manifold points now store the total normal impulse instead of the max…

…imum

include/box2d/collision.h

@@ -382,10 +382,9 @@ typedef struct b2DistanceInput
 /// Output for b2ShapeDistance
 typedef struct b2DistanceOutput
 {
-	b2Vec2 pointA; ///< Closest point on shapeA
-	b2Vec2 pointB; ///< Closest point on shapeB
-	// todo_erin implement this
-	// b2Vec2 normal;			///< Normal vector that points from A to B
+	b2Vec2 pointA;	  ///< Closest point on shapeA
+	b2Vec2 pointB;	  ///< Closest point on shapeB
+	b2Vec2 normal;	  ///< Normal vector that points from A to B
 	float distance;	  ///< The final distance, zero if overlapped
 	int iterations;	  ///< Number of GJK iterations used
 	int simplexCount; ///< The number of simplexes stored in the simplex array
@@ -491,7 +490,7 @@ B2_API b2TOIOutput b2TimeOfImpact( const b2TOIInput* input );
 /// A manifold point is a contact point belonging to a contact manifold.
 /// It holds details related to the geometry and dynamics of the contact points.
 /// Box2D uses speculative collision so some contact points may be separated.
-/// You may use the maxNormalImpulse to determine if there was an interaction during
+/// You may use the totalNormalImpulse to determine if there was an interaction during
 /// the time step.
 typedef struct b2ManifoldPoint
 {
@@ -516,9 +515,9 @@ typedef struct b2ManifoldPoint
 	/// The friction impulse
 	float tangentImpulse;
 
-	/// The maximum normal impulse applied during sub-stepping. This is important
+	/// The total normal impulse applied across sub-stepping and restitution. This is important
 	/// to identify speculative contact points that had an interaction in the time step.
-	float maxNormalImpulse;
+	float totalNormalImpulse;
 
 	/// Relative normal velocity pre-solve. Used for hit events. If the normal impulse is
 	/// zero then there was no hit. Negative means shapes are approaching.

samples/sample_collision.cpp

@@ -1229,7 +1229,7 @@ struct ShapeUserData
 };
 
 // Context for ray cast callbacks. Do what you want with this.
-struct RayCastContext
+struct CastContext
 {
 	b2Vec2 points[3];
 	b2Vec2 normals[3];
@@ -1240,7 +1240,7 @@ struct RayCastContext
 // This callback finds the closest hit. This is the most common callback used in games.
 static float RayCastClosestCallback( b2ShapeId shapeId, b2Vec2 point, b2Vec2 normal, float fraction, void* context )
 {
-	RayCastContext* rayContext = (RayCastContext*)context;
+	CastContext* rayContext = (CastContext*)context;
 
 	ShapeUserData* userData = (ShapeUserData*)b2Shape_GetUserData( shapeId );
 	if ( userData != nullptr && userData->ignore )
@@ -1266,7 +1266,7 @@ static float RayCastClosestCallback( b2ShapeId shapeId, b2Vec2 point, b2Vec2 nor
 // NOTE: shape hits are not ordered, so this may not return the closest hit
 static float RayCastAnyCallback( b2ShapeId shapeId, b2Vec2 point, b2Vec2 normal, float fraction, void* context )
 {
-	RayCastContext* rayContext = (RayCastContext*)context;
+	CastContext* rayContext = (CastContext*)context;
 
 	ShapeUserData* userData = (ShapeUserData*)b2Shape_GetUserData( shapeId );
 	if ( userData != nullptr && userData->ignore )
@@ -1294,7 +1294,7 @@ static float RayCastAnyCallback( b2ShapeId shapeId, b2Vec2 point, b2Vec2 normal,
 // behavior in the sample.
 static float RayCastMultipleCallback( b2ShapeId shapeId, b2Vec2 point, b2Vec2 normal, float fraction, void* context )
 {
-	RayCastContext* rayContext = (RayCastContext*)context;
+	CastContext* rayContext = (CastContext*)context;
 
