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