private SCNNode GetFillPlane()
{
var length = 1f - 2f * BorderSegment.Thickness;
var plane = SCNPlane.Create(length, length * this.AspectRatio);
var node = SCNNode.FromGeometry(plane);
node.Name = "fillPlane";
node.Opacity = 0.6f;
var material = plane.FirstMaterial;
material.Diffuse.Contents = UIImage.FromBundle("art.scnassets/textures/grid.png");
var textureScale = SimdExtensions.CreateFromScale(new SCNVector3(40f, 40f * this.AspectRatio, 1f));
material.Diffuse.ContentsTransform = textureScale;
material.Emission.Contents = UIImage.FromBundle("art.scnassets/textures/grid.png");
material.Emission.ContentsTransform = textureScale;
material.Diffuse.WrapS = SCNWrapMode.Repeat;
material.Diffuse.WrapT = SCNWrapMode.Repeat;
material.DoubleSided = true;
material.Ambient.Contents = UIColor.Black;
material.LightingModelName = SCNLightingModel.Constant;
return(node);
}
/// <summary>
/// Aligns the rigid bodies by correcting their orienation
/// This should be called after the simulation step
/// </summary>
private void AlignBones()
{
// orient the bodies accordingly
for (var i = this.BoneInset; i < this.simulatedTransforms.Count - this.BoneInset; i++)
{
if (!this.simulatedTransforms[i].Dynamic)
{
continue;
}
var a = this.simulatedTransforms[i - 1].Position;
var b = this.simulatedTransforms[i + 1].Position;
// this is the upVector computed for each bone of the rest pose
var transform = this.restPoseSpace * this.restPoseTransforms[i]; // todo: direction of multiply?
var y = SimdExtensions.CreateQuaternion(transform).Act(new SCNVector3(0f, 1f, 0f));
var x = SCNVector3.Normalize(b - a);
var z = SCNVector3.Normalize(SCNVector3.Cross(x, y));
y = SCNVector3.Normalize(SCNVector3.Cross(z, x));
var rot = new OpenTK.Matrix3(x.X, y.X, z.X, x.Y, y.Y, z.Y, x.Z, y.Z, z.Z);
this.simulatedTransforms[i].Orientation = new SCNQuaternion(rot.ToQuaternion());
}
}
/// <summary>
/// Returns the interpolated tangent at a given length (l from 0.0 to totalLength)
/// </summary>
public SCNVector3 Tangent(float l)
{
var s = this.FindIndex(l);
return(SCNVector3.Normalize(SimdExtensions.Mix(this.Tangents[this.lastIndex],
this.Tangents[this.lastIndex + 1],
new SCNVector3(s, s, s))));
}
/// <summary>
/// Returns the interpolated position at a given length (l from 0.0 to totalLength)
/// </summary>
public SCNVector3 Position(float l)
{
var s = this.FindIndex(l);
return(SimdExtensions.Mix(this.Positions[this.lastIndex],
this.Positions[this.lastIndex + 1],
new SCNVector3(s, s, s)));
}
private void UpdateColors()
{
var baseColor = SimdExtensions.CreateVector4(this.Team.GetColor());
for (var i = 0; i < this.colors.Count; i++)
{
var scale = (float)i / (float)this.colors.Count;
this.colors[i] = baseColor * scale;
}
}
private void PerformPlaneCollision(List <SimulatedTransform> previousTransforms, float seconds)
{
for (var i = this.BoneInset; i < this.simulatedTransforms.Count - this.BoneInset; i++)
{
if (!this.simulatedTransforms[i].Dynamic)
{
continue;
}
var p = this.simulatedTransforms[i].Position;
var v = this.simulatedTransforms[i].Velocity;
// project into the space of the base
var pM = SCNMatrix4.Identity.SetTranslation((OpenTK.Vector3)p);
var pLocal = SCNMatrix4.Invert(this.restPoseSpace) * pM;
if (pLocal.Column3.Z <= CollisionPlane)
{
pLocal.M34 = CollisionPlane;
pM = this.restPoseSpace * pLocal;
var pOnPlane = new SCNVector3(pM.Column3.X, pM.Column3.Y, pM.Column3.Z);
var blend = new SCNVector3(0.3f, 0.3f, 0.3f);
