[Solved] Lights not working how I expect

Troubleshooting General Help
1

I have a simple setup where I am creating a set of tiles and rendering them in a grid and adding a point light in the middle above them.

int[][] map = new int[][] {
        {2,0,0,0,0,0,0,0,0,0},
        {0,1,1,1,1,1,1,1,1,0},
        {0,1,0,0,0,0,0,0,1,0},
        {0,1,0,0,1,0,0,0,1,0},
        {0,1,0,1,0,1,0,0,1,0},
        {0,1,0,0,0,0,1,0,1,0},
        {0,1,0,0,0,0,0,0,1,0},
        {0,1,0,0,0,0,0,0,1,0},
        {0,1,1,1,1,1,1,1,1,0},
        {0,0,0,0,0,0,0,0,0,0}
};

app.getStateManager().attach(new FlyCamAppState());
for (int y = 0; y < map.length; y++) {
    for (int x = 0; x < map[y].length; x++) {
        Tile tile = new Tile();
        Geometry geom = new Geometry("tile-" + x + "-" + y, tile);
        Material mat1 = new Material(app.getAssetManager(),
                "Common/MatDefs/Light/Lighting.j3md");  // create a simple material
        mat1.setTexture("DiffuseMap", app.getAssetManager().loadTexture("Textures/Monkey.png"));

        geom.setMaterial(mat1);
        geom.setLocalTranslation(x, 0, y);
        app.getRootNode().attachChild(geom);
    }
}

PointLight lamp = new PointLight();
lamp.setColor(ColorRGBA.Orange);
lamp.setRadius(5f);
lamp.setPosition(new Vector3f(5f, 1f, 5f));
app.getRootNode().addLight(lamp);

My tile class looks like this:

public class Tile extends Mesh {

    public Tile() {
        Vector3f[] vertices = new Vector3f[4];
        vertices[0] = new Vector3f(-0.5f, 0, -0.5f);
        vertices[1] = new Vector3f(0.5f, 0, -0.5f);
        vertices[2] = new Vector3f(-0.5f, 0, 0.5f);
        vertices[3] = new Vector3f(0.5f, 0, 0.5f);
        Vector2f[] texCoord = new Vector2f[4];
        texCoord[0] = new Vector2f(0, 0);
        texCoord[1] = new Vector2f(0, 1);
        texCoord[2] = new Vector2f(1, 0);
        texCoord[3] = new Vector2f(1, 1);
        int[] indexes = {1, 0, 2, 2, 3, 1};
        this.setBuffer(Type.Position, 3, BufferUtils.createFloatBuffer(vertices));
        this.setBuffer(Type.TexCoord, 2, BufferUtils.createFloatBuffer(texCoord));
        this.setBuffer(Type.Index, 3, BufferUtils.createIntBuffer(indexes));
        setBuffer(Type.Normal, 3, new float[]{0, 0, 1,
                0, 0, 1,
                0, 0, 1,
                0, 0, 1});
        this.updateBound();
    }

}

What I expect to see is the tiles illuminated with an orange circle but only half of it is illuminated?!?!? In the image below the PointLight is roughly in the centre of the image. I think the x-axis runs vertically and the z-axis horizontally, if this is the case then it looks like the light is scaled down in the negative z direction from the light’s position (as you see it does have a slight curve to it). If I move the light around I get the shape of the light doesn’t change only its location.

screenshot001.png1026×794 129 KB

I get a similar issue with SpotLights.

2

Ok so it must be to do with my Tile class’ mesh definition because if I replace the tiles with a big box then it lights as I would expect. Im guessing that I have messed up the mesh buffers (order or whatever), can anyone see an obvious mistake that I’m missing?

3

Ok, my normals were pointing in the positive z direction, I’m guessing that this has the effect of folding the light in half because when I fixed the normals the light was half as bright! (edit: and of course circular as I would expect)

The fix is this:

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);
this.setBuffer(Type.Normal, 3, BufferUtils.createFloatBuffer(normals));