Fix falling body assert (#92)

API to get parent chain id
default definitions as constants
128 max worlds
removed extents from mass data
removed box2d_exports.h and implemented similar switches in api.h
user_constants.h optional and off by default
added some missing API functions
added shape filter sample
addresses #93

.clang-format

@@ -33,6 +33,7 @@ IncludeCategories:
 
 IndentExternBlock: NoIndent
 IndentCaseLabels: true
+IndentPPDirectives: BeforeHash
 IndentAccessModifiers: false
 AccessModifierOffset: -4
 

CMakeLists.txt

@@ -1,10 +1,10 @@
-cmake_minimum_required(VERSION 3.23)
+cmake_minimum_required(VERSION 3.22)
 include(FetchContent)
 
 project(box2d
 	VERSION 3.0.0
 	DESCRIPTION "A 2D physics engine for games"
-	HOMEPAGE_URL "box2d.org"
+	HOMEPAGE_URL "https://box2d.org"
 	LANGUAGES C CXX
 )
 
@@ -15,8 +15,12 @@ project(box2d
 # message(STATUS "CMake C++ compiler: ${CMAKE_CXX_COMPILER_ID}")
 message(STATUS "CMake system name: ${CMAKE_SYSTEM_NAME}")
 
-set(BOX2D_LENGTH_UNIT_PER_METER "1.0" CACHE STRING "Length units per meter")
-set(BOX2D_MAX_POLYGON_VERTICES "8" CACHE STRING "Maximum number of polygon vertices (affects performance)")
+option(BOX2D_USER_CONSTANTS "Generate user_constants.h" OFF)
+
+if (BOX2D_USER_CONSTANTS)
+	set(BOX2D_LENGTH_UNIT_PER_METER "1.0" CACHE STRING "Length units per meter")
+	set(BOX2D_MAX_POLYGON_VERTICES "8" CACHE STRING "Maximum number of polygon vertices (affects performance)")
+endif()
 
 # Needed for samples.exe to find box2d.dll
 # set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/bin")

docs/CMakeLists.txt

@@ -5,7 +5,7 @@ set(DOXYGEN_FILE_PATTERNS *.h)
 set(DOXYGEN_ENABLE_PREPROCESSING YES)
 set(DOXYGEN_MACRO_EXPANSION YES)
 set(DOXYGEN_EXPAND_ONLY_PREDEF YES)
-set(DOXYGEN_PREDEFINED BOX2D_API=)
+set(DOXYGEN_PREDEFINED B2_API=)
 
 set(DOXYGEN_IMAGE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/images")
 set(DOXYGEN_HTML_EXTRA_STYLESHEET "${CMAKE_CURRENT_SOURCE_DIR}/extra.css")

include/box2d/api.h

@@ -3,14 +3,26 @@
 
 #pragma once
 
-#include "box2d_export.h"
-
 #include <stdint.h>
 
+#if defined(_WIN32) && defined(box2d_EXPORTS)
+	// building the Box2D DLL
+	#define BOX2D_EXPORT __declspec(dllexport)
+#elif defined(_WIN32) && defined(BOX2D_DLL)
+	// using the Box2D DLL
+	#define BOX2D_EXPORT __declspec(dllimport)
+#elif defined(__GNUC__) && defined(box2d_EXPORTS)
+	// building the Box2D shared library
+	#define BOX2D_EXPORT __attribute__((visibility("default")))
+#else
+	// static library
+	#define BOX2D_EXPORT
+#endif
+
 #ifdef __cplusplus
-#define BOX2D_API extern "C" BOX2D_EXPORT
+	#define B2_API extern "C" BOX2D_EXPORT
 #else
-#define BOX2D_API BOX2D_EXPORT
+	#define B2_API BOX2D_EXPORT
 #endif
 
 /// Prototype for user allocation function.
@@ -24,14 +36,14 @@ typedef void b2FreeFcn(void* mem);
 
 /// This allows the user to override the allocation functions. These should be
 ///	set during application startup.
-BOX2D_API void b2SetAllocator(b2AllocFcn* allocFcn, b2FreeFcn* freeFcn);
+B2_API void b2SetAllocator(b2AllocFcn* allocFcn, b2FreeFcn* freeFcn);
 
 /// Total bytes allocated by Box2D
-BOX2D_API uint32_t b2GetByteCount(void);
+B2_API uint32_t b2GetByteCount(void);
 
