如何按自己的中心旋转所有对象，然后将它们转换到真实位置(它不起作用) [英] how to rotate all objects by their own centers and then translate them to the real position (it isn't working)

问题描述

有什么办法让所有与原点中心(vector3(0.0f,0.0f,0.0f))不对齐的物体都绕着自己的中心轴旋转?

What is the way to make all the objects that are not aligned with the origin center (vector3(0.0f,0.0f,0.0f)) , rotate about its own central axis?

伪代码中的问题:

vector3 vector3 objectCenter = (10,5,0); // current object center
vector3 vector3 objectPosition = (40,5,0); // Place to translate the object
vector3 objectRotation; = 45.0f;

    matrix.loadIdentity ();
    matrix.translate (objectCenter);

    //apply transformations
    matrix.rotateX (objectRotation);

    matrix.translate (-objectCenter);

    //itś work correctly until here
    //when i try to translate the object to the real position, the rotation is incorrect.

    matrix.translate (objectPosition);

我使用 C++、glm(用于矩阵管理)和 OpenGL.

I use C++, glm (to matrix manage) and OpenGL.

推荐答案

如果你想将对象本地旋转到它自己的坐标系，那么这样做:

if you want to rotate object locally to its own coordinate system then do this:

M=inverse(inverse(M)*rotation_matrix);

• M 是你的对象变换矩阵
• rotation_matrix 是任意旋转(glRotate())
• inverse 是计算逆矩阵的函数，您可以使用我的 逆矩阵计算 或这个围绕 C++ 中的 LCS x (lrotx) 实现旋转(在答案的底部)
• M is your object transform matrix
• rotation_matrix is any rotation (glRotate())
• inverse is function that computes the inverse matrix you can use mine inverse matrix computation or this rotation around LCS x (lrotx) implementation in C++ (at the bottom of the answer)

[edit1] 更多关于 M 和它所代表的坐标系的对象之间的关系

看这里:变换矩阵解剖

M 原点通常是对象的中间(或旋转运动中心点).M 的轴通常与对象对齐，例如在飞机中，X 轴通常是飞行方向.我比较习惯:

M origin is usually the middle of object (or point which is center of rotation movements). Axises of M are usually aligned with object for example in airplanes the X axis is usually the fly direction. I am more used to:

• +z轴为正向运动
• +x 为右，-x 为左
• +y 向上，-y 向下
• +z axis as forward direction movement
• +x as right, -x as left
• +y as up and -y as down

pith,yaw,roll 然后是围绕 x,y,z

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