/**
* Retrieves the indices of the particles that influece a given vertex. In the weight
* field of each influence, the squared distance from the particle to the vertex is provided.
*/
public List <ParticleInfluence> GetParticleInfluences(Vector3 vertex)
{
// TODO: try to make it faster.
List <ParticleInfluence> allInfluences = new List <ParticleInfluence>();
// Get squared distance to all particles:
for (int i = 0; i < proxy.positions.Length; ++i)
{
ParticleInfluence influence = new ParticleInfluence();
influence.particleIndex = i;
influence.bindVector = transform.InverseTransformVector(transform.TransformPoint(vertex) - proxy.GetParticlePosition(i));
influence.weight = influence.bindVector.sqrMagnitude;
allInfluences.Add(influence);
}
// Sort by distance:
allInfluences.Sort(
delegate(ParticleInfluence x, ParticleInfluence y)
{
return(x.weight.CompareTo(y.weight));
});
// Return the K nearest:
return(allInfluences.GetRange(0, numInfluences));
}
/**
* Binds the mesh to the proxy particle actor.
*/
public void BindToProxy()
{
initialized = false;
initializing = false;
if (deformedMesh == null || proxy == null)
{
return;
}
initializing = true;
influences = new ParticleInfluence[deformedMesh.vertexCount * numInfluences];
bindPoses = new Quaternion[proxy.positions.Length];
// Get particle bind poses:
for (int i = 0; i < proxy.positions.Length; ++i)
{
Quaternion proxyToLocal = Quaternion.Inverse(transform.rotation) * proxy.transform.rotation;
bindPoses[i] = Quaternion.Inverse(proxyToLocal * proxy.sharedTopology.referenceOrientation[i]);
}
Vector3[] vertices = deformedMesh.vertices;
//TODO: if the vertex position has already been processed, skip it. use unique positions only.
for (int i = 0; i < vertices.Length; ++i)
{
// Find nearest "numInfluences" proxy particles:
List <ParticleInfluence> infs = GetParticleInfluences(vertices[i]);
// Calculate weights using shepard's method:
float total = 0;
for (int j = 0; j < infs.Count; ++j)
{
ParticleInfluence pi = infs[j];
pi.weight = 1.0f / (float)Math.Pow(Mathf.Sqrt(pi.weight), falloff);
infs[j] = pi;
total += infs[j].weight;
}
// Normalize to get final linear weights:
for (int j = 0; j < infs.Count; ++j)
{
ParticleInfluence pi = infs[j];
pi.weight = pi.weight / total;
infs[j] = pi;
}
// Insert this vertex's influence in the array:
for (int j = 0; j < numInfluences; ++j)
{
influences[i * numInfluences + j] = infs[j];
}
}
initializing = false;
initialized = true;
}