 /// Prototype for the user assert callback. Return 0 to skip the debugger break.
 typedef int b2AssertFcn(const char* condition, const char* fileName, int lineNumber);
 
 /// Override the default assert callback.
 ///	@param assertFcn a non-null assert callback
-BOX2D_API void b2SetAssertFcn(b2AssertFcn* assertFcn);
+B2_API void b2SetAssertFcn(b2AssertFcn* assertFcn);

include/box2d/callbacks.h

@@ -23,7 +23,7 @@ typedef struct b2Manifold b2Manifold;
 typedef bool b2PreSolveFcn(b2ShapeId shapeIdA, b2ShapeId shapeIdB, b2Manifold* manifold, void* context);
 
 /// Register the pre-solve callback. This is optional.
-BOX2D_API void b2World_SetPreSolveCallback(b2WorldId worldId, b2PreSolveFcn* fcn, void* context);
+B2_API void b2World_SetPreSolveCallback(b2WorldId worldId, b2PreSolveFcn* fcn, void* context);
 
 /// Prototype callback for AABB queries.
 /// See b2World_Query

include/box2d/constants.h

@@ -12,14 +12,14 @@
 ///	Although most of these are not user configurable, it can be interesting for a user to see
 ///	these to understand the tuning values Box2D uses.
 
-// todo move constraint hertz/damping here
-
-#include "user_constants.h"
+#ifdef BOX2D_USER_CONSTANTS
+	#include "user_constants.h"
+#endif
 
 /// box2d bases all length units on meters, but you may need different units for your game.
 /// You can override this value to use different units.
 #ifndef b2_lengthUnitsPerMeter
-#define b2_lengthUnitsPerMeter 1.0f
+	#define b2_lengthUnitsPerMeter 1.0f
 #endif
 
 /// https://en.wikipedia.org/wiki/Pi
@@ -44,11 +44,11 @@
 /// The maximum number of vertices on a convex polygon. Changing this affects performance even if you
 ///	don't use more vertices.
 #ifndef b2_maxPolygonVertices
-#define b2_maxPolygonVertices 8
+	#define b2_maxPolygonVertices 8
 #endif
 
 /// Maximum number of simultaneous worlds that can be allocated
-#define b2_maxWorlds 32
+#define b2_maxWorlds 128
 
 /// The maximum linear translation of a body per step. This limit is very large and is used
 /// to prevent numerical problems. You shouldn't need to adjust this. Meters.

include/box2d/distance.h

@@ -17,7 +17,7 @@ typedef struct b2SegmentDistanceResult
 } b2SegmentDistanceResult;
 
 /// Compute the distance between two line segments, clamping at the end points if needed.
-BOX2D_API b2SegmentDistanceResult b2SegmentDistance(b2Vec2 p1, b2Vec2 q1, b2Vec2 p2, b2Vec2 q2);
+B2_API b2SegmentDistanceResult b2SegmentDistance(b2Vec2 p1, b2Vec2 q1, b2Vec2 p2, b2Vec2 q2);
 
 /// A distance proxy is used by the GJK algorithm. It encapsulates any shape.
 typedef struct b2DistanceProxy
@@ -63,7 +63,7 @@ typedef struct b2DistanceOutput
 /// Compute the closest points between two shapes. Supports any combination of:
 /// b2Circle, b2Polygon, b2EdgeShape. The simplex cache is input/output.
 /// On the first call set b2SimplexCache.count to zero.
-BOX2D_API b2DistanceOutput b2ShapeDistance(b2DistanceCache* cache, const b2DistanceInput* input);
+B2_API b2DistanceOutput b2ShapeDistance(b2DistanceCache* cache, const b2DistanceInput* input);
 
 /// Input parameters for b2ShapeCast
 typedef struct b2ShapeCastPairInput
@@ -78,10 +78,10 @@ typedef struct b2ShapeCastPairInput
 
 /// Perform a linear shape cast of shape B moving and shape A fixed. Determines the hit point, normal, and translation fraction.
 /// @returns true if hit, false if there is no hit or an initial overlap
-BOX2D_API b2RayCastOutput b2ShapeCast(const b2ShapeCastPairInput* input);
+B2_API b2RayCastOutput b2ShapeCast(const b2ShapeCastPairInput* input);
 
