/*
   Copyright (C) 2001-2006, William Joseph.
   All Rights Reserved.

   This file is part of GtkRadiant.

   GtkRadiant is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   GtkRadiant is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with GtkRadiant; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#if !defined( INCLUDED_RENDER_H )
#define INCLUDED_RENDER_H

/// \file
/// \brief High-level constructs for efficient OpenGL rendering.

#include "irender.h"
#include "igl.h"

#include "container/array.h"
#include "math/vector.h"
#include "math/pi.h"

#include <vector>

typedef unsigned int RenderIndex;
const GLenum RenderIndexTypeID = GL_UNSIGNED_INT;

/// \brief A resizable buffer of indices.
class IndexBuffer
{
typedef std::vector<RenderIndex> Indices;
Indices m_data;
public:
typedef Indices::iterator iterator;
typedef Indices::const_iterator const_iterator;

iterator begin(){
	return m_data.begin();
}
const_iterator begin() const {
	return m_data.begin();
}
iterator end(){
	return m_data.end();
}
const_iterator end() const {
	return m_data.end();
}

bool empty() const {
	return m_data.empty();
}
std::size_t size() const {
	return m_data.size();
}
const RenderIndex* data() const {
	return &( *m_data.begin() );
}
RenderIndex& operator[]( std::size_t index ){
	return m_data[index];
}
const RenderIndex& operator[]( std::size_t index ) const {
	return m_data[index];
}
void clear(){
	m_data.clear();
}
void reserve( std::size_t max_indices ){
	m_data.reserve( max_indices );
}
void insert( RenderIndex index ){
	m_data.push_back( index );
}
void swap( IndexBuffer& other ){
	std::swap( m_data, m_data );
}
};

namespace std
{
/// \brief Swaps the values of \p self and \p other.
/// Overloads std::swap.
inline void swap( IndexBuffer& self, IndexBuffer& other ){
	self.swap( other );
}
}

/// \brief A resizable buffer of vertices.
/// \param Vertex The vertex data type.
template<typename Vertex>
class VertexBuffer
{
typedef typename std::vector<Vertex> Vertices;
Vertices m_data;
public:
typedef typename Vertices::iterator iterator;
typedef typename Vertices::const_iterator const_iterator;

iterator begin(){
	return m_data.begin();
}
iterator end(){
	return m_data.end();
}
const_iterator begin() const {
	return m_data.begin();
}
const_iterator end() const {
	return m_data.end();
}

bool empty() const {
	return m_data.empty();
}
RenderIndex size() const {
	return RenderIndex( m_data.size() );
}
const Vertex* data() const {
	return &( *m_data.begin() );
}
Vertex& operator[]( std::size_t index ){
	return m_data[index];
}
const Vertex& operator[]( std::size_t index ) const {
	return m_data[index];
}

void clear(){
	m_data.clear();
}
void reserve( std::size_t max_vertices ){
	m_data.reserve( max_vertices );
}
void push_back( const Vertex& vertex ){
	m_data.push_back( vertex );
}
};

/// \brief A wrapper around a VertexBuffer which inserts only vertices which have not already been inserted.
/// \param Vertex The vertex data type. Must support operator<, operator== and operator!=.
/// For best performance, quantise vertices before inserting them.
template<typename Vertex>
class UniqueVertexBuffer
{
typedef VertexBuffer<Vertex> Vertices;
Vertices& m_data;

struct bnode
{
	bnode()
		: m_left( 0 ), m_right( 0 ){
	}
	RenderIndex m_left;
	RenderIndex m_right;
};

std::vector<bnode> m_btree;
RenderIndex m_prev0;
RenderIndex m_prev1;
RenderIndex m_prev2;

RenderIndex find_or_insert( const Vertex& vertex ){
	RenderIndex index = 0;

	while ( 1 )
	{
		if ( vertex < m_data[index] ) {
			bnode& node = m_btree[index];
			if ( node.m_left != 0 ) {
				index = node.m_left;
				continue;
			}
			else
			{
				node.m_left = RenderIndex( m_btree.size() );
				m_btree.push_back( bnode() );
				m_data.push_back( vertex );
				return RenderIndex( m_btree.size() - 1 );
			}
		}
		if ( m_data[index] < vertex ) {
			bnode& node = m_btree[index];
			if ( node.m_right != 0 ) {
				index = node.m_right;
				continue;
			}
			else
			{
				node.m_right = RenderIndex( m_btree.size() );
				m_btree.push_back( bnode() );
				m_data.push_back( vertex );
				return RenderIndex( m_btree.size() - 1 );
			}
		}

		return index;
	}
}
public:
UniqueVertexBuffer( Vertices& data )
	: m_data( data ), m_prev0( 0 ), m_prev1( 0 ), m_prev2( 0 ){
}

typedef typename Vertices::const_iterator iterator;

iterator begin() const {
	return m_data.begin();
}
iterator end() const {
	return m_data.end();
}

