/**
 * =========================================================================
 * File        : Brush.h
 * Project     : Pyrogenesis
 * Description : CBrush, a class representing a convex object
 * =========================================================================
 */

#ifndef maths_brush_h
#define maths_brush_h

#include "Vector3D.h"

class CBound;
class CFrustum;
class CPlane;


/**
 * Class CBrush: Represents a convex object, supports some CSG operations.
 */
class CBrush
{
public:
    CBrush() { }

    /**
     * CBrush: Construct a brush from a bounds object.
     *
     * @param bounds the CBound object to construct the brush from.
     */
    CBrush(const CBound& bounds);

    /**
     * IsEmpty: Returns whether the brush is empty.
     *
     * @return @c true if the brush is empty, @c false otherwise
     */
    bool IsEmpty() const { return m_Vertices.size() == 0; }

    /**
     * Bounds: Calculate the axis-aligned bounding box for this brush.
     *
     * @param result the resulting bounding box is stored here
     */
    void Bounds(CBound& result) const;

    /**
     * Slice: Cut the object along the given plane, resulting in a smaller (or even empty)
     * brush representing the part of the object that lies in front of the plane.
     *
     * @param plane the slicing plane
     * @param result the resulting brush is stored here
     */
    void Slice(const CPlane& plane, CBrush& result) const;

    /**
     * Intersect: Intersect the brush with the given frustum.
     *
     * @param frustum the frustum to intersect with
     * @param result the resulting brush is stored here
     */
    void Intersect(const CFrustum& frustum, CBrush& result) const;

    /**
     * Render: Renders the brush as OpenGL polygons.
     *
     * @note the winding of the brush faces is undefined (i.e. it is undefined which
     * sides of the faces are the front faces)
     */
    void Render() const;

private:
    static const uint no_vertex = ~0u;

    typedef std::vector<CVector3D> Vertices;
    typedef std::vector<uint> FaceIndices;

    Vertices m_Vertices;
    FaceIndices m_Faces;

    struct Helper;
};

#endif // maths_brush_h