無法正確定義一個QUAD

Question

我想要一個矩形立方體。 一堵牆的另一側有面，所以我看不到粉紅色。 這是多維數據集的好方面：

立方體的背面是牆壁的灰色背面：

這是代碼：

glBegin(GL_QUADS);
    //floor
    glMaterialfv(GL_FRONT, GL_DIFFUSE, floor_diffuse);
    glVertex3f(-floor_size_x / 2, 0, floor_size_z / 2);
    glVertex3f(floor_size_x / 2, 0, floor_size_z / 2);
    glVertex3f(floor_size_x / 2, 0, -floor_size_z / 2);
    glVertex3f(-floor_size_x / 2, 0, -floor_size_z / 2);

    //roof
    glMaterialfv(GL_FRONT, GL_DIFFUSE, roof_diffuse);
    glVertex3f(-floor_size_x / 2, wall_height, floor_size_z / 2);
    glVertex3f(floor_size_x / 2, wall_height, floor_size_z / 2);
    glVertex3f(floor_size_x / 2, wall_height, -floor_size_z / 2);
    glVertex3f(-floor_size_x / 2, wall_height, -floor_size_z / 2);      
    //walls
    glMaterialfv(GL_FRONT, GL_DIFFUSE, walls_diffuse);
    glVertex3f(-floor_size_x / 2, 0, floor_size_z / 2);
    glVertex3f(-floor_size_x / 2, wall_height, floor_size_z / 2);
    glVertex3f(-floor_size_x / 2, wall_height, -floor_size_z / 2);
    glVertex3f(-floor_size_x / 2, 0, -floor_size_z / 2);

    glVertex3f(floor_size_x / 2, 0, floor_size_z / 2);
    glVertex3f(floor_size_x / 2, wall_height, floor_size_z / 2);
    glVertex3f(floor_size_x / 2, wall_height, -floor_size_z / 2);
    glVertex3f(floor_size_x / 2, 0, -floor_size_z / 2);

    glVertex3f(-floor_size_x / 2, 0, -floor_size_z / 2);
    glVertex3f(-floor_size_x / 2, wall_height, -floor_size_z / 2);
    glVertex3f(floor_size_x / 2, wall_height, -floor_size_z / 2);
    glVertex3f(floor_size_x / 2, 0, -floor_size_z / 2);     

    //BAD WALL
    glVertex3f(floor_size_x / 2, 0, floor_size_z / 2);
    glVertex3f(floor_size_x / 2, wall_height, floor_size_z / 2);
    glVertex3f(-floor_size_x / 2, wall_height, floor_size_z / 2);
    glVertex3f(-floor_size_x / 2, 0, floor_size_z / 2);

    glEnd();

我已經嘗試了所有組合（逆時針）順序，但結果仍然相同。 有任何想法嗎？

Answer 1

我相信您沒有正確識別牆壁。 您創建的第一個（ X = - floor_size_x / 2 ），第3個（ Z = - floor_size_z / 2 ）和第4個（ Z = floor_size_z / 2 ）都是順時針指定的，而第二個（ X = floor_size_x / 2 ）是逆時針指定。 我猜這實際上是不正確的。