[SOLVED] Custom coloured mesh invisible with DirectionalLight

Troubleshooting
1

Hi all,

I’m currently trying to add some lighting to my scene so have put in a DirectionalLight and have converted my Material that gets applied to my Mesh Geometry (which represents a single tile of my terrain) such that it should reflect the light, by following tutorials such as http://wiki.jmonkeyengine.org/doku.php/jme3:advanced:custom_meshes and http://wiki.jmonkeyengine.org/doku.php/jme3:advanced:light_and_shadow. However unfortunately I’m still in the dark (pun most definitely intended) about what I might be missing. Here’s a small runnable example which demonstrates the issue:

public class TestApplication extends SimpleApplication {

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

@Override
public void simpleInitApp() {
    flyCam.setDragToRotate(true);
    
    Vector3f[] vertices = new Vector3f[4];
    vertices[0] = new Vector3f(0, -1, 0);
    vertices[1] = new Vector3f(0, -1, 1);
    vertices[2] = new Vector3f(1, -1, 0);
    vertices[3] = new Vector3f(1, -1, 1);

    Vector2f[] texCoord = new Vector2f[4];
    texCoord[0] = new Vector2f(0, 0);
    texCoord[1] = new Vector2f(1, 0);
    texCoord[2] = new Vector2f(0, 1);
    texCoord[3] = new Vector2f(1, 1);

    Vector3f[] normals = new Vector3f[4];
    normals[0] = new Vector3f(0, 1, 0);
    normals[1] = new Vector3f(0, 1, 0);
    normals[2] = new Vector3f(0, 1, 0);
    normals[3] = new Vector3f(0, 1, 0);

    int[] indexes = {2, 0, 1, 1, 3, 2};

    Mesh m = new Mesh();
    m.setBuffer(VertexBuffer.Type.Position, 3, BufferUtils.createFloatBuffer(vertices));
    m.setBuffer(VertexBuffer.Type.Normal, 3, BufferUtils.createFloatBuffer(normals));
    m.setBuffer(VertexBuffer.Type.TexCoord, 2, BufferUtils.createFloatBuffer(texCoord));
    m.setBuffer(VertexBuffer.Type.Index, 1, BufferUtils.createIntBuffer(indexes));

    Geometry g = new Geometry("terrainSquare", m);
    
//        Material mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
//        mat.setColor("Color", new ColorRGBA(
//                40 / 255f,
//                80 / 255f,
//                40 / 255f,
//                1));
    Material mat = new Material(assetManager, "Common/MatDefs/Light/Lighting.j3md");
    mat.setBoolean("UseMaterialColors", true);
    mat.setBoolean("UseVertexColor", true);
    mat.setBoolean("VertexLighting", true);
    mat.setColor("Ambient", new ColorRGBA(
            40 / 255f,
            80 / 255f,
            40 / 255f,
            1));
    mat.setColor("Diffuse", new ColorRGBA(
            40 / 255f,
            80 / 255f,
            40 / 255f,
            1));
    mat.setColor("Specular", new ColorRGBA(
            40 / 255f,
            80 / 255f,
            40 / 255f,
            1));
    mat.setFloat("Shininess", 50f);
            mat.getAdditionalRenderState().setWireframe(true);
    g.setMaterial(mat);
    g.updateModelBound();
    rootNode.attachChild(g);

    DirectionalLight sun = new DirectionalLight();
    sun.setColor(ColorRGBA.White);
    sun.setDirection(new Vector3f(5f, 5f, 0f));
    rootNode.addLight(sun);
}

}

I’m thinking it’s something to do with the normal values but everything looks consistent with the articles I’ve read - any ideas what I’m missing?

Thanks hugely in advance,

Ian

2

First, this is not a valid direction vector as it’s not normalized.

Second, it points up instead of down so is likely shining on the bottom of your plane.

3

Thank you very much pspeed, that’s done the trick! For some reason I was thinking the setDirection method was defining the source of the light, but after re-reading the documentation, I see that a DirectionalLight doesn’t have a position so that assumption didn’t make a whole lot of sense :stuck_out_tongue: Thanks again!

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