/*
 *	ICE OPCODE - Optimized Collision Detection
 * http://www.codercorner.com/Opcode.htm
 * 
 * Copyright (c) 2001-2008 Pierre Terdiman,  pierre@codercorner.com

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, 
including commercial applications, and to alter it and redistribute it freely, 
subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Contains AABB-related code.
 *	\file		IceAABB.cpp
 *	\author		Pierre Terdiman
 *	\date		January, 29, 2000
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	AABB class.
 *	\class		AABB
 *	\author		Pierre Terdiman
 *	\version	1.0
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Precompiled Header
#include "Stdafx.h"

using namespace Opcode;

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Computes the sum of two AABBs.
 *	\param		aabb	[in] the other AABB
 *	\return		Self-Reference
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
AABB& AABB::Add(const AABB& aabb)
{
	// Compute new min & max values
	Point Min;	GetMin(Min);
	Point Tmp;	aabb.GetMin(Tmp);
	Min.Min(Tmp);

	Point Max;	GetMax(Max);
	aabb.GetMax(Tmp);
	Max.Max(Tmp);

	// Update this
	SetMinMax(Min, Max);
	return *this;
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Makes a cube from the AABB.
 *	\param		cube	[out] the cube AABB
 *	\return		cube edge length
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
float AABB::MakeCube(AABB& cube) const
{
	Point Ext;	GetExtents(Ext);
	float Max = Ext.Max();

	Point Cnt;	GetCenter(Cnt);
	cube.SetCenterExtents(Cnt, Point(Max, Max, Max));
	return Max;
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Makes a sphere from the AABB.
 *	\param		sphere	[out] sphere containing the AABB
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void AABB::MakeSphere(Sphere& sphere) const
{
	GetExtents(sphere.mCenter);
	sphere.mRadius = sphere.mCenter.Magnitude() * 1.00001f;	// To make sure sphere::Contains(*this)	succeeds
	GetCenter(sphere.mCenter);
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Checks a box is inside another box.
 *	\param		box		[in] the other AABB
 *	\return		true if current box is inside input box
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
bool AABB::IsInside(const AABB& box) const
{
	if(box.GetMin(0)>GetMin(0))	return false;
	if(box.GetMin(1)>GetMin(1))	return false;
	if(box.GetMin(2)>GetMin(2))	return false;
	if(box.GetMax(0)<GetMax(0))	return false;
	if(box.GetMax(1)<GetMax(1))	return false;
	if(box.GetMax(2)<GetMax(2))	return false;
	return true;
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Computes the AABB planes.
 *	\param		planes	[out] 6 planes surrounding the box
 *	\return		true if success
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
bool AABB::ComputePlanes(Plane* planes)	const
{
	// Checkings
	if(!planes)	return false;

	Point Center, Extents;
	GetCenter(Center);
	GetExtents(Extents);

	// Writes normals
	planes[0].n = Point(1.0f, 0.0f, 0.0f);
	planes[1].n = Point(-1.0f, 0.0f, 0.0f);
	planes[2].n = Point(0.0f, 1.0f, 0.0f);
	planes[3].n = Point(0.0f, -1.0f, 0.0f);
	planes[4].n = Point(0.0f, 0.0f, 1.0f);
	planes[5].n = Point(0.0f, 0.0f, -1.0f);

	// Compute a point on each plane
	Point p0 = Point(Center.x+Extents.x, Center.y, Center.z);
	Point p1 = Point(Center.x-Extents.x, Center.y, Center.z);
	Point p2 = Point(Center.x, Center.y+Extents.y, Center.z);
	Point p3 = Point(Center.x, Center.y-Extents.y, Center.z);
	Point p4 = Point(Center.x, Center.y, Center.z+Extents.z);
	Point p5 = Point(Center.x, Center.y, Center.z-Extents.z);

