public FloatArray computePolygon(float[] points, int offset, int count, bool sorted)
{
int end = offset + count;
if (!sorted)
{
if (sortedPoints == null || sortedPoints.Length < count)
{
sortedPoints = new float[count];
}
Array.Copy(points, offset, sortedPoints, 0, count);
points = sortedPoints;
offset = 0;
sort(points, count);
}
FloatArray hull = this.hull;
hull.clear();
// Lower hull.
for (int i = offset; i < end; i += 2)
{
float x = points[i];
float y = points[i + 1];
while (hull.size >= 4 && ccw(x, y) <= 0)
{
hull.size -= 2;
}
hull.Add(x);
hull.Add(y);
}
List <float> l1 = new List <float>();
List <float> l2 = new List <float>();
float[] xx = new float[hull.size];
float[] yy = new float[hull.size];
l1 = hull.toArray().ToList();
l2 = hull.toArray().ToList();
for (int i = 0; i < l1.Count; i++)
{
if (i % 2 == 0)
{
xx[i / 2] = l1.ElementAt(i);
}
else
{
yy[(i - 1) / 2] = l1.ElementAt(i);
}
}
abajo = Punto.getArreglo(xx, yy);
FloatArray hullAUX = new FloatArray();
// Upper hull.
for (int i = end - 4, t = hull.size + 2; i >= offset; i -= 2)
{
float x = points[i];
float y = points[i + 1];
while (hull.size >= t && ccw(x, y) <= 0)
{
hull.size -= 2;
}
hull.Add(x);
hull.Add(y);
}
for (int i = end - 4, t = hullAUX.size + 2; i >= offset; i -= 2)
{
float x = points[i];
float y = points[i + 1];
while (hullAUX.size >= t && ccw(x, y) <= 0)
{
hullAUX.size -= 2;
}
hullAUX.Add(x);
hullAUX.Add(y);
}
l1 = hullAUX.toArray().ToList();
l2 = hullAUX.toArray().ToList();
for (int i = 0; i < l1.Count; i++)
{
if (i % 2 == 0)
{
xx[i / 2] = l1.ElementAt(i);
}
else
{
yy[(i - 1) / 2] = l1.ElementAt(i);
}
}
arriba = Punto.getArreglo(xx, yy);
Array.Sort(arriba, ConvexHull.compararPorAbsisa());
return(hull);
}
/** Computes a hull the same as {@link #computePolygon(float[], int, int, bool)} but returns indices of the specified points. */
public IntArray computeIndices(float[] points, int offset, int count, bool sorted, bool yDown)
{
int end = offset + count;
if (!sorted)
{
if (sortedPoints == null || sortedPoints.Length < count)
{
sortedPoints = new float[count];
}
Array.Copy(points, offset, sortedPoints, 0, count);
points = sortedPoints;
offset = 0;
sortWithIndices(points, count, yDown);
}
IntArray indices = this.indices;
indices.clear();
FloatArray hull = this.hull;
hull.clear();
// Lower hull.
for (int i = offset, index = i / 2; i < end; i += 2, index++)
{
float x = points[i];
float y = points[i + 1];
while (hull.size >= 4 && ccw(x, y) <= 0)
{
hull.size -= 2;
indices.size--;
}
hull.Add(x);
hull.Add(y);
indices.Add(index);
}
// Upper hull.
for (int i = end - 4, index = i / 2, t = hull.size + 2; i >= offset; i -= 2, index--)
{
float x = points[i];
float y = points[i + 1];
while (hull.size >= t && ccw(x, y) <= 0)
{
hull.size -= 2;
indices.size--;
}
hull.Add(x);
hull.Add(y);
indices.Add(index);
}
// Convert sorted to unsorted indices.
if (!sorted)
{
short[] originalIndicesArray = originalIndices.items;
int[] indicesArray = indices.items;
for (int i = 0, n = indices.size; i < n; i++)
{
indicesArray[i] = originalIndicesArray[indicesArray[i]];
}
}
return(indices);
}
