Body API now only uses b2Rot and no angles directly.

docs/hello.md

@@ -226,8 +226,8 @@ for (int i = 0; i < 90; ++i)
 {
 	b2World_Step(worldId, timeStep, subStepCount);
     b2Vec2 position = b2Body_GetPosition(bodyId);
-    float angle = b2Body_GetAngle(bodyId);
-    printf("%4.2f %4.2f %4.2f\n", position.x, position.y, angle);
+    b2Rot rotation = b2Body_GetRot(bodyId);
+    printf("%4.2f %4.2f %4.2f\n", position.x, position.y, b2Rot_GetAngle(rotation));
 }
 ```
 

docs/simulation.md

@@ -506,11 +506,11 @@ simulate movement.
 Keep in mind that the Box2D interface uses *radians*.
 
 ```c
-b2Body_SetTransform(myBodyId, position, angleInRadians);
+b2Body_SetTransform(myBodyId, position, rotation);
 b2Transform transform = b2Body_GetTransform(myBodyId);
 b2Vec2 position = b2Body_GetPosition(myBodyId);
 b2Rot rotation = b2Body_GetRotation(myBodyId);
-float angleInRadians = b2Body_GetAngle(myBodyId);
+float angleInRadians = b2Rot_GetAngle(rotation);
 ```
 
 You can access the center of mass position in local and world

include/box2d/box2d.h

@@ -200,16 +200,13 @@ B2_API b2Vec2 b2Body_GetPosition(b2BodyId bodyId);
 /// Get the world rotation of a body as a cosine/sine pair (complex number)
 B2_API b2Rot b2Body_GetRotation(b2BodyId bodyId);
 
-/// Get the body angle in radians in the range [-pi, pi]
-B2_API float b2Body_GetAngle(b2BodyId bodyId);
-
 /// Get the world transform of a body.
 B2_API b2Transform b2Body_GetTransform(b2BodyId bodyId);
 
 /// Set the world transform of a body. This acts as a teleport and is fairly expensive.
 /// @note Generally you should create a body with then intended transform.
 ///	@see b2BodyDef::position and b2BodyDef::angle
-B2_API void b2Body_SetTransform(b2BodyId bodyId, b2Vec2 position, float angle);
+B2_API void b2Body_SetTransform(b2BodyId bodyId, b2Vec2 position, b2Rot rotation);
 
 /// Get a local point on a body given a world point
 B2_API b2Vec2 b2Body_GetLocalPoint(b2BodyId bodyId, b2Vec2 worldPoint);

include/box2d/math_functions.h

@@ -262,7 +262,7 @@ B2_INLINE float b2DistanceSquared(b2Vec2 a, b2Vec2 b)
 	return c.x * c.x + c.y * c.y;
 }
 
-/// Set using an angle in radians
+/// Make a rotation using an angle in radians
 B2_INLINE b2Rot b2MakeRot(float angle)
 {
 	// todo determinism
@@ -336,7 +336,7 @@ B2_INLINE float b2ComputeAngularVelocity(b2Rot q1, b2Rot q2, float inv_h)
 	return omega;
 }
 
-/// Get the angle in radians
+/// Get the angle in radians in the range [-pi, pi]
 B2_INLINE float b2Rot_GetAngle(b2Rot q)
 {
 	// todo determinism

include/box2d/types.h

@@ -149,8 +149,8 @@ typedef struct b2BodyDef
 	///	if the body is moved after shapes have been added.
 	b2Vec2 position;
 
-	/// The initial world angle of the body in radians.
-	float angle;
+	/// The initial world rotation of the body. Use b2MakeRot() if you have an angle.
