From 4933267f33d55c6750d9b6a3aff307d9aafe972d Mon Sep 17 00:00:00 2001
From: Sebastian Eibl <sebastian.eibl@fau.de>
Date: Fri, 8 Dec 2017 16:56:04 +0100
Subject: [PATCH] coarse collision returns colliding bodies in deterministic
order
---
src/pe/ccd/HashGrids.h | 4 ++++
src/pe/ccd/SimpleCCD.cpp | 20 ++++++++++++++++----
tests/pe/HashGrids.cpp | 9 ++++++++-
3 files changed, 28 insertions(+), 5 deletions(-)
diff --git a/src/pe/ccd/HashGrids.h b/src/pe/ccd/HashGrids.h
index 060be9447..18871eff3 100644
--- a/src/pe/ccd/HashGrids.h
+++ b/src/pe/ccd/HashGrids.h
@@ -492,6 +492,10 @@ void HashGrids::HashGrid::processBodies( BodyID* bodies, size_t bodyCount, Conta
template< typename Contacts > // Contact container type
void HashGrids::collide( BodyID a, BodyID b, Contacts& contacts )
{
+ //make sure to always check in the correct order (a<b)
+ if (a->getSystemID() > b->getSystemID())
+ std::swap(a, b);
+
if( ( !a->hasInfiniteMass() || !b->hasInfiniteMass() ) && // Ignoring contacts between two fixed bodies
( a->getAABB().intersects( b->getAABB() ) ) ) // Testing for overlapping bounding boxes
{
diff --git a/src/pe/ccd/SimpleCCD.cpp b/src/pe/ccd/SimpleCCD.cpp
index b94a6669b..dee87d16b 100644
--- a/src/pe/ccd/SimpleCCD.cpp
+++ b/src/pe/ccd/SimpleCCD.cpp
@@ -57,14 +57,26 @@ PossibleContacts& SimpleCCD::generatePossibleContacts( WcTimingTree* tt ){
if (tt != NULL) tt->start("SimpleCCD");
for (auto it1 = bodies_.begin(); it1 != bodies_.end(); ++it1){
- for (auto it2 = it1 + 1; it2 !=bodies_.end(); ++it2){
+ for (auto it2 = it1 + 1; it2 !=bodies_.end(); ++it2)
+ {
if (!((*it1)->hasInfiniteMass() && (*it2)->hasInfiniteMass()))
- contacts_.push_back(std::make_pair(*it1, *it2));
+ {
+ if ( (*it1)->getSystemID() > (*it2)->getSystemID() )
+ contacts_.push_back(std::make_pair(*it2, *it1));
+ else
+ contacts_.push_back(std::make_pair(*it1, *it2));
+ }
}
- for (auto it2 = globalStorage_.begin(); it2 != globalStorage_.end(); ++it2){
+ for (auto it2 = globalStorage_.begin(); it2 != globalStorage_.end(); ++it2)
+ {
if (!((*it1)->hasInfiniteMass() && (*it2)->hasInfiniteMass()))
- contacts_.push_back(std::make_pair(*it1, *it2));
+ {
+ if ( (*it1)->getSystemID() > (*it2)->getSystemID() )
+ contacts_.push_back(std::make_pair(*it2, *it1));
+ else
+ contacts_.push_back(std::make_pair(*it1, *it2));
+ }
}
}
if (tt != NULL) tt->stop("SimpleCCD");
diff --git a/tests/pe/HashGrids.cpp b/tests/pe/HashGrids.cpp
index cc48c5b03..a1790653b 100644
--- a/tests/pe/HashGrids.cpp
+++ b/tests/pe/HashGrids.cpp
@@ -115,7 +115,7 @@ int main( int argc, char** argv )
iron, true, false, true);
syncShadowOwners<BodyTuple>( forest->getBlockForest(), storageID);
- for (int i=0; i < 100; ++i){
+ for (int step=0; step < 100; ++step){
cr( real_c(0.1) );
syncShadowOwners<BodyTuple>( forest->getBlockForest(), storageID);
@@ -132,6 +132,13 @@ int main( int argc, char** argv )
WALBERLA_LOG_DETAIL_ON_ROOT("tracked particles: " << sccd->getObservedBodyCount() << "/" << hccd->getObservedBodyCount());
WALBERLA_CHECK_EQUAL(tmp1, tmp2);
WALBERLA_LOG_DETAIL_ON_ROOT("contacts on root: " << cont1.size());
+
+ // check for correct ordering of bodies within contacts
+ for (size_t i = 0; i < cont1.size(); ++i)
+ {
+ WALBERLA_CHECK_LESS(cont1[i].getBody1()->getSystemID(), cont1[i].getBody2()->getSystemID());
+ WALBERLA_CHECK_LESS(cont2[i].getBody1()->getSystemID(), cont2[i].getBody2()->getSystemID());
+ }
}
}
--
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