c++ - 在 OpenGL C++ 中同时使用 glOrtho 和 gluPerspective

Question

当我从 glOrtho 中的欢迎屏幕转到 gluPerspective 中的另一个屏幕时，问题就出现了。 我可以同时呈现它们的唯一方法是在从欢迎屏幕单击播放后调整窗口大小时，否则我会收到黑屏。

我认为我需要修复 glVertex3f 值以使其正确呈现，因为当我直接移动到功能而不去欢迎屏幕时，多边形正确呈现

请检查下面的 gif:

void myReshape(int w, int h)
{
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    if (key1 == 3){
        glOrtho(0.0, 100.0, 0.0, 100.0, -5.0 , 10.0);
        glMatrixMode(GL_MODELVIEW);
    }
    if (key1 == 1 || key1 == 2){
        gluPerspective(45.0, (float)w/(float)h, 0.1f, 200.0);
        gluLookAt(0.0, 0.0, 5.0,0.0, 0.0, 0.0,0.0, 1.0, 0.0); 
        glMatrixMode(GL_MODELVIEW);
    }
}
void par(float x1, float x2, float y1, float y2, float z1, float z2){
    glColor3f(0.3,0.56,0.84);

    glBegin(GL_POLYGON);

    glVertex3f(x1, y1, z1);
    glVertex3f(x2, y1, z1);
    glVertex3f(x2, y2, z1);
    glVertex3f(x1, y2, z1);

    glEnd();
}
void Drawkey1/2(){

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity ();

    glTranslatef(0.0, 0.0, -22.0);
    int i;
    par(-8.7,  9.2,  9.0,  9.2, 0.0, 0.0);
    par(-8.7,  9.2, -8.5, -8.7, 0.0, 0.0);
    par(-8.5, -8.7, -8.7,  9.2, 0.0, 0.0);
    par( 9.2,  9.0, -8.7,  9.2, 0.0, 0.0);
    while(p != NULL){
        par((p -> x)/2.0,(p -> x)/2.0 + 0.4,(p -> y)/2.0,(p -> y)/2.0 + 0.4, 0.0, 0.0);
        p = p -> nexploration_ratet;
    }
    par(food_x/2.0, food_x/2.0 + 0.4 , food_y/2.0 , food_y/2.0 + 0.4, 0.0 , 0.0);
}

void Drawkey3(){
glColor3f(0.3,0.56,0.84);
glBegin(GL_POLYGON);
glVertex3f(0.0,0.0,0.0);
glColor3f(0.137,0.137,0.556);
glVertex3f(100.0,0.0,0.0);
glColor3f(0.196,0.196,0.8);
glVertex3f(100.0,100.0,0.0);
glVertex3f(0.0,100.0,0.0);
glEnd();

glColor3f(0.196,0.196,0.8);
glRectf(39.5,39.5,60.5,45.5);

glColor3f(0.8,0.8,0.8);
glRectf(40,40,60,45);
glColor3f(0.137,0.137,0.556);
drawString(47,42,0,GLUT_BITMAP_HELVETICA_18,"USER");

glColor3f(0.196,0.196,0.8);
glRectf(39.5,29.5,60.5,35.5);

glColor3f(0.8,0.8,0.8);
glRectf(40,30,60,35);
glColor3f(0.137,0.137,0.556);
drawString(41,31,0,GLUT_BITMAP_HELVETICA_18,"NETWORK_PLAY");

glColor3f(0.196,0.196,0.8);
glRectf(39.5,19.5,60.5,25.5);

glColor3f(0.8,0.8,0.8);
glRectf(40,20,60,25);
glColor3f(0.137,0.137,0.556);
drawString(46,21,0,GLUT_BITMAP_HELVETICA_18,"HOW_TO");

glColor3f(0.196,0.196,0.8);
glRectf(39.5,9.5,60.5,15.5);

glColor3f(0.8,0.8,0.8);
glRectf(40,10,60,15);
glColor3f(0.137,0.137,0.556);
drawString(47,11,0,GLUT_BITMAP_HELVETICA_18,"EXIT");


glPushMatrix();

glColor3f(0.8,0.8,0.8);
drawString(25.5,92,0,GLUT_BITMAP_TIMES_ROMAN_24,"COMPUTER GRAPHICS PROJECT ");
drawString(35.5,80,0,GLUT_BITMAP_TIMES_ROMAN_24,"SRIJANA");
glPopMatrix();
glColor3f(0.137,0.137,0.556);

}

Answer 1

更新:

通过确保从 GL_PROJECTION 转换时 glMatrixMode 不获取 GL_MODELVIEW 来修复错误