How to use screenPointToRay?

xsmasherx · June 17, 2021, 11:32am

I am trying to position an object in 3d space based on a user touch.

My plan is to get a ray and find its intersection with a “floor” plane.

What do I need to pass to screenPointToRay ? when I pass e.getUILocation() I get a ray that is very far from the camera location.

let ray = this._3dCamera.screenPointToRay(uiLocation.x, uiLocation.y);

Do I need to call screenPointToRay on the 2d camera instead? Or pass a different value?

I’m using cocos creator 3.0.0.

gist.github.com

https://gist.github.com/smasherknock/cf49a8c9407815e840fec1ce71b44c8b

gistfile1.txt

    onDragMove(e:EventMouse){
        let uiLocation = e.getUILocation();

        // // map 2d touch to 3d position
        
        let ray = this._3dCamera.screenPointToRay(uiLocation.x, uiLocation.y);
        let dist = geometry.intersect.rayPlane(ray, this._floorPlane);
        let pos = new Vec3();

        ray.computeHit(pos, dist);

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xsmasherx · June 18, 2021, 12:13am

This was not working because my camera was offset in the world; ray.o was close to the world coords of the camera.

Removing the camera offset and changing to e.getLocation fixed it.