public override void _Ready()
{
var size = GetViewportRect().Size;
var physics = new VerletWorld();
AddChild(physics);
// Attractor
var attractor = physics.CreatePoint(size / 2, radius: 24, color: Colors.LightGoldenrod, mass: 1000);
physics.AddBehavior(new AttractionBehavior(attractor, strength: 0.01f, radius: size.x));
// Create clusters
var cluster1 = new VerletCluster(
physics,
size / 4,
pointCount: 8,
diameter: 50
);
var cluster2 = new VerletCluster(
physics,
size * 0.75f,
pointCount: 8,
diameter: 50
);
// Hidden link to simulate collisions
physics.CreateLink(cluster1.Points[0], cluster2.Points[0], minimalDistance: 50, visible: false);
}
public VerletTree(VerletWorld world, Vector2 rootPosition, float angle, float length, int generations)
{
var pointSize = 10f;
var branchSize = 10f;
var root = world.CreatePoint(rootPosition, radius: pointSize, color: Colors.LightPink);
var rootTop = world.CreatePoint(rootPosition + new Vector2(0, -length), radius: pointSize, color: Colors.LightPink);
var rootLink = world.CreateLink(root, rootTop, restingDistance: length, width: branchSize);
// Fix tree root
rootTop.PinToCurrentPosition();
root.PinToCurrentPosition();
var lastLevel = new List <VerletLink>();
lastLevel.Add(rootLink);
for (var i = 0; i < generations; ++i)
{
var newLevel = new List <VerletLink>();
pointSize *= 0.66f;
branchSize *= 0.66f;
foreach (var link in lastLevel)
{
var newLength = (link.B.Position - link.A.Position) * 0.66f;
var leftPointTarget = link.B.Position + newLength.Rotated(angle);
var rightPointTarget = link.B.Position + newLength.Rotated(-angle);
var leftPoint = world.CreatePoint(leftPointTarget, radius: pointSize, color: Colors.LightPink);
var rightPoint = world.CreatePoint(rightPointTarget, radius: pointSize, color: Colors.LightPink);
var leftLink = world.CreateLink(link.B, leftPoint, restingDistance: newLength.Length(), width: branchSize, tearSensitivityFactor: 2f);
var rightLink = world.CreateLink(link.B, rightPoint, restingDistance: newLength.Length(), width: branchSize, tearSensitivityFactor: 2f);
newLevel.Add(leftLink);
newLevel.Add(rightLink);
}
lastLevel = newLevel;
}
}
public VerletClusterGraph(VerletWorld world, Vector2 centerPosition)
{
void linkClusters(VerletCluster cl1, VerletCluster cl2, float restingDistance, float minimalDistance, float linkStiffness)
{
for (int i = 0; i < cl1.Points.Count; ++i)
{
for (int j = 0; j < cl2.Points.Count; ++j)
{
var a = cl1.Points[i];
var b = cl2.Points[j];
var link = world.CreateLink(a, b);
link.RestingDistance = restingDistance;
link.MinimalDistance = minimalDistance;
link.TearSensitivity = -1;
link.Modulate = Colors.LightCyan.WithAlpha(64);
link.Stiffness = linkStiffness;
}
}
}
const float stiffness = 0.01f;
var clusters = new List <VerletCluster>()
{
new VerletCluster(
world,
centerPosition + MathUtils.RandVector2(-5, 5, -5, 5),
pointCount: 8,
diameter: 50,
tearSensitivityFactor: -1,
stiffness: stiffness
),
new VerletCluster(
world,
centerPosition + MathUtils.RandVector2(-5, 5, -5, 5),
pointCount: 12,
diameter: 75,
tearSensitivityFactor: -1,
stiffness: stiffness
),
new VerletCluster(
world,
centerPosition + MathUtils.RandVector2(-5, 5, -5, 5),
pointCount: 6,
diameter: 25,
tearSensitivityFactor: -1,
stiffness: stiffness
),
new VerletCluster(
world,
centerPosition + MathUtils.RandVector2(-5, 5, -5, 5),
pointCount: 4,
diameter: 50,
tearSensitivityFactor: -1,
stiffness: stiffness
)
};
for (int i = 0; i < clusters.Count - 1; ++i)
{
for (int j = i + 1; j < clusters.Count; ++j)
{
linkClusters(
clusters[i],
clusters[j],
restingDistance: 200,
minimalDistance: 10,
linkStiffness: 0.1f
);
}
}
}
public VerletCreature(VerletWorld world, Vector2 centerPosition, float height, float gravityScale = 1, float pointRadius = 10f, bool drawPoints = true, bool drawSupportLinks = false)
{
const float tearSensitivityFactor = -1;
const float stiffness = 0.10f;
Color supportLinkColor = Colors.LightCyan.WithAlpha(64);
float sep = height / 4;
VerletPoint createPoint()
{
return(world.CreatePoint(centerPosition + MathUtils.RandVector2(-5, 5, -5, 5), gravityScale: gravityScale, radius: pointRadius, visible: drawPoints));
}
VerletLink createLink(VerletPoint a, VerletPoint b, float distance)
{
return(world.CreateLink(a, b, restingDistance: distance, tearSensitivityFactor: tearSensitivityFactor, stiffness: stiffness));
}
VerletLink createSupportLink(VerletPoint a, VerletPoint b, float distance)
{
return(world.CreateLink(a, b, restingDistance: distance, tearSensitivityFactor: -1, stiffness: stiffness, color: supportLinkColor, visible: drawSupportLinks));
}
// Head
var topLeft = createPoint();
var topMiddle = createPoint();
var topRight = createPoint();
var topLeftSide = createPoint();
var topRightSide = createPoint();
var neckLeft = createPoint();
var neckRight = createPoint();
createLink(topMiddle, topRight, sep);
createLink(topRight, topRightSide, sep);
createLink(topRightSide, neckRight, sep);
createLink(topMiddle, topLeft, sep);
createLink(topLeft, topLeftSide, sep);
createLink(topLeftSide, neckLeft, sep);
createSupportLink(neckLeft, neckRight, sep * 2);
// Body
var bodyLeftSide = createPoint();
var bodyRightSide = createPoint();
var bottomLeft = createPoint();
var bottomMidLeft = createPoint();
var bottomMiddle = createPoint();
var bottomMidRight = createPoint();
var bottomRight = createPoint();
createLink(bodyRightSide, bottomRight, sep);
createLink(bottomRight, bottomMidRight, sep);
createLink(bottomMidRight, bottomMiddle, sep);
createLink(bodyLeftSide, bottomLeft, sep);
createLink(bottomLeft, bottomMidLeft, sep);
createLink(bottomMidLeft, bottomMiddle, sep);
createSupportLink(bodyLeftSide, bodyRightSide, sep * 3);
// Attach
createLink(neckLeft, bodyLeftSide, sep);
createLink(neckRight, bodyRightSide, sep);
createSupportLink(topMiddle, bottomMiddle, height);
createSupportLink(topLeftSide, bottomMidRight, height * 1.1f);
createSupportLink(topRightSide, bottomMidLeft, height * 1.1f);
createSupportLink(topLeft, bottomRight, height * 1.1f);
createSupportLink(topRight, bottomLeft, height * 1.1f);
}
