c++ - 调整 OpenGL 窗口的大小会导致它分崩离析

Question

由于某种原因，当我调整 OpenGL 窗口大小时，一切都崩溃了。图像失真，坐标不起作用，一切都分崩离析。我正在唱 Glut 来设置它。

//Code to setup glut
glutInitWindowSize(appWidth, appHeight);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
glutCreateWindow("Test Window");

//In drawing function
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glClear(GL_COLOR_BUFFER_BIT);

//Resize function
void resize(int w, int h)
{
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0, w, h, 0);
}

OpenGL 应用程序是严格的 2D。

这是最初的样子:http://www.picgarage.net/images/Corre_53880_651.jpeg

这是调整大小后的样子:http://www.picgarage.net/images/wrong_53885_268.jpeg

Answer 1

你不应该忘记 Hook GLUT 'reshape' 事件:

glutReshapeFunc(resize);

并重置您的视口(viewport):

void resize(int w, int h)
{
    glViewport(0, 0, width, height); //NEW
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0, w, h, 0);
}

透视投影必须考虑新的纵横比:

void resizeWindow(int width, int height)
{
    double asratio;

    if (height == 0) height = 1; //to avoid divide-by-zero

    asratio = width / (double) height;

    glViewport(0, 0, width, height); //adjust GL viewport

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(FOV, asratio, ZMIN, ZMAX); //adjust perspective
    glMatrixMode(GL_MODELVIEW);
}