+	b2Rot rotation;
 
 	/// The initial linear velocity of the body's origin. Typically in meters per second.
 	b2Vec2 linearVelocity;

samples/donut.cpp

@@ -51,7 +51,7 @@ void Donut::Spawn(b2WorldId worldId, b2Vec2 position, float scale, int groupInde
 	for (int i = 0; i < e_sides; ++i)
 	{
 		bodyDef.position = {radius * cosf(angle) + center.x, radius * sinf(angle) + center.y};
-		bodyDef.angle = angle;
+		bodyDef.rotation = b2MakeRot(angle);
 
 		m_bodyIds[i] = b2CreateBody(worldId, &bodyDef);
 		b2CreateCapsuleShape(m_bodyIds[i], &shapeDef, &capsule);

samples/sample_bodies.cpp

@@ -334,7 +334,7 @@ class Character : public Sample
 		// Chain shape
 		{
 			b2BodyDef bodyDef = b2DefaultBodyDef();
-			bodyDef.angle = 0.25f * b2_pi;
+			bodyDef.rotation = b2MakeRot(0.25f * b2_pi);
 			b2BodyId groundId = b2CreateBody(m_worldId, &bodyDef);
 
 			b2Vec2 points[4] = {{8.0f, 7.0f}, {7.0f, 8.0f}, {6.0f, 8.0f}, {5.0f, 7.0f}};
@@ -498,7 +498,7 @@ class Weeble : public Sample
 			b2BodyDef bodyDef = b2DefaultBodyDef();
 			bodyDef.type = b2_dynamicBody;
 			bodyDef.position = {0.0f, 3.0f};
-			bodyDef.angle = 0.25f * b2_pi;
+			bodyDef.rotation = b2MakeRot(0.25f * b2_pi);
 			m_weebleId = b2CreateBody(m_worldId, &bodyDef);
 
 			b2Capsule capsule = {{0.0f, -1.0f}, {0.0f, 1.0f}, 1.0f};
@@ -531,7 +531,7 @@ class Weeble : public Sample
 		ImGui::Begin("Weeble", nullptr, ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoResize);
 		if (ImGui::Button("Teleport"))
 		{
-			b2Body_SetTransform(m_weebleId, {0.0f, 5.0f}, 0.95 * b2_pi);
+			b2Body_SetTransform(m_weebleId, {0.0f, 5.0f}, b2MakeRot(0.95 * b2_pi));
 		}
 
 		if (ImGui::Button("Explode"))
@@ -789,7 +789,7 @@ class BadBody : public Sample
 			bodyDef.type = b2_dynamicBody;
 			bodyDef.position = {0.0f, 3.0f};
 			bodyDef.angularVelocity = 0.2f;
-			bodyDef.angle = 0.25f * b2_pi;
+			bodyDef.rotation = b2MakeRot(0.25f * b2_pi);
 
 			m_badBodyId = b2CreateBody(m_worldId, &bodyDef);
 
@@ -806,7 +806,7 @@ class BadBody : public Sample
 			b2BodyDef bodyDef = b2DefaultBodyDef();
 			bodyDef.type = b2_dynamicBody;
 			bodyDef.position = {2.0f, 3.0f};
-			bodyDef.angle = 0.25f * b2_pi;
+			bodyDef.rotation = b2MakeRot(0.25f * b2_pi);
 
 			b2BodyId bodyId = b2CreateBody(m_worldId, &bodyDef);
 

samples/sample_collision.cpp

@@ -1469,7 +1469,7 @@ class RayCastWorld : public Sample
 
 		b2BodyDef bodyDef = b2DefaultBodyDef();
 		bodyDef.position = {x, y};
-		bodyDef.angle = RandomFloat(-b2_pi, b2_pi);
+		bodyDef.rotation = b2MakeRot(RandomFloat(-b2_pi, b2_pi));
 
 		m_bodyIds[m_bodyIndex] = b2CreateBody(m_worldId, &bodyDef);
 
@@ -1954,7 +1954,7 @@ class OverlapWorld : public Sample
 
 		b2BodyDef bodyDef = b2DefaultBodyDef();
 		bodyDef.position = {x, y};
