/// <summary>
/// Creates a part.
/// </summary>
/// <param name="primitiveProperties">Properties of the body's shape.</param>
/// <param name="massProperties">Properties of the body's mass.</param>
/// <param name="withMainController">Adds a main BasicController for this part.</param>
public Part(JLG.PrimitiveProperties primitiveProperties, MassProperties massProperties, bool withMainController)
: base()
{
_primitiveProperties = primitiveProperties;
_massProperties = massProperties;
if (withMainController)
{
// Create Main Controller
_mainController = new BasicController(this);
if (PhysicsSystem.CurrentPhysicsSystem != null)
{
PhysicsSystem.CurrentPhysicsSystem.AddController(_mainController);
}
}
_relatedControllers = new Hashtable();
}
public override void GetMassProperties(PrimitiveProperties primitiveProperties, out float mass, out Vector3 centerOfMass, out Matrix inertiaTensor)
{
mass = 0.0f;
centerOfMass = Vector3.Zero;
inertiaTensor = Matrix.Identity;
}
public override void GetMassProperties(PrimitiveProperties primitiveProperties, out float mass, out Vector3 centerOfMass, out Matrix inertiaTensor)
{
if (primitiveProperties.MassType == PrimitiveProperties.MassTypeEnum.Mass)
{
mass = primitiveProperties.MassOrDensity;
}
else
{
if (primitiveProperties.MassDistribution == PrimitiveProperties.MassDistributionEnum.Solid)
mass = GetVolume() * primitiveProperties.MassOrDensity;
else
mass = GetSurfaceArea() * primitiveProperties.MassOrDensity;
}
centerOfMass = transform.Position + 0.5f * length * MatrixHelper.GetBackward(transform.Orientation);
/// todo check solid/shell
// first cylinder
float cylinderMass = mass * MathHelper.Pi * radius * radius * length / GetVolume();
float Ixx = 0.5f * cylinderMass * radius * radius;
float Iyy = 0.25f * cylinderMass * radius * radius + (1.0f / 12.0f) * cylinderMass * length * length;
float Izz = Iyy;
// add ends
float endMass = mass - cylinderMass;
Ixx += 0.4f * endMass * radius * radius;
Iyy += 0.4f * endMass * radius * radius + endMass * (0.5f * length) * (0.5f * length);
Izz += 0.4f * endMass * radius * radius + endMass * (0.5f * length) * (0.5f * length);
inertiaTensor = Matrix.Identity;
inertiaTensor.M11 = Ixx;
inertiaTensor.M22 = Iyy;
inertiaTensor.M33 = Izz;
// transform - e.g. see p664 of Physics-Based Animation
// todo is the order correct here? Does it matter?
// Calculate the tensor in a frame at the CoM, but aligned with the world axes
inertiaTensor = transform.Orientation * inertiaTensor * Matrix.Transpose(transform.Orientation);
// Transfer of axe theorem
inertiaTensor.M11 = inertiaTensor.M11 + mass * (centerOfMass.Y * centerOfMass.Y + centerOfMass.Z * centerOfMass.Z);
inertiaTensor.M22 = inertiaTensor.M22 + mass * (centerOfMass.Z * centerOfMass.Z + centerOfMass.X * centerOfMass.X);
inertiaTensor.M33 = inertiaTensor.M33 + mass * (centerOfMass.X * centerOfMass.X + centerOfMass.Y * centerOfMass.Y);
inertiaTensor.M12 = inertiaTensor.M21 = inertiaTensor.M12 - mass * centerOfMass.X * centerOfMass.Y;
inertiaTensor.M23 = inertiaTensor.M32 = inertiaTensor.M23 - mass * centerOfMass.Y * centerOfMass.Z;
inertiaTensor.M31 = inertiaTensor.M13 = inertiaTensor.M31 - mass * centerOfMass.Z * centerOfMass.X;
}
/// <summary>
/// Returns the mass, center of mass, and intertia tensor around the origin
/// </summary>
/// <param name="primitiveProperties"></param>
/// <param name="mass"></param>
/// <param name="centerOfMass"></param>
/// <param name="inertiaTensor"></param>
public abstract void GetMassProperties(PrimitiveProperties primitiveProperties,
out float mass, out Vector3 centerOfMass, out Matrix inertiaTensor);
/// <summary>
/// Helper to calculate the combined mass, centre of mass, and
/// inertia tensor about the origin and the CoM (for the local
/// primitives) primitiveProperties is an array of properties -
/// must be the same number as there are primitives
/// </summary>
/// <param name="primitiveProperties"></param>
/// <param name="mass"></param>
/// <param name="centerOfMass"></param>
/// <param name="inertiaTensor"></param>
/// <param name="inertiaTensorCoM"></param>
