Surface.h

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

Doom 3 GPL Source Code
Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company. 

This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).  

Doom 3 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.

Doom 3 Source Code 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 Doom 3 Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the Doom 3 Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 Source Code.  If not, please request a copy in writing from id Software at the address below.

If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

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

#ifndef __SURFACE_H__
#define __SURFACE_H__

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

        Surface base class.

        A surface is tesselated to a triangle mesh with each edge shared by
        at most two triangles.

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

typedef struct surfaceEdge_s {
        int                                             verts[2];       // edge vertices always with ( verts[0] < verts[1] )
        int                                             tris[2];        // edge triangles
} surfaceEdge_t;


class idSurface {
public:
                                                        idSurface( void );
                                                        explicit idSurface( const idSurface &surf );
                                                        explicit idSurface( const idDrawVert *verts, const int numVerts, const int *indexes, const int numIndexes );
                                                        ~idSurface( void );

        const idDrawVert &              operator[]( const int index ) const;
        idDrawVert &                    operator[]( const int index );
        idSurface &                             operator+=( const idSurface &surf );

        int                                             GetNumIndexes( void ) const { return indexes.Num(); }
        const int *                             GetIndexes( void ) const { return indexes.Ptr(); }
        int                                             GetNumVertices( void ) const { return verts.Num(); }
        const idDrawVert *              GetVertices( void ) const { return verts.Ptr(); }
        const int *                             GetEdgeIndexes( void ) const { return edgeIndexes.Ptr(); }
        const surfaceEdge_t *   GetEdges( void ) const { return edges.Ptr(); }

        void                                    Clear( void );
        void                                    SwapTriangles( idSurface &surf );
        void                                    TranslateSelf( const idVec3 &translation );
        void                                    RotateSelf( const idMat3 &rotation );

                                                        // splits the surface into a front and back surface, the surface itself stays unchanged
                                                        // frontOnPlaneEdges and backOnPlaneEdges optionally store the indexes to the edges that lay on the split plane
                                                        // returns a SIDE_?
        int                                             Split( const idPlane &plane, const float epsilon, idSurface **front, idSurface **back, int *frontOnPlaneEdges = NULL, int *backOnPlaneEdges = NULL ) const;
                                                        // cuts off the part at the back side of the plane, returns true if some part was at the front
                                                        // if there is nothing at the front the number of points is set to zero
        bool                                    ClipInPlace( const idPlane &plane, const float epsilon = ON_EPSILON, const bool keepOn = false );

                                                        // returns true if each triangle can be reached from any other triangle by a traversal
        bool                                    IsConnected( void ) const;
                                                        // returns true if the surface is closed
        bool                                    IsClosed( void ) const;
                                                        // returns true if the surface is a convex hull
        bool                                    IsPolytope( const float epsilon = 0.1f ) const;

        float                                   PlaneDistance( const idPlane &plane ) const;
        int                                             PlaneSide( const idPlane &plane, const float epsilon = ON_EPSILON ) const;

                                                        // returns true if the line intersects one of the surface triangles
        bool                                    LineIntersection( const idVec3 &start, const idVec3 &end, bool backFaceCull = false ) const;
                                                        // intersection point is start + dir * scale
        bool                                    RayIntersection( const idVec3 &start, const idVec3 &dir, float &scale, bool backFaceCull = false ) const;

protected:
        idList<idDrawVert>              verts;                  // vertices
        idList<int>                             indexes;                // 3 references to vertices for each triangle
        idList<surfaceEdge_t>   edges;                  // edges
        idList<int>                             edgeIndexes;    // 3 references to edges for each triangle, may be negative for reversed edge

protected:
        void                                    GenerateEdgeIndexes( void );
        int                                             FindEdge( int v1, int v2 ) const;
};

/*
====================
idSurface::idSurface
====================
*/
ID_INLINE idSurface::idSurface( void ) {
}

/*
=================
idSurface::idSurface
=================
*/
ID_INLINE idSurface::idSurface( const idDrawVert *verts, const int numVerts, const int *indexes, const int numIndexes ) {
        assert( verts != NULL && indexes != NULL && numVerts > 0 && numIndexes > 0 );
        this->verts.SetNum( numVerts );
        memcpy( this->verts.Ptr(), verts, numVerts * sizeof( verts[0] ) );
        this->indexes.SetNum( numIndexes );
        memcpy( this->indexes.Ptr(), indexes, numIndexes * sizeof( indexes[0] ) );
        GenerateEdgeIndexes();
}

/*
====================
idSurface::idSurface
====================
*/
ID_INLINE idSurface::idSurface( const idSurface &surf ) {
        this->verts = surf.verts;
        this->indexes = surf.indexes;
        this->edges = surf.edges;
        this->edgeIndexes = surf.edgeIndexes;
}

/*
====================
idSurface::~idSurface
====================
*/
ID_INLINE idSurface::~idSurface( void ) {
}

/*
=================
idSurface::operator[]
=================
*/
ID_INLINE const idDrawVert &idSurface::operator[]( const int index ) const {
        return verts[ index ];
};

/*
=================
idSurface::operator[]
=================
*/
ID_INLINE idDrawVert &idSurface::operator[]( const int index ) {
        return verts[ index ];
};

/*
=================
idSurface::operator+=
=================
*/
ID_INLINE idSurface &idSurface::operator+=( const idSurface &surf ) {
        int i, m, n;
        n = verts.Num();
        m = indexes.Num();
        verts.Append( surf.verts );                     // merge verts where possible ?
        indexes.Append( surf.indexes );
        for ( i = m; i < indexes.Num(); i++ ) {
                indexes[i] += n;
        }
        GenerateEdgeIndexes();
        return *this;
}

/*
=================
idSurface::Clear
=================
*/
ID_INLINE void idSurface::Clear( void ) {
        verts.Clear();
        indexes.Clear();
        edges.Clear();
        edgeIndexes.Clear();
}

/*
=================
idSurface::SwapTriangles
=================
*/
ID_INLINE void idSurface::SwapTriangles( idSurface &surf ) {
        verts.Swap( surf.verts );
        indexes.Swap( surf.indexes );
        edges.Swap( surf.edges );
        edgeIndexes.Swap( surf.edgeIndexes );
}

/*
=================
idSurface::TranslateSelf
=================
*/
ID_INLINE void idSurface::TranslateSelf( const idVec3 &translation ) {
        for ( int i = 0; i < verts.Num(); i++ ) {
                verts[i].xyz += translation;
        }
}

/*
=================
idSurface::RotateSelf
=================
*/
ID_INLINE void idSurface::RotateSelf( const idMat3 &rotation ) {
        for ( int i = 0; i < verts.Num(); i++ ) {
                verts[i].xyz *= rotation;
                verts[i].normal *= rotation;
                verts[i].tangents[0] *= rotation;
                verts[i].tangents[1] *= rotation;
        }
}

#endif /* !__SURFACE_H__ */