-		bodyDef.angle = RandomFloat(-b2_pi, b2_pi);
+		bodyDef.rotation = b2MakeRot(RandomFloat(-b2_pi, b2_pi));
 
 		m_bodyIds[m_bodyIndex] = b2CreateBody(m_worldId, &bodyDef);
 

samples/sample_events.cpp

@@ -409,7 +409,7 @@ class ContactEvent : public Sample
 		b2BodyDef bodyDef = b2DefaultBodyDef();
 		bodyDef.type = b2_dynamicBody;
 		bodyDef.position = {RandomFloat(-38.0f, 38.0f), RandomFloat(-38.0f, 38.0f)};
-		bodyDef.angle = RandomFloat(-b2_pi, b2_pi);
+		bodyDef.rotation = b2MakeRot(RandomFloat(-b2_pi, b2_pi));
 		bodyDef.linearVelocity = {RandomFloat(-5.0f, 5.0f), RandomFloat(-5.0f, 5.0f)};
 		bodyDef.angularVelocity = RandomFloat(-1.0f, 1.0f);
 		bodyDef.gravityScale = 0.0f;

samples/sample_joints.cpp

@@ -2259,12 +2259,12 @@ class ScissorLift : public Sample
 		for (int i = 0; i < N; ++i)
 		{
 			bodyDef.position = {0.0f, y};
-			bodyDef.angle = 0.15f;
+			bodyDef.rotation = b2MakeRot(0.15f);
 			b2BodyId bodyId1 = b2CreateBody(m_worldId, &bodyDef);
 			b2CreateCapsuleShape(bodyId1, &shapeDef, &capsule);
 
 			bodyDef.position = {0.0f, y};
-			bodyDef.angle = -0.15f;
+			bodyDef.rotation = b2MakeRot(-0.15f);
 
 			b2BodyId bodyId2 = b2CreateBody(m_worldId, &bodyDef);
 			b2CreateCapsuleShape(bodyId2, &shapeDef, &capsule);
@@ -2333,7 +2333,7 @@ class ScissorLift : public Sample
 		}
 
 		bodyDef.position = {0.0f, y};
-		bodyDef.angle = 0.0f;
+		bodyDef.rotation = b2Rot_identity;
 		b2BodyId platformId = b2CreateBody(m_worldId, &bodyDef);
 
 		b2Polygon box = b2MakeBox(3.0f, 0.2f);

samples/sample_shapes.cpp

@@ -329,7 +329,7 @@ class CompoundShapes : public Sample
 			b2BodyDef bodyDef = b2DefaultBodyDef();
 			bodyDef.type = b2_dynamicBody;
 			bodyDef.position = b2Body_GetPosition(m_table1Id);
-			bodyDef.angle = b2Body_GetAngle(m_table1Id);
+			bodyDef.rotation = b2Body_GetRotation(m_table1Id);
 			b2BodyId bodyId = b2CreateBody(m_worldId, &bodyDef);
 
 			b2ShapeDef shapeDef = b2DefaultShapeDef();
@@ -342,7 +342,7 @@ class CompoundShapes : public Sample
 			b2BodyDef bodyDef = b2DefaultBodyDef();
 			bodyDef.type = b2_dynamicBody;
 			bodyDef.position = b2Body_GetPosition(m_table2Id);
-			bodyDef.angle = b2Body_GetAngle(m_table2Id);
+			bodyDef.rotation = b2Body_GetRotation(m_table2Id);
 			b2BodyId bodyId = b2CreateBody(m_worldId, &bodyDef);
 
 			b2ShapeDef shapeDef = b2DefaultShapeDef();
@@ -355,7 +355,7 @@ class CompoundShapes : public Sample
 			b2BodyDef bodyDef = b2DefaultBodyDef();
 			bodyDef.type = b2_dynamicBody;
 			bodyDef.position = b2Body_GetPosition(m_ship1Id);
-			bodyDef.angle = b2Body_GetAngle(m_ship1Id);
+			bodyDef.rotation = b2Body_GetRotation(m_ship1Id);
 			// bodyDef.gravityScale = 0.0f;
 			b2BodyId bodyId = b2CreateBody(m_worldId, &bodyDef);
 
