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//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $Workfile: $
// $Date: $
// $NoKeywords: $
//=============================================================================//
#ifndef VPLANE_H
#define VPLANE_H
#ifdef _WIN32
#pragma once
#endif
#include "mathlib/vector.h"
typedef int SideType;
// Used to represent sides of things like planes.
#define SIDE_FRONT 0
#define SIDE_BACK 1
#define SIDE_ON 2
#define VP_EPSILON 0.01f
class VPlane
{
public:
VPlane();
VPlane(const Vector &vNormal, vec_t dist);
void Init(const Vector &vNormal, vec_t dist);
// Return the distance from the point to the plane.
vec_t DistTo(const Vector &vVec) const;
// Copy.
VPlane& operator=(const VPlane &thePlane);
// Returns SIDE_ON, SIDE_FRONT, or SIDE_BACK.
// The epsilon for SIDE_ON can be passed in.
SideType GetPointSide(const Vector &vPoint, vec_t sideEpsilon=VP_EPSILON) const;
// Returns SIDE_FRONT or SIDE_BACK.
SideType GetPointSideExact(const Vector &vPoint) const;
// Classify the box with respect to the plane.
// Returns SIDE_ON, SIDE_FRONT, or SIDE_BACK
SideType BoxOnPlaneSide(const Vector &vMin, const Vector &vMax) const;
#ifndef VECTOR_NO_SLOW_OPERATIONS
// Flip the plane.
VPlane Flip();
// Get a point on the plane (normal*dist).
Vector GetPointOnPlane() const;
// Snap the specified point to the plane (along the plane's normal).
Vector SnapPointToPlane(const Vector &vPoint) const;
#endif
public:
Vector m_Normal;
vec_t m_Dist;
#ifdef VECTOR_NO_SLOW_OPERATIONS
private:
// No copy constructors allowed if we're in optimal mode
VPlane(const VPlane& vOther);
#endif
};
//-----------------------------------------------------------------------------
// Inlines.
//-----------------------------------------------------------------------------
inline VPlane::VPlane()
{
}
inline VPlane::VPlane(const Vector &vNormal, vec_t dist)
{
m_Normal = vNormal;
m_Dist = dist;
}
inline void VPlane::Init(const Vector &vNormal, vec_t dist)
{
m_Normal = vNormal;
m_Dist = dist;
}
inline vec_t VPlane::DistTo(const Vector &vVec) const
{
return vVec.Dot(m_Normal) - m_Dist;
}
inline VPlane& VPlane::operator=(const VPlane &thePlane)
{
m_Normal = thePlane.m_Normal;
m_Dist = thePlane.m_Dist;
return *this;
}
#ifndef VECTOR_NO_SLOW_OPERATIONS
inline VPlane VPlane::Flip()
{
return VPlane(-m_Normal, -m_Dist);
}
inline Vector VPlane::GetPointOnPlane() const
{
return m_Normal * m_Dist;
}
inline Vector VPlane::SnapPointToPlane(const Vector &vPoint) const
{
return vPoint - m_Normal * DistTo(vPoint);
}
#endif
inline SideType VPlane::GetPointSide(const Vector &vPoint, vec_t sideEpsilon) const
{
vec_t fDist;
fDist = DistTo(vPoint);
if(fDist >= sideEpsilon)
return SIDE_FRONT;
else if(fDist <= -sideEpsilon)
return SIDE_BACK;
else
return SIDE_ON;
}
inline SideType VPlane::GetPointSideExact(const Vector &vPoint) const
{
return DistTo(vPoint) > 0.0f ? SIDE_FRONT : SIDE_BACK;
}
// BUGBUG: This should either simply use the implementation in mathlib or cease to exist.
// mathlib implementation is much more efficient. Check to see that VPlane isn't used in
// performance critical code.
inline SideType VPlane::BoxOnPlaneSide(const Vector &vMin, const Vector &vMax) const
{
int i, firstSide, side;
TableVector vPoints[8] =
{
{ vMin.x, vMin.y, vMin.z },
{ vMin.x, vMin.y, vMax.z },
{ vMin.x, vMax.y, vMax.z },
{ vMin.x, vMax.y, vMin.z },
{ vMax.x, vMin.y, vMin.z },
{ vMax.x, vMin.y, vMax.z },
{ vMax.x, vMax.y, vMax.z },
{ vMax.x, vMax.y, vMin.z },
};
firstSide = GetPointSideExact(vPoints[0]);
for(i=1; i < 8; i++)
{
side = GetPointSideExact(vPoints[i]);
// Does the box cross the plane?
if(side != firstSide)
return SIDE_ON;
}
// Ok, they're all on the same side, return that.
return firstSide;
}
#endif // VPLANE_H
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