added btCapsuleShapeX and btCapsuleShapeZ, for X and Z upaxis capsules. The default btCapsuleShape stays Y-axis, for backwards compatibility.

src/BulletCollision/CollisionShapes/btCapsuleShape.cpp

@@ -50,7 +50,9 @@ btCapsuleShape::btCapsuleShape(btScalar radius, btScalar height)
 
 
 	{
-		btVector3 pos(0,getHalfHeight(),0);
+		btVector3 pos(0,0,0);
+		pos[getUpAxis()] = getHalfHeight();
+
 		vtx = pos +vec*m_localScaling*(radius) - vec * getMargin();
 		newDot = vec.dot(vtx);
 		if (newDot > maxDot)
@@ -60,7 +62,9 @@ btCapsuleShape::btCapsuleShape(btScalar radius, btScalar height)
 		}
 	}
 	{
-		btVector3 pos(0,-getHalfHeight(),0);
+		btVector3 pos(0,0,0);
+		pos[getUpAxis()] = -getHalfHeight();
+
 		vtx = pos +vec*m_localScaling*(radius) - vec * getMargin();
 		newDot = vec.dot(vtx);
 		if (newDot > maxDot)
@@ -88,7 +92,8 @@ btCapsuleShape::btCapsuleShape(btScalar radius, btScalar height)
 		btVector3 vtx;
 		btScalar newDot;
 		{
-			btVector3 pos(0,getHalfHeight(),0);
+			btVector3 pos(0,0,0);
+			pos[getUpAxis()] = getHalfHeight();
 			vtx = pos +vec*m_localScaling*(radius) - vec * getMargin();
 			newDot = vec.dot(vtx);
 			if (newDot > maxDot)
@@ -98,7 +103,8 @@ btCapsuleShape::btCapsuleShape(btScalar radius, btScalar height)
 			}
 		}
 		{
-			btVector3 pos(0,-getHalfHeight(),0);
+			btVector3 pos(0,0,0);
+			pos[getUpAxis()] = -getHalfHeight();
 			vtx = pos +vec*m_localScaling*(radius) - vec * getMargin();
 			newDot = vec.dot(vtx);
 			if (newDot > maxDot)
@@ -122,7 +128,8 @@ void	btCapsuleShape::calculateLocalInertia(btScalar mass,btVector3& inertia) con
 	
 	btScalar radius = getRadius();
 
-	btVector3 halfExtents(radius,radius+getHalfHeight(),radius);
+	btVector3 halfExtents(radius,radius,radius);
+	halfExtents[getUpAxis()]+=getHalfHeight();
 
 	btScalar margin = CONVEX_DISTANCE_MARGIN;
 
@@ -140,6 +147,20 @@ void	btCapsuleShape::calculateLocalInertia(btScalar mass,btVector3& inertia) con
 
 }
 
+btCapsuleShapeX::btCapsuleShapeX(btScalar radius,btScalar height)
+{
+	m_implicitShapeDimensions.setValue(0.5f*height, radius,radius);
+}
+
+
+
+
+
+
+btCapsuleShapeZ::btCapsuleShapeZ(btScalar radius,btScalar height)
+{
+	m_implicitShapeDimensions.setValue(radius,radius,0.5f*height);
+}
 
 
 

src/BulletCollision/CollisionShapes/btCapsuleShape.h

@@ -22,8 +22,12 @@ subject to the following restrictions:
 
 ///btCapsuleShape represents a capsule around the Y axis
 ///A more general solution that can represent capsules is the btMultiSphereShape
+///the total height is height+2*radius, so the height is just the height between the center of each 'sphere' of the capsule caps.
 class btCapsuleShape : public btConvexInternalShape
 {
+protected:
+	///only used for btCapsuleShapeZ and btCapsuleShapeX subclasses.
+	btCapsuleShape() {};
 
 public:
 	btCapsuleShape(btScalar radius,btScalar height);
@@ -43,18 +47,82 @@ public:
 		return "CapsuleShape";
 	}
 
-	btScalar	getRadius() const
+	virtual int	getUpAxis() const
+	{
+		return 1;
+	}
+
+	virtual btScalar	getRadius() const
 	{
 		return m_implicitShapeDimensions.getX();
 	}
 
-	btScalar	getHalfHeight() const
+	virtual btScalar	getHalfHeight() const
 	{
 		return m_implicitShapeDimensions.getY();
 	}
 
 };
 
+///btCapsuleShapeX represents a capsule around the Z axis
+///the total height is height+2*radius, so the height is just the height between the center of each 'sphere' of the capsule caps.
+class btCapsuleShapeX : public btCapsuleShape
+{
+public:
+
+	btCapsuleShapeX(btScalar radius,btScalar height);
+	
+	virtual int	getUpAxis() const
+	{
+		return 0;
+	}
+
+		//debugging
+	virtual const char*	getName()const
+	{
+		return "CapsuleX";
+	}
+
+	virtual btScalar getRadius() const
+	{
+		return m_implicitShapeDimensions.getY();
+	}
+
+	virtual btScalar	getHalfHeight() const
+	{
+		return m_implicitShapeDimensions.getX();
+	}
+
+};
+
+///btCapsuleShapeZ represents a capsule around the Z axis
+///the total height is height+2*radius, so the height is just the height between the center of each 'sphere' of the capsule caps.
+class btCapsuleShapeZ : public btCapsuleShape
+{
+public:
+	btCapsuleShapeZ(btScalar radius,btScalar height);
+
+	virtual int	getUpAxis() const
+	{
+		return 2;
+	}
+		//debugging
+	virtual const char*	getName()const
+	{
+		return "CapsuleZ";
+	}
+
+	virtual btScalar getRadius() const
+	{
+		return m_implicitShapeDimensions.getX();
+	}
+
+	virtual btScalar	getHalfHeight() const
+	{
+		return m_implicitShapeDimensions.getZ();
+	}
+};
+
 
 
 #endif //BT_CAPSULE_SHAPE_H