webgl - ray 没有到达 JSON

Question

我正在尝试使用鼠标单击事件捕获 JSON 对象。我使用射线来识别物体，但由于某种原因，物体并不总是被识别出来。我怀疑这与我移动相机有关，因为当我在对象附近单击时，我被识别出来了。

你能帮我弄清楚如何根据相机移动正确设置光线吗？

这是代码：

这是鼠标按下事件的一部分 *

    document.addEventListener("mousemove", onDocumentMouseMove, false);
    document.addEventListener("mouseup", onDocumentMouseUp, false);
    document.addEventListener("mouseout", onDocumentMouseOut, false);
    mouseXOnMouseDown = event.clientX - windowHalfX;
    targetRotationOnMouseDown = targetRotation;
    var ray, intersections;
    _vector.set((event.clientX / window.innerWidth) * 2 - 1, -(event.clientY / window.innerHeight) * 2 + 1, 0);
    projector.unprojectVector(_vector, camera);
    ray = new THREE.Ray(camera.position, _vector.subSelf(camera.position).normalize());
    intersections = ray.intersectObjects(furniture);

    if (intersections.length > 0) {
        selected_block = intersections[0].object;
        _vector.set(0, 0, 0);
        selected_block.setAngularFactor(_vector);
        selected_block.setAngularVelocity(_vector);
        selected_block.setLinearFactor(_vector);
        selected_block.setLinearVelocity(_vector);
        mouse_position.copy(intersections[0].point);
        block_offset.sub(selected_block.position, mouse_position);
        intersect_plane.position.y = mouse_position.y;
    }

}

这是相机移动的一部分 *

camera.position.x = (Math.cos(timer) * 10);
camera.position.z = (Math.sin(timer) * 10);
camera.lookAt(scene.position); 

Answer 1

Hmmm, It is hard to say what your problem might be without seeing some kind of demonstration of how your program is actually acting. I would suggest looking at my demo that I have been working on today. I handle my camera, controls, and rays. I am using a JSON as well.

First you can view my demo: here to get an idea of what it is doing, what your describing sounds similar. You should be able to adapt my code if you can understand it.
--If you would like a direct link to the source code: main.js

I also have another you might find useful where I use rays and mouse collisions to spin a cube.
--Source code: main.js

Finally I'll post the guts of my mouse events and how I handle it with the trackball camera in the first demo, hopefully some of this will lead you to a solution:

/** Event fired when the mouse button is pressed down */
function onDocumentMouseDown(event) {
    event.preventDefault();

    /** Calculate mouse position and project vector through camera and mouse3D */
    mouse3D.x = mouse2D.x = (event.clientX / window.innerWidth) * 2 - 1;
    mouse3D.y = mouse2D.y = -(event.clientY / window.innerHeight) * 2 + 1;
    mouse3D.z = 0.5;
    projector.unprojectVector(mouse3D, camera);

    var ray = new THREE.Ray(camera.position, mouse3D.subSelf(camera.position).normalize());

    var intersects = ray.intersectObject(maskMesh);

    if (intersects.length > 0) {
        SELECTED = intersects[0].object;
        var intersects = ray.intersectObject(plane);
        offset.copy(intersects[0].point).subSelf(plane.position);
        killControls = true;
    }
    else if (controls.enabled == false)
        controls.enabled = true;
}

/** This event handler is only fired after the mouse down event and
    before the mouse up event and only when the mouse moves */
function onDocumentMouseMove(event) {
    event.preventDefault();

    /** Calculate mouse position and project through camera and mouse3D */
    mouse3D.x = mouse2D.x = (event.clientX / window.innerWidth) * 2 - 1;
    mouse3D.y = mouse2D.y = -(event.clientY / window.innerHeight) * 2 + 1;
    mouse3D.z = 0.5;
    projector.unprojectVector(mouse3D, camera);

    var ray = new THREE.Ray(camera.position, mouse3D.subSelf(camera.position).normalize());

    if (SELECTED) {
        var intersects = ray.intersectObject(plane);
        SELECTED.position.copy(intersects[0].point.subSelf(offset));
        killControls = true;
        return;
    }

    var intersects = ray.intersectObject(maskMesh);

    if (intersects.length > 0) {
        if (INTERSECTED != intersects[0].object) {
            INTERSECTED = intersects[0].object;
            INTERSECTED.currentHex = INTERSECTED.material.color.getHex();
            plane.position.copy(INTERSECTED.position);
        }
    }
    else {
        INTERSECTED = null;
    }
}

/** Removes event listeners when the mouse button is let go */
function onDocumentMouseUp(event) {
    event.preventDefault();
    if (INTERSECTED) {
        plane.position.copy(INTERSECTED.position);
        SELECTED = null;
        killControls = false;
    }

}

/** Removes event listeners if the mouse runs off the renderer */
function onDocumentMouseOut(event) {
    event.preventDefault();
    if (INTERSECTED) {
        plane.position.copy(INTERSECTED.position);
        SELECTED = null;
    }
}

And in order to get the desired effect shown in my first demo that I wanted, I had to add this to my animation loop in order to use the killControls flag to selectively turn on and off the trackball camera controls based on the mouse collisions:

if (!killControls) controls.update(delta);
else controls.enabled = false;