围绕世界 0,0,0 而不是对象中心旋转

Posted 2023-02-22

【中文标题】围绕世界 0,0,0 而不是对象中心旋转

【英文标题】：Rotating around world 0,0,0 instead of object center

【发布时间】：2013-01-04 15:54:27

【问题描述】：

我的对象围绕 0,0,0 旋转，但我希望它在 Y 轴上围绕自身旋转。 我知道还有其他情况

Rotating object around itself in OpenGL

glRotatef not rotating as expected

但我在旋转之前没有任何翻译，但它仍然不起作用。

我的已编辑代码：

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

glRotatef(_angle,0.0f,1.0f,0.0f);
glPushMatrix();

glTranslatef(0.0f,0.0f,-6.0f);
glBegin(GL_TRIANGLES);
    //Front
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(1.0f, 1.0f, 1.0f);

    glVertex3f(-1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, 1.0f, 1.0f);

    //Back
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, -1.0f);

    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(1.0f, -1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, -1.0f);

    //Right
    glVertex3f(1.0f, 1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, -1.0f);

    glVertex3f(1.0f, 1.0f, 1.0f);
    glVertex3f(1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);


    //Left
    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glVertex3f(-1.0f, -1.0f, -1.0f);

    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f, -1.0f);


    //Top
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(1.0f, 1.0f, 1.0f);

    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, 1.0f);


    //Bottom
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);

    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(1.0f, -1.0f, -1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);
glEnd();
glPopMatrix();

glutSwapBuffers();

我的原始代码：

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

glRotatef(angle,0.0f,1.0f,0.0f);  //The angle is a float that slowly increases until it reaches 360 Degrees, and then resets to 0.0
    /* This is a Cube */
glBegin(GL_TRIANGLES);
    //Front
    glVertex3f(-1.0f, -1.0f, -5.0f);
    glVertex3f(-1.0f, 1.0f, -5.0f);
    glVertex3f(1.0f, 1.0f, -5.0f);

    glVertex3f(-1.0f, -1.0f, -5.0f);
    glVertex3f(1.0f, -1.0f, -5.0f);
    glVertex3f(1.0f, 1.0f, -5.0f);

    //Back
    glVertex3f(-1.0f, -1.0f, -7.0f);
    glVertex3f(-1.0f, 1.0f, -7.0f);
    glVertex3f(1.0f, 1.0f, -7.0f);

    glVertex3f(-1.0f, -1.0f, -7.0f);
    glVertex3f(1.0f, -1.0f, -7.0f);
    glVertex3f(1.0f, 1.0f, -7.0f);

    //Right
    glVertex3f(1.0f, 1.0f, -5.0f);
    glVertex3f(1.0f, -1.0f, -5.0f);
    glVertex3f(1.0f, -1.0f, -7.0f);

    glVertex3f(1.0f, 1.0f, -5.0f);
    glVertex3f(1.0f, 1.0f, -7.0f);
    glVertex3f(1.0f, -1.0f, -5.0f);


    //Left
    glVertex3f(-1.0f, 1.0f, -5.0f);
    glVertex3f(-1.0f, -1.0f, -5.0f);
    glVertex3f(-1.0f, -1.0f, -7.0f);

    glVertex3f(-1.0f, 1.0f, -5.0f);
    glVertex3f(-1.0f, 1.0f, -7.0f);
    glVertex3f(-1.0f, -1.0f, -7.0f);


    //Top
    glVertex3f(-1.0f, 1.0f, -7.0f);
    glVertex3f(-1.0f, 1.0f, -5.0f);
    glVertex3f(1.0f, 1.0f, -5.0f);

    glVertex3f(-1.0f, 1.0f, -7.0f);
    glVertex3f(1.0f, 1.0f, -7.0f);
    glVertex3f(1.0f, 1.0f, -5.0f);


    //Bottom
    glVertex3f(-1.0f, -1.0f, -7.0f);
    glVertex3f(-1.0f, -1.0f, -5.0f);
    glVertex3f(1.0f, -1.0f, -5.0f);

    glVertex3f(-1.0f, -1.0f, -7.0f);
    glVertex3f(1.0f, -1.0f, -7.0f);
    glVertex3f(1.0f, -1.0f, -5.0f);
glEnd();

glutSwapBuffers();

【问题讨论】：

你应该避免使用固定功能管道。

【参考方案1】：

确保对象的中心位于其局部坐标系的原点。

对于您的立方体，您的 X/Y 似乎居中，但您的 Z 中心看起来在 -6。

【讨论】：

好的，我更改了代码，但它仍然在做同样的事情

如果在旋转之前翻译会怎样？

请注意，矩阵乘法表示的变换是“向后”的，即最后乘以堆栈的变换是第一个应用的变换。