Misc Issues (#783)

- renamed smooth segment to chain segment
- addressed several minor issues

#777
#779
#754 
#749 
#782 
#781 
#776

CMakeLists.txt

@@ -41,7 +41,6 @@ if(CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64|AMD64")
 	cmake_dependent_option(BOX2D_AVX2 "Enable AVX2" OFF "BOX2D_ENABLE_SIMD" OFF)
 endif()
 
-
 if(PROJECT_IS_TOP_LEVEL)
 	# Needed for samples.exe to find box2d.dll
 	# set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/bin")
@@ -67,6 +66,13 @@ if(PROJECT_IS_TOP_LEVEL)
 	option(BOX2D_VALIDATE "Enable heavy validation" ON)
 	option(BOX2D_UNIT_TESTS "Build the Box2D unit tests" ON)
 
+	include(GNUInstallDirs)
+
+	install(
+		DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/include/box2d"
+		DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+	)
+
 	if(MSVC AND WIN32)
 		# Enable edit and continue only in debug due to perf hit in release
 		# add_link_options($<$<CONFIG:Debug>:/INCREMENTAL>)

docs/collision.md

@@ -160,7 +160,7 @@ If edge1 did not exist this collision would seem fine. With edge1
 present, the internal collision seems like a bug. But normally when
 Box2D collides two shapes, it views them in isolation.
 
-`b2SmoothSegment` provides a mechanism for eliminating ghost
+`b2ChainSegment` provides a mechanism for eliminating ghost
 collisions by storing the adjacent *ghost* vertices. Box2D uses these
 ghost vertices to prevent internal collisions.
 
@@ -171,21 +171,21 @@ one-sided collision. The front face is to the right when looking from the first
 vertex towards the second vertex. This matches the counter-clockwise winding order
 used by polygons.
 
-### Smooth segment
-Smooth segments use a concept called *ghost vertices* that Box2D can use to eliminate ghost
+### Chain segment
+Chain segments use a concept called *ghost vertices* that Box2D can use to eliminate ghost
 collisions.
 
 ```c
-b2SmoothSegment smoothSegment = {0};
-smoothSegment.ghost1 = (b2Vec2){1.7f, 0.0f};
-smoothSegment.segment = (b2Segment){{1.0f, 0.25f}, {0.0f, 0.0f}};
-smoothSegment.ghost2 = (b2Vec2){-1.7f, 0.4f};
+b2ChainSegment chainSegment = {0};
+chainSegment.ghost1 = (b2Vec2){1.7f, 0.0f};
+chainSegment.segment = (b2Segment){{1.0f, 0.25f}, {0.0f, 0.0f}};
+chainSegment.ghost2 = (b2Vec2){-1.7f, 0.4f};
 ```
 
-These ghost vertices must align with vertices of neighboring smooth segments, making them
+These ghost vertices must align with vertices of neighboring chain segments, making them
 tedious and error-prone to setup.
 
-Smooth segments are not created directly. Instead, you can create chains of smooth
+Chain segments are not created directly. Instead, you can create chains of line
 segments. See `b2ChainDef` and `b2CreateChain()`.
 
 ## Geometric Queries

docs/migration.md

@@ -162,9 +162,9 @@ chainDef.loop = true;
 b2ChainId chainId = b2CreateChain(bodyId, &chainDef);
 ```
 
-Since chains are their own concept now, they get their own identifier, `b2ChainId`. You can view chains as macro objects, they create many `b2SmoothSegment` shapes internally. Normally you don't interact with these. However they are returned from queries. You can use `b2Shape_GetParentChain()` to get the `b2ChainId` for a smooth segment that you get from a query.
+Since chains are their own concept now, they get their own identifier, `b2ChainId`. You can view chains as macro objects, they create many `b2ChainSegment` shapes internally. Normally you don't interact with these. However they are returned from queries. You can use `b2Shape_GetParentChain()` to get the `b2ChainId` for a chain segment that you get from a query.
 
-> DO NOT destroy or modify a `b2SmoothSegment` that belongs to a chain shape directly
+> DO NOT destroy or modify a `b2ChainSegment` that belongs to a chain shape directly
 
 ### Creating a joint
 Joints are very similar in v3.0. The lack of C member functions changes initialization.

docs/simulation.md

@@ -860,16 +860,15 @@ problems. Make sure all your points are more than than about a centimeter apart.
 
 ![Self Intersection is Bad](images/self_intersect.svg)
 
-Each segment in the chain is created as a `b2SmoothSegment` shape on the body. If you have the
-shape id for a smooth segment shape, you can get the owning chain id. This will return `b2_nullChainId`
-if the shape is not a smooth segment.
+Each segment in the chain is created as a `b2ChainSegment` shape on the body. If you have the
+shape id for a chain segment shape, you can get the owning chain id. This will return `b2_nullChainId`
+if the shape is not a chain segment.
 