@@ -369,7 +369,7 @@ class CompoundShapes : public Sample
 			b2BodyDef bodyDef = b2DefaultBodyDef();
 			bodyDef.type = b2_dynamicBody;
 			bodyDef.position = b2Body_GetPosition(m_ship2Id);
-			bodyDef.angle = b2Body_GetAngle(m_ship2Id);
+			bodyDef.rotation = b2Body_GetRotation(m_ship2Id);
 			// bodyDef.gravityScale = 0.0f;
 			b2BodyId bodyId = b2CreateBody(m_worldId, &bodyDef);
 

samples/sample_stacking.cpp

@@ -854,20 +854,20 @@ class CardHouse : public Sample
 				if (i != Nb - 1)
 				{
 					bodyDef.position = {z + 0.25f, y + cardHeight - 0.015f};
-					bodyDef.angle = angle2;
+					bodyDef.rotation = b2MakeRot(angle2);
 					b2BodyId bodyId = b2CreateBody(m_worldId, &bodyDef);
 					b2CreatePolygonShape(bodyId, &shapeDef, &cardBox);
 				}
 
 				bodyDef.position = {z, y};
-				bodyDef.angle = angle1;
+				bodyDef.rotation = b2MakeRot(angle1);
 				b2BodyId bodyId = b2CreateBody(m_worldId, &bodyDef);
 				b2CreatePolygonShape(bodyId, &shapeDef, &cardBox);
 
 				z += 0.175f;
 
 				bodyDef.position = {z, y};
-				bodyDef.angle = angle0;
+				bodyDef.rotation = b2MakeRot(angle0);
 				bodyId = b2CreateBody(m_worldId, &bodyDef);
 				b2CreatePolygonShape(bodyId, &shapeDef, &cardBox);
 

src/body.c

@@ -179,7 +179,7 @@ b2BodyId b2CreateBody(b2WorldId worldId, const b2BodyDef* def)
 {
 	b2CheckDef(def);
 	B2_ASSERT(b2Vec2_IsValid(def->position));
-	B2_ASSERT(b2IsValid(def->angle));
+	B2_ASSERT(b2Rot_IsValid(def->rotation));
 	B2_ASSERT(b2Vec2_IsValid(def->linearVelocity));
 	B2_ASSERT(b2IsValid(def->angularVelocity));
 	B2_ASSERT(b2IsValid(def->linearDamping) && def->linearDamping >= 0.0f);
@@ -236,7 +236,7 @@ b2BodyId b2CreateBody(b2WorldId worldId, const b2BodyDef* def)
 	b2BodySim* bodySim = b2AddBodySim(&set->sims);
 	*bodySim = (b2BodySim){0};
 	bodySim->transform.p = def->position;
-	bodySim->transform.q = b2MakeRot(def->angle);
+	bodySim->transform.q = def->rotation;
 	bodySim->center = def->position;
 	bodySim->rotation0 = bodySim->transform.q;
 	bodySim->center0 = bodySim->center;
@@ -633,14 +633,6 @@ b2Rot b2Body_GetRotation(b2BodyId bodyId)
 	return transform.q;
 }
 
-float b2Body_GetAngle(b2BodyId bodyId)
-{
-	b2World* world = b2GetWorld(bodyId.world0);
-	b2Body* body = b2GetBodyFullId(world, bodyId);
-	b2Transform transform = b2GetBodyTransformQuick(world, body);
-	return b2Rot_GetAngle(transform.q);
-}
-
 b2Transform b2Body_GetTransform(b2BodyId bodyId)
 {
 	b2World* world = b2GetWorld(bodyId.world0);
@@ -680,8 +672,10 @@ b2Vec2 b2Body_GetWorldVector(b2BodyId bodyId, b2Vec2 localVector)
 	return b2RotateVector(transform.q, localVector);
 }
 
-void b2Body_SetTransform(b2BodyId bodyId, b2Vec2 position, float angle)
+void b2Body_SetTransform(b2BodyId bodyId, b2Vec2 position, b2Rot rotation)
 {
