OpenGL/Glut: glutTimerFunc 似乎没有启动

Question

我想使用 glutTimerFunc 在由一些网格模型组成的场景中移动相机。相机路径是用贝塞尔曲线构建的，如下所示：

if(sel == MODE_CAMERA_MOTION) {
    mode = MODE_CAMERA_MOTION;
    stepsCounter = 0;
    // Building camera track

    int i, j, k;

    for(j=0; j<MAX_CV; j++) {
        tmpCV[j][0] = CV[j][0];
        tmpCV[j][1] = CV[j][1];
        tmpCV[j][2] = CV[j][2];
    }

    for(i=0; i<STEPS; i++) {

        for(j=1; j<MAX_CV; j++) {
            for(k=0; k<MAX_CV-j; k++) {
                lerp(i/(float)(STEPS*10), tmpCV[k], tmpCV[k+1], tmpCV[k]);
            }
        }

        cameraPosition[i][0] = tmpCV[0][0];
        cameraPosition[i][1] = tmpCV[0][1];
        cameraPosition[i][2] = tmpCV[0][2];

    }

    glutTimerFunc(250, moveCamera, STEPS);
}

moveCamera 函数所在位置：

void moveCamera() {
  if (mode == MODE_CAMERA_MOTION) {

    camE[0] = cameraPosition[stepsCounter][0];
    camE[1] = cameraPosition[stepsCounter][1];
    camE[2] = cameraPosition[stepsCounter][2];

    if(stepsCounter < STEPS) {
        stepsCounter++;
    }

    else {
        /* come back to the first point */
        camE[0] = 8.8;
        camE[1] = 4.9;
        camE[2] = 9.0;
        stepsCounter = 0;
    }

  glutPostRedisplay();

  }
}

但没有动静。也许我误解了该功能的行为。我哪里错了？

Answer 1

传递给 glutTimerFunc 的函数原型应该是

void (*func)(int value)

其中glutTimerFunc的最后一个参数是传入的值。所以你的 moveCamera 应该是：

void moveCamera( int STEPS )

还有，即便如此，moveCamera函数也会被调用一次。您需要在执行结束时重新注册。这可能是一个可能的解决方案：

// instead of global STEPS and stepsCounter, we decrement at reexecution
void moveCamera( int STEPS ) {
  ... do stuff
  glutTimerFunc(250, moveCamera, STEPS-1 ); 
}

OpenGL/Glut: glutTimerFunc 似乎没有启动

OpenGL/Glut: glutTimerFunc seems not to start

opengl

camera

glut

mesh

motion