fix for skipped shape in ray cast callback (returning -1)

CMakeLists.txt

@@ -103,6 +103,15 @@ if(PROJECT_IS_TOP_LEVEL)
 	if(BOX2D_UNIT_TESTS OR BOX2D_SAMPLES OR BOX2D_BENCHMARKS)
 		SET(ENKITS_BUILD_EXAMPLES OFF CACHE BOOL "Build enkiTS examples")
 
+		# Emscripten pthread support for enkiTS
+		if(EMSCRIPTEN)
+			set(EMSCRIPTEN_PTHREADS_COMPILER_FLAGS "-pthread -s USE_PTHREADS=1")
+			set(EMSCRIPTEN_PTHREADS_LINKER_FLAGS "${EMSCRIPTEN_PTHREADS_COMPILER_FLAGS} -s ALLOW_MEMORY_GROWTH")
+			string(APPEND CMAKE_C_FLAGS " ${EMSCRIPTEN_PTHREADS_COMPILER_FLAGS}")
+			string(APPEND CMAKE_CXX_FLAGS " ${EMSCRIPTEN_PTHREADS_COMPILER_FLAGS}")
+			string(APPEND CMAKE_EXE_LINKER_FLAGS " ${EMSCRIPTEN_PTHREADS_LINKER_FLAGS}")
+		endif()
+
 		# Used in tests and samples
 		FetchContent_Declare(
 			enkits

README.md

@@ -81,7 +81,9 @@ Please file an issue or start a chat on discord.
 Box2D is developed by Erin Catto and uses the [MIT license](https://en.wikipedia.org/wiki/MIT_License).
 
 ## Sponsorship
-Support development of Box2D through [Github Sponsors](https://github.com/sponsors/erincatto)
+Support development of Box2D through [Github Sponsors](https://github.com/sponsors/erincatto).
+
+Please consider starring this repository and subscribing to my [YouTube channel](https://www.youtube.com/@erin_catto).
 
 ## Ports, wrappers, and bindings
 - https://github.com/EnokViking/Box2DBeef

samples/sample_collision.cpp

@@ -1473,6 +1473,21 @@ class RayCastWorld : public Sample
 		bodyDef.position = { x, y };
 		bodyDef.rotation = b2MakeRot( RandomFloatRange( -b2_pi, b2_pi ) );
 
+		int mod = m_bodyIndex % 3;
+		if (mod == 0)
+		{
+			bodyDef.type = b2_staticBody;
+		}
+		else if (mod == 1)
+		{
+			bodyDef.type = b2_kinematicBody;
+		}
+		else if (mod == 2)
+		{
+			bodyDef.type = b2_dynamicBody;
+			bodyDef.gravityScale = 0.0f;
+		}
+
 		m_bodyIds[m_bodyIndex] = b2CreateBody( m_worldId, &bodyDef );
 
 		b2ShapeDef shapeDef = b2DefaultShapeDef();
@@ -1816,9 +1831,9 @@ class RayCastWorld : public Sample
 	}
 
 	int m_bodyIndex;
-	b2BodyId m_bodyIds[e_maxCount];
-	ShapeUserData m_userData[e_maxCount];
-	b2Polygon m_polygons[4];
+	b2BodyId m_bodyIds[e_maxCount] = {};
+	ShapeUserData m_userData[e_maxCount] = {};
+	b2Polygon m_polygons[4] = {};
 	b2Capsule m_capsule;
 	b2Circle m_circle;
 	b2Segment m_segment;

samples/sample_continuous.cpp

@@ -947,7 +947,7 @@ class Drop : public Sample
 		float h = 0.05f;
 		for ( int j = 0; j <= count; ++j )
 		{
-			b2Polygon box = b2MakeOffsetBox( w, h, { x, 0.0f }, b2Rot_identity );
+			b2Polygon box = b2MakeOffsetBox( 0.5f * w, h, { x, 0.0f }, b2Rot_identity );
 			b2CreatePolygonShape( groundId, &shapeDef, &box );
 			x += w;
 		}

shared/human.c

@@ -515,6 +515,21 @@ void DestroyHuman( Human* human )
 	human->isSpawned = false;
 }
 
+void Human_SetVelocity( Human* human, b2Vec2 velocity )
+{
+	for ( int i = 0; i < boneId_count; ++i )
+	{
+		b2BodyId bodyId = human->bones[i].bodyId;
+
+		if ( B2_IS_NULL( bodyId ) )
+		{
+			continue;
+		}
+
+		b2Body_SetLinearVelocity( bodyId, velocity );
+	}
+}
+
 void Human_ApplyRandomAngularImpulse( Human* human, float magnitude )
 {
 	assert( human->isSpawned == true );

shared/human.h

@@ -46,6 +46,7 @@ void CreateHuman( Human* human, b2WorldId worldId, b2Vec2 position, float scale,
 
 void DestroyHuman( Human* human );
 
+void Human_SetVelocity( Human* human, b2Vec2 velocity );
 void Human_ApplyRandomAngularImpulse( Human* human, float magnitude );
 void Human_SetJointFrictionTorque( Human* human, float torque );
 void Human_SetJointSpringHertz( Human* human, float hertz );

src/array.h

@@ -19,6 +19,8 @@
 // - cannot debug
 // - breaks code navigation
 
+// todo_erin consider code-gen: https://github.com/IbrahimHindawi/haikal
+
 // Array declaration that doesn't need the type T to be defined
 #define B2_ARRAY_DECLARE( T, PREFIX )                                                                                            \
 	typedef struct                                                                                                               \

src/dynamic_tree.c

@@ -1241,13 +1241,15 @@ b2TreeStats b2DynamicTree_RayCast( const b2DynamicTree* tree, const b2RayCastInp
 			float value = callback( &subInput, nodeId, node->userData, context );
 			result.leafVisits += 1;
 
