/// <summary>
/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input and playing audio.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
void Update()
{
// UPDATE the physics!
for (int i = 0; i < 3; i++)
{
mWorld.update(1 / 120f);
}
// cursor movement.
cursorPos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
// if the user presses the A button, create a new body at the cursor position.
if (Input.GetKeyDown(KeyCode.A))
{
GameObject s = new GameObject();
JelloPhysics.ClosedShape shape = new JelloPhysics.ClosedShape();
shape.begin();
shape.addVertex(new Vector2(-1.0f, 0f));
shape.addVertex(new Vector2(0f, 1.0f));
shape.addVertex(new Vector2(1.0f, 0f));
shape.addVertex(new Vector2(0f, -1.0f));
shape.finish();
DraggableSpringBody body = new DraggableSpringBody();
body.Setup(mWorld, shape, 1f, 150, 5, 300, 15, new Vector2(cursorPos.x, cursorPos.y), ((float)UnityEngine.Random.Range(0, 360)), Vector2.one);
body.addInternalSpring(0, 2, 400f, 12f);
body.addInternalSpring(1, 3, 400f, 12f);
}
if (Input.GetKeyDown(KeyCode.B))
{
GameObject s = new GameObject();
JelloPhysics.ClosedShape shape = new JelloPhysics.ClosedShape();
shape.begin();
for (int i = 0; i < 360; i += 20)
{
shape.addVertex(new Vector2((float)Mathf.Cos(((float)-i) * Mathf.Deg2Rad), (float)Mathf.Sin(((float)-i) * Mathf.Deg2Rad)));
}
shape.finish();
DraggablePressureBody pb = new DraggablePressureBody();
pb.Setup(mWorld, shape, 1.0f, 40.0f, 10.0f, 1.0f, 300.0f, 20.0f, cursorPos, 0, Vector2.one);
pb.addTriangle(0, 10, 9);
pb.addTriangle(0, 9, 1);
pb.addTriangle(1, 9, 8);
pb.addTriangle(1, 8, 2);
pb.addTriangle(2, 8, 7);
pb.addTriangle(2, 7, 3);
pb.addTriangle(3, 7, 6);
pb.addTriangle(3, 6, 4);
pb.addTriangle(4, 6, 5);
pb.addTriangle(17, 10, 0);
pb.addTriangle(17, 11, 10);
pb.addTriangle(16, 11, 17);
pb.addTriangle(16, 12, 11);
pb.addTriangle(15, 12, 16);
pb.addTriangle(15, 13, 12);
pb.addTriangle(14, 12, 15);
pb.addTriangle(14, 13, 12);
pb.finalizeTriangles(Color.white);
pb.addInternalSpring(0, 2, 400f, 12f);
pb.addInternalSpring(1, 3, 400f, 12f);
}
// dragging!
if (Input.GetMouseButton(0))
{
if (dragBody != null)
{
PointMass pm = dragBody.getPointMass(dragPoint);
if (dragBody.GetType().Name == "DraggableSpringBody")
{
((DraggableSpringBody)dragBody).setDragForce(JelloPhysics.VectorTools.calculateSpringForce(pm.Position, pm.Velocity, cursorPos, Vector2.zero, 0.0f, 100.0f, 10.0f), dragPoint);
}
else if (dragBody.GetType().Name == "DraggablePressureBody")
{
((DraggablePressureBody)dragBody).setDragForce(JelloPhysics.VectorTools.calculateSpringForce(pm.Position, pm.Velocity, cursorPos, Vector2.zero, 0.0f, 100.0f, 10.0f), dragPoint);
}
}
}
else
{
dragBody = null;
dragPoint = -1;
}
if (Input.GetMouseButtonDown(0))
{
if (dragBody == null)
{
int body;
mWorld.getClosestPointMass(cursorPos, out body, out dragPoint);
dragBody = mWorld.getBody(body);
}
}
}
private void _handleCollisions()
{
// handle all collisions!
for (int i = 0; i < mCollisionList.Count; i++)
{
BodyCollisionInfo info = mCollisionList[i];
PointMass A = info.bodyA.getPointMass(info.bodyApm);
PointMass B1 = info.bodyB.getPointMass(info.bodyBpmA);
PointMass B2 = info.bodyB.getPointMass(info.bodyBpmB);
// velocity changes as a result of collision.
