public Triangle(int[] points, Plane plane, BlockingDirection direction)
{
this.points = points;
this.plane = plane;
this.direction = direction;
}
private static BlockingDirection GetBlockingDir(List <Vector3> points, List <Triangle> trianglesList, List <int[]> edges, int i, BlockingDirection blockedFaces, Triangle t)
{
Plane trianglePlane = new Plane(points[trianglesList[i].points[0]], points[trianglesList[i].points[1]], points[trianglesList[i].points[2]]);
List <Vector2> mappedTriangle = trianglePlane.GetMappedPoints(new List <Vector3>()
{
points[trianglesList[i].points[0]], points[trianglesList[i].points[1]], points[trianglesList[i].points[2]]
});
//if this triangle is already blocked in both directions, ignore this triangle.
if (blockedFaces == BlockingDirection.BOTH)
{
return(blockedFaces);
}
for (int i1 = 0; i1 < edges.Count; i1++)
{
// if any of the indexes match, ignore this edge
bool indexesMatch = false;
for (int i2 = 0; i2 < 3; i2++)
{
for (int i3 = 0; i3 < 2; i3++)
{
if (t.points[i2] == edges[i1][i3])
{
indexesMatch = true;
break;
}
}
if (indexesMatch)
{
break;
}
}
if (indexesMatch)
{
continue;
}
// if this line doesn't intersect with the triangle, ignore this edge.
Vector2 mappedPointA = trianglePlane.GetMappedPoint(points[edges[i1][0]]);
Vector2 mappedPointB = trianglePlane.GetMappedPoint(points[edges[i1][1]]);
bool lineIntersectsTriangle = false;
for (int i2 = 0; i2 < 3; i2++)
{
Vector2 triangleA = trianglePlane.GetMappedPoint(points[t.points[i2]]);
Vector2 triangleB = trianglePlane.GetMappedPoint(points[t.points[(i2 + 1) % 3]]);
if (AreLinesIntersecting(mappedPointA, mappedPointB, triangleA, triangleB, false))
{
lineIntersectsTriangle = true;
break;
}
}
if (!lineIntersectsTriangle)
{
continue;
}
int signA = Math.Sign(Math.Round(trianglePlane.GetDistToPlane(points[edges[i1][0]]), 2));
int signB = Math.Sign(Math.Round(trianglePlane.GetDistToPlane(points[edges[i1][1]]), 2));
// if sign A is not the same as sign B, or if sign A or sign B is 0, ignore this edge.
if (signA != signB || signA == 0 || signB == 0)
{
continue;
}
if (signA == 1)
{
if (blockedFaces == BlockingDirection.AWAY_FROM_NORMAL)
{
blockedFaces = BlockingDirection.BOTH;
break;
}
else
{
blockedFaces = BlockingDirection.TOWARDS_NORMAL;
}
}
else
{
if (blockedFaces == BlockingDirection.TOWARDS_NORMAL)
{
blockedFaces = BlockingDirection.BOTH;
break;
}
else
{
blockedFaces = BlockingDirection.AWAY_FROM_NORMAL;
}
}
}
drawTriangles--;
return(blockedFaces);
}
/* Parameters:
* points: points of the mesh
* faces: indexes of points that make up the triangles of the 3D mesh
*
* Returns:
* List of Triangles with the direction of their 'normals'/ the direction that the triangles should be rendered in. If a direction can't be determined, then it's left as 0.
