Setting line width on WireBox in 3.6.0 has no effect

NeilAgg · April 2, 2023, 6:37pm

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(assetManager,"Common/MatDefs/Misc/Unshaded.j3md");
    mat.getAdditionalRenderState().setLineWidth(25);
    ColorRGBA color = ColorRGBA.Red;
    mat.setColor("Color", color);
    geom.setMaterial(mat);
    rootNode.attachChild(geom);
  }

  public static void main(String[] args) {
    WireBoxTest app = new WireBoxTest();
    app.start();
  }
}

If I use JME 3.5.2, I get a box with exaggerated lines:

But, if I use JME 3.6.0, I get a box with thin lines:

Was there an API change that I missed?

sgold · April 2, 2023, 7:17pm

Line thickness is a feature of OpenGL’s “compatibility” profile, which JME used by default prior to v3.6.0 . It’s not implemented in OpenGL’s “3.2 core” profile, which is the new default as of v3.6.0 .

You can easily override the default programmatically using something like:

        AppSettings appSettings = new AppSettings(true);
        appSettings.setRenderer(AppSettings.LWJGL_OPENGL2); // OpenGL compatibility profile to enable thickness

        MyGame application = new MyGame();
        application.setSettings(appSettings);
        application.start();

pspeed · April 2, 2023, 7:22pm

But be aware that the writing is on the wall regarding openGL continuing to support this feature.

richtea · April 2, 2023, 9:24pm

What do we think about marking that method as deprecated with that explanation in its javadoc? (both how to get it working and that long term you probably shouldn’t)

NeilAgg · April 3, 2023, 3:35am

Well, that makes WireBox a lot less useful. I guess I will have to create a subroutine that creates a box out of cylinders.

NeilAgg · April 3, 2023, 11:43am

I created my own OutlineBox class which will create a box with an optional fill and an outline. Here is my code:

/**
 * OutlineBox.java
 */
package com.propfinancing.jme3;

import java.util.ArrayList;
import com.jme3.asset.AssetManager;
import com.jme3.material.Material;
import com.jme3.math.ColorRGBA;
import com.jme3.math.FastMath;
import com.jme3.math.Quaternion;
import com.jme3.math.Vector3f;
import com.jme3.scene.Geometry;
import com.jme3.scene.Mesh;
import com.jme3.scene.Node;
import com.jme3.scene.shape.Box;
import com.jme3.scene.shape.Cylinder;
import com.jme3.scene.shape.Sphere;

/**
 * Class to implement a box with an outline
 * @author Neil Aggarwal
 */
public class OutlineBox extends Node {
  /** Constructor 
   * @param fillColor Fill color for the box, set to null for no fill
   * @param outlineColor Outline color for the box, set to null for no outline
   */
  public OutlineBox(AssetManager assetManager, float xExt, float yExt, float zExt, 
      float lineWidth, ColorRGBA fillColor, ColorRGBA outlineColor) {
    
    // Check if we have a fill color and add a box for it
    if( fillColor != null ) {
      Mesh m = new Box(xExt, yExt, zExt);
      Geometry geom = new Geometry("Fill", m);
      Material mat = new Material(assetManager,"Common/MatDefs/Misc/Unshaded.j3md");
      mat.setColor("Color", fillColor);      
      geom.setMaterial(mat);
      attachChild(geom);
    }
    
    // Check if we have an outline color
    if( outlineColor != null ) {
      // Put spheres at each of the vertices
      for( int x=-1; x<=1; x+=2 )
        for( int y=-1; y<=1; y+=2 )
          for( int z=-1; z<=1; z+=2 ) {
            Mesh m = new Sphere(64,64,lineWidth/2);
            Geometry geom = new Geometry("Vertex", m);
            Material mat = new Material(assetManager,"Common/MatDefs/Misc/Unshaded.j3md");
            mat.setColor("Color", outlineColor);      
            geom.setMaterial(mat);
            geom.setLocalTranslation(new Vector3f(x*xExt,y*yExt,z*zExt));
            attachChild(geom);
          }

      // Add the outline segments
      ArrayList<Vector3f> rotationAxes = new ArrayList<Vector3f>();
      rotationAxes.add(Vector3f.UNIT_X);
      rotationAxes.add(Vector3f.UNIT_Y);
      rotationAxes.add(Vector3f.UNIT_Z);
      for( Vector3f rotationAxis : rotationAxes ) {
        if( rotationAxis.equals(Vector3f.UNIT_X) ) {
          for( int x=-1; x<=1; x+=2 )
            for( int z=-1; z<=1; z+=2 )
              addOutlineSegment(assetManager,rotationAxis,x*xExt,0,z*zExt,lineWidth,yExt,outlineColor);
        } else if( rotationAxis.equals(Vector3f.UNIT_Y) ) {
          for( int y=-1; y<=1; y+=2 )
            for( int z=-1; z<=1; z+=2 )
              addOutlineSegment(assetManager,rotationAxis,0,y*yExt,z*zExt,lineWidth,xExt,outlineColor);
        } else if( rotationAxis.equals(Vector3f.UNIT_Z) ) {
          for( int x=-1; x<=1; x+=2 )
            for( int y=-1; y<=1; y+=2 )
              addOutlineSegment(assetManager,null,x*xExt,y*yExt,0,lineWidth,zExt,outlineColor);
        }
      }
    }
  }
  