public void GetMassProperties(PrimitiveProperties[] primitiveProperties,
out float mass, out Vector3 centerOfMass, out Matrix inertiaTensor, out Matrix inertiaTensorCoM)
{
mass = 0.0f;
centerOfMass = Vector3.Zero;
inertiaTensor = Matrix.Identity;
inertiaTensorCoM = Matrix.Identity;
for (int prim = primitivesLocal.Count; prim-- != 0; )
{
float m;
Vector3 com;
Matrix it;
primitivesLocal[prim].GetMassProperties(primitiveProperties[prim], out m, out com, out it);
mass += m;
centerOfMass += m * com;
inertiaTensor += it;
}
if (mass > 0.0f)
{
centerOfMass /= mass;
// Transfer of axe theorem
inertiaTensorCoM.M11 = inertiaTensor.M11 - mass * (centerOfMass.Y * centerOfMass.Y + centerOfMass.Z * centerOfMass.Z);
inertiaTensorCoM.M22 = inertiaTensor.M22 - mass * (centerOfMass.Z * centerOfMass.Z + centerOfMass.X * centerOfMass.X);
inertiaTensorCoM.M33 = inertiaTensor.M33 - mass * (centerOfMass.X * centerOfMass.X + centerOfMass.Y * centerOfMass.Y);
// CHECK THIS. seems strange for me
inertiaTensorCoM.M12 = inertiaTensorCoM.M21 = inertiaTensor.M12 + mass * centerOfMass.X * centerOfMass.Y;
inertiaTensorCoM.M23 = inertiaTensorCoM.M32 = inertiaTensor.M23 + mass * centerOfMass.Y * centerOfMass.Z;
inertiaTensorCoM.M31 = inertiaTensorCoM.M13 = inertiaTensor.M31 + mass * centerOfMass.Z * centerOfMass.X;
}
}
/// <summary>
/// Helper to calculate the combined mass, centre of mass, and
/// inertia tensor about the origin and the CoM (for the local
/// primitives) primitiveProperties indicates the properties used
/// for all primitives - so the mass is the total mass
/// </summary>
/// <param name="primitiveProperties"></param>
/// <param name="mass"></param>
/// <param name="centerOfMass"></param>
/// <param name="inertiaTensor"></param>
/// <param name="inertiaTensorCoM"></param>
public void GetMassProperties(PrimitiveProperties primitiveProperties,
out float mass, out Vector3 centerOfMass, out Matrix inertiaTensor, out Matrix inertiaTensorCoM)
{
mass = 0.0f;
centerOfMass = Vector3.Zero;
inertiaTensor = new Matrix();
float totalWeighting = 0.0f;
if (primitiveProperties.MassType == PrimitiveProperties.MassTypeEnum.Mass)
{
for (int prim = primitivesLocal.Count; prim-- != 0; )
{
if (primitiveProperties.MassDistribution == PrimitiveProperties.MassDistributionEnum.Solid)
totalWeighting += primitivesLocal[prim].GetVolume();
else
totalWeighting += primitivesLocal[prim].GetSurfaceArea();
}
}
for (int prim = primitivesLocal.Count; prim-- != 0; )
{
float m; Vector3 com; Matrix it;
PrimitiveProperties primProperties = primitiveProperties;
if (primitiveProperties.MassType == PrimitiveProperties.MassTypeEnum.Mass)
{
float weighting = 0.0f;
if (primitiveProperties.MassDistribution == PrimitiveProperties.MassDistributionEnum.Solid)
weighting = primitivesLocal[prim].GetVolume();
else
weighting = primitivesLocal[prim].GetSurfaceArea();
primProperties.MassOrDensity *= weighting / totalWeighting;
}
primitivesLocal[prim].GetMassProperties(primProperties, out m, out com, out it);
mass += m;
centerOfMass += m * com;
inertiaTensor += it;
}
inertiaTensorCoM = Matrix.Identity;
if (mass > 0.0f)
{
centerOfMass /= mass;
// Transfer of axe theorem
inertiaTensorCoM.M11 = inertiaTensor.M11 - mass * (centerOfMass.Y * centerOfMass.Y + centerOfMass.Z * centerOfMass.Z);
inertiaTensorCoM.M22 = inertiaTensor.M22 - mass * (centerOfMass.Z * centerOfMass.Z + centerOfMass.X * centerOfMass.X);
inertiaTensorCoM.M33 = inertiaTensor.M33 - mass * (centerOfMass.X * centerOfMass.X + centerOfMass.Y * centerOfMass.Y);
// CHECK THIS. seems strange for me
inertiaTensorCoM.M12 = inertiaTensorCoM.M21 = inertiaTensor.M12 + mass * centerOfMass.X * centerOfMass.Y;
inertiaTensorCoM.M23 = inertiaTensorCoM.M32 = inertiaTensor.M23 + mass * centerOfMass.Y * centerOfMass.Z;
inertiaTensorCoM.M31 = inertiaTensorCoM.M13 = inertiaTensor.M31 + mass * centerOfMass.Z * centerOfMass.X;
}
if (primitiveProperties.MassType == PrimitiveProperties.MassTypeEnum.Mass)
mass = primitiveProperties.MassOrDensity;
}
/// <summary>
/// Saves all needed information to recreate an physics world object.