std::size_t size() const {
	return m_data.size();
}
const Vertex* data() const {
	return &( *m_data.begin() );
}
Vertex& operator[]( std::size_t index ){
	return m_data[index];
}
const Vertex& operator[]( std::size_t index ) const {
	return m_data[index];
}

void clear(){
	m_prev0 = 0;
	m_prev1 = 0;
	m_prev2 = 0;
	m_data.clear();
	m_btree.clear();
}
void reserve( std::size_t max_vertices ){
	m_data.reserve( max_vertices );
	m_btree.reserve( max_vertices );
}
/// \brief Returns the index of the element equal to \p vertex.
RenderIndex insert( const Vertex& vertex ){
	if ( m_data.empty() ) {
		m_data.push_back( vertex );
		m_btree.push_back( bnode() );
		return 0;
	}

	if ( m_data[m_prev0] == vertex ) {
		return m_prev0;
	}
	if ( m_prev1 != m_prev0 && m_data[m_prev1] == vertex ) {
		return m_prev1;
	}
	if ( m_prev2 != m_prev0 && m_prev2 != m_prev1 && m_data[m_prev2] == vertex ) {
		return m_prev2;
	}

	m_prev2 = m_prev1;
	m_prev1 = m_prev0;
	m_prev0 = find_or_insert( vertex );

	return m_prev0;
}
};


/// \brief A 4-byte colour.
struct Colour4b
{
	unsigned char r, g, b, a;

	Colour4b(){
	}

	Colour4b( unsigned char _r, unsigned char _g, unsigned char _b, unsigned char _a )
		: r( _r ), g( _g ), b( _b ), a( _a ){
	}
};

const Colour4b colour_vertex( 0, 255, 0, 255 );
const Colour4b colour_selected( 0, 0, 255, 255 );

inline bool operator<( const Colour4b& self, const Colour4b& other ){
	if ( self.r != other.r ) {
		return self.r < other.r;
	}
	if ( self.g != other.g ) {
		return self.g < other.g;
	}
	if ( self.b != other.b ) {
		return self.b < other.b;
	}
	if ( self.a != other.a ) {
		return self.a < other.a;
	}
	return false;
}

inline bool operator==( const Colour4b& self, const Colour4b& other ){
	return self.r == other.r && self.g == other.g && self.b == other.b && self.a == other.a;
}

inline bool operator!=( const Colour4b& self, const Colour4b& other ){
	return !operator==( self, other );
}

/// \brief A 3-float vertex.
struct Vertex3f : public Vector3
{
	Vertex3f(){
	}

	Vertex3f( float _x, float _y, float _z )
		: Vector3( _x, _y, _z ){
	}
};

inline bool operator<( const Vertex3f& self, const Vertex3f& other ){
	if ( self.x() != other.x() ) {
		return self.x() < other.x();
	}
	if ( self.y() != other.y() ) {
		return self.y() < other.y();
	}
	if ( self.z() != other.z() ) {
		return self.z() < other.z();
	}
	return false;
}

inline bool operator==( const Vertex3f& self, const Vertex3f& other ){
	return self.x() == other.x() && self.y() == other.y() && self.z() == other.z();
}

inline bool operator!=( const Vertex3f& self, const Vertex3f& other ){
	return !operator==( self, other );
}


inline Vertex3f vertex3f_from_array( const float* array ){
	return Vertex3f( array[0], array[1], array[2] );
}

inline float* vertex3f_to_array( Vertex3f& vertex ){
	return reinterpret_cast<float*>( &vertex );
}

inline const float* vertex3f_to_array( const Vertex3f& vertex ){
	return reinterpret_cast<const float*>( &vertex );
}

const Vertex3f vertex3f_identity( 0, 0, 0 );

inline Vertex3f vertex3f_for_vector3( const Vector3& vector3 ){
	return Vertex3f( vector3.x(), vector3.y(), vector3.z() );
}

inline const Vector3& vertex3f_to_vector3( const Vertex3f& vertex ){
	return vertex;
}

inline Vector3& vertex3f_to_vector3( Vertex3f& vertex ){
	return vertex;
}


/// \brief A 3-float normal.
struct Normal3f : public Vector3
{
	Normal3f(){
	}

	Normal3f( float _x, float _y, float _z )
		: Vector3( _x, _y, _z ){
	}
};

inline bool operator<( const Normal3f& self, const Normal3f& other ){
	if ( self.x() != other.x() ) {
		return self.x() < other.x();
	}
	if ( self.y() != other.y() ) {
		return self.y() < other.y();
	}
	if ( self.z() != other.z() ) {
		return self.z() < other.z();
	}
	return false;
}

inline bool operator==( const Normal3f& self, const Normal3f& other ){
	return self.x() == other.x() && self.y() == other.y() && self.z() == other.z();
}

inline bool operator!=( const Normal3f& self, const Normal3f& other ){
	return !operator==( self, other );
}


inline Normal3f normal3f_from_array( const float* array ){
	return Normal3f( array[0], array[1], array[2] );
}

inline float* normal3f_to_array( Normal3f& normal ){
	return reinterpret_cast<float*>( &normal );
}

inline const float* normal3f_to_array( const Normal3f& normal ){
	return reinterpret_cast<const float*>( &normal );
}

inline Normal3f normal3f_for_vector3( const Vector3& vector3 ){
	return Normal3f( vector3.x(), vector3.y(), vector3.z() );
}

inline const Vector3& normal3f_to_vector3( const Normal3f& normal ){
	return normal;
}

inline Vector3& normal3f_to_vector3( Normal3f& normal ){
	return normal;
}


/// \brief A 2-float texture-coordinate set.
struct TexCoord2f : public Vector2
{
	TexCoord2f(){
	}