 /// Make a proxy for use in GJK and related functions.
-BOX2D_API b2DistanceProxy b2MakeProxy(const b2Vec2* vertices, int32_t count, float radius);
+B2_API b2DistanceProxy b2MakeProxy(const b2Vec2* vertices, int32_t count, float radius);
 
 /// This describes the motion of a body/shape for TOI computation. Shapes are defined with respect to the body origin,
 /// which may not coincide with the center of mass. However, to support dynamics we must interpolate the center of mass
@@ -98,7 +98,7 @@ typedef struct b2Sweep
 	float a1, a2;
 } b2Sweep;
 
-BOX2D_API b2Transform b2GetSweepTransform(const b2Sweep* sweep, float time);
+B2_API b2Transform b2GetSweepTransform(const b2Sweep* sweep, float time);
 
 /// Input parameters for b2TimeOfImpact
 typedef struct b2TOIInput
@@ -133,4 +133,4 @@ typedef struct b2TOIOutput
 /// a fraction between [0,tMax]. This uses a swept separating axis and may miss some intermediate,
 /// non-tunneling collisions. If you change the time interval, you should call this function
 /// again.
-BOX2D_API b2TOIOutput b2TimeOfImpact(const b2TOIInput* input);
+B2_API b2TOIOutput b2TimeOfImpact(const b2TOIInput* input);

include/box2d/dynamic_tree.h

@@ -64,38 +64,38 @@ typedef struct b2DynamicTree
 } b2DynamicTree;
 
 /// Constructing the tree initializes the node pool.
-BOX2D_API b2DynamicTree b2DynamicTree_Create(void);
+B2_API b2DynamicTree b2DynamicTree_Create(void);
 
 /// Destroy the tree, freeing the node pool.
-BOX2D_API void b2DynamicTree_Destroy(b2DynamicTree* tree);
+B2_API void b2DynamicTree_Destroy(b2DynamicTree* tree);
 
 /// Create a proxy. Provide a tight fitting AABB and a userData value.
-BOX2D_API int32_t b2DynamicTree_CreateProxy(b2DynamicTree* tree, b2AABB aabb, uint32_t categoryBits, int32_t userData);
+B2_API int32_t b2DynamicTree_CreateProxy(b2DynamicTree* tree, b2AABB aabb, uint32_t categoryBits, int32_t userData);
 
 /// Destroy a proxy. This asserts if the id is invalid.
-BOX2D_API void b2DynamicTree_DestroyProxy(b2DynamicTree* tree, int32_t proxyId);
+B2_API void b2DynamicTree_DestroyProxy(b2DynamicTree* tree, int32_t proxyId);
 
 // Clone one tree to another, reusing storage in the outTree if possible
-BOX2D_API void b2DynamicTree_Clone(b2DynamicTree* outTree, const b2DynamicTree* inTree);
+B2_API void b2DynamicTree_Clone(b2DynamicTree* outTree, const b2DynamicTree* inTree);
 
 /// Move a proxy to a new AABB by removing and reinserting into the tree.
-BOX2D_API void b2DynamicTree_MoveProxy(b2DynamicTree* tree, int32_t proxyId, b2AABB aabb);
+B2_API void b2DynamicTree_MoveProxy(b2DynamicTree* tree, int32_t proxyId, b2AABB aabb);
 
 /// Enlarge a proxy and enlarge ancestors as necessary.
-BOX2D_API void b2DynamicTree_EnlargeProxy(b2DynamicTree* tree, int32_t proxyId, b2AABB aabb);
+B2_API void b2DynamicTree_EnlargeProxy(b2DynamicTree* tree, int32_t proxyId, b2AABB aabb);
 
 /// This function receives proxies found in the AABB query.
 /// @return true if the query should continue
 typedef bool b2TreeQueryCallbackFcn(int32_t proxyId, int32_t userData, void* context);
 
 /// Query an AABB for overlapping proxies. The callback class
 /// is called for each proxy that overlaps the supplied AABB.
-BOX2D_API void b2DynamicTree_QueryFiltered(const b2DynamicTree* tree, b2AABB aabb, uint32_t maskBits,
+B2_API void b2DynamicTree_QueryFiltered(const b2DynamicTree* tree, b2AABB aabb, uint32_t maskBits,
 										   b2TreeQueryCallbackFcn* callback, void* context);
 