this.simulatedTransforms[i].Position = SimdExtensions.Mix(p, pOnPlane, blend);
var correctedVelocity = (this.simulatedTransforms[i].Position - previousTransforms[i].Position) / seconds;
correctedVelocity = SCNVector3.Multiply(correctedVelocity, new SCNVector3(0.7f, 0.1f, 0.7f));
// verlet integration
this.simulatedTransforms[i].Velocity = SimdExtensions.Mix(v, correctedVelocity, blend);
p = this.simulatedTransforms[i].Position;
v = this.simulatedTransforms[i].Velocity;
}
if (pLocal.Column3.Y <= CollisionPlane + 0.3f)
{
pLocal.M24 = CollisionPlane + 0.3f;
pM = this.restPoseSpace * pLocal;
var pOnPlane = new SCNVector3(pM.Column3.X, pM.Column3.Y, pM.Column3.Z);
var blend = new SCNVector3(0.3f, 0.3f, 0.3f);
this.simulatedTransforms[i].Position = SimdExtensions.Mix(p, pOnPlane, blend);
var correctedVelocity = (this.simulatedTransforms[i].Position - previousTransforms[i].Position) / seconds;
// verlet integration
this.simulatedTransforms[i].Velocity = SimdExtensions.Mix(v, correctedVelocity, blend);
}
}
}
/// <summary>
/// Disables the simulation on the slingshot and sets the rigid bodies to be driven by the input pose
/// </summary>
public void EnableInputPose()
{
for (var i = 0; i < this.simulatedTransforms.Count; i++)
{
var l = this.OriginalTotalLength * (float)i / (float)(this.simulatedTransforms.Count - 1);
var transform = this.InputPoseTransform(l);
var position = new SCNVector3(transform.Column3.X, transform.Column3.Y, transform.Column3.Z);
this.simulatedTransforms[i].Position = position;
this.simulatedTransforms[i].Orientation = SimdExtensions.CreateQuaternion(transform);
this.simulatedTransforms[i].Velocity = SCNVector3.Zero;
this.simulatedTransforms[i].Dynamic = false;
}
}
private void InitializeHelpers()
{
this.computedInputPose = new ComputedValue <SlingShotPose>(() => this.ComputeInputPose());
this.computedTangentPositionR = new ComputedValue <SCNVector3>(() => this.TangentPosition(this.FixturePositionR));
this.computedTangentPositionL = new ComputedValue <SCNVector3>(() => this.TangentPosition(this.FixturePositionL));
this.computedBetaAngle = new ComputedValue <float>(() =>
{
var d = SCNVector3.Normalize(this.ballPosition - this.CenterPosition);
var t = SCNVector3.Normalize(this.TangentPositionL - this.ballPosition);
var quaternion = SimdExtensions.CreateQuaternion(d, t);
quaternion.ToAxisAngle(out SCNVector3 _, out float angle);
return(2f * angle);
});
this.computedCenterPosition = new ComputedValue <SCNVector3>(() =>
{
var direction = SCNVector3.Cross(this.UpVector, this.TangentPositionR - this.TangentPositionL);
return(this.ballPosition - SCNVector3.Normalize(direction) * 1.25f * this.ballRadius);
});
this.computedRestPose = new ComputedValue <SlingShotPose>(() =>
{
var data = new SlingShotPose();
for (var i = 0; i < this.restPoseTransforms.Count; i++)
{
var transform = this.restPoseSpace * this.restPoseTransforms[i];
var p = new SCNVector3(transform.Column3.X, transform.Column3.Y, transform.Column3.Z);
var t = SimdExtensions.CreateQuaternion(transform).Act(new SCNVector3(1f, 0f, 0f));
var l = 0f;
if (i > 0)
{
l = data.Lengths[i - 1] + (p - data.Positions[i - 1]).Length;
}
data.Positions.Add(p);
data.Tangents.Add(t);
data.Lengths.Add(l);
}
return(data);
});
}
private void OrientToPlane(ARPlaneAnchor planeAnchor, ARCamera camera)
{
// Get board rotation about y
this.Orientation = SimdExtensions.CreateQuaternion(planeAnchor.Transform.ToSCNMatrix4());