	TexCoord2f( float _s, float _t )
		: Vector2( _s, _t ){
	}

	float& s(){
		return x();
	}
	const float& s() const {
		return x();
	}
	float& t(){
		return y();
	}
	const float& t() const {
		return y();
	}
};

inline bool operator<( const TexCoord2f& self, const TexCoord2f& other ){
	if ( self.s() != other.s() ) {
		return self.s() < other.s();
	}
	if ( self.t() != other.t() ) {
		return self.t() < other.t();
	}
	return false;
}

inline bool operator==( const TexCoord2f& self, const TexCoord2f& other ){
	return self.s() == other.s() && self.t() == other.t();
}

inline bool operator!=( const TexCoord2f& self, const TexCoord2f& other ){
	return !operator==( self, other );
}


inline float* texcoord2f_to_array( TexCoord2f& texcoord ){
	return reinterpret_cast<float*>( &texcoord );
}

inline const float* texcoord2f_to_array( const TexCoord2f& texcoord ){
	return reinterpret_cast<const float*>( &texcoord );
}

inline const TexCoord2f& texcoord2f_from_array( const float* array ){
	return *reinterpret_cast<const TexCoord2f*>( array );
}

inline TexCoord2f texcoord2f_for_vector2( const Vector2& vector2 ){
	return TexCoord2f( vector2.x(), vector2.y() );
}

inline const Vector2& texcoord2f_to_vector2( const TexCoord2f& vertex ){
	return vertex;
}

inline Vector2& texcoord2f_to_vector2( TexCoord2f& vertex ){
	return vertex;
}

/// \brief Returns \p normal rescaled to be unit-length.
inline Normal3f normal3f_normalised( const Normal3f& normal ){
	return normal3f_for_vector3( vector3_normalised( normal3f_to_vector3( normal ) ) );
}

enum UnitSphereOctant
{
	UNITSPHEREOCTANT_000 = 0 << 0 | 0 << 1 | 0 << 2,
	UNITSPHEREOCTANT_001 = 0 << 0 | 0 << 1 | 1 << 2,
	UNITSPHEREOCTANT_010 = 0 << 0 | 1 << 1 | 0 << 2,
	UNITSPHEREOCTANT_011 = 0 << 0 | 1 << 1 | 1 << 2,
	UNITSPHEREOCTANT_100 = 1 << 0 | 0 << 1 | 0 << 2,
	UNITSPHEREOCTANT_101 = 1 << 0 | 0 << 1 | 1 << 2,
	UNITSPHEREOCTANT_110 = 1 << 0 | 1 << 1 | 0 << 2,
	UNITSPHEREOCTANT_111 = 1 << 0 | 1 << 1 | 1 << 2,
};

/// \brief Returns the octant for \p normal indicating the sign of the region of unit-sphere space it lies within.
inline UnitSphereOctant normal3f_classify_octant( const Normal3f& normal ){
	return static_cast<UnitSphereOctant>(
			   ( ( normal.x() > 0 ) << 0 ) | ( ( normal.y() > 0 ) << 1 ) | ( ( normal.z() > 0 ) << 2 )
			   );
}

/// \brief Returns \p normal with its components signs made positive based on \p octant.
inline Normal3f normal3f_fold_octant( const Normal3f& normal, UnitSphereOctant octant ){
	switch ( octant )
	{
	case UNITSPHEREOCTANT_000:
		return Normal3f( -normal.x(), -normal.y(), -normal.z() );
	case UNITSPHEREOCTANT_001:
		return Normal3f( normal.x(), -normal.y(), -normal.z() );
	case UNITSPHEREOCTANT_010:
		return Normal3f( -normal.x(), normal.y(), -normal.z() );
	case UNITSPHEREOCTANT_011:
		return Normal3f( normal.x(), normal.y(), -normal.z() );
	case UNITSPHEREOCTANT_100:
		return Normal3f( -normal.x(), -normal.y(), normal.z() );
	case UNITSPHEREOCTANT_101:
		return Normal3f( normal.x(), -normal.y(), normal.z() );
	case UNITSPHEREOCTANT_110:
		return Normal3f( -normal.x(), normal.y(), normal.z() );
	case UNITSPHEREOCTANT_111:
		return Normal3f( normal.x(), normal.y(), normal.z() );
	}
	return Normal3f();
}

