如何让GL_QUADS向侧面移动？ [英] How to have a GL_QUADS move sidewards?

问题描述

你好，我是opengl的新手，我很困惑如何使用gltranslate / glrotate让gl_quads向侧面移动，任何帮助？以下是我对gl_quads的顶点：

hello, i am new to opengl and im confused on how to use gltranslate/glrotate to let the gl_quads move sidewards, any help? following is my vertices for the gl_quads:

void display(){
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glPushMatrix();
    glTranslatef(0.3,0,0);
    //glTranslatef(0.7,0,0);
    //glRotatef(45.0,0.0,1.0,0.0);

    glBegin(GL_QUADS);
        glColor3f(1.0f, 0.5f, 0.0f);     // Orange
        glVertex2f(0,0);

        glColor3f(1.0f, 0.0f, 0.0f);     // Red
        glVertex2f(0.4,0);

        glColor3f(1.0f, 1.0f, 0.0f);     // Yellow
        glVertex2f(0.4,0.4);

        glColor3f(0.0f, 0.0f, 1.0f);     // Blue
        glVertex2f(0,0.4);


    glEnd();
    glPopMatrix();
    glutSwapBuffers();

}

我的尝试：



i试图移动位置和角度，但我应该看到它的实时模式向侧面移动

What I have tried:

i have tried moving the position and the angle but i should see the "live" mode of it moving sidewards

推荐答案

标准这样做的方法是随着时间的推移改变一些参数。由于您希望让它横向移动，然后调整x方向的平移。对于动画，通常人们设置计时器并在每个刻度上增加翻译。在Windows世界中，这意味着处理WM_TIMER消息。以下是MFC窗口的示例计时器处理例程：

The standard way of doing this is to have some parameter change over time. Since you want to have it move sideways then adjust the translation in the x direction. For animating it, usually people set a timer and increment the translation on each tick. In the windows world this means handling the WM_TIMER message. Here is a sample timer handling routine for an MFC window :

void MyWindow::OnTimer( UINT_PTR eventId )
{
    if( eventId == MyTimerId )
    {
        m_TranslationX += increment;
        Invalidate();     // cause the window to be redrawn
    }
    __super::OnTimer( eventId );
}

// the translation call in your display function will become :

glTranslatef( m_Translation, 0, 0 );

如果你愿意，你可以增加m_Translation直到它达到某个值，然后减去它一段时间，这将导致四边形向右移动，然后向左移动。

If you want to, you can increment m_Translation until it reaches a certain value and then decrement it for a while and this will cause the quads to move to the right and then to the left.

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