Method to clip a mesh/polygon

I need a function written to clip a triangle mesh. Given a geometric plane represented by a width and height and 3 dimensional position, and an opengl polygon object represented by an array of 3 dimensional vertexs and a drawing order of indices, calculate a new opengl polygon. Its basically an implementation of the Intersection of a Triangle and a Plane: [login to view URL] The plane is represented by a position in 3 dimensions, and a width and height The polygon is represented like this: Vector3 positions[] = { Vector3Make(-halfSide, -halfSide, halfSide), Vector3Make( halfSide, -halfSide, halfSide), Vector3Make(-halfSide, -halfSide, -halfSide), Vector3Make( halfSide, -halfSide, -halfSide), Vector3Make(-halfSide, halfSide, halfSide), Vector3Make( halfSide, halfSide, halfSide), Vector3Make(-halfSide, halfSide, -halfSide), Vector3Make( halfSide, halfSide, -halfSide) }; int indices[] = { // bottom 0, 2, 1, 1, 2, 3, // back 2, 6, 3, 3, 6, 7, // left 0, 4, 2, 2, 4, 6, // right 1, 3, 5, 3, 7, 5, // front 0, 1, 4, 1, 5, 4, // top 4, 5, 6, 5, 7, 6 };