/// \brief Reverses the effect of normal3f_fold_octant() on \p normal with \p octant.
/// \p normal must have been obtained with normal3f_fold_octant().
/// \p octant must have been obtained with normal3f_classify_octant().
inline Normal3f normal3f_unfold_octant( const Normal3f& normal, UnitSphereOctant octant ){
	return normal3f_fold_octant( normal, octant );
}

enum UnitSphereSextant
{
	UNITSPHERESEXTANT_XYZ = 0,
	UNITSPHERESEXTANT_XZY = 1,
	UNITSPHERESEXTANT_YXZ = 2,
	UNITSPHERESEXTANT_YZX = 3,
	UNITSPHERESEXTANT_ZXY = 4,
	UNITSPHERESEXTANT_ZYX = 5,
};

/// \brief Returns the sextant for \p normal indicating how to sort its components so that x > y > z.
/// All components of \p normal must be positive.
/// \p normal must be normalised.
inline UnitSphereSextant normal3f_classify_sextant( const Normal3f& normal ){
	return
		normal.x() >= normal.y()
		? normal.x() >= normal.z()
		? normal.y() >= normal.z()
		? UNITSPHERESEXTANT_XYZ
		: UNITSPHERESEXTANT_XZY
		: UNITSPHERESEXTANT_ZXY
		: normal.y() >= normal.z()
		? normal.x() >= normal.z()
		? UNITSPHERESEXTANT_YXZ
		: UNITSPHERESEXTANT_YZX
		: UNITSPHERESEXTANT_ZYX;
}

/// \brief Returns \p normal with its components sorted so that x > y > z based on \p sextant.
/// All components of \p normal must be positive.
/// \p normal must be normalised.
inline Normal3f normal3f_fold_sextant( const Normal3f& normal, UnitSphereSextant sextant ){
	switch ( sextant )
	{
	case UNITSPHERESEXTANT_XYZ:
		return Normal3f( normal.x(), normal.y(), normal.z() );
	case UNITSPHERESEXTANT_XZY:
		return Normal3f( normal.x(), normal.z(), normal.y() );
	case UNITSPHERESEXTANT_YXZ:
		return Normal3f( normal.y(), normal.x(), normal.z() );
	case UNITSPHERESEXTANT_YZX:
		return Normal3f( normal.y(), normal.z(), normal.x() );
	case UNITSPHERESEXTANT_ZXY:
		return Normal3f( normal.z(), normal.x(), normal.y() );
	case UNITSPHERESEXTANT_ZYX:
		return Normal3f( normal.z(), normal.y(), normal.x() );
	}
	return Normal3f();
}

/// \brief Reverses the effect of normal3f_fold_sextant() on \p normal with \p sextant.
/// \p normal must have been obtained with normal3f_fold_sextant().
/// \p sextant must have been obtained with normal3f_classify_sextant().
inline Normal3f normal3f_unfold_sextant( const Normal3f& normal, UnitSphereSextant sextant ){
	return normal3f_fold_sextant( normal, sextant );
}

const std::size_t c_quantise_normal = 1 << 6;

/// \brief All the components of \p folded must be positive and sorted so that x > y > z.
inline Normal3f normal3f_folded_quantised( const Normal3f& folded ){
	// compress
	double scale = static_cast<float>( c_quantise_normal ) / ( folded.x() + folded.y() + folded.z() );
	unsigned int zbits = static_cast<unsigned int>( folded.z() * scale );
	unsigned int ybits = static_cast<unsigned int>( folded.y() * scale );

	// decompress
	return normal3f_normalised( Normal3f(
									static_cast<float>( c_quantise_normal - zbits - ybits ),
									static_cast<float>( ybits ),
									static_cast<float>( zbits )
									) );
}

/// \brief Returns \p normal quantised by compressing and then decompressing its representation.
inline Normal3f normal3f_quantised_custom( const Normal3f& normal ){
	UnitSphereOctant octant = normal3f_classify_octant( normal );
	Normal3f folded = normal3f_fold_octant( normal, octant );
	UnitSphereSextant sextant = normal3f_classify_sextant( folded );
	folded = normal3f_fold_sextant( folded, sextant );
	return normal3f_unfold_octant( normal3f_unfold_sextant( normal3f_folded_quantised( folded ), sextant ), octant );
}



struct spherical_t
{
	double longditude, latitude;

	spherical_t( double _longditude, double _latitude )
		: longditude( _longditude ), latitude( _latitude ){
	}
};

/*
   {
   theta = 2pi * U;
   phi = acos((2 * V) - 1);

