// Creates particles for the body
protected void CreateParticles()
{
particles = new PSBParticle[numOfParticles];
predictedParticles = new PSBParticle[numOfParticles];
internalSprings = new PSBInternalSpring[numOfParticles];
// Create the particles
for (int i = 0; i < numOfParticles; i++)
{
particles[i] = new PSBParticle();
predictedParticles[i] = new PSBParticle();
particles[i].position.x = bodyRadius * Mathf.Sin((i + 1) * (2.0f * Mathf.PI) / numOfParticles);
particles[i].position.y = bodyRadius * Mathf.Cos((i + 1) * (2.0f * Mathf.PI) / numOfParticles); // + SCRSIZE/2;
// Gameobject
particles[i].gameObj = new GameObject();
particles[i].gameObj.name = "Particle_" + i;
particles[i].gameObj.transform.parent = transform;
particles[i].gameObj.transform.localPosition = Vector2.zero;
particles[i].gameObj.layer = 8;
// Rigidbody
particles[i].rBody = particles[i].gameObj.AddComponent <Rigidbody2D>();
particles[i].rBody.mass = mass;
particles[i].rBody.position = particles[i].position;
particles[i].rBody.angularDrag = 0.5f;
particles[i].rBody.drag = rigidbodyDrag;
particles[i].rBody.constraints = RigidbodyConstraints2D.FreezeRotation;
particles[i].rBody.collisionDetectionMode = CollisionDetectionMode2D.Continuous;
particles[i].rBody.gravityScale = gravityScale;
// Collider
particles[i].circleCol = particles[i].gameObj.AddComponent <CircleCollider2D>();
particles[i].circleCol.radius = particleColliderRadius;
}
}
protected Vector3[] vertices = null; // Mesh vertices...
#endregion Fields
#region Methods
// Calculates the accumululation of forces to the character
protected void AccumulateForces(ref PSBParticle[] particleArray)
{
float lengthBetweenParticles = 0f; // length of p1 - p2 vector
float hookeForceValue = 0f; // hooke force value
float pressurev = 0f; // pressure force value
float volume = 0f; // the volume of the body
Vector2 particle1Pos = Vector2.zero;// positions of spring particles p1, p2
Vector2 particle2Pos = Vector2.zero;// positions of spring particles p1, p2
Vector2 v12 = Vector2.zero; // particle1Pos.vel - particle2Pos.vel
Vector2 force = Vector2.zero; // the calculated force for each spring
// Reset all forces
for (int i = 0; i < numOfParticles ; i++)
{
particleArray[i].force = Vector2.zero;
}
// Spring force
for (int i = 0; i < numOfParticles ; i++)
{
// get positions of spring start & end particles
particle1Pos = particleArray[internalSprings[i].i].position;
particle2Pos = particleArray[internalSprings[i].j].position;
lengthBetweenParticles = (particle1Pos - particle2Pos).magnitude; // calculate square root of the distance
if (lengthBetweenParticles != 0)
{
// get velocities of start & end particles
v12 = particleArray[internalSprings[i].i].velocity - particleArray[internalSprings[i].j].velocity;
// calculate force value
hookeForceValue = (lengthBetweenParticles - internalSprings[i].length) * springConstantElasticity + (v12.x * (particle1Pos.x - particle2Pos.x) + v12.y * (particle1Pos.y - particle2Pos.y)) * springDamping / lengthBetweenParticles;
// force vector
force = ((particle1Pos - particle2Pos) / lengthBetweenParticles ) * hookeForceValue;
// accumulate force for starting particle
particleArray[internalSprings[i].i].force -= force;
// accumulate force for end particle
particleArray[internalSprings[i].j].force += force;
}
// Calculate normal vectors to springs
internalSprings[i].norm.x = (particle1Pos.y - particle2Pos.y) / lengthBetweenParticles;
internalSprings[i].norm.y = -(particle1Pos.x - particle2Pos.x) / lengthBetweenParticles;
}
// Calculate Volume of the Ball (Gauss Theorem)
for (int i = 0; i < numOfParticles; i++)
{
particle1Pos = particleArray[internalSprings[i].i].position;
particle2Pos = particleArray[internalSprings[i].j].position;
lengthBetweenParticles = (particle1Pos - particle2Pos).magnitude;
volume += 0.5f * Mathf.Abs(particle1Pos.x - particle2Pos.x) * Mathf.Abs(internalSprings[i].norm.x) * (lengthBetweenParticles);
}
// Calculate Pressure Force Distribution
for (int i = 0; i < numOfParticles; i++)
{
// Get the particles and calculate the distance between them
particle1Pos = particleArray[internalSprings[i].i].position;
particle2Pos = particleArray[internalSprings[i].j].position;
lengthBetweenParticles = (particle1Pos - particle2Pos).magnitude;
// P = 1/V * A * P * N
pressurev = lengthBetweenParticles * pressure * (1.0f/volume);
particleArray[internalSprings[i].i].force.x += internalSprings[i].norm.x * pressurev;
particleArray[internalSprings[i].i].force.y += internalSprings[i].norm.y * pressurev;
particleArray[internalSprings[i].j].force.x += internalSprings[i].norm.x * pressurev;
particleArray[internalSprings[i].j].force.y += internalSprings[i].norm.y * pressurev;
// Calculate the particle normal by using the normal of the two springs attached to it
particleArray[i].normal = (internalSprings[particleArray[i].prevInternalSpring].norm + internalSprings[particleArray[i].nextInternalSpring].norm).normalized;
}
}
// Creates particles for the body
protected void CreateParticles()
{
particles = new PSBParticle[numOfParticles];
predictedParticles = new PSBParticle[numOfParticles];
internalSprings = new PSBInternalSpring[numOfParticles];
// Create the particles
for (int i = 0; i < numOfParticles; i++)
{
particles[i] = new PSBParticle();
predictedParticles[i] = new PSBParticle();
particles[i].position.x = bodyRadius * Mathf.Sin((i + 1) * (2.0f * Mathf.PI) / numOfParticles);
particles[i].position.y = bodyRadius * Mathf.Cos((i + 1) * (2.0f * Mathf.PI) / numOfParticles);// + SCRSIZE/2;
// Gameobject
particles[i].gameObj = new GameObject();
particles[i].gameObj.name = "Particle_" + i;
particles[i].gameObj.transform.parent = transform;
particles[i].gameObj.transform.localPosition = Vector2.zero;
particles[i].gameObj.layer = 8;
// Rigidbody
particles[i].rBody = particles[i].gameObj.AddComponent<Rigidbody2D>();
particles[i].rBody.mass = mass;
particles[i].rBody.position = particles[i].position;
particles[i].rBody.angularDrag = 0.5f;
particles[i].rBody.drag = rigidbodyDrag;
particles[i].rBody.constraints = RigidbodyConstraints2D.FreezeRotation;
particles[i].rBody.collisionDetectionMode = CollisionDetectionMode2D.Continuous;
particles[i].rBody.gravityScale = gravityScale;
// Collider
particles[i].circleCol = particles[i].gameObj.AddComponent<CircleCollider2D>();
particles[i].circleCol.radius = particleColliderRadius;
}
}