/// </summary>
/// <param name="filePath"></param>
/// <param name="overwrite"></param>
/// <param name="skin"></param>
/// <param name="primitiveProperties"></param>
/// <param name="massProperties">"Null" will cause re-calculation of the mass properties. If you are saving loaded data: Re-calc might cause data loss!</param>
/// <returns></returns>
public static bool Save(string filePath, bool overwrite, CollisionSkin skin, PrimitiveProperties primitiveProperties, MassProperties? massProperties)
{
if (!File.Exists(filePath) || (File.Exists(filePath) && overwrite))
{
PhysicsObjectData data = new PhysicsObjectData();
data.SetPrimitiveProperties(primitiveProperties);
for (int i = 0; i < skin.NumPrimitives; i++)
{
data.Add(skin.GetPrimitiveLocal(i), skin.GetMaterialID(i), skin.GetMaterialProperties(i));
}
if (massProperties.HasValue)
{
data.MassProperties = massProperties.Value;
}
else
{
data.CalculateMassProperties();
}
XmlSerializer xmlSerializer = new XmlSerializer(typeof(PhysicsObjectData));
TextWriter textWriter = new StreamWriter(filePath);
xmlSerializer.Serialize(textWriter, data);
textWriter.Close();
return true;
}
else
{
MessageBox.Show("Can't write to file \"" + filePath + "\".", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
return false;
}
}
/// <summary>
/// Loads a physics world object.
/// </summary>
/// <param name="filePath"></param>
/// <param name="skin"></param>
/// <param name="body"></param>
/// <param name="massProperties"></param>
/// <returns></returns>
public static bool Load(string filePath, out CollisionSkin skin, out Body body, out PrimitiveProperties primitiveProperties, out MassProperties massProperties)
{
skin = null;
body = null;
primitiveProperties = new PrimitiveProperties(PrimitiveProperties.MassDistributionEnum.Solid, PrimitiveProperties.MassTypeEnum.Mass, 0.001f);
massProperties = MassProperties.Zero;
if (File.Exists(filePath))
{
XmlSerializer xmlSerializer = new XmlSerializer(typeof(PhysicsObjectData));
TextReader textReader = new StreamReader(filePath);
PhysicsObjectData data = (PhysicsObjectData)xmlSerializer.Deserialize(textReader);
textReader.Close();
if (data != null && data.MaterialPrimitivePairs != null && data.MaterialPrimitivePairs.Count > 0)
{
body = new JigLibSDX.Physics.Body();
skin = new JigLibSDX.Collision.CollisionSkin(body);
body.CollisionSkin = skin;
primitiveProperties = data.PrimitiveProperties;
for (int i = 0; i < data.MaterialPrimitivePairs.Count; i++)
{
if (data.MaterialPrimitivePairs[i].MaterialID == (int)MaterialTable.MaterialID.UserDefined)
{
skin.AddPrimitive(data.MaterialPrimitivePairs[i].Primitive, data.MaterialPrimitivePairs[i].MaterialID);
}
else
{
skin.AddPrimitive(data.MaterialPrimitivePairs[i].Primitive, data.MaterialPrimitivePairs[i].MaterialProperties);
}
}
massProperties = data.MassProperties;
body.BodyInertia = massProperties.InertiaTensorCoM;
body.Mass = massProperties.Mass;
body.MoveTo(Vector3.Zero, Matrix.Identity);
skin.ApplyLocalTransform(new Transform(-massProperties.CenterOfMass, Matrix.Identity));
body.EnableBody();
}
return true;
}
else
{
MessageBox.Show("File \"" + filePath + "\" not found.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
return false;
}
}
public void SetPrimitiveProperties(PrimitiveProperties primitiveProperties)
{
_primitiveProperties = primitiveProperties;
}
public override void GetMassProperties(PrimitiveProperties primitiveProperties, out float mass, out Vector3 centerOfMass, out Matrix inertiaTensor)
{
if (primitiveProperties.MassType == PrimitiveProperties.MassTypeEnum.Mass)
{
mass = primitiveProperties.MassOrDensity;
}
else
{
if (primitiveProperties.MassDistribution == PrimitiveProperties.MassDistributionEnum.Solid)
mass = GetVolume() * primitiveProperties.MassOrDensity;
else
mass = GetSurfaceArea() * primitiveProperties.MassOrDensity;
}
centerOfMass = GetCentre();
// First calculate inertia in local frame, then shift to origin
Vector3 sides = sideLengths;
// todo check solid/shell
float Ixx = (1.0f / 12.0f) * mass * (sides.Y * sides.Y + sides.Z * sides.Z);
float Iyy = (1.0f / 12.0f) * mass * (sides.X * sides.X + sides.Z * sides.Z);
float Izz = (1.0f / 12.0f) * mass * (sides.X * sides.X + sides.Y * sides.Y);
inertiaTensor = Matrix.Identity;
inertiaTensor.M11 = Ixx;
inertiaTensor.M22 = Iyy;
inertiaTensor.M33 = Izz;
// transform - e.g. see p664 of Physics-Based Animation
// todo is the order correct here? Does it matter?