 	ShapeUserData* userData = (ShapeUserData*)b2Shape_GetUserData( shapeId );
 	if ( userData != nullptr && userData->ignore )
@@ -1326,7 +1326,7 @@ static float RayCastMultipleCallback( b2ShapeId shapeId, b2Vec2 point, b2Vec2 no
 // This ray cast collects multiple hits along the ray and sorts them.
 static float RayCastSortedCallback( b2ShapeId shapeId, b2Vec2 point, b2Vec2 normal, float fraction, void* context )
 {
-	RayCastContext* rayContext = (RayCastContext*)context;
+	CastContext* rayContext = (CastContext*)context;
 
 	ShapeUserData* userData = (ShapeUserData*)b2Shape_GetUserData( shapeId );
 	if ( userData != nullptr && userData->ignore )
@@ -1380,7 +1380,7 @@ static float RayCastSortedCallback( b2ShapeId shapeId, b2Vec2 point, b2Vec2 norm
 	return 1.0f;
 }
 
-class RayCastWorld : public Sample
+class CastWorld : public Sample
 {
 public:
 	enum Mode
@@ -1404,7 +1404,7 @@ class RayCastWorld : public Sample
 		e_maxCount = 64
 	};
 
-	explicit RayCastWorld( Settings& settings )
+	explicit CastWorld( Settings& settings )
 		: Sample( settings )
 	{
 		if ( settings.restart == false )
@@ -1602,7 +1602,7 @@ class RayCastWorld : public Sample
 
 	void UpdateGui() override
 	{
-		float height = 300.0f;
+		float height = 320.0f;
 		ImGui::SetNextWindowPos( ImVec2( 10.0f, g_camera.m_height - height - 50.0f ), ImGuiCond_Once );
 		ImGui::SetNextWindowSize( ImVec2( 200.0f, height ) );
 
@@ -1739,6 +1739,10 @@ class RayCastWorld : public Sample
 				case e_sorted:
 					g_draw.DrawString( 5, m_textLine, "Cast mode: sorted - gather up to 3 shapes sorted by closeness" );
 					break;
+
+				default:
+					assert( false );
+					break;
 			}
 
 			m_textLine += m_textIncrement;
@@ -1747,7 +1751,7 @@ class RayCastWorld : public Sample
 										RayCastSortedCallback };
 			b2CastResultFcn* modeFcn = fcns[m_mode];
 
-			RayCastContext context = { };
+			CastContext context = { };
 
 			// Must initialize fractions for sorting
 			context.fractions[0] = FLT_MAX;
@@ -1847,7 +1851,7 @@ class RayCastWorld : public Sample
 
 	static Sample* Create( Settings& settings )
 	{
-		return new RayCastWorld( settings );
+		return new CastWorld( settings );
 	}
 
 	int m_bodyIndex;
@@ -1876,7 +1880,7 @@ class RayCastWorld : public Sample
 	bool m_dragging;
 };
 
-static int sampleRayCastWorld = RegisterSample( "Collision", "Ray Cast World", RayCastWorld::Create );
+static int sampleRayCastWorld = RegisterSample( "Collision", "Ray Cast World", CastWorld::Create );
 
 class OverlapWorld : public Sample
 {

samples/sample_events.cpp

@@ -1016,7 +1016,7 @@ class ContactEvent : public Sample
 						for ( int k = 0; k < manifold.pointCount; ++k )
 						{
 							b2ManifoldPoint point = manifold.points[k];
-							g_draw.DrawSegment( point.point, point.point + point.maxNormalImpulse * normal, b2_colorBlueViolet );
+							g_draw.DrawSegment( point.point, point.point + point.totalNormalImpulse * normal, b2_colorBlueViolet );
 							g_draw.DrawPoint( point.point, 10.0f, b2_colorWhite );
 						}
 					}
@@ -1046,7 +1046,7 @@ class ContactEvent : public Sample
 						for ( int k = 0; k < manifold.pointCount; ++k )
 						{
 							b2ManifoldPoint point = manifold.points[k];
-							g_draw.DrawSegment( point.point, point.point + point.maxNormalImpulse * normal, b2_colorYellowGreen );
+							g_draw.DrawSegment( point.point, point.point + point.totalNormalImpulse * normal, b2_colorYellowGreen );
 							g_draw.DrawPoint( point.point, 10.0f, b2_colorWhite );
 						}
 					}

src/contact.c

@@ -569,7 +569,7 @@ bool b2UpdateContact( b2World* world, b2ContactSim* contactSim, b2Shape* shapeA,
 
