[SOLVED] Quad and PointLight, rotation of quad affects the lighting?

Troubleshooting graphics
1

Hi again, different topic now.

I have a spatial that I create like this:

private Spatial createShip(int ship) {
    Quad quad = new Quad(CoreViewConstants.SHIPSIZE, CoreViewConstants.SHIPSIZE);
    //<-- Move into the material?
    float halfSize = CoreViewConstants.SHIPSIZE * 0.5f;
    quad.setBuffer(VertexBuffer.Type.Position, 3, this.getArray(halfSize));
    //-->
    quad.updateBound();
    Geometry geom = new Geometry("Ship", quad);
    Material mat = assets.loadMaterial("Materials/ShipMaterialLight.j3m");
    //Material mat = assets.loadMaterial("Materials/ShipMaterialUnshaded.j3m");

    geom.setMaterial(mat);
    setShipMaterialVariables(geom, ship);
    //mat.setInt("numTilesOffsetY", ship);

    geom.setQueueBucket(RenderQueue.Bucket.Transparent);
    
    PointLight myLight = new PointLight();
    myLight.setColor(ColorRGBA.White);
    myLight.setRadius(20);
    rootNode.addLight(myLight);
    ShipLightControl lightControl = new ShipLightControl(myLight);
    geom.addControl(lightControl);

    //Test:
    //AmbientLight al = new AmbientLight();
    //al.setColor(ColorRGBA.White.mult(1.3f));
    //rootNode.addLight(al);
    //<--
    
    return geom;
}

The ShipLightControl is this:

public class ShipLightControl extends LightControl {

PointLight pointLight;
Vector3f pos;

public ShipLightControl(PointLight pointLight) {
    super(pointLight);

    this.pointLight = pointLight;
}

@Override
public void update(float tpf) {
    //super.update(tpf);
    if (this.enabled && this.getSpatial() != null && pointLight != null) {
        pos = this.getSpatial().getLocalTranslation();
        pointLight.setPosition(pos.add(0, 0, 2));
    }
}
}

The material of the ship is this:

Material ShipMaterialLight : MatDefs/StaticSprite/StaticSpriteLightShader.j3md {
 MaterialParameters {
    //AniTexMap : Flip Textures/Subspace/ships.bmp
    numTilesX : 10
    numTilesY : 32
    numTilesOffsetX : 0
    numTilesOffsetY : 3

    DiffuseMap : Flip Textures/Subspace/ships.bmp
    UseMaterialColors : true
    Specular : 1.0 1.0 1.0 1.0
    Diffuse : 1.0 1.0 1.0 1.0
    Shininess : 1.0
 }
AdditionalRenderState {
  Blend Alpha
  Wireframe Off
}
}

I try to position the light above the ship-quad, so that the ship is illuminated by the light. It works to begin with:

image

But when I rotate the quad, the light fades:

image

image

image

Anyone have any pointers or places I can look to fix this ?

In the Docs, it says that there are these:

g_LightPosition: the position of the light

use for PointLight: x,y,z contain the world position of the light, the w component contains 1/lightRadius

But doesnt mention anything about direction for a pointlight. My shader is based on the lighting.j3md - I’m trying to see if lighting.j3md has been updated since I looked at it.

2

A pointLight doesn’t have a direction, it has a radius and a linear falloff from its location around its radius.

3

Okay, so that confirmed that. I’m probably to look into my Lighting j3md / vert / frag and see if have done something there that is affecting the light direction.

4

I’m not sure what your shader is doing but usually any problems with lighting revolve around bad normals. Are they pointing in the right direction?

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5

No idea. Haven’t dealt with normals before. The texture is a bitmap. No idea where to start.

6

Judging by the other threads you’ve created, you make your own quad.

Try the built-in quad mesh - which will contain the correct normals.

1 Like
7

Thanks. I found this now (knowing what to search for is important)
https://wiki.jmonkeyengine.org/docs/jme3/advanced/custom_meshes.html#example-using-meshes-with-lighting-j3md

Will read up on that. I have probably skipped this in the past just using Unshaded.

8

Hmm, I tried setting the normals :slight_smile:

{...
    Quad quad = new Quad(CoreViewConstants.SHIPSIZE, CoreViewConstants.SHIPSIZE);
    float halfSize = CoreViewConstants.SHIPSIZE * 0.5f;
    quad.setBuffer(VertexBuffer.Type.Position, 3, BufferUtils.createFloatBuffer(this.getVertices(halfSize)));
    quad.setBuffer(VertexBuffer.Type.Normal, 3, BufferUtils.createFloatBuffer(getNormals()));
...}

private float[] getVertices(float halfSize) {
    float[] res = new float[]{
        halfSize, 0, -halfSize,
        -halfSize, 0, -halfSize,
        -halfSize, 0, halfSize,
        halfSize, 0, halfSize
    };
    return res;
}
private float[] getNormals() {
    float[] normals = new float[12];
    normals = new float[]{0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0};

    return normals;
}

}

My game is in the xz-plane, y is up. I think there’s a discrepancy between the JavaDocs and the examples/Wiki of what is default “up”, but nonetheless, I didnt get through yet.It ends up unlit/black. Will have to see if I can get it working with a “default” Quad as you mentioned.

9

I think I got it working. I had the wrong position on the light according to both normals and “up”. Thanks for the help @jayfella!

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