*/
private static List <Triangle> GetKnownTriangles(List <Vector3> points, List <int[]> triangles)
{
List <Triangle> trianglesList = new List <Triangle>();
for (int i = 0; i < triangles.Count; i++)
{
Array.Sort(triangles[i]);
}
List <int[]> edges = new List <int[]>();
// go through all the points for each triangle, find points that are either in front of or behind those triangles.
for (int i = 0; i < triangles.Count; i++)
{
edges.Add(new int[] { triangles[i][0], triangles[i][1] });
edges.Add(new int[] { triangles[i][0], triangles[i][2] });
edges.Add(new int[] { triangles[i][1], triangles[i][2] });
Plane trianglePlane = new Plane(points[triangles[i][0]], points[triangles[i][1]], points[triangles[i][2]]);
List <Vector2> mappedTriangle = trianglePlane.GetMappedPoints(new List <Vector3>()
{
points[triangles[i][0]], points[triangles[i][1]], points[triangles[i][2]]
});
BlockingDirection blockedFaces = BlockingDirection.NONE;
for (int i1 = 0; i1 < points.Count; i1++)
{
if (i1 == triangles[i][0] || i1 == triangles[i][1] || i1 == triangles[i][2])
{
//ignore this point if it's one of the triangle's points
continue;
}
Vector2 mappedPoint = trianglePlane.GetMappedPoint(points[i1]);
if (!PointInTriangle(mappedPoint, mappedTriangle[0], mappedTriangle[1], mappedTriangle[2]))
{
//ignore this point if it's not behind the triangle
continue;
}
//rounding accuracy to hundredths place to
int pointSign = Math.Sign(Math.Round(trianglePlane.GetDistToPlane(points[i1]), 2));
if (pointSign == 0)
{
//ignore this point if it's on the same plane
continue;
}
if (pointSign == 1)
{
if (blockedFaces == BlockingDirection.AWAY_FROM_NORMAL)
{
blockedFaces = BlockingDirection.BOTH;
break;
}
else
{
if (drawTriangles > 0)
{
}
blockedFaces = BlockingDirection.TOWARDS_NORMAL;
}
}
else
{
if (blockedFaces == BlockingDirection.TOWARDS_NORMAL)
{
blockedFaces = BlockingDirection.BOTH;
break;
}
else
{
if (drawTriangles > 0)
{
}
blockedFaces = BlockingDirection.AWAY_FROM_NORMAL;
}
}
}
trianglesList.Add(new Triangle(triangles[i], trianglePlane, blockedFaces));
}
drawTriangles = 1;
// go through all the connections for each triangle, find lines that are either in front of or behind those triangles.
for (int i = 0; i < trianglesList.Count; i++)
{
Plane trianglePlane = new Plane(points[triangles[i][0]], points[triangles[i][1]], points[triangles[i][2]]);
List <Vector2> mappedTriangle = trianglePlane.GetMappedPoints(new List <Vector3>()
{
points[triangles[i][0]], points[triangles[i][1]], points[triangles[i][2]]
});
BlockingDirection blockedFaces = trianglesList[i].direction;
//if this triangle is already blocked in both directions, ignore this triangle.
if (blockedFaces == BlockingDirection.BOTH)
{
continue;
}
for (int i1 = 0; i1 < edges.Count; i1++)
{
// if any of the indexes match, ignore this edge
bool indexesMatch = false;
for (int i2 = 0; i2 < 3; i2++)
{
for (int i3 = 0; i3 < 2; i3++)
{
if (trianglesList[i].points[i2] == edges[i1][i3])
{
indexesMatch = true;
break;
}
}
if (indexesMatch)
{
break;
}
}
if (indexesMatch)
{
continue;
}
// if this line doesn't intersect with the triangle, ignore this edge.
Vector2 mappedPointA = trianglePlane.GetMappedPoint(points[edges[i1][0]]);
Vector2 mappedPointB = trianglePlane.GetMappedPoint(points[edges[i1][1]]);
bool lineIntersectsTriangle = false;
for (int i2 = 0; i2 < 3; i2++)
{
Vector2 triangleA = trianglePlane.GetMappedPoint(points[trianglesList[i].points[i2]]);
Vector2 triangleB = trianglePlane.GetMappedPoint(points[trianglesList[i].points[(i2 + 1) % 3]]);
if (AreLinesIntersecting(mappedPointA, mappedPointB, triangleA, triangleB, false))
{
lineIntersectsTriangle = true;
break;
}
}
if (!lineIntersectsTriangle)
{
continue;
}
int signA = Math.Sign(Math.Round(trianglePlane.GetDistToPlane(points[edges[i1][0]]), 2));
int signB = Math.Sign(Math.Round(trianglePlane.GetDistToPlane(points[edges[i1][1]]), 2));
// if sign A is not the same as sign B, or if sign A or sign B is 0, ignore this edge.