 		mp2->normalImpulse = 0.0f;
 		mp2->tangentImpulse = 0.0f;
-		mp2->maxNormalImpulse = 0.0f;
+		mp2->totalNormalImpulse = 0.0f;
 		mp2->normalVelocity = 0.0f;
 		mp2->persisted = false;
 

src/contact_solver.c

@@ -128,7 +128,7 @@ void b2PrepareOverflowContacts( b2StepContext* context )
 
 			cp->normalImpulse = warmStartScale * mp->normalImpulse;
 			cp->tangentImpulse = warmStartScale * mp->tangentImpulse;
-			cp->maxNormalImpulse = 0.0f;
+			cp->totalNormalImpulse = 0.0f;
 
 			b2Vec2 rA = mp->anchorA;
 			b2Vec2 rB = mp->anchorB;
@@ -311,7 +311,7 @@ void b2SolveOverflowContacts( b2StepContext* context, bool useBias )
 			float newImpulse = b2MaxFloat( cp->normalImpulse + impulse, 0.0f );
 			impulse = newImpulse - cp->normalImpulse;
 			cp->normalImpulse = newImpulse;
-			cp->maxNormalImpulse = b2MaxFloat( cp->maxNormalImpulse, impulse );
+			cp->totalNormalImpulse += newImpulse;
 			totalNormalImpulse += newImpulse;
 
 			// apply normal impulse
@@ -433,7 +433,7 @@ void b2ApplyOverflowRestitution( b2StepContext* context )
 				// if the normal impulse is zero then there was no collision
 				// this skips speculative contact points that didn't generate an impulse
 				// The max normal impulse is used in case there was a collision that moved away within the sub-step process
-				if ( cp->relativeVelocity > -threshold || cp->maxNormalImpulse == 0.0f )
+				if ( cp->relativeVelocity > -threshold || cp->totalNormalImpulse == 0.0f )
 				{
 					continue;
 				}
@@ -455,7 +455,7 @@ void b2ApplyOverflowRestitution( b2StepContext* context )
 				float newImpulse = b2MaxFloat( cp->normalImpulse + impulse, 0.0f );
 				impulse = newImpulse - cp->normalImpulse;
 				cp->normalImpulse = newImpulse;
-				cp->maxNormalImpulse = b2MaxFloat( cp->maxNormalImpulse, impulse );
+				cp->totalNormalImpulse += impulse;
 
 				// apply contact impulse
 				b2Vec2 P = b2MulSV( impulse, normal );
@@ -485,8 +485,6 @@ void b2StoreOverflowImpulses( b2StepContext* context )
 	b2ContactSim* contacts = color->contactSims.data;
 	int contactCount = color->contactSims.count;
 
-	// float hitEventThreshold = context->world->hitEventThreshold;
-
 	for ( int i = 0; i < contactCount; ++i )
 	{
 		const b2ContactConstraint* constraint = constraints + i;
@@ -498,7 +496,7 @@ void b2StoreOverflowImpulses( b2StepContext* context )
 		{
 			manifold->points[j].normalImpulse = constraint->points[j].normalImpulse;
 			manifold->points[j].tangentImpulse = constraint->points[j].tangentImpulse;
-			manifold->points[j].maxNormalImpulse = constraint->points[j].maxNormalImpulse;
+			manifold->points[j].totalNormalImpulse = constraint->points[j].totalNormalImpulse;
 			manifold->points[j].normalVelocity = constraint->points[j].relativeVelocity;
 		}
 
@@ -1001,12 +999,12 @@ typedef struct b2ContactConstraintSIMD
 	b2FloatW normalMass1, tangentMass1;
 	b2FloatW baseSeparation1;
 	b2FloatW normalImpulse1;
-	b2FloatW maxNormalImpulse1;
+	b2FloatW totalNormalImpulse1;
 	b2FloatW tangentImpulse1;
 	b2Vec2W anchorA2, anchorB2;
 	b2FloatW baseSeparation2;
 	b2FloatW normalImpulse2;
-	b2FloatW maxNormalImpulse2;
+	b2FloatW totalNormalImpulse2;
 	b2FloatW tangentImpulse2;
 	b2FloatW normalMass2, tangentMass2;
 	b2FloatW restitution;
@@ -1492,7 +1490,7 @@ void b2PrepareContactsTask( int startIndex, int endIndex, b2StepContext* context
 
