/// <summary> /// Add extruded point(s) based on two neighbouring line segments. /// </summary> /// <param name="linePointAndForwardSegment">A line point and its corresponding segment.</param> /// <param name="previousLinePointAndForwardSegment">The previous line point and its corresponding segment.</param> /// <param name="nextLinePoint">The next line point (since its parameter, uv etc will be needed).</param> /// <param name="lineSegmentIndexToAssign">Line segment index to assign the extruded point coming from.</param> /// <param name="extrusionAmount">The extrusion amount.</param> /// <param name="extrudedLinePoints">The list of all extruded line points.</param> /// <param name="findParameter">Delegate for determining altered point parameter.</param> private static void AddPointExtrusionFromPreviousNextSegments(LinePointUVAndSegment linePointAndForwardSegment, LinePointUVAndSegment previousLinePointAndForwardSegment, LinePointUV nextLinePoint, int lineSegmentIndexToAssign, float extrusionAmount, List <ExtrudedPointUV> extrudedLinePoints, GetShiftedScaledParameter findParameter) { double extrusionMagnitudeFractionFirstTangent; bool segmentIntersection = LineSegmentUtil.DoNeighbouringSegmentTangentsFromCommonPointIntersect(previousLinePointAndForwardSegment.SegmentTangent, linePointAndForwardSegment.SegmentTangent, Mathf.Sign(extrusionAmount), out extrusionMagnitudeFractionFirstTangent); if (segmentIntersection) { //Concave section; expect intersection of neighbouring line segments around this point var extrusionDistanceAlongTangents = Mathf.Abs((float)extrusionMagnitudeFractionFirstTangent * extrusionAmount); bool intersectionOccursOutOfSegment = extrusionDistanceAlongTangents >= Mathf.Min(previousLinePointAndForwardSegment.SegmentLength, linePointAndForwardSegment.SegmentLength); if (intersectionOccursOutOfSegment) { AttemptAddNaiveExtrudedPointsWhenTheirExtrudedSegmentsDoNotIntersect(linePointAndForwardSegment, previousLinePointAndForwardSegment, lineSegmentIndexToAssign, extrusionAmount, extrudedLinePoints, findParameter, extrusionDistanceAlongTangents); } else { var intersection = LineSegmentUtil.GetExtrudedSegmentNeighbouringIntersectionPoint(linePointAndForwardSegment.Point, previousLinePointAndForwardSegment.SegmentTangent, extrusionMagnitudeFractionFirstTangent, extrusionAmount); var linePointOfThisIntersection = new LinePointUV(findParameter(linePointAndForwardSegment.Parameter), intersection, linePointAndForwardSegment.UV); extrudedLinePoints.Add(new ExtrudedPointUV(linePointOfThisIntersection, lineSegmentIndexToAssign, lineSegmentIndexToAssign - 1)); } } else { //Convex section, expect a circular fan of points around this point. RangeF rangeFromPreviousPoints = new RangeF(findParameter(previousLinePointAndForwardSegment.Parameter), findParameter(linePointAndForwardSegment.Parameter)); RangeF rangeFromNextPoints = new RangeF(findParameter(linePointAndForwardSegment.Parameter), findParameter(nextLinePoint.Parameter)); RangeF parameterRangeToUse = new RangeF(rangeFromPreviousPoints.FromFractionUnclamped(0.6f), rangeFromNextPoints.FromFractionUnclamped(0.4f)); var extrudedFromPreviousNormal = linePointAndForwardSegment.Point + extrusionAmount * previousLinePointAndForwardSegment.SegmentNormal; var extrudedFromNextNormal = linePointAndForwardSegment.Point + extrusionAmount * linePointAndForwardSegment.SegmentNormal; var diffBetweenExtrusion = (extrudedFromNextNormal - extrudedFromPreviousNormal).magnitude; var minNeighbouringSegmentDistance = Mathf.Min(previousLinePointAndForwardSegment.SegmentLength, linePointAndForwardSegment.SegmentLength); float absExtrusionAmount = Mathf.Abs(extrusionAmount); var comparisonDistance = Mathf.Min(minNeighbouringSegmentDistance, absExtrusionAmount); var angleBetweenSegmentNormals = Mathf.Acos(Mathf.Clamp(Vector3.Dot(previousLinePointAndForwardSegment.SegmentNormal, linePointAndForwardSegment.SegmentNormal), -1f, 1f)); int numPointsFromDistance = Mathf.CeilToInt(diffBetweenExtrusion / comparisonDistance); if (numPointsFromDistance <= 2) { numPointsFromDistance++; } //NB Want at least the end-points, and if distance is large enough to need 2 naturally, 3 seems to looks better. int numPointsFromAngle = Mathf.CeilToInt(angleBetweenSegmentNormals / _convexExtrusionMinimumAngleRadians); int numPoints = Mathf.Max(numPointsFromDistance, numPointsFromAngle); for (int i = 0; i < numPoints; i++) { float fraction = numPoints == 1 ? 0.5f : i / (numPoints - 1.0f); var averageTangent = previousLinePointAndForwardSegment.SegmentTangent.AverageDirectionVector(linePointAndForwardSegment.SegmentTangent, fraction); var averageNormal = NormalUtil.NormalFromTangent(averageTangent); var extrudedVector = linePointAndForwardSegment.Point + averageNormal * extrusionAmount; var parameter = parameterRangeToUse.FromFractionUnclamped(fraction); Vector2 newUV = GetUVParameterOfFanPoint(linePointAndForwardSegment, previousLinePointAndForwardSegment, nextLinePoint, absExtrusionAmount, angleBetweenSegmentNormals, fraction); var newLinePointInFan = new LinePointUV(parameter, extrudedVector, newUV); extrudedLinePoints.Add(new ExtrudedPointUV(newLinePointInFan, lineSegmentIndexToAssign, lineSegmentIndexToAssign - 1)); } } }
/// <summary> /// Gets a set of line point and segments in reverse direction, with reversed parameters. /// </summary> /// <param name="originalLineSegments">List of line points with segments connecting to the next point in the line.</param> /// <param name="lastLinePoint">The final line point.</param> private static List <LinePointUVAndSegment> GetReversedSegmentsAndReversedParameters(List <LinePointUVAndSegment> originalLineSegments, LinePointUV lastLinePoint) { List <LinePointUVAndSegment> reversedSegments = new List <LinePointUVAndSegment>(); RangeF originalSegmentsParameterRange = new RangeF(originalLineSegments[0].Parameter, lastLinePoint.Parameter); var originalSegmentsParameterRangeMaxPlusMin = originalSegmentsParameterRange.Min + originalSegmentsParameterRange.Max; var endIndex = originalLineSegments.Count - 1; for (int i = endIndex; i >= 0; i--) { var originPoint = i == endIndex ? lastLinePoint : originalLineSegments[i + 1].LinePoint; var currentSegmentForward = originalLineSegments[i]; originPoint.Parameter = originalSegmentsParameterRangeMaxPlusMin - originPoint.Parameter; var segment = new LinePointUVAndSegment(originPoint, currentSegmentForward.Point, -currentSegmentForward.SegmentTangent, -currentSegmentForward.SegmentNormal, currentSegmentForward.SegmentLength); reversedSegments.Add(segment); } return(reversedSegments); }
/// <summary> /// Determine the UV parameter of a fan point. /// </summary> /// <param name="linePointAndForwardSegment">A line point and its corresponding segment.</param> /// <param name="previousLinePointAndForwardSegment">The previous line point and its corresponding segment.</param> /// <param name="nextLinePoint">The next line point (since its parameter, uv etc will be needed).</param> /// <param name="absExtrusionAmount">Absolute value of the extrusion amount.</param> /// <param name="angleBetweenSegmentNormals">Angle between segment normals of <paramref name="previousLinePointAndForwardSegment"/> and <paramref name="linePointAndForwardSegment"/>.</param> /// <param name="fraction">Fraction along the fan.