// Join two polygons (assuming that they are adjacent and share an edge)
public Polygon Join(Polygon other)
{
int thisEdgeId = -1;
int otherEdgeId = -1;
for (int i = 0; i < Length() && thisEdgeId == -1; i++)
{
Vector3 thisFrom = Vertex(i);
Vector3 thisTo = Vertex((i + 1) % Length());
for (int j = 0; j < other.Length(); j++)
{
Vector3 otherFrom = other.Vertex(j);
Vector3 otherTo = other.Vertex((j + 1) % other.Length());
if ((thisFrom - otherTo).sqrMagnitude < 0.001f && (thisTo - otherFrom).sqrMagnitude < 0.001f)
{
thisEdgeId = i;
otherEdgeId = j;
break;
}
}
}
if (thisEdgeId == -1)
{
return(null);
}
Polygon res = new Polygon();
// add current points
for (int i = 0; i < Length(); i++)
{
res.vertices.Add(vertices[(i + thisEdgeId + 1) % Length()]);
}
otherEdgeId = otherEdgeId + 2; // skip current since this equals the last vertex of res
// add vertices from other
for (int i = 0; i < other.Length() - 2; i++)
{
res.vertices.Add(other.vertices[(i + otherEdgeId) % other.Length()]);
}
// remove any edge (where two edges share endpoints but has different directions
for (int i = 0; i < res.Length(); i++)
{
var thisVert = res.Vertex(i);
var nextNextVert = res.Vertex((i + 2) % res.Length());
bool almostEqual = (thisVert - nextNextVert).sqrMagnitude < 0.001f;
if (almostEqual)
{
var vects = new int[] { (i + 1) % res.Length(), i };
System.Array.Sort(vects);
res.vertices.RemoveRange(vects[1], 1);
res.vertices.RemoveRange(vects[0], 1);
i = i + 2;
}
}
return(res);
}
public void Polygon_Vertices()
{
Point[] actual = thePolygon.Vertices.ToArray();
Assert.Equal(expected.Length, actual.Length);
for (int i = 0; i < expected.Length; i++)
{
Assert.Equal(expected[i], actual[i]);
}
for (int i = 0; i < expected.Length; i++)
{
Assert.Equal(expected[i], thePolygon.Vertex(i));
Assert.Equal(expected[i], thePolygon.Vertex(i + expected.Length));
Assert.Equal(expected[i], thePolygon.Vertex(i - expected.Length));
}
}
public ColoredParticleRenderer(Polygon polygon)
{
if (polygon.Length < 3)
{
throw new ArgumentException("The polygon must have at least three vertices.", nameof(polygon));
}
_verticesPerParticle = 3 + (polygon.Length - 3) * 3; // First three vertices contribute one triangle; each remaining vertex contributes one triangle
_polygonVertices = new GraphicsPoint[_verticesPerParticle];
_polygonVertices[0] = (GraphicsPoint)polygon.Vertex(0);
_polygonVertices[1] = (GraphicsPoint)polygon.Vertex(1);
_polygonVertices[2] = (GraphicsPoint)polygon.Vertex(2);
for (int i = 3, c = 3; i < polygon.Length; i++)
{
_polygonVertices[c++] = _polygonVertices[0];
_polygonVertices[c++] = (GraphicsPoint)polygon.Vertex(i - 1);
_polygonVertices[c++] = (GraphicsPoint)polygon.Vertex(i);
}
}
public static GraphicsPoint[] Tesselate(this Polygon polygon)
{
var result = new GraphicsPoint[polygon.Length];
for (int i = 0, sign = 1; i < polygon.Length; i++, sign = -sign)
{
result[i] = (GraphicsPoint)polygon.Vertex(i * sign);
}
return(result);
}
/// <summary>
/// Splits a polygon by a given plane, resulting in two polygons. Note
/// that this function assumes that the polygon intersects the split plane.
/// </summary>
/// <param name="poly"></param>
/// <param name="splitPlane"></param>
/// <returns>Two polygons in a list.</returns>
public static List <Polygon> SplitPolygon(Polygon poly, Plane splitPlane)
{
Polygon front = new Polygon();
Polygon back = new Polygon();
front.Used = poly.Used;
front.Plane = poly.Plane;
back.Used = poly.Used;
back.Plane = poly.Plane;
Vector3 pointA, pointB;
PointClassification sideA, sideB;
pointA = poly.Vertices.Last();
sideA = ClassifyPoint(pointA, splitPlane);
for (int i = 0; i < poly.Vertices.Count; i++)
{
pointB = poly.Vertex(i);
sideB = ClassifyPoint(pointB, splitPlane);
if (sideB == PointClassification.Front)
{
if (sideA == PointClassification.Back)
{
Vector3 v = (pointB - pointA).normalized;
Ray r = new Ray(pointA, v);
float e;
splitPlane.Raycast(r, out e);
Vector3 intersectionPoint = pointA + v * e;
front.AddVertex(intersectionPoint);
back.AddVertex(intersectionPoint);
}
front.AddVertex(pointB);
}
else if (sideB == PointClassification.Back)
{
if (sideA == PointClassification.Front)
{
Vector3 v = (pointB - pointA).normalized;
Ray r = new Ray(pointA, v);
float e;
splitPlane.Raycast(r, out e);
Vector3 intersectionPoint = pointA + v * e;
front.AddVertex(intersectionPoint);
back.AddVertex(intersectionPoint);
}
back.AddVertex(pointB);
}
else
{
front.AddVertex(pointB);
back.AddVertex(pointB);
}
pointA = pointB;
sideA = sideB;
}
return(new List <Polygon>()
{
front, back
});
}
// Join two polygons (assuming that they are adjacent and share an edge)
public Polygon Join(Polygon other)
{
int thisEdgeId = -1;
int otherEdgeId = -1;
for (int i=0;i<Length() && thisEdgeId == -1;i++){
Vector3 thisFrom = Vertex(i);
Vector3 thisTo = Vertex((i+1)%Length());
for (int j=0;j<other.Length();j++){
Vector3 otherFrom = other.Vertex(j);
Vector3 otherTo = other.Vertex((j+1)%other.Length());
if ((thisFrom-otherTo).sqrMagnitude < 0.001f && (thisTo-otherFrom).sqrMagnitude < 0.001f){
thisEdgeId = i;
otherEdgeId = j;
break;
}
}
}
if (thisEdgeId == -1){
return null;
}
Polygon res = new Polygon();
// add current points
for (int i=0;i<Length();i++){
res.vertices.Add(vertices[(i+thisEdgeId+1)%Length()]);
}
otherEdgeId=otherEdgeId+2; // skip current since this equals the last vertex of res
// add vertices from other
for (int i=0;i<other.Length()-2;i++){
res.vertices.Add(other.vertices[(i+otherEdgeId)%other.Length()]);
}
// remove any edge (where two edges share endpoints but has different directions
for (int i=0;i<res.Length();i++){
var thisVert = res.Vertex(i);
var nextNextVert = res.Vertex((i+2)%res.Length());
bool almostEqual = (thisVert - nextNextVert).sqrMagnitude < 0.001f;
if (almostEqual){
var vects = new int[]{(i+1)%res.Length(),i};
System.Array.Sort(vects);
res.vertices.RemoveRange(vects[1],1);
res.vertices.RemoveRange(vects[0],1);
i = i+2;
}
}
return res;
}
