Line width not working on Linux

[ndebruyn]

Hi all,

Does anyone here know why “LineWidth” is ignored on Linux, however on Windows there is no problem rendering correctly?
My code I use on both:

Material wireMaterial = new Material(application.getAssetManager(), "Common/MatDefs/Misc/Unshaded.j3md");
wireMaterial.setColor("Color", colorRGBA);
wireMaterial.getAdditionalRenderState().setWireframe(true);
wireMaterial.getAdditionalRenderState().setBlendMode(RenderState.BlendMode.Color);
wireMaterial.getAdditionalRenderState().setLineWidth(3);
wireMaterial.getAdditionalRenderState().setPolyOffset(-3, -3);
wireMaterial.getAdditionalRenderState().setFaceCullMode(RenderState.FaceCullMode.Front);
wireMaterial.getAdditionalRenderState().setDepthFunc(RenderState.TestFunction.Less);
outlineSpatial.setMaterial(wireMaterial);
outlineSpatial.setCullHint(Spatial.CullHint.Never);

And the results on Linux:

However on Windows it is working:

[ndebruyn]

So after some searching the forum I found this topic. It seems like the line width was removed in newer opengl’s.

Setting line width on WireBox in 3.6.0 has no effect

I am using this code to set the line width on a WireBox: package jme3; import com.jme3.app.SimpleApplication; import com.jme3.material.Material; import com.jme3.math.ColorRGBA; import com.jme3.scene.Geometry; import com.jme3.scene.Mesh; import com.jme3.scene.debug.WireBox; public class WireBoxTest extends SimpleApplication { @Override public void simpleInitApp() { Mesh m = new WireBox(2, 2, 2); Geometry geom = new Geometry("WireBox", m); Material mat = new Material(assetManage…

After I force the renderer to OPENGL2 it seems to work, however, why is it then working on Windows without OPENGL2?

settings.setRenderer(AppSettings.LWJGL_OPENGL2);

[zzuegg]

It might work on windows on your gpu. Unfortunately opengl is was never strictly specified and some features are up to the vendor.

[sgold]

It might work on windows on your gpu. Unfortunately opengl is was never strictly specified and some features are up to the vendor.

That matches with my recollection of this issue.

[pspeed]

Late to the party but concur with others, line-width has always had spotty support even at its height of fashion.

[ndebruyn]

Any other solution to draw a line?

[zzuegg]

If you need a line you can extrude a quad. If you only need it for an outline effect there are other options.

[ndebruyn]

Yes, typically for an outline effect.

[zzuegg]

Im a shader loving person so i would go stencil

How to do outline with stencil buffer?

Tracked down and fixed in: Stencil buffer fix by zzuegg · Pull Request #2325 · jMonkeyEngine/jmonkeyengine · GitHub [Screenshot 2024-10-28 102503]

Mainly because of the flexibility like overlapping, highlighting parts behind other objects.

[ndebruyn]

Thanks, I will check it out.

[pspeed]

Another old fashioned “outline” trick is to draw the mesh inside out using a solid color and with each vertex slightly pushed out along its normal. Sort of an inside out shell slightly bigger than the object.

[zzuegg]

Probably a good idea to implement that first since you need the balooning for the stencil outline too.

[ndebruyn]

This is what I get when I make use of the balooning method. However the more complex shapes would be a problem. But this could work for now.

[zzuegg]

Nice bow you have already done the hard part for stencil too. All left is setting the values for stencil testing/writing in the additional renderstate of the material.
And make sure you have enabled a depth texture with stencil component.

At least the pumpkin would not have the internal line. Not sure about the trunk since itt seems to be a normal issue.

[pspeed]

@ndebruyn

I make use of the balooning method. However the more complex shapes would be a problem.

Did you do it by scaling or by having a vert shader that pushes the vertex out a little by their normals?

The first only works for simple objects. The second will work for a lot more types of objects (like donuts, animals, characters, etc.)… most complex shapes will look ok with the second method.

[ndebruyn]

Yeah, these are all just based on the first method.

I did go the other route with a CartoonFilter where each object can have its own outline width and color, however, for some reason, some of the models I tried does not work that good.

Here is the filter examples:

[pspeed]

It’s true that sharp corners will suffer with this method without separate averaged normal buffers.