var boardAngle = this.EulerAngles.Y;
// If plane is longer than deep, rotate 90 degrees
if (planeAnchor.Extent.X > planeAnchor.Extent.Z)
{
boardAngle += (float)Math.PI / 2f;
}
// Normalize angle to closest 180 degrees to camera angle
boardAngle = boardAngle.NormalizedAngle(camera.EulerAngles.Y, (float)Math.PI);
this.Rotate(boardAngle);
}
private void SlideInWorld(SCNVector3 start, SCNVector3 velocity)
{
var maxSlideIteration = 4;
var iteration = 0;
var stop = false;
var replacementPoint = start;
var options = new SCNPhysicsTest()
{
CollisionBitMask = (int)Bitmask.Collision,
SearchMode = SCNPhysicsSearchMode.Closest,
};
while (!stop)
{
var from = SCNMatrix4.Identity;
SimdExtensions.SetPosition(ref from, start);
var to = SCNMatrix4.Identity;
SimdExtensions.SetPosition(ref to, start + velocity);
var contacts = this.PhysicsWorld.ConvexSweepTest(this.characterCollisionShape, from, to, options.Dictionary);
if (contacts.Any())
{
(velocity, start) = this.HandleSlidingAtContact(contacts.FirstOrDefault(), start, velocity);
iteration += 1;
if (velocity.LengthSquared <= (10E-3 * 10E-3) || iteration >= maxSlideIteration)
{
replacementPoint = start;
stop = true;
}
}
else
{
replacementPoint = start + velocity;
stop = true;
}
}
this.characterNode.WorldPosition = replacementPoint - this.collisionShapeOffsetFromModel;
}
/// <summary>
/// Computes and applies the custom forces for the slingshot rope.
/// This should be called every frame.
/// </summary>
private void ApplyForces()
{
var b = new SCNVector3(SimBlend, SimBlend, SimBlend);
for (var i = this.BoneInset; i < this.simulatedTransforms.Count - this.BoneInset; i++)
{
if (!this.simulatedTransforms[i].Dynamic)
{
continue;
}
var force = SCNVector3.Zero;
if (i > 0)
{
var restA = this.RestPose.Positions[i - 1];
var restB = this.RestPose.Positions[i];
var currentA = this.simulatedTransforms[i - 1].Position;
var currentB = this.simulatedTransforms[i].Position;
var restDistance = (restA - restB).Length;
var currentDistance = (currentA - currentB).Length;
force += SCNVector3.Normalize(currentA - currentB) * (currentDistance - restDistance) * SimNeighborStrength;
}
if (i < this.simulatedTransforms.Count - 1)
{
var restA = this.RestPose.Positions[i + 1];
var restB = this.RestPose.Positions[i];
var currentA = this.simulatedTransforms[i + 1].Position;
var currentB = this.simulatedTransforms[i].Position;
var restDistance = (restA - restB).Length;
var currentDistance = (currentA - currentB).Length;
force += SCNVector3.Normalize(currentA - currentB) * (currentDistance - restDistance) * SimNeighborStrength;
}
force += (this.RestPose.Positions[i] - this.simulatedTransforms[i].Position) * SimRestPoseStrength;
var vel = this.simulatedTransforms[i].Velocity;
this.simulatedTransforms[i].Velocity = SimdExtensions.Mix(vel, force, b);
}
}
private void AverageVelocities()
{
var currentTransforms = new List <SimulatedTransform>();
currentTransforms.AddRange(this.simulatedTransforms);
for (var i = this.BoneInset; i < this.SimulatedTransformCount - this.BoneInset; i++)
{
if (!this.simulatedTransforms[i].Dynamic)
{
continue;
}
var a = currentTransforms[i - 1].Velocity;
var b = currentTransforms[i].Velocity;
var c = currentTransforms[i + 1].Velocity;
var ab = SimdExtensions.Mix(a, b, new SCNVector3(0.5f, 0.5f, 0.5f));
var bc = SimdExtensions.Mix(b, c, new SCNVector3(0.5f, 0.5f, 0.5f));
this.simulatedTransforms[i].Velocity = SimdExtensions.Mix(ab, bc, t: new SCNVector3(0.5f, 0.5f, 0.5f));
