为什么我的立方体的两侧不显示？

Question

我想显示从 - （ - 50，-50，-50）延伸到（50,50,50）的盒子的5个边（仅显示顶侧）。我的立方体绘图功能如下：

void drawRectangularPrism(Coordinate corner, Coordinate dimensions)
{
    glPushMatrix();
    glBegin(GL_QUADS);
    // back face
    glNormal3f(0, 0, 1);
    glVertex3f(corner.x, corner.y, corner.z);
    glVertex3f(corner.x + dimensions.x, corner.y, corner.z);
    glVertex3f(corner.x + dimensions.x, corner.y + dimensions.y, corner.z);
    glVertex3f(corner.x, corner.y + dimensions.y, corner.z);
    // bottom face
    glNormal3f(0, 1, 0);
    glVertex3f(corner.x, corner.y, corner.z);
    glVertex3f(corner.x, corner.y, corner.z + dimensions.z);
    glVertex3f(corner.x + dimensions.x, corner.y, corner.z + dimensions.z);
    glVertex3f(corner.x + dimensions.x, corner.y, corner.z);
    // top face
    glNormal3f(0, -1, 0);
    glVertex3f(corner.x, corner.y + dimensions.y, corner.z);
    glVertex3f(corner.x, corner.y + dimensions.y, corner.z + dimensions.z);
    glVertex3f(corner.x + dimensions.x, corner.y + dimensions.y, corner.z + dimensions.z);
    glVertex3f(corner.x + dimensions.x, corner.y + dimensions.y, corner.z);
    // right face
    glNormal3f(-1, 0, 0);
    glVertex3f(corner.x + dimensions.x, corner.y, corner.z);
    glVertex3f(corner.x + dimensions.x, corner.y, corner.z + dimensions.z);
    glVertex3f(corner.x + dimensions.x, corner.y + dimensions.y, corner.z + dimensions.z);
    glVertex3f(corner.x + dimensions.x, corner.y + dimensions.y, corner.z);
    // left face
    glNormal3f(1, 0, 0);
    glVertex3f(corner.x, corner.y, corner.z);
    glVertex3f(corner.x, corner.y, corner.z + dimensions.z);
    glVertex3f(corner.x, corner.y + dimensions.y, corner.z + dimensions.z);
    glVertex3f(corner.x, corner.y + dimensions.y, corner.z);
    glEnd();
    glPopMatrix();
}

如果它有用，这是我设置OpenGL渲染的函数：

void init()
{
    glClearColor(1.0, 1.0, 1.0, 1.0); // Clear the background of our window to white
    GLfloat specular[] = {1.0, 1.0, 1.0, 1.0}, shininess[] = {50.0}, emission[] = {0.0, 0.0, 0.0, 1.0},
        lightPosition[] = {1.0, 1.0, 1.0, 0.0}, lightAmbient[] = {0.0, 0.0, 0.0, 1.0},
        lightDiffuse[] = {1.0, 1.0, 1.0, 1.0}, lightSpecular[] = {1.0, 1.0, 0.0, 1.0};
    glShadeModel(GL_SMOOTH);
    glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE);
    glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, specular);
    glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, shininess);
    glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, emission);
    glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
    glLightfv(GL_LIGHT0, GL_AMBIENT, lightAmbient);
    glLightfv(GL_LIGHT0, GL_DIFFUSE, lightDiffuse);
    glLightfv(GL_LIGHT0, GL_SPECULAR, lightSpecular);
    glEnable(GL_LIGHT0);

    //glEnable(GL_DEPTH_TEST); // makes objects overlap correctly / or not?!
    glEnable(GL_LIGHTING);
    glEnable(GL_COLOR_MATERIAL);
    glEnable(GL_CULL_FACE); // makes it faster?!
}

最终结果：

为什么不显示多维数据集的顶部和左侧？

Answer 1

顶部/底部，左/右面对仅因偏移而异，这表示您未考虑顶点绕组顺序。请先查看glFrontFace。

Answer 2

你的四边形最有可能被

淘汰

glEnable(GL_CULL_FACE);

删除它，它应该工作