Three.js检测点击对象纹理的无透明像素

Question

我有几个THREE.PlaneGeometry，其人脸纹理在脸部周围有透明像素。

我正在使用THREE.Raycaster来检测鼠标指针下的对象，当我得到相交列表时 - 我需要知道点击是否在透明像素上，如果是这种情况 - 移动到下一个交叉对象。

这样的事情：

var onStageMouseDown = function( event ) {

    event.preventDefault();

    // stageEl - is the element that contain the renderer
    var vector = new THREE.Vector3( 
        ( event.offsetX / stageEl.offsetWidth ) * 2 - 1, 
        - ( event.offsetY / stageEl.offsetHeight ) * 2 + 1, 
        0.5 );

    projector.unprojectVector( vector, camera );

    var ray = new THREE.Raycaster( camera.position, vector.sub( camera.position ).normalize() );

    // objects - is list of meshes
    var intersects = ray.intersectObjects( objects );    

    for(var i=0; i<intersects.length; i++) {

        // this is what I don't know how to calculate....
        var PointIsTransparentPixelOnMeshTexture = ?;

        if ( PointIsTransparentPixelOnMeshTexture ) continue;

        alert( "You clicked on "+intersects[i].object.name );
        return;

        }


    alert( "You clicked no one " );

    }

任何想法？

感谢。