static void GenerateTip(BezierSegment segment, bool atStart, float t, PathEnding ending, float halfThickness, TessellationOptions tessellateOptions, List <Vector2> verts, List <UInt16> inds)
{
// The tip includes the vertices at the end itself
Vector2 tan, nrm;
var pos = VectorUtils.EvalFull(segment, t, out tan, out nrm);
int indexStart = verts.Count;
switch (ending)
{
case PathEnding.Chop:
if (atStart)
{
verts.Add(pos + nrm * halfThickness);
verts.Add(pos - nrm * halfThickness);
}
else
{
// Not much, path segments are always expected to be generated perpendicular to the path
// at the segment point location, so we don't have to do anything for the ending
}
break;
case PathEnding.Square:
if (atStart)
{
verts.Add(pos + nrm * halfThickness - tan * halfThickness);
verts.Add(pos - nrm * halfThickness - tan * halfThickness);
verts.Add(pos + nrm * halfThickness);
verts.Add(pos - nrm * halfThickness);
inds.Add((UInt16)(indexStart + 0));
inds.Add((UInt16)(indexStart + 3));
inds.Add((UInt16)(indexStart + 1));
inds.Add((UInt16)(indexStart + 0));
inds.Add((UInt16)(indexStart + 2));
inds.Add((UInt16)(indexStart + 3));
}
else
{
// Relying on the last two vertices, and just adding two of our own here
verts.Add(pos + nrm * halfThickness + tan * halfThickness);
verts.Add(pos - nrm * halfThickness + tan * halfThickness);
inds.Add((UInt16)(indexStart + 0 - 2));
inds.Add((UInt16)(indexStart + 3 - 2));
inds.Add((UInt16)(indexStart + 1 - 2));
inds.Add((UInt16)(indexStart + 0 - 2));
inds.Add((UInt16)(indexStart + 2 - 2));
inds.Add((UInt16)(indexStart + 3 - 2));
}
break;
case PathEnding.Round:
float arcSign = atStart ? -1 : 1;
int arcSegments = CalculateArcSteps(halfThickness, 0, Mathf.PI, tessellateOptions);
for (int i = 1; i < arcSegments; i++)
{
float angle = Mathf.PI * (i / (float)arcSegments);
verts.Add(pos + Matrix2D.RotateLH(angle) * nrm * halfThickness * arcSign);
}
if (atStart)
{
// Note how we maintain the last two vertices being setup for connection by the rest of the path vertices
int indexTipStart = verts.Count;
verts.Add(pos + nrm * halfThickness);
verts.Add(pos - nrm * halfThickness);
for (int i = 1; i < arcSegments; i++)
{
inds.Add((UInt16)(indexTipStart + 1));
inds.Add((UInt16)(indexStart + i - 1));
inds.Add((UInt16)(indexStart + i));
}
}
else
{
inds.Add((UInt16)(indexStart - 1));
inds.Add((UInt16)(indexStart - 2));
inds.Add((UInt16)(indexStart + 0));
for (int i = 1; i < arcSegments - 1; i++)
{
inds.Add((UInt16)(indexStart - 1));
inds.Add((UInt16)(indexStart + i - 1));
inds.Add((UInt16)(indexStart + i));
}
}
break;
default:
System.Diagnostics.Debug.Assert(false); // Joining has its own function
break;
}
}
static JoiningInfo ForeseeJoining(BezierSegment end, BezierSegment start, float halfThickness, float endSegmentLength)
{
JoiningInfo joinInfo = new JoiningInfo();
// The joining generates the vertices at both ends as well as the joining itself
joinInfo.JoinPos = end.P3;
joinInfo.TanAtEnd = VectorUtils.EvalTangent(end, 1.0f);
joinInfo.NormAtEnd = Vector2.Perpendicular(joinInfo.TanAtEnd);
joinInfo.TanAtStart = VectorUtils.EvalTangent(start, 0.0f);
joinInfo.NormAtStart = Vector2.Perpendicular(joinInfo.TanAtStart);
// If the tangents are continuous at the join location, we don't have
// to generate a corner, we do a "simple" join by just connecting the vertices
// from the two segments directly
float cosAngleBetweenTans = Vector2.Dot(joinInfo.TanAtEnd, joinInfo.TanAtStart);
joinInfo.SimpleJoin = Mathf.Approximately(Mathf.Abs(cosAngleBetweenTans), 1.0f);
if (joinInfo.SimpleJoin)
{
return(null);
}
joinInfo.PosThicknessEnd = joinInfo.JoinPos + joinInfo.NormAtEnd * halfThickness;