  /** Add an outline segment */
  private void addOutlineSegment(AssetManager assetManager, Vector3f rotationAxis, 
      float x, float y, float z,
      float lineWidth, float extent, ColorRGBA outlineColor) {
    Mesh m = new Cylinder(64,24,lineWidth/2f,extent*2);
    Geometry geom = new Geometry("Segment", m);
    Material mat = new Material(assetManager,"Common/MatDefs/Misc/Unshaded.j3md");
    mat.setColor("Color", outlineColor);      
    geom.setMaterial(mat);
    if( rotationAxis != null ) {
      Quaternion rotation = new Quaternion().fromAngleAxis(90*FastMath.DEG_TO_RAD,rotationAxis);
      geom.setLocalRotation(rotation);
    }
    geom.setLocalTranslation(new Vector3f(x,y,z));
    attachChild(geom);    
  }
}

Please let me know if anyone has suggestions on how to improve it.
Also, if people want me to contribute it to JME, I am willing to do so.

oxplay2 · April 3, 2023, 2:25pm

We miss general purpose what you need achieve.

For example i guess it could be done simple and optimal way with shaders.

similar to “outline” here that is not exactly same, but might be substitute for what you need:
https://library.jmonkeyengine.org/#!entry=24022%2F5246c9ac-3f4c-4a5d-9fb0-470eb4026246

NeilAgg · April 3, 2023, 2:43pm

I am using JME to create images for my 3D Math Puzzles. They look like this:

Each box in the puzzle uses a Box object and I them to be outlined. I am using a black outline for the white boxes and a white outline for the black boxes.

That looks like it is set up to outline one object at a time. Do you think I can use it to outline many objects at once?

NeilAgg · April 3, 2023, 3:27pm

According to the readme for SelectObjectOutliner, it has two modes.
One gives bad looking results and the other does not take depth into account.
Neither mode will work for me since I want a good looking result which hides overlayed objects.

sgold · April 3, 2023, 4:04pm

Each box in the puzzle uses a Box object and I them to be outlined. I am using a black outline for the white boxes and a white outline for the black boxes.

I’m unclear why you can’t use the default line thickness, which is 1 pixel.

pspeed · April 3, 2023, 4:23pm

Note that if you built the borders into your textures (or the shaders) then you wouldn’t get this nasty aliasing:

…the big downside of GL lines is that no matter what width you use, you will always have aliasing without cranking up AA (which is expensive compared to easy alternatives).

NeilAgg · April 3, 2023, 4:29pm

My lines became very light and mostly dotted. I wanted to make them slightly heavier.

NeilAgg · April 3, 2023, 4:31pm

I am not sure what you mean by this. Is there a guide to explain it somewhere?

pspeed · April 3, 2023, 4:37pm

What does your texture look like that you put on your blocks?

NeilAgg · April 3, 2023, 5:01pm

I did not use a texture. I just created them with the Unshaded material. I guess they use the default texture.

pspeed · April 3, 2023, 5:03pm

So each square is a quad and a wire frame? Or full cube and a wire frame?

I don’t really know enough about your geometry to help further and I don’t have much time to play 20 questions today.

The basic idea is that instead of having a white side to your cube that you would put a texture there with a black border.

NeilAgg · April 3, 2023, 5:13pm

I posted the code I used to generate it in a post in this thread.

For each block, I created a white box and then used 6 black spheres (One at each vertex) and 12 black cylinders (One along each edge) to outline it.

I see the texture guide in the tutorial. I will play with it. Thanks!

pspeed · April 3, 2023, 5:17pm

I know what you are doing to make your cyclinder box thing.

I don’t know how you are currently building your actual game puzzle scene thing… and I don’t know how/why the fat-wire box comes into play.

Textures get filtered which is why lines/borders look better in them when you can get away with it. Your scene seems like the exact right fit.

NeilAgg · April 3, 2023, 5:26pm

I read the tutorial page on textures and it seems simple enough.

Since my box is 3D and the texture is a PNG file (which is 2D), how will it map the texture onto the object? Does the image get applied to each face? Does it scale up and down or do I need to make the texture the exact size of each face?

pspeed · April 3, 2023, 7:02pm

If you are really new to 3D graphics then you might want to read about UVs.