   U = theta / 2pi;
   V = (cos(phi) + 1) / 2;
   }

   longitude = atan(y / x);
   latitude = acos(z);
 */
struct uniformspherical_t
{
	double U, V;

	uniformspherical_t( double U_, double V_ )
		: U( U_ ), V( V_ ){
	}
};


inline spherical_t spherical_from_normal3f( const Normal3f& normal ){
	return spherical_t( normal.x() == 0 ? c_pi / 2 : normal.x() > 0 ? atan( normal.y() / normal.x() ) : atan( normal.y() / normal.x() ) + c_pi, acos( normal.z() ) );
}

inline Normal3f normal3f_from_spherical( const spherical_t& spherical ){
	return Normal3f(
			   static_cast<float>( cos( spherical.longditude ) * sin( spherical.latitude ) ),
			   static_cast<float>( sin( spherical.longditude ) * sin( spherical.latitude ) ),
			   static_cast<float>( cos( spherical.latitude ) )
			   );
}

inline uniformspherical_t uniformspherical_from_spherical( const spherical_t& spherical ){
	return uniformspherical_t( spherical.longditude * c_inv_2pi, ( cos( spherical.latitude ) + 1 ) * 0.5 );
}

inline spherical_t spherical_from_uniformspherical( const uniformspherical_t& uniformspherical ){
	return spherical_t( c_2pi * uniformspherical.U, acos( ( 2 * uniformspherical.V ) - 1 ) );
}

inline uniformspherical_t uniformspherical_from_normal3f( const Normal3f& normal ){
	return uniformspherical_from_spherical( spherical_from_normal3f( normal ) );
	//return uniformspherical_t(atan2(normal.y / normal.x) * c_inv_2pi, (normal.z + 1) * 0.5);
}

inline Normal3f normal3f_from_uniformspherical( const uniformspherical_t& uniformspherical ){
	return normal3f_from_spherical( spherical_from_uniformspherical( uniformspherical ) );
}

/// \brief Returns a single-precision \p component quantised to \p precision.
inline float float_quantise( float component, float precision ){
	return float_snapped( component, precision );
}

/// \brief Returns a double-precision \p component quantised to \p precision.
inline double double_quantise( double component, double precision ){
	return float_snapped( component, precision );
}

inline spherical_t spherical_quantised( const spherical_t& spherical, float snap ){
	return spherical_t( double_quantise( spherical.longditude, snap ), double_quantise( spherical.latitude, snap ) );
}

inline uniformspherical_t uniformspherical_quantised( const uniformspherical_t& uniformspherical, float snap ){
	return uniformspherical_t( double_quantise( uniformspherical.U, snap ), double_quantise( uniformspherical.V, snap ) );
}

/// \brief Returns a \p vertex quantised to \p precision.
inline Vertex3f vertex3f_quantised( const Vertex3f& vertex, float precision ){
	return Vertex3f( float_quantise( vertex.x(), precision ), float_quantise( vertex.y(), precision ), float_quantise( vertex.z(), precision ) );
}

/// \brief Returns a \p normal quantised to a fixed precision.
inline Normal3f normal3f_quantised( const Normal3f& normal ){
	return normal3f_quantised_custom( normal );
	//return normal3f_from_spherical(spherical_quantised(spherical_from_normal3f(normal), snap));
	//return normal3f_from_uniformspherical(uniformspherical_quantised(uniformspherical_from_normal3f(normal), snap));
	//  float_quantise(normal.x, snap), float_quantise(normal.y, snap), float_quantise(normal.y, snap));
}

/// \brief Returns a \p texcoord quantised to \p precision.
inline TexCoord2f texcoord2f_quantised( const TexCoord2f& texcoord, float precision ){
	return TexCoord2f( float_quantise( texcoord.s(), precision ), float_quantise( texcoord.t(), precision ) );
}

/// \brief Standard vertex type for lines and points.
struct PointVertex
{
	Colour4b colour;
	Vertex3f vertex;

	PointVertex(){
	}
	PointVertex( Vertex3f _vertex )
		: colour( Colour4b( 255, 255, 255, 255 ) ), vertex( _vertex ){
	}
	PointVertex( Vertex3f _vertex, Colour4b _colour )
		: colour( _colour ), vertex( _vertex ){
	}
};

inline bool operator<( const PointVertex& self, const PointVertex& other ){
	if ( self.vertex != other.vertex ) {
		return self.vertex < other.vertex;
	}
	if ( self.colour != other.colour ) {
		return self.colour < other.colour;
	}
	return false;
}

inline bool operator==( const PointVertex& self, const PointVertex& other ){
	return self.colour == other.colour && self.vertex == other.vertex;
}

inline bool operator!=( const PointVertex& self, const PointVertex& other ){
	return !operator==( self, other );
}

/// \brief Standard vertex type for lit/textured meshes.
struct ArbitraryMeshVertex
{
	TexCoord2f texcoord;
	Normal3f normal;
	Vertex3f vertex;
	Normal3f tangent;
	Normal3f bitangent;

