public static List <List <IntPoint> > CreateSlice(Mesh mesh,
Plane plane,
Matrix4X4 transformTo0Plane,
IBvhItem acccelerator = null,
bool includeBehindThePlane = true)
{
var unorderedSegments = GetUnorderdSegments(mesh, plane, transformTo0Plane, acccelerator, includeBehindThePlane);
// connect all the segments together into polygons
return(FindClosedPolygons(unorderedSegments));
}
public BvhIterator(IBvhItem referenceItem, Matrix4X4 initialTransform = default(Matrix4X4), int initialDepth = 0, Func <BvhIterator, bool> decentFilter = null)
{
TransformToWorld = initialTransform;
if (TransformToWorld == default(Matrix4X4))
{
TransformToWorld = Matrix4X4.Identity;
}
Depth = initialDepth;
Bvh = referenceItem;
this.DecentFilter = decentFilter;
}
public static void RenderBounds(DrawEventArgs e, WorldView world, Matrix4X4 transformToWorld, IBvhItem bvh, int depth = int.MinValue)
{
for (int i = 0; i < 4; i++)
{
Vector3 bottomStartPosition = Vector3Ex.Transform(bvh.GetAxisAlignedBoundingBox().GetBottomCorner(i), transformToWorld);
var bottomStartScreenPos = world.GetScreenPosition(bottomStartPosition);
Vector3 bottomEndPosition = Vector3Ex.Transform(bvh.GetAxisAlignedBoundingBox().GetBottomCorner((i + 1) % 4), transformToWorld);
var bottomEndScreenPos = world.GetScreenPosition(bottomEndPosition);
Vector3 topStartPosition = Vector3Ex.Transform(bvh.GetAxisAlignedBoundingBox().GetTopCorner(i), transformToWorld);
var topStartScreenPos = world.GetScreenPosition(topStartPosition);
Vector3 topEndPosition = Vector3Ex.Transform(bvh.GetAxisAlignedBoundingBox().GetTopCorner((i + 1) % 4), transformToWorld);
var topEndScreenPos = world.GetScreenPosition(topEndPosition);
e.Graphics2D.Line(bottomStartScreenPos, bottomEndScreenPos, Color.Black);
e.Graphics2D.Line(topStartScreenPos, topEndScreenPos, Color.Black);
e.Graphics2D.Line(topStartScreenPos, bottomStartScreenPos, Color.Black);
}
if (bvh is ITriangle tri)
{
for (int i = 0; i < 3; i++)
{
var vertexPos = tri.GetVertex(i);
var screenCenter = Vector3Ex.Transform(vertexPos, transformToWorld);
var screenPos = world.GetScreenPosition(screenCenter);
e.Graphics2D.Circle(screenPos, 3, Color.Red);
}
}
else
{
var center = bvh.GetCenter();
var worldCenter = Vector3Ex.Transform(center, transformToWorld);
var screenPos2 = world.GetScreenPosition(worldCenter);
if (depth != int.MinValue)
{
e.Graphics2D.Circle(screenPos2, 3, Color.Yellow);
e.Graphics2D.DrawString($"{depth},", screenPos2.X + 12 * depth, screenPos2.Y);
}
}
}
public BvhItemView(IBvhItem item, Matrix4X4 matrix)
{
this.BvhItem = item;
this.WorldMatrix = matrix;
}
public static List <Segment> GetUnorderdSegments(Mesh mesh,
Plane plane,
Matrix4X4 meshTo0Plane,
IBvhItem acccelerator = null,
bool includeBehindThePlane = true)
{
// collect all the segments this plane intersects and record them in unordered segments in z 0 space
var unorderedSegments = new List <Segment>();
if (acccelerator != null)
{
foreach (var bvhItem in acccelerator.GetCrossing(plane))
{
var faceIndex = -1;
if (bvhItem is MinimalTriangle minimalTriangle)
{
faceIndex = minimalTriangle.FaceIndex;
}
else if (bvhItem is MinimalTriangle triangleShape)
{
faceIndex = triangleShape.FaceIndex;
}
var face = mesh.Faces[faceIndex];
if (!includeBehindThePlane)
{
// make sure some part of this face is in front of the plane
if (plane.GetDistanceFromPlane(mesh.Vertices[face.v0]) < .001 &&
plane.GetDistanceFromPlane(mesh.Vertices[face.v1]) < .001 &&
plane.GetDistanceFromPlane(mesh.Vertices[face.v2]) < .001)
{
// skip this face as it is behind the plane
continue;
}
}
if (face.GetCutLine(mesh.Vertices, plane, out Vector3 start, out Vector3 end))
{
var startAtZ0 = Vector3Ex.Transform(start, meshTo0Plane);
var endAtZ0 = Vector3Ex.Transform(end, meshTo0Plane);
unorderedSegments.Add(
new Segment(
new IntPoint(startAtZ0.X, startAtZ0.Y),
new IntPoint(endAtZ0.X, endAtZ0.Y)));
}
}
}
else
{
for (var faceIndex = 0; faceIndex < mesh.Faces.Count; faceIndex++)
{
var face = mesh.Faces[faceIndex];
if (face.GetCutLine(mesh.Vertices, plane, out Vector3 start, out Vector3 end))
{
var startAtZ0 = Vector3Ex.Transform(start, meshTo0Plane);
var endAtZ0 = Vector3Ex.Transform(end, meshTo0Plane);
unorderedSegments.Add(
new Segment(
new IntPoint(startAtZ0.X, startAtZ0.Y),
new IntPoint(endAtZ0.X, endAtZ0.Y)));
}
}
}
return(unorderedSegments);
}
public static List <Segment> GetUnorderdSegments(Mesh mesh, Plane plane, IBvhItem acccelerator = null, bool includeBehindThePlane = true)
{
return(GetUnorderdSegments(mesh, plane, GetTransformTo0Plane(plane), acccelerator, includeBehindThePlane));
}
public static BvhIterator Filter(this IBvhItem item, Func <BvhIterator, bool> decentFilter = null)
{
return(new BvhIterator(item, Matrix4X4.Identity, 0, decentFilter));
}
