change line length

[Hartha]

Hello,

 

I'm trying to create a line [ linesMesh] with only tow points  and change it's length dynamically or change the second point position,

is there any way to do that ? 

[JCPalmer]

Looks like Babylon.LineMesh stores its vertices just like any other mesh, so mesh.updateVerticesData() should work.

[jerome]

Just re-use the function MeshBuilder.CreateLines() with the parameter "instance" : http://doc.babylonjs.com/tutorials/mesh_createxxx_methods_with_options_parameter#lines

[JCPalmer]

As the ops issue looks solved by @jerome, I have a couple of questions on why a line system was implemented this way.  The business end of loading is done by VertexData.CreateLineSystem.  I was wondering do indices really need to be loaded?  I thought it was made optional at some point.  Since there is no vertex duplication, it would be a good candidate.

I have been looking at ways to port Blender particle / stranded hair.  I would need about 25,000, 6 segment lines.  Even though indices are calculated instead of passed, I would like to know If I could side-step the potential bit 16 int issue on old hardware by not using them?

Any implementation could have a fairly complex representation (relative positioning to the last segment) to reduce file size.  So, would probably try to instance a LineMesh directly, once unpacked.

I am not sure went I plan to attempt this, but does it look something like this would have to be the only thing in a scene to even work?

[JCPalmer]

Also, can a LineMesh have an armature?  A character could look left / right.  The hair would not have to "fly", but the roots still be on the head in the same place.  If not, will have to make a custom Mesh class, and abandon LineMesh as an alternative.

[jerome]

Actually a line system can render many lines at once, or lines and segments, or plenty of different things that would be displayed with no surface. So indices are needed.

It's on my todo list to add the line and line system per vertex color... so one render call to display several differently colored lines/segments