Vector2 bVel = new Vector2();
bVel.x = (B1.Velocity.x + B2.Velocity.x) * 0.5f;
bVel.y = (B1.Velocity.y + B2.Velocity.y) * 0.5f;
Vector2 relVel = new Vector2();
relVel.x = A.Velocity.x - bVel.x;
relVel.y = A.Velocity.y - bVel.y;
float relDot;
// Vector2.Dot(ref relVel, ref info.normal, out relDot);
relDot = Vector2.Dot(relVel, info.normal);
// collision filter!
if (!mMaterialPairs[info.bodyA.Material, info.bodyB.Material].CollisionFilter(info.bodyA, info.bodyApm, info.bodyB, info.bodyBpmA, info.bodyBpmB, info.hitPt, relDot))
{
continue;
}
if (info.penetration > mPenetrationThreshold)
{
//Console.WriteLine("penetration above Penetration Threshold!! penetration={0} threshold={1} difference={2}",
// info.penetration, mPenetrationThreshold, info.penetration-mPenetrationThreshold);
mPenetrationCount++;
continue;
}
float b1inf = 1.0f - info.edgeD;
float b2inf = info.edgeD;
float b2MassSum = ((float.IsPositiveInfinity(B1.Mass)) || (float.IsPositiveInfinity(B2.Mass))) ? float.PositiveInfinity : (B1.Mass + B2.Mass);
float massSum = A.Mass + b2MassSum;
float Amove;
float Bmove;
if (float.IsPositiveInfinity(A.Mass))
{
Amove = 0f;
Bmove = (info.penetration) + 0.001f;
}
else if (float.IsPositiveInfinity(b2MassSum))
{
Amove = (info.penetration) + 0.001f;
Bmove = 0f;
}
else
{
Amove = (info.penetration * (b2MassSum / massSum));
Bmove = (info.penetration * (A.Mass / massSum));
}
float B1move = Bmove * b1inf;
float B2move = Bmove * b2inf;
float AinvMass = (float.IsPositiveInfinity(A.Mass)) ? 0f : 1f / A.Mass;
float BinvMass = (float.IsPositiveInfinity(b2MassSum)) ? 0f : 1f / b2MassSum;
float jDenom = AinvMass + BinvMass;
Vector2 numV = new Vector2();
float elas = 1f + mMaterialPairs[info.bodyA.Material, info.bodyB.Material].Elasticity;
numV.x = relVel.x * elas;
numV.y = relVel.y * elas;
float jNumerator;
// Vector2.Dot(ref numV, ref info.normal, out jNumerator);
jNumerator = Vector2.Dot(numV, info.normal);
jNumerator = -jNumerator;
float j = jNumerator / jDenom;
if (!float.IsPositiveInfinity(A.Mass))
{
A.Position.x += info.normal.x * Amove;
A.Position.y += info.normal.y * Amove;
}
if (!float.IsPositiveInfinity(B1.Mass))
{
B1.Position.x -= info.normal.x * B1move;
B1.Position.y -= info.normal.y * B1move;
}
if (!float.IsPositiveInfinity(B2.Mass))
{
B2.Position.x -= info.normal.x * B2move;
B2.Position.y -= info.normal.y * B2move;
}
Vector2 tangent = new Vector2();
VectorTools.getPerpendicular(ref info.normal, ref tangent);
float friction = mMaterialPairs[info.bodyA.Material, info.bodyB.Material].Friction;
float fNumerator;
// Vector2.Dot(ref relVel, ref tangent, out fNumerator);
fNumerator = Vector2.Dot(relVel, tangent);
fNumerator *= friction;
float f = fNumerator / jDenom;
// adjust velocity if relative velocity is moving toward each other.
if (relDot <= 0.0001f)
{
if (!float.IsPositiveInfinity(A.Mass))
{
A.Velocity.x += (info.normal.x * (j / A.Mass)) - (tangent.x * (f / A.Mass));
A.Velocity.y += (info.normal.y * (j / A.Mass)) - (tangent.y * (f / A.Mass));
}
if (!float.IsPositiveInfinity(b2MassSum))
{
B1.Velocity.x -= (info.normal.x * (j / b2MassSum) * b1inf) - (tangent.x * (f / b2MassSum) * b1inf);
B1.Velocity.y -= (info.normal.y * (j / b2MassSum) * b1inf) - (tangent.y * (f / b2MassSum) * b1inf);
}
if (!float.IsPositiveInfinity(b2MassSum))
{
B2.Velocity.x -= (info.normal.x * (j / b2MassSum) * b2inf) - (tangent.x * (f / b2MassSum) * b2inf);
B2.Velocity.y -= (info.normal.y * (j / b2MassSum) * b2inf) - (tangent.y * (f / b2MassSum) * b2inf);
}
}
}
mCollisionList.Clear();
}