public MonotoneBox(Vertex2D vertex1, Vertex2D vertex2, MonotonicityChange lowMonoChange,
MonotonicityChange hiMonoChange, bool xInPositiveMonotonicity, bool yInPositiveMonotonicity) : this()
{
this.Vertex1 = vertex1;
this.Vertex2 = vertex2;
this.LowChange = lowMonoChange;
this.HiChange = hiMonoChange;
XInPositiveMonotonicity = xInPositiveMonotonicity;
YInPositiveMonotonicity = yInPositiveMonotonicity;
Left = Math.Min(vertex1.X, vertex2.X);
Right = Math.Max(vertex1.X, vertex2.X);
Bottom = Math.Min(vertex1.Y, vertex2.Y);
Top = Math.Max(vertex1.Y, vertex2.Y);
}
public MonotoneBox(IList <PointLight> p, int lowIndex, int hiIndex, MonotonicityChange lowMonoChange,
MonotonicityChange hiMonoChange, int xDirection, int yDirection) : this()
{
this.LowIndex = lowIndex;
this.HiIndex = hiIndex;
this.LowChange = lowMonoChange;
this.HiChange = hiMonoChange;
XInPositiveMonotonicity = xDirection > 0;
YInPositiveMonotonicity = yDirection > 0;
Left = Math.Min(p[lowIndex].X, p[hiIndex].X);
Right = Math.Max(p[lowIndex].X, p[hiIndex].X);
Bottom = Math.Min(p[lowIndex].Y, p[hiIndex].Y);
Top = Math.Max(p[lowIndex].Y, p[hiIndex].Y);
}
/// <summary>
/// Partitions the into monotone boxes.
/// </summary>
/// <param name="polygon">The polygon.</param>
/// <param name="divideAt">The divide at.</param>
/// <returns>System.Collections.Generic.IEnumerable<TVGL.TwoDimensional.MonotoneBox>.</returns>
/// <exception cref="MonotoneBox">polygon.Vertices[0], polygon.Vertices[1], MonotonicityChange.Both, MonotonicityChange.Both, true, true</exception>
public static IEnumerable <MonotoneBox> PartitionIntoMonotoneBoxes(this Polygon polygon, MonotonicityChange divideAt = MonotonicityChange.Both)
{
polygon.MakePolygonEdgesIfNonExistent();
var numPoints = polygon.Vertices.Count;
if (numPoints <= 1)
{
yield return
(new MonotoneBox(polygon.Vertices[0], polygon.Vertices[0], MonotonicityChange.Both,
MonotonicityChange.Both, true, true));
yield break;
}
if (numPoints <= 2)
{
yield return
(new MonotoneBox(polygon.Vertices[0], polygon.Vertices[1], MonotonicityChange.Both,
MonotonicityChange.Both, true, true));
yield break;
}
var initBoxIndex = -1;
var initBoxMonoChange = MonotonicityChange.Neither;
Vertex2D beginBoxVertex = null;
var beginBoxMonoChange = MonotonicityChange.Neither;
var tolerance = polygon.GetToleranceForPolygon();
var i = 0;
while (i % numPoints != initBoxIndex)
{
var vertex = polygon.Vertices[i % numPoints];
var monoChange = GetMonotonicityChange(vertex, tolerance);
if (monoChange == MonotonicityChange.SameAsPrevious || monoChange == MonotonicityChange.Neither)
{
continue;
}
if (monoChange == MonotonicityChange.Both ||
(monoChange == MonotonicityChange.X && (divideAt == MonotonicityChange.X || divideAt == MonotonicityChange.Both)) ||
(monoChange == MonotonicityChange.Y && (divideAt == MonotonicityChange.Y || divideAt == MonotonicityChange.Both)))
{
if (initBoxIndex < 0)
{
initBoxIndex = i;
beginBoxVertex = vertex;
initBoxMonoChange = beginBoxMonoChange = monoChange;
}
else
{
yield return(new MonotoneBox(beginBoxVertex, vertex, beginBoxMonoChange, monoChange,
vertex.X >= beginBoxVertex.X, vertex.Y >= beginBoxVertex.Y));
beginBoxVertex = vertex;
beginBoxMonoChange = monoChange;
}
}
i++;
}
var lastVertex = polygon.Vertices[initBoxIndex];
yield return(new MonotoneBox(beginBoxVertex, lastVertex,
beginBoxMonoChange, initBoxMonoChange,
lastVertex.X - beginBoxVertex.X >= 0,
lastVertex.Y - beginBoxVertex.Y >= 0));
}