	ArbitraryMeshVertex() : tangent( 0, 0, 0 ), bitangent( 0, 0, 0 ){
	}
	ArbitraryMeshVertex( Vertex3f _vertex, Normal3f _normal, TexCoord2f _texcoord )
		: texcoord( _texcoord ), normal( _normal ), vertex( _vertex ), tangent( 0, 0, 0 ), bitangent( 0, 0, 0 ){
	}
};

inline bool operator<( const ArbitraryMeshVertex& self, const ArbitraryMeshVertex& other ){
	if ( self.texcoord != other.texcoord ) {
		return self.texcoord < other.texcoord;
	}
	if ( self.normal != other.normal ) {
		return self.normal < other.normal;
	}
	if ( self.vertex != other.vertex ) {
		return self.vertex < other.vertex;
	}
	return false;
}

inline bool operator==( const ArbitraryMeshVertex& self, const ArbitraryMeshVertex& other ){
	return self.texcoord == other.texcoord && self.normal == other.normal && self.vertex == other.vertex;
}

inline bool operator!=( const ArbitraryMeshVertex& self, const ArbitraryMeshVertex& other ){
	return !operator==( self, other );
}

const float c_quantise_vertex = 1.f / static_cast<float>( 1 << 3 );

/// \brief Returns \p v with vertex quantised to a fixed precision.
inline PointVertex pointvertex_quantised( const PointVertex& v ){
	return PointVertex( vertex3f_quantised( v.vertex, c_quantise_vertex ), v.colour );
}

const float c_quantise_texcoord = 1.f / static_cast<float>( 1 << 8 );

/// \brief Returns \p v with vertex, normal and texcoord quantised to a fixed precision.
inline ArbitraryMeshVertex arbitrarymeshvertex_quantised( const ArbitraryMeshVertex& v ){
	return ArbitraryMeshVertex( vertex3f_quantised( v.vertex, c_quantise_vertex ), normal3f_quantised( v.normal ), texcoord2f_quantised( v.texcoord, c_quantise_texcoord ) );
}


/// \brief Sets up the OpenGL colour and vertex arrays for \p array.
inline void pointvertex_gl_array( const PointVertex* array ){
	glColorPointer( 4, GL_UNSIGNED_BYTE, sizeof( PointVertex ), &array->colour );
	glVertexPointer( 3, GL_FLOAT, sizeof( PointVertex ), &array->vertex );
}

class RenderablePointArray : public OpenGLRenderable
{
const Array<PointVertex>& m_array;
const GLenum m_mode;
public:
RenderablePointArray( const Array<PointVertex>& array, GLenum mode )
	: m_array( array ), m_mode( mode ){
}
void render( RenderStateFlags state ) const {
#define NV_DRIVER_BUG 1
#if NV_DRIVER_BUG
	glColorPointer( 4, GL_UNSIGNED_BYTE, 0, 0 );
	glVertexPointer( 3, GL_FLOAT, 0, 0 );
	glDrawArrays( GL_TRIANGLE_FAN, 0, 0 );
#endif
	pointvertex_gl_array( m_array.data() );
	glDrawArrays( m_mode, 0, GLsizei( m_array.size() ) );
}
};

class RenderablePointVector : public OpenGLRenderable
{
std::vector<PointVertex> m_vector;
const GLenum m_mode;
public:
RenderablePointVector( GLenum mode )
	: m_mode( mode ){
}

void render( RenderStateFlags state ) const {
	pointvertex_gl_array( &m_vector.front() );
	glDrawArrays( m_mode, 0, GLsizei( m_vector.size() ) );
}

std::size_t size() const {
	return m_vector.size();
}
bool empty() const {
	return m_vector.empty();
}
void clear(){
	m_vector.clear();
}
void reserve( std::size_t size ){
	m_vector.reserve( size );
}
void push_back( const PointVertex& point ){
	m_vector.push_back( point );
}
};


class RenderableVertexBuffer : public OpenGLRenderable
{
const GLenum m_mode;
const VertexBuffer<PointVertex>& m_vertices;
public:
RenderableVertexBuffer( GLenum mode, const VertexBuffer<PointVertex>& vertices )
	: m_mode( mode ), m_vertices( vertices ){
}

void render( RenderStateFlags state ) const {
	pointvertex_gl_array( m_vertices.data() );
	glDrawArrays( m_mode, 0, m_vertices.size() );
}
};

class RenderableIndexBuffer : public OpenGLRenderable
{
const GLenum m_mode;
const IndexBuffer& m_indices;
const VertexBuffer<PointVertex>& m_vertices;
public:
RenderableIndexBuffer( GLenum mode, const IndexBuffer& indices, const VertexBuffer<PointVertex>& vertices )
	: m_mode( mode ), m_indices( indices ), m_vertices( vertices ){
}

void render( RenderStateFlags state ) const {
#if 1
	pointvertex_gl_array( m_vertices.data() );
	glDrawElements( m_mode, GLsizei( m_indices.size() ), RenderIndexTypeID, m_indices.data() );
#else
	glBegin( m_mode );
	if ( state & RENDER_COLOURARRAY != 0 ) {
		for ( std::size_t i = 0; i < m_indices.size(); ++i )
		{
			glColor4ubv( &m_vertices[m_indices[i]].colour.r );
			glVertex3fv( &m_vertices[m_indices[i]].vertex.x );
		}
	}
	else
	{
		for ( std::size_t i = 0; i < m_indices.size(); ++i )
		{
			glVertex3fv( &m_vertices[m_indices[i]].vertex.x );
		}
	}
	glEnd();
#endif
}
};


class RemapXYZ
{
public:
static void set( Vertex3f& vertex, float x, float y, float z ){
	vertex.x() = x;
	vertex.y() = y;
	vertex.z() = z;
}
};

class RemapYZX
{
public:
static void set( Vertex3f& vertex, float x, float y, float z ){
	vertex.x() = z;
	vertex.y() = x;
	vertex.z() = y;
}
};

class RemapZXY
{
public:
static void set( Vertex3f& vertex, float x, float y, float z ){
	vertex.x() = y;
	vertex.y() = z;
	vertex.z() = x;
}
};

template<typename remap_policy>
inline void draw_circle( const std::size_t segments, const float radius, PointVertex* vertices, remap_policy remap ){
	const double increment = c_pi / double(segments << 2);

	std::size_t count = 0;
	float x = radius;
	float y = 0;
	while ( count < segments )
	{
		PointVertex* i = vertices + count;
		PointVertex* j = vertices + ( ( segments << 1 ) - ( count + 1 ) );

		PointVertex* k = i + ( segments << 1 );
		PointVertex* l = j + ( segments << 1 );

		PointVertex* m = i + ( segments << 2 );
		PointVertex* n = j + ( segments << 2 );
		PointVertex* o = k + ( segments << 2 );
		PointVertex* p = l + ( segments << 2 );

		remap_policy::set( i->vertex, x,-y, 0 );
		remap_policy::set( k->vertex,-y,-x, 0 );
		remap_policy::set( m->vertex,-x, y, 0 );
		remap_policy::set( o->vertex, y, x, 0 );

		++count;

		{
			const double theta = increment * count;
			x = static_cast<float>( radius * cos( theta ) );
			y = static_cast<float>( radius * sin( theta ) );
		}

		remap_policy::set( j->vertex, y,-x, 0 );
		remap_policy::set( l->vertex,-x,-y, 0 );
		remap_policy::set( n->vertex,-y, x, 0 );
		remap_policy::set( p->vertex, x, y, 0 );
	}
}

#if 0
class PointVertexArrayIterator
{
PointVertex* m_point;
public:
PointVertexArrayIterator( PointVertex* point )
	: m_point( point ){
}
PointVertexArrayIterator& operator++(){
	++m_point;
	return *this;
}
PointVertexArrayIterator operator++( int ){
	PointVertexArrayIterator tmp( *this );
	++m_point;
	return tmp;
}
Vertex3f& operator*(){
	return m_point.vertex;
}
Vertex3f* operator->(){
	return &( operator*() );
}
}

template<typename remap_policy, typename iterator_type
		 inline void draw_circle( const std::size_t segments, const float radius, iterator_type start, remap_policy remap ){
			 const float increment = c_pi / (double)( segments << 2 );

			 std::size_t count = 0;
			 iterator_type pxpy( start );
			 iterator_type pypx( pxpy + ( segments << 1 ) );
			 iterator_type pynx( pxpy + ( segments << 1 ) );
			 iterator_type nxpy( pypx + ( segments << 1 ) );
			 iterator_type nxny( pypx + ( segments << 1 ) );
			 iterator_type nynx( nxpy + ( segments << 1 ) );
			 iterator_type nypx( nxpy + ( segments << 1 ) );
			 iterator_type pxny( start );
			 while ( count < segments )
			 {
				 const float theta = increment * count;
				 const float x = radius * cos( theta );
				 const float y = radius * sin( theta );

				 remap_policy::set( ( *pxpy ), x, y, 0 );
				 remap_policy::set( ( *pxny ), x,-y, 0 );
				 remap_policy::set( ( *nxpy ),-x, y, 0 );
				 remap_policy::set( ( *nxny ),-x,-y, 0 );

				 remap_policy::set( ( *pypx ), y, x, 0 );
				 remap_policy::set( ( *pynx ), y,-x, 0 );
				 remap_policy::set( ( *nypx ),-y, x, 0 );
				 remap_policy::set( ( *nynx ),-y,-x, 0 );
			 }
		 }

		 template<typename remap_policy, typename iterator_type
				  inline void draw_semicircle( const std::size_t segments, const float radius, iterator_type start, remap_policy remap )
				  {
					  const float increment = c_pi / (double)( segments << 2 );

					  std::size_t count = 0;
					  iterator_type pxpy( start );
					  iterator_type pypx( pxpy + ( segments << 1 ) );
					  iterator_type pynx( pxpy + ( segments << 1 ) );
					  iterator_type nxpy( pypx + ( segments << 1 ) );
					  iterator_type nxny( pypx + ( segments << 1 ) );
					  iterator_type nynx( nxpy + ( segments << 1 ) );
					  iterator_type nypx( nxpy + ( segments << 1 ) );
					  iterator_type pxny( start );
					  while ( count < segments )
					  {
						  const float theta = increment * count;
						  const float x = radius * cos( theta );
						  const float y = radius * sin( theta );

						  remap_policy::set( ( *pxpy ), x, y, 0 );
						  remap_policy::set( ( *pxny ), x,-y, 0 );
						  remap_policy::set( ( *nxpy ),-x, y, 0 );
						  remap_policy::set( ( *nxny ),-x,-y, 0 );

