OpenGL 字体颜色问题

刚写了一个OpenGL字体显示类, 发现颜色总是不对, 部分代码如下:

    //绘制文字
    glPushAttrib(GL_LIST_BIT | GL_COLOR_BUFFER_BIT | GL_ENABLE_BIT);
    glDisable(GL_LIGHTING);

    //文字位置
    if(m_screen)
    {
        double x=m_x,y=m_y;
        switch(m_layout)
        {
        case(LEFT_BOTTOM):break;
        case(LEFT_TOP):///左上角
            y = m_parent->GetGLWindow()->GetSize().y-m_y;
            break;
        case(RIGHT_BOTTOM):///右下角
            x = m_parent->GetGLWindow()->GetSize().x-m_x;
            break;
        case(RIGHT_TOP):///右上角
            x = m_parent->GetGLWindow()->GetSize().x-m_x;
            y = m_parent->GetGLWindow()->GetSize().y-m_y;
            break;
        case(LEFT_CENTER):///左侧中心
            y = 0.5*m_parent->GetGLWindow()->GetSize().y+m_y;
            break;
        case(TOP_CENTER):///顶部中心
            x = 0.5*m_parent->GetGLWindow()->GetSize().x+m_x;
            y = m_parent->GetGLWindow()->GetSize().y-m_y;
            break;
        case(BOTTOM_CENTER):///底部中性
            x = 0.5*m_parent->GetGLWindow()->GetSize().x+m_x;
            break;
        case(RIGHT_CENTER):///右侧中心
            x = m_parent->GetGLWindow()->GetSize().x-m_x;
            y = 0.5*m_parent->GetGLWindow()->GetSize().y+m_y;
            break;
        case(CENTER):///屏幕中心
            x = 0.5*m_parent->GetGLWindow()->GetSize().x+m_x;
            y = 0.5*m_parent->GetGLWindow()->GetSize().y+m_y;
            break;
        }
        glWindowPos2d(x,y);
    }
    else
        glRasterPos3d(m_x,m_y,m_z);
    
    //文字颜色,必须在glWindowPos2d和glRasterPos3d前
    glColor4fv(Color); //<------

    //调用显示列表
    glListBase(m_base);
    glCallLists(m_list_len,GL_UNSIGNED_INT,m_lists);
    glPopAttrib();

 

百思不得其解, 翻开Red Book找到了答案:

  8.1.3 选择位图的颜色

  ... 光栅颜色状态变量被设置为调用函数glRasterPos*()时的颜色, ...

 

显然只需要调整glColor*和 glRasterPos*的位置即可, 修改后的代码如下:

    //绘制文字
    glPushAttrib(GL_LIST_BIT | GL_COLOR_BUFFER_BIT | GL_ENABLE_BIT);
    glDisable(GL_LIGHTING);

    //文字颜色,必须在glWindowPos2d和glRasterPos3d前
    glColor4fv(Color);

    //文字位置
    if(m_screen)
    {
        double x=m_x,y=m_y;
        switch(m_layout)
        {
        case(LEFT_BOTTOM):break;
        case(LEFT_TOP):///左上角
            y = m_parent->GetGLWindow()->GetSize().y-m_y;
            break;
        case(RIGHT_BOTTOM):///右下角
            x = m_parent->GetGLWindow()->GetSize().x-m_x;
            break;
        case(RIGHT_TOP):///右上角
            x = m_parent->GetGLWindow()->GetSize().x-m_x;
            y = m_parent->GetGLWindow()->GetSize().y-m_y;
            break;
        case(LEFT_CENTER):///左侧中心
            y = 0.5*m_parent->GetGLWindow()->GetSize().y+m_y;
            break;
        case(TOP_CENTER):///顶部中心
            x = 0.5*m_parent->GetGLWindow()->GetSize().x+m_x;
            y = m_parent->GetGLWindow()->GetSize().y-m_y;
            break;
        case(BOTTOM_CENTER):///底部中性
            x = 0.5*m_parent->GetGLWindow()->GetSize().x+m_x;
            break;
        case(RIGHT_CENTER):///右侧中心
            x = m_parent->GetGLWindow()->GetSize().x-m_x;
            y = 0.5*m_parent->GetGLWindow()->GetSize().y+m_y;
            break;
        case(CENTER):///屏幕中心
            x = 0.5*m_parent->GetGLWindow()->GetSize().x+m_x;
            y = 0.5*m_parent->GetGLWindow()->GetSize().y+m_y;
            break;
        }
        glWindowPos2d(x,y);
    }
    else
        glRasterPos3d(m_x,m_y,m_z);

    //调用显示列表
    glListBase(m_base);
    glCallLists(m_list_len,GL_UNSIGNED_INT,m_lists);
    glPopAttrib();