Joint events (#942)

Added joint events for when a joint force or torque exceeds a specified
threshold.
Joint definitions now include a base `b2JointDef` for common properties.
Joint definitions now use local frames (b2Transform) instead of bespoke
local axes and reference angles.
The mouse and motor joints are now controlled by updating the joint
frames.
Flipped order of arguments in b2RelativeAngle to match similar
functions.
Improved joint debug draw.

Author: erincatto

CMakeLists.txt

@@ -31,6 +31,12 @@ if (MSVC OR APPLE)
 			add_compile_options(-fsanitize=address -fsanitize-address-use-after-scope -fsanitize=undefined)
 			add_link_options(-fsanitize=address -fsanitize-address-use-after-scope -fsanitize=undefined)
 		endif()
+	else()
+		if(MSVC AND PROJECT_IS_TOP_LEVEL)
+			# enable hot reloading
+			add_compile_options("$<$<CONFIG:Debug>:/ZI>")
+			add_link_options("$<$<CONFIG:Debug>:/INCREMENTAL>")
+		endif()
 	endif()
 endif()
 
@@ -67,13 +73,6 @@ if(PROJECT_IS_TOP_LEVEL)
 	option(BOX2D_UNIT_TESTS "Build the Box2D unit tests" ON)
 
 	if(BOX2D_UNIT_TESTS OR BOX2D_SAMPLES OR BOX2D_BENCHMARKS)
-
-		if(MSVC AND NOT BOX2D_SANITIZE)
-			# enable hot reloading
-			add_compile_options("$<$<CONFIG:Debug>:/ZI>")
-			add_link_options("$<$<CONFIG:Debug>:/INCREMENTAL>")
-		endif()
-
 		# Emscripten pthread support for enkiTS
 		if(EMSCRIPTEN)
 			set(EMSCRIPTEN_PTHREADS_COMPILER_FLAGS "-pthread -s USE_PTHREADS=1")

include/box2d/box2d.h

@@ -50,6 +50,9 @@ B2_API b2SensorEvents b2World_GetSensorEvents( b2WorldId worldId );
 /// Get contact events for this current time step. The event data is transient. Do not store a reference to this data.
 B2_API b2ContactEvents b2World_GetContactEvents( b2WorldId worldId );
 
+/// Get the joint events for the current time step. The event data is transient. Do not store a reference to this data.
+B2_API b2JointEvents b2World_GetJointEvents( b2WorldId worldId );
+
 /// Overlap test for all shapes that *potentially* overlap the provided AABB
 B2_API b2TreeStats b2World_OverlapAABB( b2WorldId worldId, b2AABB aabb, b2QueryFilter filter, b2OverlapResultFcn* fcn,
 										void* context );
@@ -745,29 +748,17 @@ B2_API b2BodyId b2Joint_GetBodyB( b2JointId jointId );
 /// Get the world that owns this joint
 B2_API b2WorldId b2Joint_GetWorld( b2JointId jointId );
 
-/// Set the local anchor on bodyA
-B2_API void b2Joint_SetLocalAnchorA( b2JointId jointId, b2Vec2 localAnchor );
-
-/// Get the local anchor on bodyA
-B2_API b2Vec2 b2Joint_GetLocalAnchorA( b2JointId jointId );
-
-/// Set the local anchor on bodyB
-B2_API void b2Joint_SetLocalAnchorB( b2JointId jointId, b2Vec2 localAnchor );
+/// Set the local frame on bodyA
+B2_API void b2Joint_SetLocalFrameA( b2JointId jointId, b2Transform localFrame );
 
-/// Get the local anchor on bodyB
-B2_API b2Vec2 b2Joint_GetLocalAnchorB( b2JointId jointId );
+/// Get the local frame on bodyA
+B2_API b2Transform b2Joint_GetLocalFrameA( b2JointId jointId );
 
-/// Get the joint reference angle in radians (revolute, prismatic, and weld)
-B2_API float b2Joint_GetReferenceAngle( b2JointId jointId );
+/// Set the local frame on bodyB
+B2_API void b2Joint_SetLocalFrameB( b2JointId jointId, b2Transform localFrame );
 
-/// Set the joint reference angle in radians, must be in [-pi,pi]. (revolute, prismatic, and weld)
-B2_API void b2Joint_SetReferenceAngle( b2JointId jointId, float angleInRadians );
-
-/// Set the local axis on bodyA (prismatic and wheel)
-B2_API void b2Joint_SetLocalAxisA( b2JointId jointId, b2Vec2 localAxis );
-
-/// Get the local axis on bodyA (prismatic and wheel)
-B2_API b2Vec2 b2Joint_GetLocalAxisA( b2JointId jointId );
+/// Get the local frame on bodyB
+B2_API b2Transform b2Joint_GetLocalFrameB( b2JointId jointId );
 
 /// Toggle collision between connected bodies
 B2_API void b2Joint_SetCollideConnected( b2JointId jointId, bool shouldCollide );
@@ -887,29 +878,15 @@ B2_API float b2DistanceJoint_GetMotorForce( b2JointId jointId );
  * @defgroup motor_joint Motor Joint
  * @brief Functions for the motor joint.
  *
- * The motor joint is used to drive the relative transform between two bodies. It takes
- * a relative position and rotation and applies the forces and torques needed to achieve
- * that relative transform over time.
+ * The motor joint is used to drive the relative transform between two bodies. The target
+ * is set by updating the local frames using b2Joint_SetLocalFrameA or b2Joint_SetLocalFrameB.
  * @{
  */
 