                          //remap_policy::set((*pypx), y, x, 0);
                          //remap_policy::set((*pynx), y,-x, 0);
                          //remap_policy::set((*nypx),-y, x, 0);
                          //remap_policy::set((*nynx),-y,-x, 0);
					  }
				  }


#endif

inline void draw_quad( const float radius, PointVertex* quad ){
	( *quad ++ ).vertex = Vertex3f( -radius, radius, 0 );
	( *quad ++ ).vertex = Vertex3f( radius, radius, 0 );
	( *quad ++ ).vertex = Vertex3f( radius, -radius, 0 );
	( *quad ++ ).vertex = Vertex3f( -radius, -radius, 0 );
}

inline void draw_cube( const float radius, PointVertex* cube ){
	( *cube ++ ).vertex = Vertex3f( -radius, -radius, -radius );
	( *cube ++ ).vertex = Vertex3f( radius, -radius, -radius );
	( *cube ++ ).vertex = Vertex3f( -radius, radius, -radius );
	( *cube ++ ).vertex = Vertex3f( radius, radius, -radius );
	( *cube ++ ).vertex = Vertex3f( -radius, -radius, radius );
	( *cube ++ ).vertex = Vertex3f( radius, -radius, radius );
	( *cube ++ ).vertex = Vertex3f( -radius, radius, radius );
	( *cube ++ ).vertex = Vertex3f( radius, radius, radius );
}


/// \brief Calculates the tangent vectors for a triangle \p a, \p b, \p c and stores the tangent in \p s and the bitangent in \p t.
inline void ArbitraryMeshTriangle_calcTangents( const ArbitraryMeshVertex& a, const ArbitraryMeshVertex& b, const ArbitraryMeshVertex& c, Vector3& s, Vector3& t ){
	s = Vector3( 0, 0, 0 );
	t = Vector3( 0, 0, 0 );
	{
		Vector3 cross(
			vector3_cross(
				vector3_subtracted(
					Vector3( b.vertex.x(), b.texcoord.s(), b.texcoord.t() ),
					Vector3( a.vertex.x(), a.texcoord.s(), a.texcoord.t() )
					),
				vector3_subtracted(
					Vector3( c.vertex.x(), c.texcoord.s(), c.texcoord.t() ),
					Vector3( a.vertex.x(), a.texcoord.s(), a.texcoord.t() )
					)
				)
			);

		if ( fabs( cross.x() ) > 0.000001f ) {
			s.x() = -cross.y() / cross.x();
		}

		if ( fabs( cross.x() ) > 0.000001f ) {
			t.x() = -cross.z() / cross.x();
		}
	}

	{
		Vector3 cross(
			vector3_cross(
				vector3_subtracted(
					Vector3( b.vertex.y(), b.texcoord.s(), b.texcoord.t() ),
					Vector3( a.vertex.y(), a.texcoord.s(), a.texcoord.t() )
					),
				vector3_subtracted(
					Vector3( c.vertex.y(), c.texcoord.s(), c.texcoord.t() ),
					Vector3( a.vertex.y(), a.texcoord.s(), a.texcoord.t() )
					)
				)
			);

		if ( fabs( cross.x() ) > 0.000001f ) {
			s.y() = -cross.y() / cross.x();
		}

		if ( fabs( cross.x() ) > 0.000001f ) {
			t.y() = -cross.z() / cross.x();
		}
	}

	{
		Vector3 cross(
			vector3_cross(
				vector3_subtracted(
					Vector3( b.vertex.z(), b.texcoord.s(), b.texcoord.t() ),
					Vector3( a.vertex.z(), a.texcoord.s(), a.texcoord.t() )
					),
				vector3_subtracted(
					Vector3( c.vertex.z(), c.texcoord.s(), c.texcoord.t() ),
					Vector3( a.vertex.z(), a.texcoord.s(), a.texcoord.t() )
					)
				)
			);

		if ( fabs( cross.x() ) > 0.000001f ) {
			s.z() = -cross.y() / cross.x();
		}

		if ( fabs( cross.x() ) > 0.000001f ) {
			t.z() = -cross.z() / cross.x();
		}
	}
}

inline void ArbitraryMeshTriangle_sumTangents( ArbitraryMeshVertex& a, ArbitraryMeshVertex& b, ArbitraryMeshVertex& c ){
	Vector3 s, t;

	ArbitraryMeshTriangle_calcTangents( a, b, c, s, t );

	reinterpret_cast<Vector3&>( a.tangent ) += s;
	reinterpret_cast<Vector3&>( b.tangent ) += s;
	reinterpret_cast<Vector3&>( c.tangent ) += s;

	reinterpret_cast<Vector3&>( a.bitangent ) += t;
	reinterpret_cast<Vector3&>( b.bitangent ) += t;
	reinterpret_cast<Vector3&>( c.bitangent ) += t;
}


#endif