	// Compute d
	planes[0].d = -(planes[0].n|p0);
	planes[1].d = -(planes[1].n|p1);
	planes[2].d = -(planes[2].n|p2);
	planes[3].d = -(planes[3].n|p3);
	planes[4].d = -(planes[4].n|p4);
	planes[5].d = -(planes[5].n|p5);

	return true;
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Computes the aabb points.
 *	\param		pts	[out] 8 box points
 *	\return		true if success
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
bool AABB::ComputePoints(Point* pts)	const
{
	// Checkings
	if(!pts)	return false;

	// Get box corners
	Point min;	GetMin(min);
	Point max;	GetMax(max);

	//     7+------+6			0 = ---
	//     /|     /|			1 = +--
	//    / |    / |			2 = ++-
	//   / 4+---/--+5			3 = -+-
	// 3+------+2 /    y   z	4 = --+
	//  | /    | /     |  /		5 = +-+
	//  |/     |/      |/		6 = +++
	// 0+------+1      *---x	7 = -++

	// Generate 8 corners of the bbox
	pts[0] = Point(min.x, min.y, min.z);
	pts[1] = Point(max.x, min.y, min.z);
	pts[2] = Point(max.x, max.y, min.z);
	pts[3] = Point(min.x, max.y, min.z);
	pts[4] = Point(min.x, min.y, max.z);
	pts[5] = Point(max.x, min.y, max.z);
	pts[6] = Point(max.x, max.y, max.z);
	pts[7] = Point(min.x, max.y, max.z);

	return true;
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Gets vertex normals.
 *	\param		pts	[out] 8 box points
 *	\return		true if success
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const Point* AABB::GetVertexNormals()	const
{
	static float VertexNormals[] = 
	{
		-INVSQRT3,	-INVSQRT3,	-INVSQRT3,
		INVSQRT3,	-INVSQRT3,	-INVSQRT3,
		INVSQRT3,	INVSQRT3,	-INVSQRT3,
		-INVSQRT3,	INVSQRT3,	-INVSQRT3,
		-INVSQRT3,	-INVSQRT3,	INVSQRT3,
		INVSQRT3,	-INVSQRT3,	INVSQRT3,
		INVSQRT3,	INVSQRT3,	INVSQRT3,
		-INVSQRT3,	INVSQRT3,	INVSQRT3
	};
	return (const Point*)VertexNormals;
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Returns edges.
 *	\return		24 indices (12 edges) indexing the list returned by ComputePoints()
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const udword* AABB::GetEdges() const
{
	static udword Indices[] = {
	0, 1,	1, 2,	2, 3,	3, 0,
	7, 6,	6, 5,	5, 4,	4, 7,
	1, 5,	6, 2,
	3, 7,	4, 0
	};
	return Indices;
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
 *	Returns edge normals.
 *	\return		edge normals in local space
 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const Point* AABB::GetEdgeNormals() const
{
	static float EdgeNormals[] = 
	{
		0,			-INVSQRT2,	-INVSQRT2,	// 0-1
		INVSQRT2,	0,			-INVSQRT2,	// 1-2
		0,			INVSQRT2,	-INVSQRT2,	// 2-3
		-INVSQRT2,	0,			-INVSQRT2,	// 3-0

		0,			INVSQRT2,	INVSQRT2,	// 7-6
		INVSQRT2,	0,			INVSQRT2,	// 6-5
		0,			-INVSQRT2,	INVSQRT2,	// 5-4
		-INVSQRT2,	0,			INVSQRT2,	// 4-7

		INVSQRT2,	-INVSQRT2,	0,			// 1-5
		INVSQRT2,	INVSQRT2,	0,			// 6-2
		-INVSQRT2,	INVSQRT2,	0,			// 3-7
		-INVSQRT2,	-INVSQRT2,	0			// 4-0
	};
	return (const Point*)EdgeNormals;
}

