Question

我的OpenGL项目中的动画有些麻烦（窗口在几秒钟后没有响应或点击时，动画被卡住并在看似随机的点上循环）所以我被建议添加一个空闲的回调然后使Display函数只在每次调用时呈现“当前”帧。

虽然我不知道如何让我的Display功能只渲染“当前”帧。

这是我的Display功能：

// GLUT display callback function
void Display(void)
{
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
    glLoadIdentity(); // transformations are represented by matrices
    // for placing camera
    gluLookAt(0,1,50,0,0,0,0,1,0);
    // for mouse movement
    glTranslatef(g_fTransX,g_fTransY,g_fZoom);
    glRotatef   (g_fSpinX,1.0f,0.0f,0.0f);
    glRotatef   (g_fSpinY,0.0f,1.0f,0.0f);

    glLightfv(GL_LIGHT0,GL_POSITION,lpos);

    // xyz axes
    glDisable(GL_LIGHTING);
    glLineWidth(2.0);
    glBegin(GL_LINES);
        glColor3f(1.0, 0.0, 0.0);
        glVertex3f(0.0, 0.0, 0.0);
        glVertex3f(20.0, 0.0, 0.0);

        glColor3f(0.0, 1.0, 0.0);
        glVertex3f(0.0, 0.0, 0.0);
        glVertex3f(0.0, 20.0, 0.0);

        glColor3f(0.0, 0.0, 1.0);
        glVertex3f(0.0, 0.0, 0.0);
        glVertex3f(0.0, 0.0, 20.0);
    glEnd();
    glEnable(GL_LIGHTING);

    float Ambient_m[] = {0.0f,1.0f,0.0f,0.0f};
    glMaterialfv(GL_FRONT,GL_AMBIENT,Ambient_m);
    float Ambient_l[] = {0.2f,0.2f,0.2f,0.0f};
    glLightfv(GL_LIGHT0,GL_AMBIENT,Ambient_l);

    // implementing our custom cylinder function
    //draw_cylinder(g_translate_x, g_translate_y, g_dof3_angle);

    // our csg object with 4 DOF
    GLUquadricObj * qobj = gluNewQuadric();

    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
    //draw_lamp(g_dof3_angle);
    //glutSwapBuffers();

    /*animate(time_from, time_to, dof1_from, dof1_to,
    dof2_from, dof2_to, dof3_from, dof3_to,
    dof4_from, dof4_to, dof5_from, dof5_to,
    dof6_from, dof6_to, dof7_from, dof7_to)*/

    animate_lamp(0.0f, 5.0f, 0.0f, 0.0f,
        0.0f, 0.0f, 0.0f, 0.0f,
        0.0f, 45.0f, 0.0f, -45.0f,
        0.0f, 0.0f, 0.0f, 0.0f);

    animate_lamp(5.0f, 7.0f, 0.0f, 5.0f,
        0.0f, 5.0f, 0.0f, 0.0f,
        45.0f, -45.0f, -45.0f, 45.0f,
        0.0f, 0.0f, 0.0f, 0.0f);

    animate_lamp(7.0f, 10.0f, 5.0f, 10.0f,
        5.0f, 0.0f, 0.0f, 0.0f,
        45.0f, -45.0f, -45.0f, 45.0f,
        0.0f, 0.0f, 0.0f, 0.0f);



    //glutSwapBuffers(); // swap back buffer to front buffer (which is drawn on screen)

}

Answer 1

很简单 - 在某处存储动画的当前状态（因为你正在使用C ++，你可以为它创建一个对象），然后，在你的渲染函数中，从该对象中查询状态并渲染它。 / p>

这是一个简化的例子：

class AnimationData
{
  float pos;

public:
  void step() { pos += 0.1f; }

  void render() const
  {
    glBegin(GL_TRIANGLES);
    glVertex3f(pos, 1.f, 1.f);
    glVertex3f(pos, -1.f, 1.f);
    glVertex3f(pos + 1.f, 0.f, 1.f);
    glEnd(GL_TRIANGLES);
  }
};

AnimationData myAnimation;

void Display()
{
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
    glLoadIdentity(); // transformations are represented by matrices
    // for placing camera
    gluLookAt(0,1,50,0,0,0,0,1,0);
    // for mouse movement
    glTranslatef(g_fTransX,g_fTransY,g_fZoom);
    glRotatef   (g_fSpinX,1.0f,0.0f,0.0f);
    glRotatef   (g_fSpinY,0.0f,1.0f,0.0f);

    glLightfv(GL_LIGHT0,GL_POSITION,lpos);

    // And any other setup

    myAnimation.render();

    glutSwapBuffers();
}


void timerCallbackFunction()
{
  myAnimation.step();
  glutPostRedisplay();
}

每次调用timerCallbackFunction()时，都会通过向右移动一个三角形来设置动画。显示功能只是将三角形呈现在当前位置。

如何使我的显示功能仅渲染＆＃34;当前＆＃34;每次被称为框架？

1 个答案: