Camera.contains(nullBound) returns FrustumIntersect.Inside!

Ali_RS · February 4, 2021, 6:45am

@sgold, @pspeed does this make sense to you?

jMonkeyEngine/jmonkeyengine/blob/67119862d10fb0be8b98e930cc35fa0e6fd017cf/jme3-core/src/main/java/com/jme3/renderer/Camera.java#L1021-L1025


public FrustumIntersect contains(BoundingVolume bound) {
    if (bound == null) {
        return FrustumIntersect.Inside;
    }

shouldn’t it return FrustumIntersect.Outside if bound is null?

sgold · February 4, 2021, 7:00am

I believe a null bound indicates an empty volume, so it should return Outside.

Ali_RS · February 4, 2021, 7:07am

Thanks for the response.

Do you think fixing it would be a breaking change for v3.3?

sgold · February 4, 2021, 7:29am

At this point, I think it’s a moot question: there aren’t any more 3.3.x releases planned.

pspeed · February 4, 2021, 11:11am

JME is inconsistent on this point and it seems very few places in the code were hardened for this idea. In at least a few cases, we’ve swung the other way of “always return some bound”.

For example, see: Node returns null bounding volume. · Issue #954 · jMonkeyEngine/jmonkeyengine · GitHub

It may be that the “right solution” is to have a NullBound that never intersects anything and can have a constant instance that these cases return instead of null.

Ali_RS · February 5, 2021, 7:08am

Thanks @pspeed

For InstancedGeometry I ended up following the same approach used in the Node class.

github.com

jMonkeyEngine/jmonkeyengine/blob/72ffa40aa3960bff24bcb7c0cac1fea3eaf99967/jme3-core/src/main/java/com/jme3/scene/instancing/InstancedGeometry.java#L395-L397


if (resultBound == null) {
    resultBound = new BoundingBox(getWorldTranslation(), 0f, 0f, 0f);
}