 /// Create a motor joint
 /// @see b2MotorJointDef for details
 B2_API b2JointId b2CreateMotorJoint( b2WorldId worldId, const b2MotorJointDef* def );
 
-/// Set the motor joint linear offset target
-B2_API void b2MotorJoint_SetLinearOffset( b2JointId jointId, b2Vec2 linearOffset );
-
-/// Get the motor joint linear offset target
-B2_API b2Vec2 b2MotorJoint_GetLinearOffset( b2JointId jointId );
-
-/// Set the motor joint angular offset target in radians. This angle will be unwound
-/// so the motor will drive along the shortest arc.
-B2_API void b2MotorJoint_SetAngularOffset( b2JointId jointId, float angularOffset );
-
-/// Get the motor joint angular offset target in radians
-B2_API float b2MotorJoint_GetAngularOffset( b2JointId jointId );
-
 /// Set the motor joint maximum force, usually in newtons
 B2_API void b2MotorJoint_SetMaxForce( b2JointId jointId, float maxForce );
 
@@ -943,12 +920,6 @@ B2_API float b2MotorJoint_GetCorrectionFactor( b2JointId jointId );
 /// @see b2MouseJointDef for details
 B2_API b2JointId b2CreateMouseJoint( b2WorldId worldId, const b2MouseJointDef* def );
 
-/// Set the mouse joint target
-B2_API void b2MouseJoint_SetTarget( b2JointId jointId, b2Vec2 target );
-
-/// Get the mouse joint target
-B2_API b2Vec2 b2MouseJoint_GetTarget( b2JointId jointId );
-
 /// Set the mouse joint spring stiffness in Hertz
 B2_API void b2MouseJoint_SetSpringHertz( b2JointId jointId, float hertz );
 

include/box2d/math_functions.h

@@ -92,6 +92,9 @@ B2_API bool b2IsValidVec2( b2Vec2 v );
 /// Is this a valid rotation? Not NaN or infinity. Is normalized.
 B2_API bool b2IsValidRotation( b2Rot q );
 
+/// Is this a valid transform? Not NaN or infinity. Rotation is normalized.
+B2_API bool b2IsValidTransform( b2Transform t );
+
 /// Is this a valid bounding box? Not Nan or infinity. Upper bound greater than or equal to lower bound.
 B2_API bool b2IsValidAABB( b2AABB aabb );
 
@@ -373,6 +376,13 @@ B2_INLINE b2Rot b2MakeRot( float radians )
 	return B2_LITERAL( b2Rot ){ cs.cosine, cs.sine };
 }
 
+/// Make a rotation using a unit vector
+B2_INLINE b2Rot b2MakeRotFromUnitVector( b2Vec2 unitVector )
+{
+	B2_ASSERT( b2IsNormalized( unitVector ) );
+	return B2_LITERAL( b2Rot ){ unitVector.x, unitVector.y };
+}
+
 /// Compute the rotation between two unit vectors
 B2_API b2Rot b2ComputeRotationBetweenUnitVectors( b2Vec2 v1, b2Vec2 v2 );
 
@@ -454,26 +464,27 @@ B2_INLINE b2Rot b2MulRot( b2Rot q, b2Rot r )
 	return qr;
 }
 
-/// Transpose multiply two rotations: qT * r
-B2_INLINE b2Rot b2InvMulRot( b2Rot q, b2Rot r )
+/// Transpose multiply two rotations: inv(a) * b
+/// This rotates a vector local in frame b into a vector local in frame a
+B2_INLINE b2Rot b2InvMulRot( b2Rot a, b2Rot b )
 {
-	// [ qc qs] * [rc -rs] = [qc*rc+qs*rs -qc*rs+qs*rc]
-	// [-qs qc]   [rs  rc]   [-qs*rc+qc*rs qs*rs+qc*rc]
-	// s(q - r) = qc * rs - qs * rc
-	// c(q - r) = qc * rc + qs * rs
-	b2Rot qr;
-	qr.s = q.c * r.s - q.s * r.c;
-	qr.c = q.c * r.c + q.s * r.s;
-	return qr;
+	// [ ac as] * [bc -bs] = [ac*bc+qs*bs -ac*bs+as*bc]
+	// [-as ac]   [bs  bc]   [-as*bc+ac*bs as*bs+ac*bc]
+	// s(a - b) = ac * bs - as * bc
+	// c(a - b) = ac * bc + as * bs
+	b2Rot r;
+	r.s = a.c * b.s - a.s * b.c;
+	r.c = a.c * b.c + a.s * b.s;
+	return r;
 }
 
-/// relative angle between b and a (rot_b * inv(rot_a))
-B2_INLINE float b2RelativeAngle( b2Rot b, b2Rot a )
+/// Relative angle between a and b
+B2_INLINE float b2RelativeAngle( b2Rot a, b2Rot b )
 {
 	// sin(b - a) = bs * ac - bc * as
 	// cos(b - a) = bc * ac + bs * as
-	float s = b.s * a.c - b.c * a.s;
-	float c = b.c * a.c + b.s * a.s;
+	float s = a.c * b.s - a.s * b.c;
+	float c = a.c *b.c + a.s * b.s;
 	return b2Atan2( s, c );
 }