private void ComputeColliders()
{
// Get colliders
GameObject[] collidersGO = GameObject.FindGameObjectsWithTag("SPHCollider");
SPHCollider[] colliders = new SPHCollider[collidersGO.Length];
for (int i = 0; i < colliders.Length; i++)
{
colliders[i].Init(collidersGO[i].transform);
}
for (int i = 0; i < particles.Length; i++)
{
for (int j = 0; j < colliders.Length; j++)
{
// Check collision
Vector3 penetrationNormal;
Vector3 penetrationPosition;
float penetrationLength;
if (Intersect(colliders[j], particles[i].position, parameters[particles[i].parameterID].particleRadius, out penetrationNormal, out penetrationPosition, out penetrationLength))
{
particles[i].velocity = DampVelocity(colliders[j], particles[i].velocity, penetrationNormal, 1.0f - parameters[particles[i].parameterID].particleDrag);
particles[i].position = penetrationPosition - penetrationNormal * Mathf.Abs(penetrationLength);
}
}
}
}
private static Vector3 DampVelocity(SPHCollider collider, float3 velocity, float3 penetrationNormal, float drag)
{
float3 newVelocity = math.dot(velocity, penetrationNormal) * penetrationNormal * BOUND_DAMPING
+ math.dot(velocity, collider.right) * collider.right * drag
+ math.dot(velocity, collider.up) * collider.up * drag;
newVelocity = math.dot(newVelocity, new float3(0, 0, 1)) * new float3(0, 0, 1)
+ math.dot(newVelocity, new float3(1, 0, 0)) * new float3(1, 0, 0)
+ math.dot(newVelocity, new float3(0, 1, 0)) * new float3(0, 1, 0);
return newVelocity;
}
private static Vector3 DampVelocity(SPHCollider collider, Vector3 velocity, Vector3 penetrationNormal, float drag)
{
Vector3 newVelocity = Vector3.Dot(velocity, penetrationNormal) * penetrationNormal * BOUND_DAMPING
+ Vector3.Dot(velocity, collider.right) * collider.right * drag
+ Vector3.Dot(velocity, collider.up) * collider.up * drag;
newVelocity = Vector3.Dot(newVelocity, Vector3.forward) * Vector3.forward
+ Vector3.Dot(newVelocity, Vector3.right) * Vector3.right
+ Vector3.Dot(newVelocity, Vector3.up) * Vector3.up;
return(newVelocity);
}
private static bool Intersect(SPHCollider collider, Vector3 position, float radius, out Vector3 penetrationNormal, out Vector3 penetrationPosition, out float penetrationLength)
{
Vector3 colliderProjection = collider.position - position;
penetrationNormal = Vector3.Cross(collider.right, collider.up);
penetrationLength = Mathf.Abs(Vector3.Dot(colliderProjection, penetrationNormal)) - (radius / 2.0f);
penetrationPosition = collider.position - colliderProjection;
return(penetrationLength < 0.0f &&
Mathf.Abs(Vector3.Dot(colliderProjection, collider.right)) < collider.scale.x &&
Mathf.Abs(Vector3.Dot(colliderProjection, collider.up)) < collider.scale.y);
}
private static bool Intersect(SPHCollider collider, float3 position, float radius, out float3 penetrationNormal, out float3 penetrationPosition, out float penetrationLength)
{
float3 colliderProjection = collider.position - position;
penetrationNormal = math.cross(collider.right, collider.up);
penetrationLength = math.abs(math.dot(colliderProjection, penetrationNormal)) - (radius / 2.0f);
penetrationPosition = collider.position - colliderProjection;
return(penetrationLength < 0.0f &&
math.abs(math.dot(colliderProjection, collider.right)) < collider.scale.x &&
math.abs(math.dot(colliderProjection, collider.up)) < collider.scale.y);
}
void UpdateColliders()
{
// Get colliders
GameObject[] collidersGO = GameObject.FindGameObjectsWithTag("SPHCollider");
if (collidersArray == null || collidersArray.Length != collidersGO.Length)
{
collidersArray = new SPHCollider[collidersGO.Length];
if (collidersBuffer != null)
{
collidersBuffer.Dispose();
}
collidersBuffer = new ComputeBuffer(collidersArray.Length, SIZE_SPHCOLLIDER);
}
for (int i = 0; i < collidersArray.Length; i++)
{
collidersArray[i] = new SPHCollider(collidersGO[i].transform);
}
collidersBuffer.SetData(collidersArray);
shader.SetBuffer(kernelComputeColliders, "colliders", collidersBuffer);
}
