小编典典

如何在Three.js轴上旋转3D对象?

javascript

我对Three.js的旋转有很大的疑问,我想在自己的一款游戏中旋转3D立方体。

//init
geometry = new THREE.CubeGeometry grid, grid, grid
material = new THREE.MeshLambertMaterial {color:0xFFFFFF * Math.random(), shading:THREE.FlatShading, overdraw:true, transparent: true, opacity:0.8}
for i in [1...@shape.length]
    othergeo = new THREE.Mesh new THREE.CubeGeometry(grid, grid, grid)
    othergeo.position.x = grid * @shape[i][0]
    othergeo.position.y = grid * @shape[i][1]
    THREE.GeometryUtils.merge geometry, othergeo
@mesh = new THREE.Mesh geometry, material

//rotate
@mesh.rotation.y += y * Math.PI / 180
@mesh.rotation.x += x * Math.PI / 180
@mesh.rotation.z += z * Math.PI / 180

并且(x,y,z)可以是(1、0、0)

则多维数据集可以旋转,但是问题在于多维数据集绕其自身的轴旋转,因此,旋转后,它无法按预期旋转。

并且我尝试使用 matrixRotationWorld 作为

@mesh.matrixRotationWorld.x += x * Math.PI / 180
@mesh.matrixRotationWorld.y += y * Math.PI / 180
@mesh.matrixRotationWorld.z += z * Math.PI / 180

但它不起作用,我不以错误的方式使用它,还是有其他方法。

因此,如何让3D立方体绕世界轴旋转???


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2020-05-01

共1个答案

小编典典

这是我使用的两个功能。它们基于矩阵旋转。并可以绕任意轴旋转。要使用世界上的轴旋转,您需要使用第二个函数rotateAroundWorldAxis()。

// Rotate an object around an arbitrary axis in object space
var rotObjectMatrix;
function rotateAroundObjectAxis(object, axis, radians) {
    rotObjectMatrix = new THREE.Matrix4();
    rotObjectMatrix.makeRotationAxis(axis.normalize(), radians);

    // old code for Three.JS pre r54:
    // object.matrix.multiplySelf(rotObjectMatrix);      // post-multiply
    // new code for Three.JS r55+:
    object.matrix.multiply(rotObjectMatrix);

    // old code for Three.js pre r49:
    // object.rotation.getRotationFromMatrix(object.matrix, object.scale);
    // old code for Three.js r50-r58:
    // object.rotation.setEulerFromRotationMatrix(object.matrix);
    // new code for Three.js r59+:
    object.rotation.setFromRotationMatrix(object.matrix);
}

var rotWorldMatrix;
// Rotate an object around an arbitrary axis in world space       
function rotateAroundWorldAxis(object, axis, radians) {
    rotWorldMatrix = new THREE.Matrix4();
    rotWorldMatrix.makeRotationAxis(axis.normalize(), radians);

    // old code for Three.JS pre r54:
    //  rotWorldMatrix.multiply(object.matrix);
    // new code for Three.JS r55+:
    rotWorldMatrix.multiply(object.matrix);                // pre-multiply

    object.matrix = rotWorldMatrix;

    // old code for Three.js pre r49:
    // object.rotation.getRotationFromMatrix(object.matrix, object.scale);
    // old code for Three.js pre r59:
    // object.rotation.setEulerFromRotationMatrix(object.matrix);
    // code for r59+:
    object.rotation.setFromRotationMatrix(object.matrix);
}

因此,您应该在anim函数中调用这些函数(requestAnimFrame回调),从而在x轴上旋转90度:

var xAxis = new THREE.Vector3(1,0,0);
rotateAroundWorldAxis(mesh, xAxis, Math.PI / 180);
2020-05-01