/// <summary>
/// Compares two <see cref="UParameterIndexAndMonotonicity"/> values by their u parameters.
/// </summary>
/// <param name="first">The first value</param>
/// <param name="second">The second value</param>
private static int CompareUParameterIndexAndMonotonicityByUParameter(UParameterIndexAndMonotonicity first, UParameterIndexAndMonotonicity second)
{
return(first.UParameter.CompareTo(second.UParameter));
}
/// <summary>
/// For a contour consisting of one portion monotonically increasing in u-parameter and the other monotonically decreasing, return the <see cref="SingleContourSegmentwiseCoverage"/>
/// where there are matching points (at the same u-parameter) on both the increasing and decreasing portions.
/// </summary>
/// <param name="monotonicIncreasingChunk">Portion of contour with monotonically increasing u-parameters</param>
/// <param name="monotonicDecreasingChunk">Portion of contour with monotonically decreasing u-parameters</param>
internal static SingleContourSegmentwiseCoverage GetSingleContourSegmentwiseCoverage(ExtrudedContourMonotonicChunk monotonicIncreasingChunk, ExtrudedContourMonotonicChunk monotonicDecreasingChunk)
{
List <UParameterIndexAndMonotonicity> allContourPointUParameters = new List <UParameterIndexAndMonotonicity>();
List <Vector2WithUV> monotonicIncreasingPoints = monotonicIncreasingChunk.Points;
List <Vector2WithUV> monotonicDecreasingPoints = monotonicDecreasingChunk.Points;
//Skip the last point in each chunk so as to not double-count the 'endpoints' of min/max u-parameter
for (int i = 0; i < monotonicIncreasingPoints.Count - 1; i++)
{
allContourPointUParameters.Add(new UParameterIndexAndMonotonicity(monotonicIncreasingPoints[i].UV.x, i, true));
}
for (int i = 1; i < monotonicDecreasingPoints.Count; i++)
{
allContourPointUParameters.Add(new UParameterIndexAndMonotonicity(monotonicDecreasingPoints[i].UV.x, i, false));
}
allContourPointUParameters.Sort(CompareUParameterIndexAndMonotonicityByUParameter);
allContourPointUParameters.RemoveAt(allContourPointUParameters.Count - 1);
allContourPointUParameters.RemoveAt(0);
int numInBetweenUParameters = allContourPointUParameters.Count;
var firstPoint = monotonicIncreasingPoints[0];
var lastPoint = monotonicDecreasingPoints[monotonicDecreasingPoints.Count - 1];
List <Vector2WithUV> increasingChunkPoints = new List <Vector2WithUV>();
List <Vector2WithUV> decreasingChunkPoints = new List <Vector2WithUV>();
for (int i = 0; i < numInBetweenUParameters; i++)
{
UParameterIndexAndMonotonicity uParameterIndexAndMonotonicity = allContourPointUParameters[i];
ExtrudedContourMonotonicChunk givenMonotonicChunk = uParameterIndexAndMonotonicity.IsMonotonicIncreasing ? monotonicIncreasingChunk : monotonicDecreasingChunk;
ExtrudedContourMonotonicChunk otherMonotonicChunk = uParameterIndexAndMonotonicity.IsMonotonicIncreasing ? monotonicDecreasingChunk : monotonicIncreasingChunk;
Vector2WithUV givenMonotonicChunkPoint = givenMonotonicChunk.Points[uParameterIndexAndMonotonicity.Index];
Vector2WithUV matchingMonotonicChunkPoint;
bool gotMatchingPoint = otherMonotonicChunk.GetClosestPoint(uParameterIndexAndMonotonicity.UParameter, out matchingMonotonicChunkPoint);
if (gotMatchingPoint)
{
var increasingPoint = uParameterIndexAndMonotonicity.IsMonotonicIncreasing ? givenMonotonicChunkPoint : matchingMonotonicChunkPoint;
var decreasingPoint = uParameterIndexAndMonotonicity.IsMonotonicIncreasing ? matchingMonotonicChunkPoint : givenMonotonicChunkPoint;
increasingChunkPoints.Add(increasingPoint);
decreasingChunkPoints.Add(decreasingPoint);
}
}
//Now remove connected segments pairs that are effectively duplicates of a neighbouring segment
for (int i = increasingChunkPoints.Count - 1; i > 0; i--)
{
var increasingPoint = increasingChunkPoints[i];
var decreasingPoint = increasingChunkPoints[i];
var prevIncreasingPoint = increasingChunkPoints[i - 1];
var prevDecreasingPoint = increasingChunkPoints[i - 1];
bool increasingAreClose = ConnectedSegmentPointsAreClose(prevIncreasingPoint, increasingPoint);
bool decreasingAreClose = ConnectedSegmentPointsAreClose(prevDecreasingPoint, decreasingPoint);
if (increasingAreClose && decreasingAreClose)
{
increasingChunkPoints.RemoveAt(i);
decreasingChunkPoints.RemoveAt(i);
}
}
return(new SingleContourSegmentwiseCoverage(firstPoint, lastPoint, increasingChunkPoints, decreasingChunkPoints));
}
