diff options
| author | Joe Ludwig <[email protected]> | 2013-06-26 15:22:04 -0700 |
|---|---|---|
| committer | Joe Ludwig <[email protected]> | 2013-06-26 15:22:04 -0700 |
| commit | 39ed87570bdb2f86969d4be821c94b722dc71179 (patch) | |
| tree | abc53757f75f40c80278e87650ea92808274aa59 /mp/src/game/shared/rope_helpers.cpp | |
| download | source-sdk-2013-39ed87570bdb2f86969d4be821c94b722dc71179.tar.xz source-sdk-2013-39ed87570bdb2f86969d4be821c94b722dc71179.zip | |
First version of the SOurce SDK 2013
Diffstat (limited to 'mp/src/game/shared/rope_helpers.cpp')
| -rw-r--r-- | mp/src/game/shared/rope_helpers.cpp | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/mp/src/game/shared/rope_helpers.cpp b/mp/src/game/shared/rope_helpers.cpp new file mode 100644 index 00000000..4150a74f --- /dev/null +++ b/mp/src/game/shared/rope_helpers.cpp @@ -0,0 +1,140 @@ +//========= 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;
+}
+
+
|