Java OpenGL常态化误解？

我正试图让我的照明在OpenGL中工作，使用LWJGL作为实现库。我想我遇到的问题是，我没有正确设置法线，因此照明在某些角度下无法工作。下面是我正在测试的多维数据集的代码：

glBegin(GL_QUADS);

glColor3f(r,g,b);

glNormal3f(position.x, position.y, position.z - radius - 0.1f);
glVertex3f(position.x + radius, position.y + radius, position.z - radius);
glVertex3f(position.x + radius, position.y - radius, position.z - radius);
glVertex3f(position.x - radius, position.y - radius, position.z - radius);
glVertex3f(position.x - radius, position.y + radius, position.z - radius);

glNormal3f(position.x, position.y, position.z + radius + 0.1f);
glVertex3f(position.x + radius, position.y + radius, position.z + radius);
glVertex3f(position.x + radius, position.y - radius, position.z + radius);
glVertex3f(position.x - radius, position.y - radius, position.z + radius);
glVertex3f(position.x - radius, position.y + radius, position.z + radius);

glNormal3f(position.x - radius - 0.1f, position.y, position.z);
glVertex3f(position.x - radius, position.y + radius, position.z + radius);
glVertex3f(position.x - radius, position.y - radius, position.z + radius);
glVertex3f(position.x - radius, position.y - radius, position.z - radius);
glVertex3f(position.x - radius, position.y + radius, position.z - radius);

glNormal3f(position.x + radius + 0.1f, position.y, position.z);
glVertex3f(position.x + radius, position.y + radius, position.z + radius);
glVertex3f(position.x + radius, position.y - radius, position.z + radius);
glVertex3f(position.x + radius, position.y - radius, position.z - radius);
glVertex3f(position.x + radius, position.y + radius, position.z - radius);

glNormal3f(position.x, position.y - radius - 0.1f, position.z);
glVertex3f(position.x + radius, position.y - radius, position.z + radius);
glVertex3f(position.x - radius, position.y - radius, position.z + radius);
glVertex3f(position.x - radius, position.y - radius, position.z - radius);
glVertex3f(position.x + radius, position.y - radius, position.z - radius);

glNormal3f(position.x, position.y + radius + 0.1f, position.z);
glVertex3f(position.x + radius, position.y + radius, position.z + radius);
glVertex3f(position.x - radius, position.y + radius, position.z + radius);
glVertex3f(position.x - radius, position.y + radius, position.z - radius);
glVertex3f(position.x + radius, position.y + radius, position.z - radius);

glEnd();

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法向量是相对于顶点本身的，并且总是标准化的（即：它们的长度为1）

这样的一句话：

glNormal3f(position.x, position.y, position.z - radius - 0.1f);

应替换为：

glNormal3f(0.0f, 0.0f, 1.0f);

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所以这应该做什么，它实际上在做什么？我只是想确保我的法线是正确的，因为我不知道我是否正确地理解如何计算它们。。。它是表面前面的一个点？对吗？@PhilippeParé：不，它不是曲面前面的点，而是垂直于曲面的方向，由长度为1的向量表示。使用跨越三角形的向量的叉积，以R³计算它们。