How to test whether a point is inside or outside the closed face?

OpenGL OpenGL: Advanced Coding
1

How to test whether a point is inside or outside the closed face?
Is there any ready method in opengl?
tell me something.Thank you first:)

2

I’m not sure if OpenGL can do that for you, but this link might be helpful:

http://nehe.gamedev.net/data/articles/article.asp?article=10

3

thank you for that:)