New capsule collider

include/box2d/box2d.h

@@ -467,6 +467,9 @@ B2_API b2ShapeType b2Shape_GetType( b2ShapeId shapeId );
 /// Get the id of the body that a shape is attached to
 B2_API b2BodyId b2Shape_GetBody( b2ShapeId shapeId );
 
+/// Get the world that owns this shape
+B2_API b2WorldId b2Shape_GetWorld( b2ShapeId shapeId );
+
 /// Returns true If the shape is a sensor
 B2_API bool b2Shape_IsSensor( b2ShapeId shapeId );
 
@@ -600,6 +603,16 @@ B2_API b2ChainId b2CreateChain( b2BodyId bodyId, const b2ChainDef* def );
 /// Destroy a chain shape
 B2_API void b2DestroyChain( b2ChainId chainId );
 
+/// Get the world that owns this chain shape
+B2_API b2WorldId b2Chain_GetWorld( b2ChainId chainId );
+
+/// Get the number of segments on this chain
+B2_API int b2Chain_GetSegmentCount( b2ChainId chainId );
+
+/// Fill a user array with chain segment shape ids up to the specified capacity. Returns
+///	the actual number of segments returned.
+B2_API int b2Chain_GetSegments( b2ChainId chainId, b2ShapeId* segmentArray, int capacity );
+
 /// Set the chain friction
 /// @see b2ChainDef::friction
 B2_API void b2Chain_SetFriction( b2ChainId chainId, float friction );
@@ -634,6 +647,9 @@ B2_API b2BodyId b2Joint_GetBodyA( b2JointId jointId );
 /// Get body B id on a joint
 B2_API b2BodyId b2Joint_GetBodyB( b2JointId jointId );
 
+/// Get the world that owns this joint
+B2_API b2WorldId b2Joint_GetWorld( b2JointId jointId );
+
 /// Get the local anchor on bodyA
 B2_API b2Vec2 b2Joint_GetLocalAnchorA( b2JointId jointId );
 

include/box2d/collision.h

@@ -183,15 +183,25 @@ B2_API b2Polygon b2MakePolygon( const b2Hull* hull, float radius );
 B2_API b2Polygon b2MakeOffsetPolygon( const b2Hull* hull, float radius, b2Transform transform );
 
 /// Make a square polygon, bypassing the need for a convex hull.
+/// @param h the half-width
 B2_API b2Polygon b2MakeSquare( float h );
 
 /// Make a box (rectangle) polygon, bypassing the need for a convex hull.
+/// @param hx the half-width
+/// @param hy the half-height
 B2_API b2Polygon b2MakeBox( float hx, float hy );
 
 /// Make a rounded box, bypassing the need for a convex hull.
+/// @param hx the half-width
+/// @param hy the half-height
+/// @param radius the radius of the rounded extension
 B2_API b2Polygon b2MakeRoundedBox( float hx, float hy, float radius );
 
 /// Make an offset box, bypassing the need for a convex hull.
+/// @param hx the half-width
+/// @param hy the half-height
+/// @param center the local position of the center of the box
+/// @param rotation the local rotation of the box
 B2_API b2Polygon b2MakeOffsetBox( float hx, float hy, b2Vec2 center, b2Rot rotation );
 
 /// Transform a polygon. This is useful for transferring a shape from one body to another.

samples/sample_bodies.cpp

@@ -785,7 +785,7 @@ class BadBody : public Sample
 			b2BodyDef bodyDef = b2DefaultBodyDef();
 			bodyDef.type = b2_dynamicBody;
 			bodyDef.position = { 0.0f, 3.0f };
-			bodyDef.angularVelocity = 0.2f;
+			bodyDef.angularVelocity = 0.5f;
 			bodyDef.rotation = b2MakeRot( 0.25f * b2_pi );
 
 			m_badBodyId = b2CreateBody( m_worldId, &bodyDef );

samples/sample_collision.cpp

@@ -2232,6 +2232,9 @@ class Manifold : public Sample
 		m_smgcapCache2 = b2_emptyDistanceCache;
 
 		m_transform = b2Transform_identity;
+		m_transform.p.x = 1.0f;
+		m_transform.p.y = 0.0f;
+		//m_transform.q = b2MakeRot( 0.5f * b2_pi );
 		m_angle = 0.0f;
 		m_round = 0.1f;
 
@@ -2371,7 +2374,7 @@ class Manifold : public Sample
 		b2Vec2 increment = { 4.0f, 0.0f };
 
 		b2HexColor color1 = b2_colorAquamarine;
-		b2HexColor color2 = b2_colorMagenta;
+		b2HexColor color2 = b2_colorPaleGoldenrod;
 
 		if ( m_enableCaching == false )
 		{
@@ -2462,20 +2465,21 @@ class Manifold : public Sample
 
