Im having problems calculating the planes for a viewing frustum given a camera''s position and oreintation. Any websites on the matter? or can someone give me some ideas? thanks.

I got this out of an OpenGL program I''ve downloaded somewhere. I don''t use
it because I use DX, but it might prove useful. I plan on using frustrum
planes myself sometime in the future:

    struct PlaneInfo {	vector	Normal;	float	D;	void	Set(float nx, float ny, float nz, float d) {		Normal.SetXYZ(nx, ny, nz);		D = d;	}};static PlaneInfo	FrustumPlane[6];static PlaneInfo	TransformedFrustumPlane[6];void	DisplayReshape(int w, int h)// Called when window changes dimensions.  Set up viewport & projection matrix.{	glViewport(0, 0, w, h);	//	// Set up projection matrix.	// This is slightly non-standard, since I prefer right-handed view coordinates, while	// OpenGL defaults to a left-handed system.	//	float	nearz = 4.0;	float	farz = 80000;	float	AspectRatio = float(h) / float(w);	float	ViewAngleH = 90 * (PI / 180);	float	ViewAngleV = atan(tan(ViewAngleH/2) * AspectRatio) * 2;		glMatrixMode(GL_PROJECTION);	glLoadIdentity();	float	m[16];	int	i;	for (i = 0; i < 16; i++) m<i> = 0;	m[0] = -1.0 / tan(ViewAngleH / 2);	m[5] = -m[0] / AspectRatio;	m[10] = (farz + nearz) / (farz - nearz);	m[11] = 1;	m[14] = - 2 * farz * nearz / (farz - nearz);		glMultMatrixf(m);	glMatrixMode(GL_MODELVIEW);	// Compute values for the frustum planes.	FrustumPlane[0].Set(0, 0, 1, nearz);	// near.	FrustumPlane[1].Set(0, 0, -1, -farz);	// far.	FrustumPlane[2].Set(-cos(ViewAngleH/2), 0, sin(ViewAngleH/2), 0);	// left.	FrustumPlane[3].Set(cos(ViewAngleH/2), 0, sin(ViewAngleH/2), 0);	// right.	FrustumPlane[4].Set(0, -cos(ViewAngleV/2), sin(ViewAngleV/2), 0);	// top.	FrustumPlane[5].Set(0, cos(ViewAngleV/2), sin(ViewAngleV/2), 0);	// bottom.}void	Display()// Display function.{	// Turn on z-buffering.	glDepthFunc(GL_LEQUAL);	glEnable(GL_DEPTH_TEST);	// Set up the view matrix.	glMatrixMode(GL_MODELVIEW);	glLoadIdentity();	matrix	ViewMatrix;	ViewMatrix.View(ViewerDir, ViewerUp, ViewerLoc);	OGLViewMatrix(ViewMatrix);	// Transform the frustum planes from view coords into world coords.	int	i;	for (i = 0; i < 6; i++) {		// Rotate the plane from view coords into world coords.  I''m pretty sure this is not a slick		// way to do this <img src="smile.gif" width=15 height=15 align=middle>		PlaneInfo&	tp = TransformedFrustumPlane[i];		PlaneInfo&	p = FrustumPlane[i];		ViewMatrix.ApplyInverseRotation(&tp.Normal, p.Normal);		vector	v;		ViewMatrix.ApplyInverse(&v, p.Normal * p.D);		tp.D = v * tp.Normal;	}		// Clear buffers.	glClearColor(0, 0, 0, 0);	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	// Draw the quadtree.	if (root) {		root->Update(RootCornerData, (const float*) ViewerLoc, Detail);		TriangleCounter += root->Render(RootCornerData, Textured);	}	// Show frame.	glutSwapBuffers();}    

From what I can tell, it looks like your 6 basic frustrum planes are setup
in local space at the origin. Then when it is time to use them at some
point in world space, all six planes are transformed. I haven''t studied
the code much yet, so I am unfamilar exactly how the planes are transformed.
But it looks like they do something with the planes'' normals and D equation
values.