 					( (float*)&constraint->normalImpulse1 )[j] = warmStartScale * mp->normalImpulse;
 					( (float*)&constraint->tangentImpulse1 )[j] = warmStartScale * mp->tangentImpulse;
-					( (float*)&constraint->maxNormalImpulse1 )[j] = 0.0f;
+					( (float*)&constraint->totalNormalImpulse1 )[j] = 0.0f;
 
 					float rnA = b2Cross( rA, normal );
 					float rnB = b2Cross( rB, normal );
@@ -1529,7 +1527,7 @@ void b2PrepareContactsTask( int startIndex, int endIndex, b2StepContext* context
 
 					( (float*)&constraint->normalImpulse2 )[j] = warmStartScale * mp->normalImpulse;
 					( (float*)&constraint->tangentImpulse2 )[j] = warmStartScale * mp->tangentImpulse;
-					( (float*)&constraint->maxNormalImpulse2 )[j] = 0.0f;
+					( (float*)&constraint->totalNormalImpulse2 )[j] = 0.0f;
 
 					float rnA = b2Cross( rA, normal );
 					float rnB = b2Cross( rB, normal );
@@ -1552,7 +1550,7 @@ void b2PrepareContactsTask( int startIndex, int endIndex, b2StepContext* context
 					( (float*)&constraint->baseSeparation2 )[j] = 0.0f;
 					( (float*)&constraint->normalImpulse2 )[j] = 0.0f;
 					( (float*)&constraint->tangentImpulse2 )[j] = 0.0f;
-					( (float*)&constraint->maxNormalImpulse2 )[j] = 0.0f;
+					( (float*)&constraint->totalNormalImpulse2 )[j] = 0.0f;
 					( (float*)&constraint->anchorA2.X )[j] = 0.0f;
 					( (float*)&constraint->anchorA2.Y )[j] = 0.0f;
 					( (float*)&constraint->anchorB2.X )[j] = 0.0f;
@@ -1591,7 +1589,7 @@ void b2PrepareContactsTask( int startIndex, int endIndex, b2StepContext* context
 				( (float*)&constraint->baseSeparation1 )[j] = 0.0f;
 				( (float*)&constraint->normalImpulse1 )[j] = 0.0f;
 				( (float*)&constraint->tangentImpulse1 )[j] = 0.0f;
-				( (float*)&constraint->maxNormalImpulse1 )[j] = 0.0f;
+				( (float*)&constraint->totalNormalImpulse1 )[j] = 0.0f;
 				( (float*)&constraint->normalMass1 )[j] = 0.0f;
 				( (float*)&constraint->tangentMass1 )[j] = 0.0f;
 
@@ -1602,7 +1600,7 @@ void b2PrepareContactsTask( int startIndex, int endIndex, b2StepContext* context
 				( (float*)&constraint->baseSeparation2 )[j] = 0.0f;
 				( (float*)&constraint->normalImpulse2 )[j] = 0.0f;
 				( (float*)&constraint->tangentImpulse2 )[j] = 0.0f;
-				( (float*)&constraint->maxNormalImpulse2 )[j] = 0.0f;
+				( (float*)&constraint->totalNormalImpulse2 )[j] = 0.0f;
 				( (float*)&constraint->normalMass2 )[j] = 0.0f;
 				( (float*)&constraint->tangentMass2 )[j] = 0.0f;
 
@@ -1749,7 +1747,7 @@ void b2SolveContactsTask( int startIndex, int endIndex, b2StepContext* context,
 			b2FloatW newImpulse = b2MaxW( b2SubW( c->normalImpulse1, negImpulse ), b2ZeroW() );
 			b2FloatW impulse = b2SubW( newImpulse, c->normalImpulse1 );
 			c->normalImpulse1 = newImpulse;
-			c->maxNormalImpulse1 = b2MaxW( c->maxNormalImpulse1, newImpulse );
+			c->totalNormalImpulse1 = b2AddW( c->totalNormalImpulse1, newImpulse );
 
 			totalNormalImpulse = b2AddW( totalNormalImpulse, newImpulse );
 