</param> private static Vector2 GetUVParameterOfFanPoint(LinePointUVAndSegment linePointAndForwardSegment, LinePointUVAndSegment previousLinePointAndForwardSegment, LinePointUV nextLinePoint, float absExtrusionAmount, float angleBetweenSegmentNormals, float fraction) { var currentPointUv = linePointAndForwardSegment.UV; bool isInPreviousHalfOfArc = fraction < 0.5f; var fractionFromNeighbour = isInPreviousHalfOfArc ? fraction : 1f - fraction; var fanArcLength = angleBetweenSegmentNormals * absExtrusionAmount; var neighbouringSegmentHalfLength = 0.5f * (isInPreviousHalfOfArc ? previousLinePointAndForwardSegment.SegmentLength : linePointAndForwardSegment.SegmentLength); var distance = neighbouringSegmentHalfLength + fractionFromNeighbour * fanArcLength; var distanceToHalfFan = neighbouringSegmentHalfLength + 0.5f * fanArcLength; var uvFractionFromNeighbouringHalfPoint = distance / distanceToHalfFan; var neighbouringPoint = isInPreviousHalfOfArc ? previousLinePointAndForwardSegment.LinePoint : nextLinePoint; var averageNeighbourAndCurrentPoint = neighbouringPoint.AverageWith(linePointAndForwardSegment.LinePoint, 0.5f); var averageNeighbourAndCurrentPointUv = averageNeighbourAndCurrentPoint.UV; var newUV = averageNeighbourAndCurrentPointUv * (1f - uvFractionFromNeighbouringHalfPoint) + currentPointUv * uvFractionFromNeighbouringHalfPoint; return(newUV); }
/// <summary> /// Atempt to add naively-extruded points when the extrusion from two neighbouring segments would intersect outside of those extruded segments. /// </summary> /// <param name="linePointAndForwardSegment">First segment.</param> /// <param name="previousLinePointAndForwardSegment">Previous segment.</param> /// <param name="lineSegmentIndexToAssign">Line segment index to assign the extruded point coming from.</param> /// <param name="extrusionAmount">The extrusion amount.</param> /// <param name="extrudedLinePoints">The list of all extruded line points.</param> /// <param name="findParameter">Delegate for determining altered point parameter.</param> /// <param name="extrusionIntersectionDistanceAlongTangents">The extrusion intersection distance along segment tangent directions.</param> private static void AttemptAddNaiveExtrudedPointsWhenTheirExtrudedSegmentsDoNotIntersect(LinePointUVAndSegment linePointAndForwardSegment, LinePointUVAndSegment previousLinePointAndForwardSegment, int lineSegmentIndexToAssign, float extrusionAmount, List <ExtrudedPointUV> extrudedLinePoints, GetShiftedScaledParameter findParameter, float extrusionIntersectionDistanceAlongTangents) { bool intersectionOccursOutOfBothSegments = extrusionIntersectionDistanceAlongTangents >= Mathf.Max(previousLinePointAndForwardSegment.SegmentLength, linePointAndForwardSegment.SegmentLength); if (intersectionOccursOutOfBothSegments) { //Nothing to do here, since any additional points will not contribute to any chunks that are not too close to the original line. } else { var extrudedFromCenterPointPreviousSegmentNormal = new ExtrudedPointUV(linePointAndForwardSegment.LinePoint, findParameter(linePointAndForwardSegment.Parameter), previousLinePointAndForwardSegment.SegmentNormal, extrusionAmount, lineSegmentIndexToAssign - 1);//Previous segment's index extrudedLinePoints.Add(extrudedFromCenterPointPreviousSegmentNormal); var extrudedFromCenterPointCurrentSegmentNormal = new ExtrudedPointUV(linePointAndForwardSegment.LinePoint, findParameter(linePointAndForwardSegment.Parameter), linePointAndForwardSegment.SegmentNormal, extrusionAmount, lineSegmentIndexToAssign);//Current segment's index extrudedLinePoints.Add(extrudedFromCenterPointCurrentSegmentNormal); //NB Here we are just adding the 'naive' points without computing the intersection, and relying on the overall intersection algorithm to take care of the rest. } }