/*****************************************************************************
The Dark Mod GPL Source Code

This file is part of the The Dark Mod Source Code, originally based
on the Doom 3 GPL Source Code as published in 2011.

The Dark Mod Source Code 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 3 of the License,
or (at your option) any later version. For details, see LICENSE.TXT.

Project: The Dark Mod (http://www.thedarkmod.com/)

******************************************************************************/

#ifndef __TRACEMODEL_H__
#define __TRACEMODEL_H__

/*
===============================================================================

	A trace model is an arbitrary polygonal model which is used by the
	collision detection system to find collisions, contacts or the contents
	of a volume. For collision detection speed reasons the number of vertices
	and edges are limited. The trace model can have any shape. However convex
	models are usually preferred.

===============================================================================
*/

class idVec3;
class idMat3;
class idBounds;

// trace model type
typedef enum {
	TRM_INVALID,		// invalid trm
	TRM_BOX,			// box
	TRM_OCTAHEDRON,		// octahedron
	TRM_DODECAHEDRON,	// dodecahedron
	TRM_CYLINDER,		// cylinder approximation
	TRM_CONE,			// cone approximation
	TRM_BONE,			// two tetrahedrons attached to each other
	TRM_POLYGON,		// arbitrary convex polygon
	TRM_POLYGONVOLUME,	// volume for arbitrary convex polygon
	TRM_CUSTOM			// loaded from map model or ASE/LWO
} traceModel_t;

// these are bit cache limits
#define MAX_TRACEMODEL_VERTS		32
#define MAX_TRACEMODEL_EDGES		63
#define MAX_TRACEMODEL_POLYS		32

typedef idVec3 traceModelVert_t;

typedef struct {
	int					v[2];
	idVec3				normal;
} traceModelEdge_t;

typedef struct {
	idVec3				normal;
	float				dist;
	idBounds			bounds;
	int					numEdges;
	int					firstEdge;
} traceModelPoly_t;

class idTraceModel {

public:
	traceModel_t		type = TRM_INVALID;
	int					numVerts = 0;
	traceModelVert_t	verts[MAX_TRACEMODEL_VERTS];
	int					numEdges = 0;
	traceModelEdge_t	edges[MAX_TRACEMODEL_EDGES+1];
	int					numPolys = 0;
	traceModelPoly_t	polys[MAX_TRACEMODEL_POLYS];
	int					numEdgeUses = 0;
	int					edgeUses[MAX_TRACEMODEL_EDGES*2];
	idVec3				offset;					// offset to center of model
	idBounds			bounds{idVec3(0.0f)};	// bounds of model
	bool				isConvex;				// true when model is convex

public:
						idTraceModel( void ) = default;
						// axial bounding box
						idTraceModel( const idBounds &boxBounds );
						// cylinder approximation
						idTraceModel( const idBounds &cylBounds, const int numSides );
						// bone
						idTraceModel( const float length, const float width );

						// axial box
	void				SetupBox( const idBounds &boxBounds );
	void				SetupBox( const float size );
						// octahedron
	void				SetupOctahedron( const idBounds &octBounds );
	void				SetupOctahedron( const float size );
						// dodecahedron
	void				SetupDodecahedron( const idBounds &dodBounds );
	void				SetupDodecahedron( const float size );
						// cylinder approximation
	void				SetupCylinder( const idBounds &cylBounds, const int numSides );
	void				SetupCylinder( const float height, const float width, const int numSides );
						// cone approximation
	void				SetupCone( const idBounds &coneBounds, const int numSides );
	void				SetupCone( const float height, const float width, const int numSides );
						// two tetrahedrons attached to each other
	void				SetupBone( const float length, const float width );
						// arbitrary convex polygon
	void				SetupPolygon( const idVec3 *v, const int count );
	void				SetupPolygon( const idWinding &w );
						// generate edge normals
	int					GenerateEdgeNormals( void );
						// translate the trm
	void				Translate( const idVec3 &translation );
						// rotate the trm
						// rotate the trm or apply non-singular linear transform
	void				Rotate( const idMat3 &rotation, bool isRotationOrthogonal = true );
						// scale the trm
	void				Scale( const idVec3 &scale );
						// shrink the model m units on all sides
	void				Shrink( const float m );
						// compare
	bool				Compare( const idTraceModel &trm ) const;
	bool				operator==(	const idTraceModel &trm ) const;
	bool				operator!=(	const idTraceModel &trm ) const;
						// get the area of one of the polygons
	float				GetPolygonArea( int polyNum ) const;
						// get the silhouette edges
	int					GetProjectionSilhouetteEdges( const idVec3 &projectionOrigin, int silEdges[MAX_TRACEMODEL_EDGES] ) const;
	int					GetParallelProjectionSilhouetteEdges( const idVec3 &projectionDir, int silEdges[MAX_TRACEMODEL_EDGES] ) const;
						// calculate mass properties assuming an uniform density
	void				GetMassProperties( const float density, float &mass, idVec3 &centerOfMass, idMat3 &inertiaTensor ) const;

private:
	void				InitBox( void );
	void				InitOctahedron( void );
	void				InitDodecahedron( void );
	void				InitBone( void );

	void				ProjectionIntegrals( int polyNum, int a, int b, struct projectionIntegrals_s &integrals ) const;
	void				PolygonIntegrals( int polyNum, int a, int b, int c, struct polygonIntegrals_s &integrals ) const;
	void				VolumeIntegrals( struct volumeIntegrals_s &integrals ) const;
	void				VolumeFromPolygon( idTraceModel &trm, float thickness ) const;
	int					GetOrderedSilhouetteEdges( const int edgeIsSilEdge[MAX_TRACEMODEL_EDGES+1], int silEdges[MAX_TRACEMODEL_EDGES] ) const;
};


ID_INLINE idTraceModel::idTraceModel( const idBounds &boxBounds ) {
	InitBox();
	SetupBox( boxBounds );
}

ID_INLINE idTraceModel::idTraceModel( const idBounds &cylBounds, const int numSides ) {
	SetupCylinder( cylBounds, numSides );
}

ID_INLINE idTraceModel::idTraceModel( const float length, const float width ) {
	InitBone();
	SetupBone( length, width );
}

ID_INLINE bool idTraceModel::operator==( const idTraceModel &trm ) const {
	return Compare( trm );
}

ID_INLINE bool idTraceModel::operator!=( const idTraceModel &trm ) const {
	return !Compare( trm );
}

#endif /* !__TRACEMODEL_H__ */