joinInfo.NegThicknessEnd = joinInfo.JoinPos - joinInfo.NormAtEnd * halfThickness;
joinInfo.PosThicknessStart = joinInfo.JoinPos + joinInfo.NormAtStart * halfThickness;
joinInfo.NegThicknessStart = joinInfo.JoinPos - joinInfo.NormAtStart * halfThickness;
if (joinInfo.SimpleJoin)
{
joinInfo.PosThicknessClosingPoint = Vector2.LerpUnclamped(joinInfo.PosThicknessEnd, joinInfo.PosThicknessStart, 0.5f);
joinInfo.NegThicknessClosingPoint = Vector2.LerpUnclamped(joinInfo.NegThicknessEnd, joinInfo.NegThicknessStart, 0.5f);
}
else
{
joinInfo.PosThicknessClosingPoint = VectorUtils.IntersectLines(joinInfo.PosThicknessEnd, joinInfo.PosThicknessEnd + joinInfo.TanAtEnd, joinInfo.PosThicknessStart, joinInfo.PosThicknessStart + joinInfo.TanAtStart);
joinInfo.NegThicknessClosingPoint = VectorUtils.IntersectLines(joinInfo.NegThicknessEnd, joinInfo.NegThicknessEnd + joinInfo.TanAtEnd, joinInfo.NegThicknessStart, joinInfo.NegThicknessStart + joinInfo.TanAtStart);
if (float.IsInfinity(joinInfo.PosThicknessClosingPoint.x) || float.IsInfinity(joinInfo.PosThicknessClosingPoint.y))
{
joinInfo.PosThicknessClosingPoint = joinInfo.JoinPos;
}
if (float.IsInfinity(joinInfo.NegThicknessClosingPoint.x) || float.IsInfinity(joinInfo.NegThicknessClosingPoint.y))
{
joinInfo.NegThicknessClosingPoint = joinInfo.JoinPos;
}
}
// Should we round the positive thickness side or the negative thickness side?
joinInfo.RoundPosThickness = PointOnTheLeftOfLine(Vector2.zero, joinInfo.TanAtEnd, joinInfo.TanAtStart);
// Inner corner vertex should be calculated by intersection of the inner segments
Vector2[] startTrail = null, endTrail = null;
Vector2 intersectionOnStart = Vector2.zero, intersectionOnEnd = Vector2.zero;
if (!joinInfo.SimpleJoin)
{
BezierSegment endFlipped = VectorUtils.FlipSegment(end);
Vector2 thicknessClosingPoint = joinInfo.RoundPosThickness ? joinInfo.PosThicknessClosingPoint : joinInfo.NegThicknessClosingPoint;
Vector2 meetingPoint = end.P3;
Vector2 thicknessDiagonalEnd = meetingPoint + (thicknessClosingPoint - meetingPoint) * 10.0f;
startTrail = LineBezierThicknessIntersect(
start, joinInfo.RoundPosThickness ? -halfThickness : halfThickness, meetingPoint, thicknessDiagonalEnd,
out joinInfo.InnerCornerDistFromStart, out intersectionOnStart);
endTrail = LineBezierThicknessIntersect(
endFlipped, joinInfo.RoundPosThickness ? halfThickness : -halfThickness, meetingPoint, thicknessDiagonalEnd,
out joinInfo.InnerCornerDistToEnd, out intersectionOnEnd);
}
bool intersectionFound = false;
if ((startTrail != null) && (endTrail != null))
{
var intersect = VectorUtils.IntersectLines(startTrail[0], startTrail[1], endTrail[0], endTrail[1]);
var isOnStartTrail = PointOnLineIsWithinSegment(startTrail[0], startTrail[1], intersect);
var isOnEndTrail = PointOnLineIsWithinSegment(endTrail[0], endTrail[1], intersect);
if (!float.IsInfinity(intersect.x) && isOnStartTrail && isOnEndTrail)
{
var vStart = intersectionOnStart - intersect;
var vEnd = intersectionOnEnd - intersect;
joinInfo.InnerCornerDistFromStart += (vStart == Vector2.zero) ? 0.0f : vStart.magnitude;
joinInfo.InnerCornerDistToEnd += (vEnd == Vector2.zero) ? 0.0f : vEnd.magnitude;
joinInfo.InnerCornerDistToEnd = endSegmentLength - joinInfo.InnerCornerDistToEnd;
joinInfo.InnerCornerVertex = intersect; // Found it!
intersectionFound = true;
}
}
if (!intersectionFound)
{
joinInfo.InnerCornerVertex = joinInfo.JoinPos + ((joinInfo.TanAtStart - joinInfo.TanAtEnd) / 2.0f).normalized * halfThickness;
joinInfo.InnerCornerDistFromStart = 0;
joinInfo.InnerCornerDistToEnd = endSegmentLength;
}
return(joinInfo);
}