if (signA != signB || signA == 0 || signB == 0)
{
continue;
}
if (signA == 1)
{
if (blockedFaces == BlockingDirection.AWAY_FROM_NORMAL)
{
blockedFaces = BlockingDirection.BOTH;
break;
}
else
{
blockedFaces = BlockingDirection.TOWARDS_NORMAL;
}
}
else
{
if (blockedFaces == BlockingDirection.TOWARDS_NORMAL)
{
blockedFaces = BlockingDirection.BOTH;
break;
}
else
{
blockedFaces = BlockingDirection.AWAY_FROM_NORMAL;
}
}
}
drawTriangles--;
trianglesList[i].direction = blockedFaces;
}
return(trianglesList);
}
private static int GetFirstKnownTriangle(List <Vector3> points, List <Triangle> trianglesList, out BlockingDirection dir)
{
List <int[]> edges = new List <int[]>();
for (int i = 0; i < trianglesList.Count; i++)
{
edges.Add(new int[] { trianglesList[i].points[0], trianglesList[i].points[1] });
edges.Add(new int[] { trianglesList[i].points[0], trianglesList[i].points[2] });
edges.Add(new int[] { trianglesList[i].points[1], trianglesList[i].points[2] });
}
for (int i = 0; i < trianglesList.Count; i++)
{
Plane trianglePlane = new Plane(points[trianglesList[i].points[0]], points[trianglesList[i].points[1]], points[trianglesList[i].points[2]]);
List <Vector2> mappedTriangle = trianglePlane.GetMappedPoints(new List <Vector3>()
{
points[trianglesList[i].points[0]], points[trianglesList[i].points[1]], points[trianglesList[i].points[2]]
});
BlockingDirection blockedFaces = BlockingDirection.NONE;
for (int i1 = 0; i1 < points.Count; i1++)
{
if (i1 == trianglesList[i].points[0] || i1 == trianglesList[i].points[1] || i1 == trianglesList[i].points[2])
{
//ignore this point if it's one of the triangle's points
continue;
}
Vector2 mappedPoint = trianglePlane.GetMappedPoint(points[i1]);
if (!PointInTriangle(mappedPoint, mappedTriangle[0], mappedTriangle[1], mappedTriangle[2]))
{
//ignore this point if it's not behind the triangle
continue;
}
//rounding accuracy to hundredths place to
int pointSign = Math.Sign(Math.Round(trianglePlane.GetDistToPlane(points[i1]), 2));
if (pointSign == 0)
{
//ignore this point if it's on the same plane
continue;
}
if (pointSign == 1)
{
if (blockedFaces == BlockingDirection.AWAY_FROM_NORMAL)
{
blockedFaces = BlockingDirection.BOTH;
break;
}
else
{
if (drawTriangles > 0)
{
}
blockedFaces = BlockingDirection.TOWARDS_NORMAL;
}
}
else
{
if (blockedFaces == BlockingDirection.TOWARDS_NORMAL)
{
blockedFaces = BlockingDirection.BOTH;
break;
}
else
{
if (drawTriangles > 0)
{
}
blockedFaces = BlockingDirection.AWAY_FROM_NORMAL;
}
}
}
Triangle t = new Triangle(trianglesList[i].points, trianglePlane, blockedFaces);
t.direction = GetBlockingDir(points, trianglesList, edges, i, t.direction, t);
if (t.GetDirInt() != 0)
{
dir = t.direction;
return(i);
}
}
dir = BlockingDirection.NONE;
return(-1);
}