// Calculate the tensor in a frame at the CoM, but aligned with the world axes
inertiaTensor = Matrix.Transpose(transform.Orientation) * inertiaTensor * transform.Orientation;
// Transfer of axe theorem
inertiaTensor.M11 = inertiaTensor.M11 + mass * (centerOfMass.Y * centerOfMass.Y + centerOfMass.Z * centerOfMass.Z);
inertiaTensor.M22 = inertiaTensor.M22 + mass * (centerOfMass.Z * centerOfMass.Z + centerOfMass.X * centerOfMass.X);
inertiaTensor.M33 = inertiaTensor.M33 + mass * (centerOfMass.X * centerOfMass.X + centerOfMass.Y * centerOfMass.Y);
inertiaTensor.M12 = inertiaTensor.M21 = inertiaTensor.M12 - mass * centerOfMass.X * centerOfMass.Y;
inertiaTensor.M23 = inertiaTensor.M32 = inertiaTensor.M23 - mass * centerOfMass.Y * centerOfMass.Z;
inertiaTensor.M31 = inertiaTensor.M13 = inertiaTensor.M31 - mass * centerOfMass.Z * centerOfMass.X;
}
private void Initialize(Primitive primitive, MaterialProperties materialProperties, PrimitiveProperties primitiveProperties, bool enableBody)
{
float mass;
Vector3 centerOfMass;
Matrix inertiaTensor;
Matrix inertiaTensorCoM;
// Set variables ...
_primitive = primitive;
_primitiveProperties = primitiveProperties;
_materialProperties = materialProperties;
// Create and link Body and CollisionSkin.
_body = new Body();
_skin = new CollisionSkin(_body);
_body.CollisionSkin = _skin;
// Add primitive to CollisionSkin.
_skin.AddPrimitive(primitive, materialProperties);
// Set body properties.
_skin.GetMassProperties(primitiveProperties, out mass, out centerOfMass, out inertiaTensor, out inertiaTensorCoM);
_body.BodyInertia = inertiaTensorCoM;
_body.Mass = mass;
// Sync CollisionSkin and Body.
_body.MoveTo(Vector3.Zero, Matrix.Identity);
_skin.ApplyLocalTransform(new Transform(-centerOfMass, Matrix.Identity));
// Enable Body.
if (enableBody)
{
_body.EnableBody();
}
else
{
_body.DisableBody();
}
}
/// <summary>
/// Initializes a new BasicObject.
/// </summary>
/// <param name="primitive">Primitive that will define the CollisionSkin.</param>
/// <param name="materialProperties"></param>
/// <param name="primitiveProperties"></param>
/// <param name="enableBody"></param>
public BasicObject(Primitive primitive, MaterialProperties materialProperties, PrimitiveProperties primitiveProperties, bool enableBody)
{
Initialize(primitive, materialProperties, primitiveProperties, enableBody);
}
/// <summary>
/// Initializes a new BasicObject. Body is enabled by default.
/// </summary>
/// <param name="primitive">Primitive that will define the CollisionSkin.</param>
/// <param name="materialProperties"></param>
/// <param name="primitiveProperties"></param>
public BasicObject(Primitive primitive, MaterialProperties materialProperties, PrimitiveProperties primitiveProperties)
{
Initialize(primitive, materialProperties, primitiveProperties, true);
}