// ===========================================================================
//  (C) 1996-98 Vienna University of Technology
// ===========================================================================
//  NAME:       bboxarea
//  TYPE:       c++ code
//  PROJECT:    Bounding Box Area
//  CONTENT:    Computes area of 2D projection of 3D oriented bounding box
//  VERSION:    1.0
// ===========================================================================
//  AUTHORS:    ds      Dieter Schmalstieg
//              ep      Erik Pojar
// ===========================================================================
//  HISTORY:
//
//  19-sep-99 15:23:03  ds      last modification
//  01-dec-98 15:23:03  ep      created
// ===========================================================================

//----------------------------------------------------------------------------
// SAMPLE CODE STARTS HERE
//----------------------------------------------------------------------------

// NOTE: This sample program requires OPEN INVENTOR!

//indexlist: this table stores the 64 possible cases of classification of
//the eyepoint with respect to the 6 defining planes of the bbox (2^6=64)
//only 26 (3^3-1, where 1 is "inside" cube) of these cases are valid.
//the first 6 numbers in each row are the indices of the bbox vertices that
//form the outline of which we want to compute the area (counterclockwise
//ordering), the 7th entry means the number of vertices in the outline.
//there are 6 cases with a single face and and a 4-vertex outline, and
//20 cases with 2 or 3 faces and a 6-vertex outline. a value of 0 indicates
//an invalid case.


// Original list was made of 7 items, I added an 8th element:
// - to padd on a cache line
// - to repeat the first entry to avoid modulos
//
// I also replaced original ints with sbytes.

static const sbyte gIndexList[64][8] =
{
    {-1,-1,-1,-1,-1,-1,-1,   0}, // 0 inside
    { 0, 4, 7, 3, 0,-1,-1,   4}, // 1 left
    { 1, 2, 6, 5, 1,-1,-1,   4}, // 2 right
    {-1,-1,-1,-1,-1,-1,-1,   0}, // 3 -
    { 0, 1, 5, 4, 0,-1,-1,   4}, // 4 bottom
    { 0, 1, 5, 4, 7, 3, 0,   6}, // 5 bottom, left
    { 0, 1, 2, 6, 5, 4, 0,   6}, // 6 bottom, right
    {-1,-1,-1,-1,-1,-1,-1,   0}, // 7 -
    { 2, 3, 7, 6, 2,-1,-1,   4}, // 8 top
    { 0, 4, 7, 6, 2, 3, 0,   6}, // 9 top, left
    { 1, 2, 3, 7, 6, 5, 1,   6}, //10 top, right
    {-1,-1,-1,-1,-1,-1,-1,   0}, //11 -
    {-1,-1,-1,-1,-1,-1,-1,   0}, //12 -
    {-1,-1,-1,-1,-1,-1,-1,   0}, //13 -
    {-1,-1,-1,-1,-1,-1,-1,   0}, //14 -
    {-1,-1,-1,-1,-1,-1,-1,   0}, //15 -
    { 0, 3, 2, 1, 0,-1,-1,   4}, //16 front
    { 0, 4, 7, 3, 2, 1, 0,   6}, //17 front, left
    { 0, 3, 2, 6, 5, 1, 0,   6}, //18 front, right
    {-1,-1,-1,-1,-1,-1,-1,   0}, //19 -
    { 0, 3, 2, 1, 5, 4, 0,   6}, //20 front, bottom
    { 1, 5, 4, 7, 3, 2, 1,   6}, //21 front, bottom, left
    { 0, 3, 2, 6, 5, 4, 0,   6}, //22 front, bottom, right
    {-1,-1,-1,-1,-1,-1,-1,   0}, //23 -
    { 0, 3, 7, 6, 2, 1, 0,   6}, //24 front, top
    { 0, 4, 7, 6, 2, 1, 0,   6}, //25 front, top, left
    { 0, 3, 7, 6, 5, 1, 0,   6}, //26 front, top, right
    {-1,-1,-1,-1,-1,-1,-1,   0}, //27 -
    {-1,-1,-1,-1,-1,-1,-1,   0}, //28 -
    {-1,-1,-1,-1,-1,-1,-1,   0}, //29 -
    {-1,-1,-1,-1,-1,-1,-1,   0}, //30 -
    {-1,-1,-1,-1,-1,-1,-1,   0}, //31 -
    { 4, 5, 6, 7, 4,-1,-1,   4}, //32 back
    { 0, 4, 5, 6, 7, 3, 0,   6}, //33 back, left
    { 1, 2, 6, 7, 4, 5, 1,   6}, //34 back, right
    {-1,-1,-1,-1,-1,-1,-1,   0}, //35 -
    { 0, 1, 5, 6, 7, 4, 0,   6}, //36 back, bottom
    { 0, 1, 5, 6, 7, 3, 0,   6}, //37 back, bottom, left
    { 0, 1, 2, 6, 7, 4, 0,   6}, //38 back, bottom, right
    {-1,-1,-1,-1,-1,-1,-1,   0}, //39 -
    { 2, 3, 7, 4, 5, 6, 2,   6}, //40 back, top
    { 0, 4, 5, 6, 2, 3, 0,   6}, //41 back, top, left
    { 1, 2, 3, 7, 4, 5, 1,   6}, //42 back, top, right
    {-1,-1,-1,-1,-1,-1,-1,   0}, //43 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //44 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //45 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //46 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //47 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //48 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //49 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //50 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //51 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //52 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //53 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //54 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //55 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //56 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //57 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //58 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //59 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //60 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //61 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}, //62 invalid
    {-1,-1,-1,-1,-1,-1,-1,   0}  //63 invalid
};

