//-----------------------------------------------------------------------------
// Project            	GeometryKit
// Class		G3DPlane
// Creator            	Philippe C.D. Robert
// Maintainer         	Philippe C.D. Robert
// Creation Date      	Thu Sep  9 11:05:08 CEST 1999
//
// Copyright (c) Philippe C.D. Robert
//
// The GeometryKit is free software; you can redistribute it and/or modify it 
// under the terms of the GNU LGPL Version 2 as published by the Free 
// Software Foundation
//
// $Id: G3DPlane.h,v 1.6 2001/01/05 20:50:48 robert Exp $
//-----------------------------------------------------------------------------

/*
 * A Plane is defined as ax+by+cz+d=0 where
 *
 * 	normal   = (a,b,c), stored in values[0..2]
 *	distance = d, stored in values[3]
 *
 */
 
#ifndef __G3DPlane_h_INCLUDE
#define __G3DPlane_h_INCLUDE

#import <Foundation/Foundation.h>
#import <GeometryKit/G3DIntersecting.h>

@class G3DTuple3f;
@class G3DMatrix4f;
@class G3DBox;
@class G3DLine;
@class G3DSphere;

@interface G3DPlane : NSObject <NSCoding, NSCopying, G3DIntersecting>
{
    float values[4];
}

//-----------------------------------------------------------------------------
// class methods
//-----------------------------------------------------------------------------

+ (G3DPlane *)plane;
+ (G3DPlane *)planeWithElements:(float *)vals;
+ (G3DPlane *)planeWithNormal:(G3DTuple3f *)norm point:(G3DTuple3f *)tuple;
+ (G3DPlane *)planeWithPlane:(G3DPlane *)aPlane;

//-----------------------------------------------------------------------------
// init and free
//-----------------------------------------------------------------------------

- (id)init;
  // Initialises a plane with normal (0,0,1) and d = 0

- (id)initWithElements:(float *)vals;
  // Designated initialiser

- (id)initWithNormal:(G3DTuple3f *)norm point:(G3DTuple3f *)aTuple;

- (id)initWithPlane:(G3DPlane *)aPlane;

//-----------------------------------------------------------------------------
// math
//-----------------------------------------------------------------------------

- (void)shiftByDistance:(float)factor;

- (BOOL)intersectsObject:(id)anObject;

- (BOOL)intersectsLine:(G3DLine *)line intersection:(G3DTuple3f *)pt;
- (BOOL)intersectsSphere:(G3DSphere *)sph;
  // Invokes the appropriate method in G3DSphere

- (BOOL)intersectsPlane:(G3DPlane *)pl;
  // Based on the Algorithm as descibed in Graphics Gem III, P.519

- (BOOL)intersectsBox:(G3DBox *)aBox;
  // Invokes the appropriate method in G3DBox

- (void)transform:(G3DMatrix4f *)aMatrix;
  // Calculates m * [n1,n2,n3,d], such as it can be used by OpenGL

- (BOOL)isParallel:(G3DPlane *)aPlane;
- (BOOL)isEqualToPlane:(G3DPlane *)aPlane;

- (BOOL)isInHalfSpace:(G3DTuple3f *)vec;
  // The half space is defined by the normal of the plane

- (float)distanceFromPoint:(G3DTuple3f *)aTuple;

//-----------------------------------------------------------------------------
// accessor methods
//-----------------------------------------------------------------------------

- (void)setDistance:(float)aDistance;
- (float)distance;

- (void)setNormal:(G3DTuple3f *)aNorm;
- (G3DTuple3f *)normal;
  // setNormal normalises aNorm before setting it

- (void)setElements:(float *)vals;
- (void)getElements:(float *)vals;
- (float *)elements;

//-----------------------------------------------------------------------------
// NSCoding
//-----------------------------------------------------------------------------

- (void)encodeWithCoder:(NSCoder *)aCoder;
- (id)initWithCoder:(NSCoder *)aCoder;

//-----------------------------------------------------------------------------
// NSCopying
//-----------------------------------------------------------------------------

- (id)copyWithZone:(NSZone *)zone;

@end

extern NSString *G3DPlaneException;

#endif