 		// capsule-capsule
 		{
-			b2Capsule capsule = { { -0.5f, 0.0f }, { 0.5f, 0.0 }, 0.25f };
+			b2Capsule capsule1 = { { -0.5f, 0.0f }, { 0.5f, 0.0 }, 0.25f };
+			b2Capsule capsule2 = { { 0.25f, 0.0f }, { 1.0f, 0.0 }, 0.1f };
 
 			b2Transform transform1 = { offset, b2Rot_identity };
 			b2Transform transform2 = { b2Add( m_transform.p, offset ), m_transform.q };
 
-			b2Manifold m = b2CollideCapsules( &capsule, transform1, &capsule, transform2 );
+			b2Manifold m = b2CollideCapsules( &capsule1, transform1, &capsule2, transform2 );
 
-			b2Vec2 v1 = b2TransformPoint( transform1, capsule.center1 );
-			b2Vec2 v2 = b2TransformPoint( transform1, capsule.center2 );
-			g_draw.DrawSolidCapsule( v1, v2, capsule.radius, color1 );
+			b2Vec2 v1 = b2TransformPoint( transform1, capsule1.center1 );
+			b2Vec2 v2 = b2TransformPoint( transform1, capsule1.center2 );
+			g_draw.DrawSolidCapsule( v1, v2, capsule1.radius, color1 );
 
-			v1 = b2TransformPoint( transform2, capsule.center1 );
-			v2 = b2TransformPoint( transform2, capsule.center2 );
-			g_draw.DrawSolidCapsule( v1, v2, capsule.radius, color2 );
+			v1 = b2TransformPoint( transform2, capsule2.center1 );
+			v2 = b2TransformPoint( transform2, capsule2.center2 );
+			g_draw.DrawSolidCapsule( v1, v2, capsule2.radius, color2 );
 
 			DrawManifold( &m, transform1.p, transform2.p );
 

samples/sample_continuous.cpp

@@ -389,6 +389,62 @@ class SkinnyBox : public Sample
 
 static int sampleSkinnyBox = RegisterSample( "Continuous", "Skinny Box", SkinnyBox::Create );
 
+class SpeculativeBug : public Sample
+{
+public:
+	explicit SpeculativeBug( Settings& settings )
+		: Sample( settings )
+	{
+		if ( settings.restart == false )
+		{
+			g_camera.m_center = { 1.0f, 5.0f };
+			g_camera.m_zoom = 25.0f * 0.25f;
+		}
+
+		{
+			b2BodyDef bodyDef = b2DefaultBodyDef();
+			b2BodyId groundId = b2CreateBody( m_worldId, &bodyDef );
+
+			b2Segment segment = { { -10.0f, 0.0f }, { 10.0f, 0.0f } };
+			b2ShapeDef shapeDef = b2DefaultShapeDef();
+			b2CreateSegmentShape( groundId, &shapeDef, &segment );
+
+			shapeDef.friction = 0.0f;
+			b2Polygon box = b2MakeOffsetBox( 0.05f, 1.0f, { 0.0f, 1.0f }, b2Rot_identity );
+			b2CreatePolygonShape( groundId, &shapeDef, &box );
+		}
+
+		b2BodyDef bodyDef = b2DefaultBodyDef();
+		bodyDef.type = b2_dynamicBody;
+		for (int i = 0; i < 2; ++i)
+		{
+			if (i == 0)
+			{
+				bodyDef.position = { -0.8f, 0.25f };
+				bodyDef.isAwake = false;
+			}
+			else
+			{
+				bodyDef.position = { 0.8f, 2.0f };
+				bodyDef.isAwake = true;
+			}
+
+			b2BodyId bodyId = b2CreateBody( m_worldId, &bodyDef );
+
+			b2ShapeDef shapeDef = b2DefaultShapeDef();
+			b2Capsule capsule = { { -0.5f, 0.0f }, { 0.5f, 0.0f }, 0.25f };
+			b2CreateCapsuleShape( bodyId, &shapeDef, &capsule );
+		}
+	}
+
+	static Sample* Create( Settings& settings )
+	{
+		return new SpeculativeBug( settings );
+	}
+};
+
+static int sampleSpeculativeBug = RegisterSample( "Continuous", "Speculative Bug", SpeculativeBug::Create );
+
 // This sample shows ghost collisions
 class GhostCollision : public Sample
 {

src/array.h

@@ -5,7 +5,7 @@
 
 #include "core.h"
 
