/// <summary>
/// This function will check if any vertex of a triangle is touching this triangle
/// </summary>
/// <param name="other">The <see cref="PTriangle"/> to check collision with</param>
/// <returns>A bool indicating whether or not the <see cref="PTriangle"/>s are touching</returns>
/// https://stackoverflow.com/questions/2778240/detection-of-triangle-collision-in-2d-space
public bool IsTouching(PTriangle other)
{
bool inPointOne = ContainsPoint(other.VertexOne);
bool inPointTwo = ContainsPoint(other.VertexTwo);
bool inPointThree = ContainsPoint(other.VertexThree);
bool inPointFour = other.ContainsPoint(this.VertexOne);
bool inPointFive = other.ContainsPoint(this.VertexTwo);
bool inPointSix = other.ContainsPoint(this.VertexThree);
if (inPointOne || inPointTwo || inPointThree)
{
return(true);
}
if (inPointFour || inPointFive || inPointSix)
{
return(true);
}
return(false);
}
/// <summary>
/// Checks whether or not a given vertex is an ear of the given polygon
/// </summary>
/// <param name="vertices">Vertices composing the edges of the polygon</param>
/// <param name="vert">The vertex to check</param>
/// <param name="clockwise">Indicates which direction the vertices list rotates around the polygon</param>
/// <returns>A bool indicating if the vertex is an ear</returns>
private bool VertexIsEar(List <Vector2> vertices, int vert, bool clockwise)
{
if (vert < 0 || vert >= vertices.Count)
{
throw new ArgumentOutOfRangeException("Argument vert out of range");
}
// Get vertices for the relevant triangle
int vert1 = vertices.GetPrevIndex(vert);
int vert2 = vert;
int vert3 = vertices.GetNextIndex(vert);
// Determine if the angle at vert is reflex
float crossProd = Vector2.CrossProduct(vertices[vert1], vertices[vert2], vertices[vert3]);
if ((crossProd > 0 && clockwise) || (crossProd < 0 && !clockwise))
{
return(false);
}
// Check if any point is inside the triangle formed from this vertex
PTriangle tri = new PTriangle(vertices[vert1], vertices[vert2], vertices[vert3]);
for (int i = 0; i < vertices.Count; i++)
{
// No point checking the vertices of the current triangle
if (i != vert1 && i != vert2 && i != vert3)
{
if (tri.ContainsPoint(vertices[i]))
{
return(false);
}
}
}
return(true);
}