const sbyte* AABB::ComputeOutline(const Point& local_eye, sdword& num)	const
{
	// Get box corners
	Point min;	GetMin(min);
	Point max;	GetMax(max);

	// Compute 6-bit code to classify eye with respect to the 6 defining planes of the bbox
	int pos = ((local_eye.x < min.x) ?  1 : 0)	// 1 = left
			+ ((local_eye.x > max.x) ?  2 : 0)	// 2 = right
			+ ((local_eye.y < min.y) ?  4 : 0)	// 4 = bottom
			+ ((local_eye.y > max.y) ?  8 : 0)	// 8 = top
			+ ((local_eye.z < min.z) ? 16 : 0)	// 16 = front
			+ ((local_eye.z > max.z) ? 32 : 0);	// 32 = back

	// Look up number of vertices in outline
	num = (sdword)gIndexList[pos][7];
	// Zero indicates invalid case
	if(!num) return null;

	return &gIndexList[pos][0];
}

// calculateBoxArea: computes the screen-projected 2D area of an oriented 3D bounding box

//const Point&		eye,		//eye point (in bbox object coordinates)
//const AABB&			box,		//3d bbox
//const Matrix4x4&	mat,		//free transformation for bbox
//float width, float height, int& num)
float AABB::ComputeBoxArea(const Point& eye, const Matrix4x4& mat, float width, float height, sdword& num)	const
{
	const sbyte* Outline = ComputeOutline(eye, num);
	if(!Outline)	return -1.0f;

	// Compute box vertices
	Point vertexBox[8], dst[8];
	ComputePoints(vertexBox);

	// Transform all outline corners into 2D screen space
	for(sdword i=0;i<num;i++)
	{
		HPoint Projected;
		vertexBox[Outline[i]].ProjectToScreen(width, height, mat, Projected);
		dst[i] = Projected;
	}

	float Sum = (dst[num-1][0] - dst[0][0]) * (dst[num-1][1] + dst[0][1]);

	for(int i=0; i<num-1; i++)
		Sum += (dst[i][0] - dst[i+1][0]) * (dst[i][1] + dst[i+1][1]);

	return Sum * 0.5f;	//return computed value corrected by 0.5
}