如何将正交相机转换为透视并返回？

Question

我正在使用 combinecamera.js 和 orbitcontrols.js https://github.com/mrdoob/three.js/blob/master/examples/js/cameras/CombinedCamera.js https://github.com/mrdoob/three.js/blob/master/examples/js/controls/OrbitControls.js

我让它工作，以便可以切换相机，并且都可以放大和缩小。 但是，orbitcontrols 会重新定位透视相机以模拟缩放，而正交相机不会这样做（它会改变 fov 等）..

这最终导致相机远截头体平面在透视模式下移动（我想要这个），并且它在正交模式下不移动（我想要它移动）。

我已通过重新定位透视和正交相机来解决此问题。正交相机不使用其位置来确定缩放，因此存在问题。

问题是当我在相机之间切换时，它们的缩放量似乎不同。

我想问题是，我如何让正交相机依靠相机位置来确定变焦量，以便它看起来总是具有与透视相机相似的变焦？

Answer 1

好的，经过大量试验后，我找到了一种骇人听闻的方法来获得足够接近的结果。 我意外地发现，如果将远截头体值设置为 25，它将完美地工作.. 所以我做了一个等式来补偿值是否不同。它已经足够接近了，但也许有人可以看到它可以改进的地方？

我换成了combinedcamera.js

halfHeight /= this.zoom;
halfWidth /= this.zoom;

与

halfHeight /= ((this.cameraP.far/25)*this.zoom);
halfWidth /= ((this.cameraP.far/25)*this.zoom);

我在combinedcamera.js 中添加了这一行

this.cameraO.far = this.cameraP.far+((this.cameraP.far/25)*this.zoom)-0.5;

就在这之前

this.cameraO.updateProjectionMatrix();

这是完整的部分

 THREE.CombinedCamera.prototype.toOrthographic = function () {

// Switches to the Orthographic camera estimating viewport from Perspective

var fov = this.fov;
var aspect = this.cameraP.aspect;
var near = this.cameraP.near;
var far = this.cameraP.far;

// The size that we set is the mid plane of the viewing frustum

var hyperfocus = ( near + far ) / 2;

var halfHeight = Math.tan( fov * Math.PI / 180 / 2 ) * hyperfocus;
var planeHeight = 2 * halfHeight;
var planeWidth = planeHeight * aspect;
var halfWidth = planeWidth / 2;

halfHeight /= ((this.cameraP.far/25)*this.zoom);
halfWidth /= ((this.cameraP.far/25)*this.zoom);

this.cameraO.left = -halfWidth;
this.cameraO.right = halfWidth;
this.cameraO.top = halfHeight;
this.cameraO.bottom = -halfHeight;

// this.cameraO.left = -farHalfWidth;
// this.cameraO.right = farHalfWidth;
// this.cameraO.top = farHalfHeight;
// this.cameraO.bottom = -farHalfHeight;

// this.cameraO.left = this.left / this.zoom;
// this.cameraO.right = this.right / this.zoom;
// this.cameraO.top = this.top / this.zoom;
// this.cameraO.bottom = this.bottom / this.zoom;

this.cameraO.far = this.cameraP.far+((this.cameraP.far/25)*this.zoom)-0.5;
this.cameraO.updateProjectionMatrix();

this.near = this.cameraO.near;
this.far = this.cameraO.far;
this.projectionMatrix = this.cameraO.projectionMatrix;

this.inPerspectiveMode = false;
this.inOrthographicMode = true;

 };

对于透视相机，我也将 this.zoom 更改为 1

 THREE.CombinedCamera.prototype.toPerspective = function () {

// Switches to the Perspective Camera

this.near = this.cameraP.near;
this.far = this.cameraP.far;

this.cameraP.fov =  this.fov / 1 ;

this.cameraP.updateProjectionMatrix();

this.projectionMatrix = this.cameraP.projectionMatrix;

this.inPerspectiveMode = true;
this.inOrthographicMode = false;

 };

另外，我必须调整轨道控制

this.dollyIn = function ( dollyScale ) {

    if ( dollyScale === undefined ) {

        dollyScale = getZoomScale();

    }

        scale /= dollyScale;
        scope.object.zoom = Math.max( this.minZoom, Math.min( this.maxZoom, this.object.zoom * dollyScale ) );
};

this.dollyOut = function ( dollyScale ) {

    if ( dollyScale === undefined ) {

        dollyScale = getZoomScale();

    }

        scale *= dollyScale;
        scope.object.zoom = Math.max( this.minZoom, Math.min( this.maxZoom, this.object.zoom / dollyScale ) );
};