-// Macro based dynamic arrays
+// Macro generated functions for dynamic arrays
 // Pros
 // - type safe
 // - array data debuggable (visible count and capacity)
@@ -46,10 +46,10 @@
 // Inline array functions that need the type T to be defined
 #define B2_ARRAY_INLINE( T, PREFIX )                                                                                             \
 	/* Resize */                                                                                                                 \
-	static inline void PREFIX##Array_Resize( PREFIX##Array* a, int count )                                                         \
+	static inline void PREFIX##Array_Resize( PREFIX##Array* a, int count )                                                       \
 	{                                                                                                                            \
 		PREFIX##Array_Reserve( a, count );                                                                                       \
-		a->count = count;                                                                                                         \
+		a->count = count;                                                                                                        \
 	}                                                                                                                            \
 	/* Get */                                                                                                                    \
 	static inline T* PREFIX##Array_Get( PREFIX##Array* a, int index )                                                            \
@@ -122,10 +122,12 @@
 	/* Create */                                                                                                                 \
 	PREFIX##Array PREFIX##Array_Create( int capacity )                                                                           \
 	{                                                                                                                            \
-		PREFIX##Array a;                                                                                                         \
-		a.data = b2Alloc( capacity * sizeof( T ) );                                                                              \
-		a.count = 0;                                                                                                             \
-		a.capacity = capacity;                                                                                                   \
+		PREFIX##Array a = { 0 };                                                                                                 \
+		if ( capacity > 0 )                                                                                                      \
+		{                                                                                                                        \
+			a.data = b2Alloc( capacity * sizeof( T ) );                                                                          \
+			a.capacity = capacity;                                                                                               \
+		}                                                                                                                        \
 		return a;                                                                                                                \
 	}                                                                                                                            \
 	/* Reserve */                                                                                                                \

src/body.c

@@ -744,6 +744,11 @@ void b2Body_SetLinearVelocity( b2BodyId bodyId, b2Vec2 linearVelocity )
 	b2World* world = b2GetWorld( bodyId.world0 );
 	b2Body* body = b2GetBodyFullId( world, bodyId );
 
+	if ( body->type == b2_staticBody )
+	{
+		return;
+	}
+
 	if ( b2LengthSquared( linearVelocity ) > 0.0f )
 	{
 		b2WakeBody( world, body );
@@ -763,6 +768,11 @@ void b2Body_SetAngularVelocity( b2BodyId bodyId, float angularVelocity )
 	b2World* world = b2GetWorld( bodyId.world0 );
 	b2Body* body = b2GetBodyFullId( world, bodyId );
 
+	if (body->type == b2_staticBody || body->fixedRotation)
+	{
+		return;
+	}
+
 	if ( angularVelocity != 0.0f )
 	{
 		b2WakeBody( world, body );

src/broad_phase.c

@@ -1,7 +1,9 @@
 // SPDX-FileCopyrightText: 2023 Erin Catto
 // SPDX-License-Identifier: MIT
 
+#if defined( _MSC_VER ) && !defined( _CRT_SECURE_NO_WARNINGS )
 #define _CRT_SECURE_NO_WARNINGS
+#endif
 
 #include "broad_phase.h"
 

src/core.c

@@ -82,6 +82,11 @@ void b2SetAllocator( b2AllocFcn* allocFcn, b2FreeFcn* freeFcn )
 
 void* b2Alloc( int size )
 {
+	if (size == 0)
+	{
+		return NULL;
+	}
+
 	// This could cause some sharing issues, however Box2D rarely calls b2Alloc.
 	atomic_fetch_add_explicit( &b2_byteCount, size, memory_order_relaxed );
 

src/distance.c

@@ -38,8 +38,8 @@ b2SegmentDistanceResult b2SegmentDistance( b2Vec2 p1, b2Vec2 q1, b2Vec2 p2, b2Ve
 	b2Vec2 r = b2Sub( p1, p2 );
 	float dd1 = b2Dot( d1, d1 );
 	float dd2 = b2Dot( d2, d2 );
-	float rd2 = b2Dot( r, d2 );
 	float rd1 = b2Dot( r, d1 );
+	float rd2 = b2Dot( r, d2 );
 
 	const float epsSqr = FLT_EPSILON * FLT_EPSILON;
 

src/distance_joint.c

@@ -1,7 +1,9 @@
 // SPDX-FileCopyrightText: 2023 Erin Catto
 // SPDX-License-Identifier: MIT
 
+#if defined( _MSC_VER ) && !defined( _CRT_SECURE_NO_WARNINGS )
 #define _CRT_SECURE_NO_WARNINGS
+#endif
 
 #include "body.h"
 #include "core.h"

src/joint.c

@@ -789,6 +789,12 @@ b2BodyId b2Joint_GetBodyB( b2JointId jointId )
 	return b2MakeBodyId( world, joint->edges[1].bodyId );
 }
 
+b2WorldId b2Joint_GetWorld( b2JointId jointId )
+{
+	b2World* world = b2GetWorld( jointId.world0 );
+	return ( b2WorldId ){ jointId.world0 + 1, world->revision };
+}
+
 b2Vec2 b2Joint_GetLocalAnchorA( b2JointId jointId )
 {
 	b2World* world = b2GetWorld( jointId.world0 );