transient-pointer-manager.js

update() {
    let transientPointerFoundThisFrame = false;

    for (let input of this.engine.xr.session.inputSources) {
        if (input.targetRayMode !== 'transient-pointer') continue;

        // If we made it this far, we're dealing w/ a transient-pointer
        transientPointerFoundThisFrame = true;

        // Get the pose from the session from using the targetRaySpace and the currentRefSpace
        // https://developer.mozilla.org/en-US/docs/Web/API/XRFrame/getPose
        this.controllerPose = this.engine.xr.frame.getPose(
            input.targetRaySpace,
            this.engine.xr.currentReferenceSpace
        );

        // Returns an XRPose containing an XRRigidTransform:
        // https://developer.mozilla.org/en-US/docs/Web/API/XRPose
        // https://developer.mozilla.org/en-US/docs/Web/API/XRRigidTransform

        // Format data for gl-matrix types vec3 and quat
        let posePosition = vec3.fromValues(
            this.controllerPose.transform.position.x,
            this.controllerPose.transform.position.y,
            this.controllerPose.transform.position.z
        )
        let rotQuat = quat.fromValues(
            this.controllerPose.transform.orientation.x,
            this.controllerPose.transform.orientation.y,
            this.controllerPose.transform.orientation.z,
            this.controllerPose.transform.orientation.w,
        )

        // the returned pose is in reference space
        // add the world position of its reference space to get the pose's world pos
        let worldPos = vec3.create()
        let refSpacePos = vec3.create()
        this.refSpace.getPositionWorld(refSpacePos)
        vec3.add(worldPos, posePosition, refSpacePos)

        // Try to get directional vec
        let dirVec = vec3.create();
        let forwardVec = vec3.fromValues(0,0,-1); // in ref space, z+ is "backwards"
        vec3.transformQuat(dirVec, forwardVec, rotQuat)

        // Next raycast from this transform to the static collision layer
        const rayHit = this.engine.physics.rayCast(worldPos, dirVec, 1 << 0);

        if (rayHit.hitCount > 0) {
            this.isPinching = true;
            console.log("hit something!", rayHit.locations[0])

            this.debugSphere.active = true;
            this.debugSphere.setPositionWorld(rayHit.locations[0])

            // Re-use the controller pose but discard the Y
            let gripPosInRefSpace = vec3.fromValues(
                this.controllerPose.transform.position.x,
                0.01,
                this.controllerPose.transform.position.z
            );

            // add the world position of the reference space to get the pose's world pos
            let gripWorldPos = vec3.create();
            vec3.add(gripWorldPos, gripPosInRefSpace, rayHit.locations[0]);

            this.lastWorldPos = gripWorldPos;
            this.debugSphere.setPositionWorld(gripWorldPos);
        }
        break;
    }
    if (!transientPointerFoundThisFrame) {
        this.isPinching = false;
    }
}