 /// Query an AABB for overlapping proxies. The callback class
 /// is called for each proxy that overlaps the supplied AABB.
-BOX2D_API void b2DynamicTree_Query(const b2DynamicTree* tree, b2AABB aabb, b2TreeQueryCallbackFcn* callback, void* context);
+B2_API void b2DynamicTree_Query(const b2DynamicTree* tree, b2AABB aabb, b2TreeQueryCallbackFcn* callback, void* context);
 
 /// This function receives clipped raycast input for a proxy. The function
 /// returns the new ray fraction.
@@ -111,7 +111,7 @@ typedef float b2TreeRayCastCallbackFcn(const b2RayCastInput* input, int32_t prox
 /// number of proxies in the tree.
 /// @param input the ray-cast input data. The ray extends from p1 to p1 + maxFraction * (p2 - p1).
 /// @param callback a callback class that is called for each proxy that is hit by the ray.
-BOX2D_API void b2DynamicTree_RayCast(const b2DynamicTree* tree, const b2RayCastInput* input, uint32_t maskBits,
+B2_API void b2DynamicTree_RayCast(const b2DynamicTree* tree, const b2RayCastInput* input, uint32_t maskBits,
 									 b2TreeRayCastCallbackFcn* callback, void* context);
 
 /// This function receives clipped raycast input for a proxy. The function
@@ -128,35 +128,35 @@ typedef float b2TreeShapeCastCallbackFcn(const b2ShapeCastInput* input, int32_t
 /// number of proxies in the tree.
 /// @param input the ray-cast input data. The ray extends from p1 to p1 + maxFraction * (p2 - p1).
 /// @param callback a callback class that is called for each proxy that is hit by the ray.
-BOX2D_API void b2DynamicTree_ShapeCast(const b2DynamicTree* tree, const b2ShapeCastInput* input, uint32_t maskBits,
+B2_API void b2DynamicTree_ShapeCast(const b2DynamicTree* tree, const b2ShapeCastInput* input, uint32_t maskBits,
 									   b2TreeShapeCastCallbackFcn* callback, void* context);
 
 /// Validate this tree. For testing.
-BOX2D_API void b2DynamicTree_Validate(const b2DynamicTree* tree);
+B2_API void b2DynamicTree_Validate(const b2DynamicTree* tree);
 
 /// Compute the height of the binary tree in O(N) time. Should not be
 /// called often.
-BOX2D_API int32_t b2DynamicTree_GetHeight(const b2DynamicTree* tree);
+B2_API int32_t b2DynamicTree_GetHeight(const b2DynamicTree* tree);
 
 /// Get the maximum balance of the tree. The balance is the difference in height of the two children of a node.
-BOX2D_API int32_t b2DynamicTree_GetMaxBalance(const b2DynamicTree* tree);
+B2_API int32_t b2DynamicTree_GetMaxBalance(const b2DynamicTree* tree);
 
 /// Get the ratio of the sum of the node areas to the root area.
-BOX2D_API float b2DynamicTree_GetAreaRatio(const b2DynamicTree* tree);
+B2_API float b2DynamicTree_GetAreaRatio(const b2DynamicTree* tree);
 
 /// Build an optimal tree. Very expensive. For testing.
-BOX2D_API void b2DynamicTree_RebuildBottomUp(b2DynamicTree* tree);
+B2_API void b2DynamicTree_RebuildBottomUp(b2DynamicTree* tree);
 
 /// Get the number of proxies created
-BOX2D_API int32_t b2DynamicTree_GetProxyCount(const b2DynamicTree* tree);
+B2_API int32_t b2DynamicTree_GetProxyCount(const b2DynamicTree* tree);
 
 /// Rebuild the tree while retaining subtrees that haven't changed. Returns the number of boxes sorted.
-BOX2D_API int32_t b2DynamicTree_Rebuild(b2DynamicTree* tree, bool fullBuild);
+B2_API int32_t b2DynamicTree_Rebuild(b2DynamicTree* tree, bool fullBuild);
 
 /// Shift the world origin. Useful for large worlds.
 /// The shift formula is: position -= newOrigin
 /// @param newOrigin the new origin with respect to the old origin
-BOX2D_API void b2DynamicTree_ShiftOrigin(b2DynamicTree* tree, b2Vec2 newOrigin);
+B2_API void b2DynamicTree_ShiftOrigin(b2DynamicTree* tree, b2Vec2 newOrigin);
 
 /// Get proxy user data
 /// @return the proxy user data or 0 if the id is invalid