public static FEMScene Create(Vector2f origin, float scale, int numPoints)
{
FEMScene Scene = new FEMScene();
Scene.Substeps = 40;
Scene.Drag = 1.0f;
Scene.LameLambda = 10000.0f;
Scene.LameMu = 10000.0f;
Scene.Damping = 80.0f;
Scene.Friction = 0.95f;
Scene.Toughness = 20000.0f;
List <Vector2f> points = new List <Vector2f>();
//Random.InitState(0);
for (int i = 0; i < numPoints; ++i)
{
float rx = Random.Range(-scale, scale) * 0.5f;
float ry = Random.Range(-scale, scale) * 0.5f;
points.Add(origin + new Vector2f(rx, ry));
}
List <Vector2f> verts;
List <int> tris;
Mesher.TriangulateDelaunay(points, out verts, out tris);
// generate elements
for (int i = 0; i < verts.Count; ++i)
{
Scene.Particles.Add(new FEMParticle(verts[i], 1.0f));
}
for (int i = 0; i < tris.Count / 3; ++i)
{
Scene.Triangles.Add(new Triangle(tris[i * 3], tris[i * 3 + 1], tris[i * 3 + 2]));
}
// assign index to particles
for (int i = 0; i < Scene.Particles.Count; ++i)
{
Scene.Particles[i].index = i;
}
Scene.CreateElements();
return(Scene);
}
public static FEMScene Create(Vector2f origin, float inner, float outer, int segments)
{
FEMScene Scene = new FEMScene();
Scene.Substeps = 40;
Scene.Drag = 1.0f;
Scene.LameLambda = 10000.0f;
Scene.LameMu = 10000.0f;
Scene.Damping = 80.0f;
Scene.Friction = 0.95f;
Scene.Toughness = 20000.0f;
List <Vector2f> verts = new List <Vector2f>();
List <int> tris = new List <int>();
Mesher.CreateTorus(verts, tris, inner, outer, segments);
// generate elements
for (int i = 0; i < verts.Count; ++i)
{
Scene.Particles.Add(new FEMParticle(origin + verts[i], 1.0f));
}
for (int i = 0; i < tris.Count / 3; ++i)
{
Scene.Triangles.Add(new Triangle(tris[i * 3], tris[i * 3 + 1], tris[i * 3 + 2]));
}
// assign index to particles
for (int i = 0; i < Scene.Particles.Count; ++i)
{
Scene.Particles[i].index = i;
}
Scene.CreateElements();
return(Scene);
}
public static FEMScene Create(Texture2D img)
{
FEMScene Scene = new FEMScene();
if (img == null)
{
return(Scene);
}
Scene.Substeps = 80;
Scene.Drag = 0.1f;
Scene.LameLambda = 42000.0f;
Scene.LameMu = 42000.0f;
Scene.Damping = 250.0f;
Scene.Friction = 0.8f;
Scene.Toughness = 40000.0f;
List <Vector2f> points = new List <Vector2f>();
List <Vector2f> bpoints = new List <Vector2f>();
// controls how finely the object is sampled
aspect = (float)img.height / img.width;
float fw = img.width;
float fh = img.height;
int inc = Mathf.FloorToInt(img.width * resolution);
int margin = Mathf.Max((inc - 1) / 2, 1);
// distribute points interior to the object or near it's boundary
for (int y = 0; y < img.height; y += inc)
{
for (int x = 0; x < img.width; x += inc)
{
// if value non-zero then add a point
int n = Neighbours(img, x, y, margin);
if (n > 0)
{
Vector2f uv = new Vector2f(x / fw, y / fh);
points.Add(uv);
}
}
}
// distribute points on the boundary
for (int y = 0; y < img.height; y++)
{
for (int x = 0; x < img.width; x++)
{
if (EdgeDetect(img, x, y))
{
Vector2f uv = new Vector2f(x / fw, y / fh);
bpoints.Add(uv);
}
}
}
// triangulate
int iterations = 7;
List <Vector2f> verts;
List <int> tris;
Mesher.TriangulateVariational(points, bpoints, iterations, out verts, out tris);
//no longer used
points = null;
bpoints = null;
// discard triangles whose centroid is not inside the shape
for (int i = 0; i < tris.Count;)
{
Vector2f p = verts[tris[i + 0]];
Vector2f q = verts[tris[i + 1]];
Vector2f r = verts[tris[i + 2]];
Vector2f c = (p + q + r) / 3.0f;
//int x = Mathf.FloorToInt(c.x * fw);
//int y = Mathf.FloorToInt(c.y * fh);
//Color col = img.GetPixel(x, y);
Color col = img.GetPixelBilinear(c.x, c.y);
if (col.grayscale == 0.0f)
{
tris.RemoveRange(i, 3);
}
else
{
i += 3;
}
}
// generate particles
for (int i = 0; i < verts.Count; ++i)
{
Vector2f uv = verts[i];
Scene.Particles.Add(new FEMParticle(ToWorldPos(uv), uv, 0.0f));
}
// generate elements and assign mass based on connected area
for (int t = 0; t < tris.Count; t += 3)
{
int i = tris[t];
int j = tris[t + 1];
int k = tris[t + 2];
// calculate tri area
Vector2f a = Scene.Particles[i].p;
Vector2f b = Scene.Particles[j].p;
Vector2f c = Scene.Particles[k].p;
float area = 0.5f * Vector2f.Cross(b - a, c - a);
float mass = density * area / 3.0f;
Scene.Particles[i].invMass += mass;
Scene.Particles[j].invMass += mass;
Scene.Particles[k].invMass += mass;
Scene.Triangles.Add(new Triangle(i, j, k));
}
// convert mass to invmass
for (int i = 0; i < Scene.Particles.Count; ++i)
{
if (Scene.Particles[i].invMass > 0.0f)
{
Scene.Particles[i].invMass = 1.0f / Scene.Particles[i].invMass;
}
}
// assign index to particles
for (int i = 0; i < Scene.Particles.Count; ++i)
{
Scene.Particles[i].index = i;
}
Scene.CreateElements();
return(Scene);
}