+			// The user may return -1 to indicate this shape should be skipped
+
 			if ( value == 0.0f )
 			{
 				// The client has terminated the ray cast.
 				return result;
 			}
 
-			if ( 0.0f < value && value < maxFraction )
+			if ( 0.0f < value && value <= maxFraction )
 			{
 				// Update segment bounding box.
 				maxFraction = value;

src/timer.c

@@ -76,14 +76,123 @@ void b2Yield()
 	SwitchToThread();
 }
 
-#elif defined( __linux__ ) || defined( __APPLE__ ) || defined( __EMSCRIPTEN__ )
+#elif defined( __linux__ ) || defined( __EMSCRIPTEN__ )
 
 #include <sched.h>
 #include <sys/time.h>
 #include <time.h>
 
 b2Timer b2CreateTimer( void )
 {
+	// todo_erin
+
+	//struct timespec ts;
+	//clock_gettime( CLOCK_MONOTONIC_RAW, &ts );
+
+	//struct timespec res;
+	//clock_getres( CLOCK_MONOTONIC, &res );
+
+	b2Timer timer;
+	struct timeval t;
+	gettimeofday( &t, 0 );
+	timer.start_sec = t.tv_sec;
+	timer.start_usec = t.tv_usec;
+	return timer;
+}
+
+float b2GetMilliseconds( const b2Timer* timer )
+{
+	struct timeval t;
+	gettimeofday( &t, 0 );
+	time_t start_sec = timer->start_sec;
+	suseconds_t start_usec = (suseconds_t)timer->start_usec;
+
+	// http://www.gnu.org/software/libc/manual/html_node/Elapsed-Time.html
+	if ( t.tv_usec < start_usec )
+	{
+		int nsec = ( start_usec - t.tv_usec ) / 1000000 + 1;
+		start_usec -= 1000000 * nsec;
+		start_sec += nsec;
+	}
+
+	if ( t.tv_usec - start_usec > 1000000 )
+	{
+		int nsec = ( t.tv_usec - start_usec ) / 1000000;
+		start_usec += 1000000 * nsec;
+		start_sec -= nsec;
+	}
+	return 1000.0f * ( t.tv_sec - start_sec ) + 0.001f * ( t.tv_usec - start_usec );
+}
+
+float b2GetMillisecondsAndReset( b2Timer* timer )
+{
+	struct timeval t;
+	gettimeofday( &t, 0 );
+	time_t start_sec = timer->start_sec;
+	suseconds_t start_usec = (suseconds_t)timer->start_usec;
+
+	// http://www.gnu.org/software/libc/manual/html_node/Elapsed-Time.html
+	if ( t.tv_usec < start_usec )
+	{
+		int nsec = ( start_usec - t.tv_usec ) / 1000000 + 1;
+		start_usec -= 1000000 * nsec;
+		start_sec += nsec;
+	}
+
+	if ( t.tv_usec - start_usec > 1000000 )
+	{
+		int nsec = ( t.tv_usec - start_usec ) / 1000000;
+		start_usec += 1000000 * nsec;
+		start_sec -= nsec;
+	}
+
+	timer->start_sec = t.tv_sec;
+	timer->start_usec = t.tv_usec;
+
+	return 1000.0f * ( t.tv_sec - start_sec ) + 0.001f * ( t.tv_usec - start_usec );
+}
+
+void b2SleepMilliseconds( int milliseconds )
+{
+	struct timespec ts;
+	ts.tv_sec = milliseconds / 1000;
+	ts.tv_nsec = ( milliseconds % 1000 ) * 1000000;
+	nanosleep( &ts, NULL );
+}
+
+void b2Yield()
+{
+	sched_yield();
+}
+
+#elif defined( __APPLE__ )
+
+#include <sched.h>
+#include <sys/time.h>
+#include <time.h>
+
+//#include <mach/mach_time.h>
+
+b2Timer b2CreateTimer( void )
+{
+	// todo_erin
+	//#include <mach/mach_time.h>
+
+	//// Get current time
+	//uint64_t start = mach_absolute_time();
+
+	//// To convert to nanoseconds, you'll need to use mach_timebase_info
+	//mach_timebase_info_data_t timebase;
+	//mach_timebase_info( &timebase );
+
+	//// Convert to nanoseconds
+	//uint64_t elapsed_ns = ( start * timebase.numer ) / timebase.denom;
+
+	//mach_timebase_info_data_t timebase;
+	//mach_timebase_info( &timebase );
+	//// timebase.numer and timebase.denom can be used to calculate frequency
+	//// Specifically, frequency = 1e9 / (timebase.numer / timebase.denom)
+
 	b2Timer timer;
 	struct timeval t;
 	gettimeofday( &t, 0 );

src/world.c

@@ -2146,7 +2146,13 @@ static float RayCastCallback( const b2RayCastInput* input, int proxyId, int shap
 	{
 		b2ShapeId id = { shapeId + 1, world->worldId, shape->revision };
 		float fraction = worldContext->fcn( id, output.point, output.normal, output.fraction, worldContext->userContext );
-		worldContext->fraction = fraction;
+
+		// The user may return -1 to skip this shape
+		if (0.0f <= fraction && fraction <= 1.0f)
+		{
+			worldContext->fraction = fraction;
+		}
+
 		return fraction;
 	}