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| 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/public/rope_physics.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/public/rope_physics.cpp')
| -rw-r--r-- | mp/src/public/rope_physics.cpp | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/mp/src/public/rope_physics.cpp b/mp/src/public/rope_physics.cpp new file mode 100644 index 00000000..fb4204a0 --- /dev/null +++ b/mp/src/public/rope_physics.cpp @@ -0,0 +1,152 @@ +//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose:
+//
+// $NoKeywords: $
+//
+//=============================================================================//
+
+
+#include "rope_physics.h"
+#include "tier0/dbg.h"
+
+// memdbgon must be the last include file in a .cpp file!!!
+#include "tier0/memdbgon.h"
+
+CBaseRopePhysics::CBaseRopePhysics( CSimplePhysics::CNode *pNodes, int nNodes, CRopeSpring *pSprings, float *flSpringDistsSqr )
+{
+ m_pNodes = pNodes;
+ m_pSprings = pSprings;
+ m_flNodeSpringDistsSqr = flSpringDistsSqr;
+ m_flSpringDist = m_flSpringDistSqr = 1;
+ Restart();
+
+ // Initialize the nodes.
+ for ( int i=0; i < nNodes; i++ )
+ {
+ pNodes[i].m_vPos.Init();
+ pNodes[i].m_vPrevPos.Init();
+ pNodes[i].m_vPredicted.Init();
+ }
+
+ SetNumNodes( nNodes );
+
+ m_pDelegate = NULL;
+}
+
+
+void CBaseRopePhysics::SetNumNodes( int nNodes )
+{
+ m_nNodes = nNodes;
+
+ // Setup the springs.
+ for( int i=0; i < NumSprings(); i++ )
+ {
+ m_pSprings[i].m_pNode1 = &m_pNodes[i].m_vPos;
+ m_pSprings[i].m_pNode2 = &m_pNodes[i+1].m_vPos;
+ Assert( m_pSprings[i].m_pNode1->IsValid() );
+ Assert( m_pSprings[i].m_pNode2->IsValid() );
+
+ m_flNodeSpringDistsSqr[i] = m_flSpringDistSqr / NumSprings();
+ }
+}
+
+
+void CBaseRopePhysics::Restart()
+{
+ m_Physics.Init( 1.0 / 50 );
+}
+
+
+void CBaseRopePhysics::ResetSpringLength( float flSpringDist )
+{
+ m_flSpringDist = max( flSpringDist, 0 );
+ m_flSpringDistSqr = m_flSpringDist * m_flSpringDist;
+
+ for( int i=0; i < NumSprings(); i++ )
+ {
+ m_flNodeSpringDistsSqr[i] = m_flSpringDistSqr / NumSprings();
+ }
+}
+
+float CBaseRopePhysics::GetSpringLength() const
+{
+ return m_flSpringDist;
+}
+
+void CBaseRopePhysics::ResetNodeSpringLength( int iStartNode, float flSpringDist )
+{
+ m_flNodeSpringDistsSqr[iStartNode] = flSpringDist * flSpringDist;
+}
+
+void CBaseRopePhysics::SetupSimulation( float flSpringDist, CSimplePhysics::IHelper *pDelegate )
+{
+ ResetSpringLength( flSpringDist );
+ SetDelegate( pDelegate );
+}
+
+
+void CBaseRopePhysics::SetDelegate( CSimplePhysics::IHelper *pDelegate )
+{
+ m_pDelegate = pDelegate;
+}
+
+
+void CBaseRopePhysics::Simulate( float dt )
+{
+ static float flEnergy = 0.98;
+ m_Physics.Simulate( m_pNodes, m_nNodes, this, dt, flEnergy );
+}
+
+
+void CBaseRopePhysics::GetNodeForces( CSimplePhysics::CNode *pNodes, int iNode, Vector *pAccel )
+{
+ if( m_pDelegate )
+ m_pDelegate->GetNodeForces( pNodes, iNode, pAccel );
+ else
+ pAccel->Init( 0, 0, 0 );
+}
+
+
+void CBaseRopePhysics::ApplyConstraints( CSimplePhysics::CNode *pNodes, int nNodes )
+{
+ // Handle springs..
+ //
+ // Iterate multiple times here. If we don't, then gravity tends to
+ // win over the constraint solver and it's impossible to get straight ropes.
+ static int nIterations = 3;
+ for( int iIteration=0; iIteration < nIterations; iIteration++ )
+ {
+ for( int i=0; i < NumSprings(); i++ )
+ {
+ CRopeSpring *s = &m_pSprings[i];
+
+ Vector vTo = *s->m_pNode1 - *s->m_pNode2;
+
+ float flDistSqr = vTo.LengthSqr();
+
+ // If we don't have an overall spring distance, see if we have a per-node one
+ float flSpringDist = m_flSpringDistSqr;
+ if ( !flSpringDist )
+ {
+ // TODO: This still isn't enough. Ropes with different spring lengths
+ // per-node will oscillate forever.
+ flSpringDist = m_flNodeSpringDistsSqr[i];
+ }
+
+ if( flDistSqr > flSpringDist )
+ {
+ float flDist = (float)sqrt( flDistSqr );
+ vTo *= 1 - (m_flSpringDist / flDist);
+
+ *s->m_pNode1 -= vTo * 0.5f;
+ *s->m_pNode2 += vTo * 0.5f;
+ }
+ }
+
+ if( m_pDelegate )
+ m_pDelegate->ApplyConstraints( pNodes, nNodes );
+ }
+}
+
+
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