@@ -1801,7 +1799,7 @@ void b2SolveContactsTask( int startIndex, int endIndex, b2StepContext* context,
 			b2FloatW newImpulse = b2MaxW( b2SubW( c->normalImpulse2, negImpulse ), b2ZeroW() );
 			b2FloatW impulse = b2SubW( newImpulse, c->normalImpulse2 );
 			c->normalImpulse2 = newImpulse;
-			c->maxNormalImpulse2 = b2MaxW( c->maxNormalImpulse2, newImpulse );
+			c->totalNormalImpulse2 = b2AddW( c->totalNormalImpulse2, newImpulse );
 
 			totalNormalImpulse = b2AddW( totalNormalImpulse, newImpulse );
 
@@ -1934,7 +1932,7 @@ void b2ApplyRestitutionTask( int startIndex, int endIndex, b2StepContext* contex
 		{
 			// Set effective mass to zero if restitution should not be applied
 			b2FloatW mask1 = b2GreaterThanW( b2AddW( c->relativeVelocity1, threshold ), zero );
-			b2FloatW mask2 = b2EqualsW( c->maxNormalImpulse1, zero );
+			b2FloatW mask2 = b2EqualsW( c->totalNormalImpulse1, zero );
 			b2FloatW mask = b2OrW( mask1, mask2 );
 			b2FloatW mass = b2BlendW( c->normalMass1, zero, mask );
 
@@ -1972,7 +1970,7 @@ void b2ApplyRestitutionTask( int startIndex, int endIndex, b2StepContext* contex
 		{
 			// Set effective mass to zero if restitution should not be applied
 			b2FloatW mask1 = b2GreaterThanW( b2AddW( c->relativeVelocity2, threshold ), zero );
-			b2FloatW mask2 = b2EqualsW( c->maxNormalImpulse2, zero );
+			b2FloatW mask2 = b2EqualsW( c->totalNormalImpulse2, zero );
 			b2FloatW mask = b2OrW( mask1, mask2 );
 			b2FloatW mass = b2BlendW( c->normalMass2, zero, mask );
 
@@ -2030,8 +2028,8 @@ void b2StoreImpulsesTask( int startIndex, int endIndex, b2StepContext* context )
 		const float* normalImpulse2 = (float*)&c->normalImpulse2;
 		const float* tangentImpulse1 = (float*)&c->tangentImpulse1;
 		const float* tangentImpulse2 = (float*)&c->tangentImpulse2;
-		const float* maxNormalImpulse1 = (float*)&c->maxNormalImpulse1;
-		const float* maxNormalImpulse2 = (float*)&c->maxNormalImpulse2;
+		const float* totalNormalImpulse1 = (float*)&c->totalNormalImpulse1;
+		const float* totalNormalImpulse2 = (float*)&c->totalNormalImpulse2;
 		const float* normalVelocity1 = (float*)&c->relativeVelocity1;
 		const float* normalVelocity2 = (float*)&c->relativeVelocity2;
 
@@ -2044,12 +2042,12 @@ void b2StoreImpulsesTask( int startIndex, int endIndex, b2StepContext* context )
 
 			m->points[0].normalImpulse = normalImpulse1[laneIndex];
 			m->points[0].tangentImpulse = tangentImpulse1[laneIndex];
-			m->points[0].maxNormalImpulse = maxNormalImpulse1[laneIndex];
+			m->points[0].totalNormalImpulse = totalNormalImpulse1[laneIndex];
 			m->points[0].normalVelocity = normalVelocity1[laneIndex];
 
 			m->points[1].normalImpulse = normalImpulse2[laneIndex];
 			m->points[1].tangentImpulse = tangentImpulse2[laneIndex];
-			m->points[1].maxNormalImpulse = maxNormalImpulse2[laneIndex];
+			m->points[1].totalNormalImpulse = totalNormalImpulse2[laneIndex];
 			m->points[1].normalVelocity = normalVelocity2[laneIndex];
 		}
 	}

src/contact_solver.h

@@ -14,7 +14,7 @@ typedef struct b2ContactConstraintPoint
 	float relativeVelocity;
 	float normalImpulse;
 	float tangentImpulse;
-	float maxNormalImpulse;
+	float totalNormalImpulse;
 	float normalMass;
 	float tangentMass;
 } b2ContactConstraintPoint;