public static CGSize Size(this SCNNode self)
{
SCNVector3 min = SCNVector3.Zero, max = SCNVector3.Zero;
self.GetBoundingBox(ref min, ref max);
return(new CGSize(max.X - min.X, max.Y - min.Y));
}
public static void Center(this SCNNode self)
{
SCNVector3 min = SCNVector3.Zero, max = SCNVector3.Zero;
self.GetBoundingBox(ref min, ref max);
self.Pivot = SCNMatrix4.CreateTranslation(min.X + (self.Width() * 0.5F), min.Y + (self.Height() * 0.5F), 0);
}
public static SCNVector3 GetExtents(this SCNNode self)
{
var min = default(SCNVector3);
var max = default(SCNVector3);
self.GetBoundingBox(ref min, ref max);
return(max - min);
}
private void CenterPivot(SCNNode node)
{
var min = new SCNVector3();
var max = new SCNVector3();
if (node.GetBoundingBox(ref min, ref max))
{
node.Pivot = new SCNMatrix4(CATransform3D.MakeTranslation(
min.X + (max.X - min.X) / 2,
min.Y + (max.Y - min.Y) / 2,
min.Z + (max.Z - min.Z) / 2));
}
}
// Returns the size of the horizontal parts of the node's bounding box.
// x is the width, y is the depth.
public static OpenTK.Vector2 GetHorizontalSize(this SCNNode node)
{
var minBox = SCNVector3.Zero;
var maxBox = SCNVector3.Zero;
node.GetBoundingBox(ref minBox, ref maxBox);
// Scene is y-up, horizontal extent is calculated on x and z
var sceneWidth = Math.Abs(maxBox.X - minBox.X);
var sceneLength = Math.Abs(maxBox.Z - minBox.Z);
return(new OpenTK.Vector2(sceneWidth, sceneLength));
}
public static void CalculateMassFromDensity(this SCNNode node, string name, float density)
{
if (node.PhysicsBody != null)
{
// our naming convention lets us parse the shape geometry
var boundingBoxMin = SCNVector3.Zero;
var boundingBoxMax = SCNVector3.Zero;
node.GetBoundingBox(ref boundingBoxMin, ref boundingBoxMax);
var bounds = (boundingBoxMax - boundingBoxMin);
// calculate as a cylinder going up
if (node.Name.StartsWith("block_cylinder", StringComparison.Ordinal))
{
var radius = bounds.X / 2f;
var mass = (float)Math.PI * radius * radius * bounds.Y;
node.PhysicsBody.Mass = density * mass;
}
else if (node.Name.StartsWith("block_halfCylinder", StringComparison.Ordinal))
{
// half cylinder going up
var radius = Math.Min(bounds.X, bounds.Z);
var mass = (float)Math.PI * radius * radius * bounds.Y / 2f;
node.PhysicsBody.Mass = density * mass;
}
else if (node.Name.StartsWith("block_quarterCylinder", StringComparison.Ordinal))
{
// this is a cylinder lying sideways
var radius = Math.Min(bounds.Y, bounds.Z);
var mass = (float)Math.PI * radius * radius * bounds.X / 4f;
node.PhysicsBody.Mass = density * mass;
}
else
{
// for now, treat as box shape
node.PhysicsBody.Mass = density * bounds.X * bounds.Y * bounds.Z;
}
}
}
private SCNNode SetupVehicle(SCNScene scene)
{
var carScene = SCNScene.FromFile("rc_car", ResourceManager.ResourceFolder, (NSDictionary)null);
var chassisNode = carScene.RootNode.FindChildNode("rccarBody", false);
chassisNode.Position = new SCNVector3(0f, 10f, 30f);
chassisNode.Rotation = new SCNVector4(0f, 1f, 0f, (float)Math.PI);
var body = SCNPhysicsBody.CreateDynamicBody();
body.AllowsResting = false;
body.Mass = 80f;
body.Restitution = 0.1f;
body.Friction = 0.5f;
body.RollingFriction = 0f;
chassisNode.PhysicsBody = body;
var frontCameraNode = SCNNode.Create();
frontCameraNode.Position = new SCNVector3(0f, 3.5f, 2.5f);
frontCameraNode.Rotation = new SCNVector4(0f, 1f, 0f, (float)Math.PI);
frontCameraNode.Camera = SCNCamera.Create();
frontCameraNode.Camera.XFov = 75f;
frontCameraNode.Camera.ZFar = 500f;
chassisNode.AddChildNode(frontCameraNode);
scene.RootNode.AddChildNode(chassisNode);
var pipeNode = chassisNode.FindChildNode("pipe", true);
reactor = SCNParticleSystem.Create("reactor", ResourceManager.ResourceFolder);
reactor.ParticleImage = ResourceManager.GetResourcePath("spark.png");
reactorDefaultBirthRate = reactor.BirthRate;
reactor.BirthRate = 0;
pipeNode.AddParticleSystem(reactor);
SCNNode wheel0Node = chassisNode.FindChildNode("wheelLocator_FL", true);
SCNNode wheel1Node = chassisNode.FindChildNode("wheelLocator_FR", true);
SCNNode wheel2Node = chassisNode.FindChildNode("wheelLocator_RL", true);
SCNNode wheel3Node = chassisNode.FindChildNode("wheelLocator_RR", true);
var wheel0 = SCNPhysicsVehicleWheel.Create(wheel0Node);
var wheel1 = SCNPhysicsVehicleWheel.Create(wheel1Node);
var wheel2 = SCNPhysicsVehicleWheel.Create(wheel2Node);
var wheel3 = SCNPhysicsVehicleWheel.Create(wheel3Node);
var min = SCNVector3.Zero;
var max = SCNVector3.Zero;
wheel0Node.GetBoundingBox(ref min, ref max);
float wheelHalfWidth = 0.5f * (max.X - min.X);
wheel0.ConnectionPosition = SCNVector3.Add(wheel0Node.ConvertPositionToNode(SCNVector3.Zero, chassisNode), new SCNVector3(wheelHalfWidth, 0f, 0f));
wheel1.ConnectionPosition = SCNVector3.Subtract(wheel1Node.ConvertPositionToNode(SCNVector3.Zero, chassisNode), new SCNVector3(wheelHalfWidth, 0f, 0f));
wheel2.ConnectionPosition = SCNVector3.Add(wheel2Node.ConvertPositionToNode(SCNVector3.Zero, chassisNode), new SCNVector3(wheelHalfWidth, 0f, 0f));
wheel3.ConnectionPosition = SCNVector3.Subtract(wheel3Node.ConvertPositionToNode(SCNVector3.Zero, chassisNode), new SCNVector3(wheelHalfWidth, 0f, 0f));
var vehicle = SCNPhysicsVehicle.Create(chassisNode.PhysicsBody,
new SCNPhysicsVehicleWheel[] { wheel0, wheel1, wheel2, wheel3 });
scene.PhysicsWorld.AddBehavior(vehicle);
this.vehicle = vehicle;
return(chassisNode);
}