无法正确定义一个QUAD

Question

我想要一个矩形立方体。一面墙面朝错，所以看不到粉红色。这是多维数据集的好方面：

在立方体的背面有墙的灰色背面：

这是代码：

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();

我已尝试顺时针顺序的所有组合（计数器），但结果仍然相同。有任何想法吗？

Answer 1

我相信你错误地识别你的墙壁。您创建的第一个（X = - floor_size_x / 2），第三个（Z = - floor_size_z / 2）和第四个（Z = floor_size_z / 2）都是顺时针指定的，而第二个（X = floor_size_x / 2）是指定计数器-顺时针。我猜这实际上是不正确的。