 ```c
 b2ChainId chainId = b2SHape_GetParentChain(myShapeId);
 ```
 
-You cannot create a smooth segment shape directly.
-
+You cannot create a chain segment shape directly.
 
 ### Sensors
 Sometimes game logic needs to know when two shapes overlap yet there
@@ -1181,7 +1180,7 @@ or disable a joint.
 You can specify user data for any joint type and you can provide a flag
 to prevent the attached bodies from colliding with each other. This is
 the default behavior and you must set the `collideConnected`
-Boolean to allow collision between to connected bodies.
+Boolean to allow collision between two connected bodies.
 
 Many joint definitions require that you provide some geometric data.
 Often a joint will be defined by anchor points. These are points fixed
@@ -1493,13 +1492,6 @@ when multiple dynamic bodies interact. You can make this as large as you
 like. The frequency and damping ratio are used to create a spring/damper
 effect similar to the distance joint.
 
-### Wheel Joint
-The wheel joint restricts a point on bodyB to a line on bodyA. The wheel
-joint also provides a suspension spring and a motor. See the `Driving` sample
-for details.
-
-![Wheel Joint](images/wheel_joint.svg)
-
 ### Weld Joint
 The weld joint attempts to constrain all relative motion between two
 bodies. See the `Cantilever` sample to see how the weld joint
@@ -1522,6 +1514,12 @@ proportional the maximum motor force and torque. See `b2MotorJointDef` and
 the `MotorJoint` sample for details.
 
 ### Wheel Joint
+The wheel joint restricts a point on bodyB to a line on bodyA. The wheel
+joint also provides a suspension spring and a motor. See the `Driving` sample
+for details.
+
+![Wheel Joint](images/wheel_joint.svg)
+
 The wheel joint is designed specifically for vehicles. It provides a translation
 and rotation. The translation has a spring and damper to simulate the vehicle
 suspension. The rotation allows the wheel to rotate. You can specify an rotational

include/box2d/box2d.h

@@ -529,9 +529,9 @@ B2_API b2Circle b2Shape_GetCircle( b2ShapeId shapeId );
 /// Get a copy of the shape's line segment. Asserts the type is correct.
 B2_API b2Segment b2Shape_GetSegment( b2ShapeId shapeId );
 
-/// Get a copy of the shape's smooth line segment. These come from chain shapes.
+/// Get a copy of the shape's chain segment. These come from chain shapes.
 /// Asserts the type is correct.
-B2_API b2SmoothSegment b2Shape_GetSmoothSegment( b2ShapeId shapeId );
+B2_API b2ChainSegment b2Shape_GetChainSegment( b2ShapeId shapeId );
 
 /// Get a copy of the shape's capsule. Asserts the type is correct.
 B2_API b2Capsule b2Shape_GetCapsule( b2ShapeId shapeId );
@@ -557,7 +557,7 @@ B2_API void b2Shape_SetSegment( b2ShapeId shapeId, const b2Segment* segment );
 ///	@see b2Body_ApplyMassFromShapes
 B2_API void b2Shape_SetPolygon( b2ShapeId shapeId, const b2Polygon* polygon );
 
-/// Get the parent chain id if the shape type is b2_smoothSegmentShape, otherwise
+/// Get the parent chain id if the shape type is a chain segment, otherwise
 /// returns b2_nullChainId.
 B2_API b2ChainId b2Shape_GetParentChain( b2ShapeId shapeId );
 

include/box2d/collision.h

@@ -13,7 +13,7 @@ typedef struct b2Capsule b2Capsule;
 typedef struct b2DistanceCache b2DistanceCache;
 typedef struct b2Polygon b2Polygon;
 typedef struct b2Segment b2Segment;
-typedef struct b2SmoothSegment b2SmoothSegment;
+typedef struct b2ChainSegment b2ChainSegment;
 
 typedef struct b2Hull b2Hull;
 
@@ -153,10 +153,10 @@ typedef struct b2Segment
 	b2Vec2 point2;
 } b2Segment;
 
-/// A smooth line segment with one-sided collision. Only collides on the right side.
+/// A line segment with one-sided collision. Only collides on the right side.
 /// Several of these are generated for a chain shape.
 /// ghost1 -> point1 -> point2 -> ghost2
-typedef struct b2SmoothSegment
+typedef struct b2ChainSegment
 {
 	/// The tail ghost vertex
 	b2Vec2 ghost1;
@@ -169,7 +169,7 @@ typedef struct b2SmoothSegment
 
 	/// The owning chain shape index (internal usage only)
 	int32_t chainId;
-} b2SmoothSegment;
+} b2ChainSegment;
 
 /// Validate ray cast input data (NaN, etc)
 B2_API bool b2IsValidRay( const b2RayCastInput* input );
@@ -554,16 +554,16 @@ B2_API b2Manifold b2CollidePolygons( const b2Polygon* polygonA, b2Transform xfA,
 B2_API b2Manifold b2CollideSegmentAndPolygon( const b2Segment* segmentA, b2Transform xfA, const b2Polygon* polygonB,
 											  b2Transform xfB );
 
