Jump to content
  • Advertisement
Sign in to follow this  
ongamex92

3D Level editor, Multiple tools, and selections

This topic is 557 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I'm trying to develop a "general purpose"  level editor. Here is a GIF https://twitter.com/ongamex92/status/814251826660904960
 
So far so good, The current structure that's implemented is fairly basic:
?I've got "scene nodes", each node has an "attribute list" which stores all the important data for that node(type could be, float1/2/3/4, quaternion, int, an array of these, and TODO: link to other nodes and/or attributes).
 
When the user wants to create a new node type (for example a game object) the procedure the following:
?1) Create a class that inherits form INode.
2) Create a descriptor which tell what are the default attribute for this node type.
3) Optionally, but usually, create a class that handles the drawing of that specific node type in the viewport.
4) Register the above to the Scene manager
?5) Tadaaa, you can not create node of that type in the scene.
 
That works flawlessly, until something a bit more complex is encountered.

?I want to create a simple spline with multiple points, lets say for example, that I want a path and I'm going to assign a unit to patrol along it.

?So I follow the steps above, and I got a node. Now is the that for me to able to modify the curve in the viewport:

?I need to be able to select the control points of the curve, move them around and create new points. The problem that I have is that my manipulation tools (move, rotate, scale, select) only work on nodes! The points that are used by the spline aren't nodes, they are just data stored in the node!

The Question is:
 
How should I design my editor for this to work?
?The quickest solution is to make every point a different node, and make the spline point at these nodes... I do not like this solution as it introduces too many nodes for something as simple as Float3.
 
What is implemented in 3ds Max and Maya is works amazing.
?Maya has the concept of tools. By using a tool Maya enters a specific regime where you can only manipulate things that are *selectable* by the tool. For example when you are in a polygon edit mode you cannot select polygons and  other scene object simultaneously.
 
The interesting thing in Maya is that if you create curve node, select the tool to edit the spline control vertices, and select one you will see In the script output:
"select -r curve1.cv[4] ;" Which technically means that In Maya you can select Attributes!?!?!?!?

?I have the same concept of tools, but they can only select nodes, so I'm far far away from what Maya has.

?Do you have any experience writing similar tools?
Do you have any suggestions about what I can do?
How is this thing (some something similar) implemented in you editor?

 

Share this post


Link to post
Share on other sites
Advertisement

The quickest solution is to make every point a different node, and make the spline point at these nodes... I do not like this solution as it introduces too many nodes for something as simple as Float3.

 

But that too many nodes don't need to end up in the game, so who cares?

Optimiziation should be the last you think of for a never ending, never good enough, maybe replaced by something differnt... project like a level editor. You can do this optimization in the output, or even in the games import function.

Flexibility and keeping it maintable is more important, so i'd use one node per control point.

 

You already have the necessary transformation tools for nodes -> no need to add something for the control point case.

You already plan for links between nodes, that can serve for the order of control points in the spline.

You could do things like using differnet parents for the start and the end of the curve, so allowing e.g. to connect bezier splines and manipulate the knots without breaking continuosity.

Probably more unexpected advantages show up later...

Share this post


Link to post
Share on other sites

Thanks for the suggestion guys.

 

I currently have no game on my hands, I do this thing in my spare time, so I can put a little bit of extra effort to make the thing a bit more flexible, after all I may end up adding a different tool which could take even more advandage if I managed to make the spline editor. Afterall the guys at Autodesk made it somehow, I just cannot grasp they did it(or an alternative way).

?Otherwise if I had to do it today I would definitely go with nodes.

Edited by imoogiBG

Share this post


Link to post
Share on other sites

so I can put a little bit of extra effort to make the thing a bit more flexible

 

So, say you do the extra effort and make splines a special case of your data structure AND also you make a special spline editor.

You added 2 things (although you already have all required basics: node data structure and node transform tools).

In the future you may add a cool tool that aligns all selected control points vertically - nice. But wait, would'nt it be even nicer to have aligning tools for the nodes as well? No problem - put a little bit of extra effort and implement it a second time :)

 

You get what i mean - you actually limit flexibility and increase mainteance cost by adding special cases.

 

3DSMax Spline editor is very powerful, but the implementation can be done on top of nodes or float3's - does not matter.

Probably 3DSMax is built a lot on the 'special case for anything' approach i advise against, but it's not made by one guy in his sparetime.

You know XSI as well? XSI exposes its data strucures visually in a large tree, just by looking at it i learned a lot about how it probably works.

(If Max is more about technical construction, XSI is more the kind of character developement tool)

Share this post


Link to post
Share on other sites

Well I'm not trying tp hardcode the spline,

technically I'm trying to think of an abstraction that can handle selecting and editing object of different types. For example the spline is a node, and when you try to edit it you can "edit" the data in the viewport itself, meaning that all the tools you have should just work like: move, rotate, scale, focus camera ect.
 

If the solution is hardcoding the spline editor just for having a spline editor I wouldn't do it.

?I'm looking for an abstraction that is flexible enough to handle such situations. For example in the future I may end up with a NURBs terrain editor, If I managed to make the splines works flawlessly, and develop a good abstraction
?that could scale, that would be great! Otherwise if I do not of course I would reuse my nodes code and ect ect. So again I'm looking for a way to change my abreaction, and to look at the problem form different angles where a much better solution may lie.

Edited by imoogiBG

Share this post


Link to post
Share on other sites

I'm really sorry If I somehow frustrated any of you guys, I really did not meant it.

 

 

so just for the sake of argument,  putting away making every control point of the spline being a separate node(and because I currently thing that it's not an elegant solution, as it will increase code complexity In several places as parsing for example, you have to agree that having a simple array I way clear than having a chain of nodes).

?The design problem that I have is that: just because something is selectable in the viewport that doesn't mean that it is a node. That the abstraction that I'm probably looking for.

?In the spirit of reusing code for manipulator tools, and undo/redo that is already implemented, I came up with a somewhat mixed solution.
?

So when a Spline node is selected, and the user enables the "Spline edit tool" the editor will change regime, making the spline edit tool the main focus.
?When the spline edit tool is created, it will create a few "special helper" nodes(I still need figure out how to implement them), for each control point. These nodes will act as regular nodes, except that they will get deleted when the tool is ready and they do not get saved to the scene.

?So this is what I will try to code tomorrow if nothing better shows up.

Edited by imoogiBG

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!