var center = SimdExtensions.Mix(currentTransforms[i - 1].Position, currentTransforms[i + 1].Position, new SCNVector3(0.5f, 0.5f, 0.5f));
this.simulatedTransforms[i].Position = SimdExtensions.Mix(this.simulatedTransforms[i].Position, center, new SCNVector3(SmoothRope, SmoothRope, SmoothRope));
}
}
private void UpdateBorderAspectRatio()
{
var borderSize = new CGSize(1f, this.AspectRatio);
foreach (var segment in this.borderSegments)
{
segment.BorderSize = borderSize;
}
if (this.FillPlane.Geometry is SCNPlane plane)
{
var length = 1 - 2 * BorderSegment.Thickness;
plane.Height = length * this.AspectRatio;
var textureScale = SimdExtensions.CreateFromScale(new SCNVector3(40f, 40f * this.AspectRatio, 1f));
if (plane.FirstMaterial != null)
{
plane.FirstMaterial.Diffuse.ContentsTransform = textureScale;
plane.FirstMaterial.Emission.ContentsTransform = textureScale;
}
}
this.isBorderOpen = false;
}
public SlingShotPose ComputeInputPose()
{
// note the -1 here differs from other usage
var data = new SlingShotPose {
UpVector = -this.UpVector /* negated because the strap Y-axis points down */
};
var startBend = this.CurrentLengthL / this.CurrentTotalLength;
var endBend = 1f - this.CurrentLengthR / this.CurrentTotalLength;
var leatherOnStraights = this.OriginalLeatherLength - this.CurrentLengthOnBall;
var segmentAStart = 0f;
var segmentAEnd = this.CurrentLengthL - leatherOnStraights * 0.5f;
var segmentCStart = segmentAEnd + this.OriginalLeatherLength;
var segmentCEnd = this.CurrentTotalLength;
var originalLeatherRange = this.OriginalLeatherLength / this.OriginalTotalLength;
var currentLeatherRange = this.OriginalLeatherLength / this.CurrentTotalLength;
for (var i = 0; i < this.SimulatedTransformCount; i++)
{
var l = this.OriginalTotalLength * (float)i / (float)(this.SimulatedTransformCount - 1f);
var u = l / this.OriginalTotalLength;
// remap the u value depending on the material (rubber vs leather)
var isRubber = Math.Abs(0.5f - u) > originalLeatherRange * 0.5f;
if (isRubber)
{
if (u < 0.5f)
{
u = u / (0.5f - originalLeatherRange * 0.5f);
u = (segmentAStart + (segmentAEnd - segmentAStart) * u) / this.CurrentTotalLength;
}
else
{
u = 1f - (1f - u) / (0.5f - originalLeatherRange * 0.5f);
u = (segmentCStart + (segmentCEnd - segmentCStart) * u) / this.CurrentTotalLength;
}
}
else
{
u = (startBend + endBend) * 0.5f - (0.5f - u) * (currentLeatherRange / originalLeatherRange);
}
var p = SCNVector3.Zero;
var t = SCNVector3.UnitX;
if (u < startBend)
{
// left straight
var value = u / startBend;
p = SimdExtensions.Mix(this.FixturePositionL,
this.TangentPositionL,
new SCNVector3(value, value, value)); // left rubber band
t = SCNVector3.Normalize(this.TangentPositionL - this.FixturePositionL);
}
else if (u > endBend)
{
// right straight
var value = (1f - u) / (1f - endBend);
p = SimdExtensions.Mix(this.FixturePositionR,
this.TangentPositionR,
new SCNVector3(value, value, value)); // right rubber band
t = SCNVector3.Normalize(this.FixturePositionR - this.TangentPositionR);
}
else
{
// on the ball
var upv = this.UpVector;
var rot = SCNQuaternion.FromAxisAngle(upv, -this.BetaAngle * (u - startBend) / (endBend - startBend));
p = this.ballPosition + rot.Act(this.TangentPositionL - this.ballPosition);
t = SCNVector3.Cross(upv, SCNVector3.Normalize(this.ballPosition - p));
}
data.Positions.Add(p);
data.Tangents.Add(t);
data.Lengths.Add(l);
}
return(data);
}