-/// Compute the contact manifold between a smooth segment and a circle
-B2_API b2Manifold b2CollideSmoothSegmentAndCircle( const b2SmoothSegment* smoothSegmentA, b2Transform xfA,
+/// Compute the contact manifold between a chain segment and a circle
+B2_API b2Manifold b2CollideChainSegmentAndCircle( const b2ChainSegment* segmentA, b2Transform xfA,
 												   const b2Circle* circleB, b2Transform xfB );
 
-/// Compute the contact manifold between an segment and a capsule
-B2_API b2Manifold b2CollideSmoothSegmentAndCapsule( const b2SmoothSegment* smoothSegmentA, b2Transform xfA,
+/// Compute the contact manifold between a chain segment and a capsule
+B2_API b2Manifold b2CollideChainSegmentAndCapsule( const b2ChainSegment* segmentA, b2Transform xfA,
 													const b2Capsule* capsuleB, b2Transform xfB, b2DistanceCache* cache );
 
-/// Compute the contact manifold between a smooth segment and a rounded polygon
-B2_API b2Manifold b2CollideSmoothSegmentAndPolygon( const b2SmoothSegment* smoothSegmentA, b2Transform xfA,
+/// Compute the contact manifold between a chain segment and a rounded polygon
+B2_API b2Manifold b2CollideChainSegmentAndPolygon( const b2ChainSegment* segmentA, b2Transform xfA,
 													const b2Polygon* polygonB, b2Transform xfB, b2DistanceCache* cache );
 
 /**@}*/

include/box2d/types.h

@@ -292,8 +292,8 @@ typedef enum b2ShapeType
 	/// A convex polygon
 	b2_polygonShape,
 
-	/// A smooth segment owned by a chain shape
-	b2_smoothSegmentShape,
+	/// A line segment owned by a chain shape
+	b2_chainSegmentShape,
 
 	/// The number of shape types
 	b2_shapeTypeCount
@@ -356,7 +356,7 @@ typedef struct b2ShapeDef
 /// @ingroup shape
 B2_API b2ShapeDef b2DefaultShapeDef( void );
 
-/// Used to create a chain of edges. This is designed to eliminate ghost collisions with some limitations.
+/// Used to create a chain of line segments. This is designed to eliminate ghost collisions with some limitations.
 ///	- chains are one-sided
 ///	- chains have no mass and should be used on static bodies
 ///	- chains have a counter-clockwise winding order
@@ -366,7 +366,7 @@ B2_API b2ShapeDef b2DefaultShapeDef( void );
 ///	- a chain shape should not self intersect (this is not validated)
 ///	- an open chain shape has NO COLLISION on the first and final edge
 ///	- you may overlap two open chains on their first three and/or last three points to get smooth collision
-///	- a chain shape creates multiple smooth edges shapes on the body
+///	- a chain shape creates multiple line segment shapes on the body
 /// https://en.wikipedia.org/wiki/Polygonal_chain
 /// Must be initialized using b2DefaultChainDef().
 ///	@warning Do not use chain shapes unless you understand the limitations. This is an advanced feature.

samples/CMakeLists.txt

@@ -45,6 +45,7 @@ add_library(imgui STATIC
 	${IMGUI_DIR}/backends/imgui_impl_glfw.cpp
 	${IMGUI_DIR}/backends/imgui_impl_opengl3.cpp
 )
+
 target_link_libraries(imgui PUBLIC glfw glad)
 target_include_directories(imgui PUBLIC ${IMGUI_DIR} ${IMGUI_DIR}/backends)
 target_compile_definitions(imgui PUBLIC IMGUI_DISABLE_OBSOLETE_FUNCTIONS)

samples/sample_bodies.cpp

@@ -289,7 +289,7 @@ static int sampleBodyType = RegisterSample( "Bodies", "Body Type", BodyType::Cre
 
 /// This is a test of typical character collision scenarios. This does not
 /// show how you should implement a character in your application.
-/// Instead this is used to test smooth collision on edge chains.
+/// Instead this is used to test smooth collision on chain shapes.
 class Character : public Sample
 {
 public:
@@ -347,7 +347,7 @@ class Character : public Sample
 
 		// Square tiles. This shows that adjacency shapes may have non-smooth collision. Box2D has no solution
 		// to this problem.
-		// TODO_ERIN try this: https://briansemrau.github.io/dealing-with-ghost-collisions/
+		// todo_erin try this: https://briansemrau.github.io/dealing-with-ghost-collisions/
 		{
 			b2BodyDef bodyDef = b2DefaultBodyDef();
 			b2BodyId groundId = b2CreateBody( m_worldId, &bodyDef );
@@ -454,8 +454,6 @@ class Character : public Sample
 		m_textLine += m_textIncrement;
 		g_draw.DrawString( 5, m_textLine, "Limitation: square and hexagon can snag on aligned boxes." );
 		m_textLine += m_textIncrement;
-		g_draw.DrawString( 5, m_textLine, "Feature: edge chains have smooth collision inside and out." );
-		m_textLine += m_textIncrement;
 	}
 
 	static Sample* Create( Settings& settings )