+	B2_ASSERT(b2Vec2_IsValid(position));
+	B2_ASSERT(b2Rot_IsValid(rotation));
 	B2_ASSERT(b2Body_IsValid(bodyId));
 	b2World* world = b2GetWorld(bodyId.world0);
 	B2_ASSERT(world->locked == false);
@@ -690,7 +684,7 @@ void b2Body_SetTransform(b2BodyId bodyId, b2Vec2 position, float angle)
 	b2BodySim* bodySim = b2GetBodySim(world, body);
 
 	bodySim->transform.p = position;
-	bodySim->transform.q = b2MakeRot(angle);
+	bodySim->transform.q = rotation;
 	bodySim->center = b2TransformPoint(bodySim->transform, bodySim->localCenter);
 
 	bodySim->rotation0 = bodySim->transform.q;

src/types.c

@@ -27,6 +27,7 @@ b2BodyDef b2DefaultBodyDef(void)
 {
 	b2BodyDef def = {0};
 	def.type = b2_staticBody;
+	def.rotation = b2Rot_identity;
 	def.sleepThreshold = 0.05f * b2_lengthUnitsPerMeter;
 	def.gravityScale = 1.0f;
 	def.enableSleep = true;

test/test_determinism.c

@@ -25,7 +25,7 @@ enum
 };
 
 b2Vec2 finalPositions[2][e_count];
-float finalAngles[2][e_count];
+b2Rot finalRotations[2][e_count];
 
 typedef struct TaskData
 {
@@ -162,7 +162,7 @@ void TiltedStacks(int testIndex, int workerCount)
 	for (int i = 0; i < e_count; ++i)
 	{
 		finalPositions[testIndex][i] = b2Body_GetPosition(bodies[i]);
-		finalAngles[testIndex][i] = b2Body_GetAngle(bodies[i]);
+		finalRotations[testIndex][i] = b2Body_GetRotation(bodies[i]);
 	}
 
 	b2DestroyWorld(worldId);
@@ -189,12 +189,13 @@ int DeterminismTest(void)
 	{
 		b2Vec2 p1 = finalPositions[0][i];
 		b2Vec2 p2 = finalPositions[1][i];
-		float a1 = finalAngles[0][i];
-		float a2 = finalAngles[1][i];
+		b2Rot rot1 = finalRotations[0][i];
+		b2Rot rot2 = finalRotations[1][i];
 
 		ENSURE(p1.x == p2.x);
 		ENSURE(p1.y == p2.y);
-		ENSURE(a1 == a2);
+		ENSURE(rot1.c == rot2.c);
+		ENSURE(rot1.s == rot2.s);
 	}
 
 	return 0;

test/test_world.c

@@ -68,7 +68,7 @@ int HelloWorld(void)
 	int subStepCount = 4;
 
 	b2Vec2 position = b2Body_GetPosition(bodyId);
-	float angle = b2Body_GetAngle(bodyId);
+	b2Rot rotation = b2Body_GetRotation(bodyId);
 
 	// This is our little game loop.
 	for (int i = 0; i < 90; ++i)
@@ -79,9 +79,9 @@ int HelloWorld(void)
 
 		// Now print the position and angle of the body.
 		position = b2Body_GetPosition(bodyId);
-		angle = b2Body_GetAngle(bodyId);
+		rotation = b2Body_GetRotation(bodyId);
 
-		//printf("%4.2f %4.2f %4.2f\n", position.x, position.y, angle);
+		//printf("%4.2f %4.2f %4.2f\n", position.x, position.y, b2Rot_GetAngle(rotation));
 	}
 
 	// When the world destructor is called, all bodies and joints are freed. This can
@@ -90,7 +90,7 @@ int HelloWorld(void)
 
 	ENSURE(b2AbsFloat(position.x) < 0.01f);
 	ENSURE(b2AbsFloat(position.y - 1.00f) < 0.01f);
-	ENSURE(b2AbsFloat(angle) < 0.01f);
+	ENSURE(b2AbsFloat(b2Rot_GetAngle(rotation)) < 0.01f);
 
 	return 0;
 }