCode · Posted: Thu Mar 08, 2007 2:01 pm Post subject:

Well yes you can do it like that. But that will take a lot of memory as you will need to remember all states. Another method is to create 'atomic' command objects, which is much better. This object can undo and redo a small thing like (add vertex, change texture, etc.). Undoing and redoing is then nothing else then to call the undo or redo method of the object. All these objects are on one stack and you can undo all the changes and go back again by redoing all changes.
_________________
Dennis Taapken

http://www.lioncode.com

Paul-Jan · Posted: Fri Mar 09, 2007 6:55 pm Post subject:

Straight from the GoF Very Happy

. While nice and clean to implement from scratch, refactoring the existing DeleD code to fit this particular pattern is not exactly a breeze.

LIONCode · Posted: Fri Mar 09, 2007 7:01 pm Post subject:

That is probably very true Smile

I will email with Jeroen to find out what a redo for DeleD would take.
_________________
Dennis Taapken

http://www.lioncode.com

Jeroen · Posted: Sun Apr 08, 2007 3:00 pm Post subject:

Although I have not implemented Redo in the way Lioncode explained, Redo will be vailable in the next version of DeleD! Smile