mirror of
https://github.com/nillerusr/source-engine.git
synced 2024-12-23 06:36:54 +00:00
141 lines
3.2 KiB
C++
141 lines
3.2 KiB
C++
//========= Copyright Valve Corporation, All rights reserved. ============//
|
|
//
|
|
// Purpose:
|
|
//
|
|
// $NoKeywords: $
|
|
//=============================================================================//
|
|
|
|
#include "cbase.h"
|
|
#include "rope_helpers.h"
|
|
#include "basetypes.h"
|
|
#include "mathlib/mathlib.h"
|
|
#include "rope_shared.h"
|
|
#include "rope_physics.h"
|
|
#include "networkvar.h"
|
|
|
|
// memdbgon must be the last include file in a .cpp file!!!
|
|
#include "tier0/memdbgon.h"
|
|
|
|
class CHangRope : public CRopePhysics<512>
|
|
{
|
|
DECLARE_CLASS( CHangRope, CRopePhysics<512> );
|
|
|
|
// CRopePhysics overrides.
|
|
public:
|
|
|
|
virtual void GetNodeForces( CSimplePhysics::CNode *pNodes, int iNode, Vector *pAccel )
|
|
{
|
|
pAccel->Init( ROPE_GRAVITY );
|
|
}
|
|
|
|
|
|
virtual void ApplyConstraints( CSimplePhysics::CNode *pNodes, int nNodes )
|
|
{
|
|
// Apply spring forces.
|
|
BaseClass::ApplyConstraints( pNodes, nNodes );
|
|
|
|
|
|
// Lock the endpoints.
|
|
pNodes[0].m_vPos = m_vEndPoints[0];
|
|
pNodes[nNodes-1].m_vPos = m_vEndPoints[1];
|
|
|
|
|
|
// Calculate how far it is hanging down and adjust if necessary.
|
|
float flCurHangDist = 0;
|
|
for ( int i=0; i < NumNodes(); i++ )
|
|
{
|
|
float hang = fabs( m_flStartZ - GetNode(i)->m_vPos.z );
|
|
if ( hang > flCurHangDist )
|
|
flCurHangDist = hang;
|
|
}
|
|
|
|
// Adjust our spring length accordingly.
|
|
if ( flCurHangDist < m_flWantedHangDist )
|
|
m_flCurSlack += 1;
|
|
else
|
|
m_flCurSlack -= 1;
|
|
|
|
ApplyNewSpringLength();
|
|
}
|
|
|
|
|
|
// Helpers.
|
|
public:
|
|
|
|
void ApplyNewSpringLength()
|
|
{
|
|
ResetSpringLength( (m_flRopeLength + m_flCurSlack + ROPESLACK_FUDGEFACTOR) / (NumNodes() - 1) );
|
|
}
|
|
|
|
|
|
// Variables used to adjust the rope slack.
|
|
public:
|
|
|
|
Vector m_vEndPoints[2];
|
|
bool m_bAdjustSlack;
|
|
|
|
float m_flRopeLength;
|
|
float m_flCurSlack;
|
|
|
|
float m_flWantedHangDist;
|
|
float m_flStartZ;
|
|
|
|
};
|
|
|
|
|
|
|
|
void CalcRopeStartingConditions(
|
|
const Vector &vStartPos,
|
|
const Vector &vEndPos,
|
|
int const nNodes,
|
|
float const desiredHang,
|
|
float *pOutputLength,
|
|
float *pOutputSlack
|
|
)
|
|
{
|
|
CHangRope rope;
|
|
|
|
// Initialize the rope as a straight line with no slack as our first approximation.
|
|
// We then relax the rope by adding slack until it hangs to the desired height.
|
|
//
|
|
// The spring length equation is:
|
|
// springLength = (ropeLength + slack + ROPESLACK_FUDGEFACTOR) / (nNodes - 1)
|
|
//
|
|
// We want our rope to be a straight line, so:
|
|
// springLength = ropeLength / (nNodes-1)
|
|
//
|
|
// Therefore our initial slack is -ROPESLACK_FUDGEFACTOR
|
|
rope.m_flCurSlack = -ROPESLACK_FUDGEFACTOR;
|
|
|
|
rope.m_vEndPoints[0] = vStartPos;
|
|
rope.m_vEndPoints[1] = vEndPos;
|
|
|
|
rope.m_flRopeLength = (vEndPos - vStartPos).Length();
|
|
rope.m_flWantedHangDist = desiredHang;
|
|
|
|
rope.m_flStartZ = MIN( vStartPos.z, vEndPos.z ); // Calculate hang as the Z distance from the
|
|
// lowest endpoint to the bottom of the rope.
|
|
|
|
rope.SetNumNodes( nNodes );
|
|
|
|
// Set the node positions.
|
|
for ( int i=0; i < rope.NumNodes(); i++ )
|
|
{
|
|
CSimplePhysics::CNode *pNode = rope.GetNode( i );
|
|
|
|
float t = (float)i / (rope.NumNodes() - 1);
|
|
VectorLerp( vStartPos, vEndPos, t, pNode->m_vPos );
|
|
pNode->m_vPrevPos = pNode->m_vPos;
|
|
}
|
|
|
|
// Now simulate a little and stretch out to let it hang down.
|
|
rope.Restart();
|
|
rope.Simulate( 3 );
|
|
|
|
// Set outputs.
|
|
*pOutputLength = rope.m_flRopeLength;
|
|
*pOutputSlack = rope.m_flCurSlack;
|
|
}
|
|
|
|
|