opengl中的背景颜色 [英] background colour in opengl

问题描述

我想在按下按钮后改变窗口的背景颜色，但是我的程序不工作，有人可以告诉我为什么，提前感谢

  int main（int argc，char * argv []）
 {
 glutInit（& argc，argv）; 
 glutInitDisplayMode（GLUT_SINGLE | GLUT_RGB）; 
 glutInitWindowSize（800，600）; 
 glutInitWindowPosition（300,50）; 
 glutCreateWindow（GLRect）; 
 
 glClearColor（1.0f，0.0f，0.0f，1.0f）; < --- 
 
 glutDisplayFunc（RenderScene）; 
 glutReshapeFunc（ChangeSize）; 
 glutMainLoop（）; 
 
系统（暂停）; 
 glClearColor（0.0f，1.0f，0.0f，1.0f）; < --- 
 
 return 0; 
 
  

解决方案

glClearColor 不会自行清除 - 它只是设置实际清除时的颜色。要自行清算，你需要用（至少） COLOR_BUFFER_BIT 来调用 glClear 。

编辑：自从我使用glut之后已经有一段时间了，所以这些细节可能是错误的，但是如果内存提供服务，为了响应键盘上的按键来改变屏幕颜色，你可以做这样的事情：

$ p $ void keyboard（unsigned char key，int x，int y）
{
//当用户按下某个键时，我们将在红色和蓝色之间切换：
GLfloat颜色[] [3] = {{0.0f，0.0f，1.0f}，{1.0f，0.0 f，0.0f}};
static int返回;

switch（key）{
case 27：
exit（0）;
默认值：
返回^ = 1;
glClearColor（colors [back] [0]，colors [back] [1]，colors [back] [2]，1.0f）;
glutPostRedisplay（）;
}
}

void draw（）{
glClear（GL_COLOR_BUFFER_BIT）;
//其他绘图在这里...
}

int main（）{

// glutInit，glutInitDisplayMode等

glutDisplayFunc（draw）;
glutKeyboardFunc（键盘）;
glutMainLoop（）;
}


基本上，您将所有绘图函数传递给 glutDisplayFunc 。几乎其他任何东西都只是改变状态，然后调用 PostRedisplayFunc（）; 来告诉过剩的窗口需要重绘。警告：正如我所说，因为我使用了过量的产品已经有一段时间了，我还没有测试过这个代码。根据我的记忆，它显示了一个过剩的程序的一般结构，但不要指望它完全按照原样工作。

I want to change background color of the window after pressing the button, but my program doesn't work, can somebody tell me why, thanks in advance

int main(int argc, char* argv[])
    {
        glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
        glutInitWindowSize(800, 600);
        glutInitWindowPosition(300,50);
    glutCreateWindow("GLRect");

glClearColor(1.0f, 0.0f, 0.0f, 1.0f);   <---

    glutDisplayFunc(RenderScene);
        glutReshapeFunc(ChangeSize);
    glutMainLoop();

    system("pause");
glClearColor(0.0f, 1.0f, 0.0f, 1.0f);   <---

        return 0;
    }

解决方案

glClearColor does not do any clearing itself -- it just sets what the color will be when you do actually clear. To do the clearing itself, you need to call glClear with (at least) COLOR_BUFFER_BIT.

Edit: it's been quite a while since I used glut, so the details of this could be wrong, but if memory serves, to change the screen color in response to pressing a key on the keyboard, you'd do something like this:

void keyboard (unsigned char key, int x, int y)
{
    // we'll switch between red and blue when the user presses a key:
    GLfloat colors[][3] = { { 0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f } };
    static int back;

    switch (key) {
    case 27: 
        exit(0);
    default:
        back ^= 1;
        glClearColor(colors[back][0], colors[back][1], colors[back][2], 1.0f);
        glutPostRedisplay();
    }
}

void draw() { 
    glClear(GL_COLOR_BUFFER_BIT);
    // other drawing here...
}

int main() { 

    // glutInit, glutInitDisplayMode, etc.

     glutDisplayFunc(draw);
     glutKeyboardFunc(keyboard);
     glutMainLoop();
}

Basically, you do all your drawing in whatever function you pass to glutDisplayFunc. Almost anything else just changes the state, then calls PostRedisplayFunc(); to tell glut that the window needs to be redrawn. Warning: as I said, it's been a while since I used glut and I haven't tested this code. It shows the general structure of a glut program to the best of my recollection, but don't expect it to work exactly as-is.

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