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STARK: Use a non inclusive 2D segment intersection test

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Paths ending on the walkmesh bounds should not be treated as leading outside
of the walkmesh.
This commit is contained in:
Bastien Bouclet 2017-06-10 13:39:42 +02:00
parent 883755b5f8
commit 511f7198ba
2 changed files with 31 additions and 2 deletions
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32
engines/stark/resources/floor.cpp
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@ -279,12 +279,40 @@ bool FloorEdge::isFloorBorder() const {
return _faceIndex2 == -1;
}
bool FloorEdge::intersectLine2d(const Math::Line3d &s1, const Math::Line3d &s2) {
const Math::Vector3d &s1begin = s1.begin();
const Math::Vector3d &s1end = s1.end();
const Math::Vector3d &s2begin = s2.begin();
const Math::Vector3d &s2end = s2.end();
float denom = ((s2end.y() - s2begin.y()) * (s1end.x() - s1begin.x())) -
((s2end.x() - s2begin.x()) * (s1end.y() - s1begin.y()));
float nume_a = ((s2end.x() - s2begin.x()) * (s1begin.y() - s2begin.y())) -
((s2end.y() - s2begin.y()) * (s1begin.x() - s2begin.x()));
float nume_b = ((s1end.x() - s1begin.x()) * (s1begin.y() - s2begin.y())) -
((s1end.y() - s1begin.y()) * (s1begin.x() - s2begin.x()));
if (denom == 0.0f) {
return false; // Segments are collinear
}
float ua = nume_a / denom;
float ub = nume_b / denom;
// Non inclusive bounds check, one of the vertices of one segment being inside
// the other segment is not considered to be an intersection.
// This is the only difference with Line3d::intersectLine2d.
return ua > 0 && ua < 1 && ub > 0 && ub < 1;
}
bool FloorEdge::intersectsSegment(const Floor *floor, const Math::Line3d &segment) const {
Math::Vector3d vertex1 = floor->getVertex(_vertexIndex1);
Math::Vector3d vertex2 = floor->getVertex(_vertexIndex2);
Math::Line3d edgeSement = Math::Line3d(vertex1, vertex2);
Math::Line3d edgeSegment = Math::Line3d(vertex1, vertex2);
return edgeSement.intersectLine2d(segment, nullptr, false);
return intersectLine2d(edgeSegment, segment);
}
void FloorEdge::enable(bool e) {

1
engines/stark/resources/floor.h
View File

@ -103,6 +103,7 @@ public:
private:
void addNeighboursFromFace(const FloorFace *face);
static bool intersectLine2d(const Math::Line3d &s1, const Math::Line3d &s2);
uint16 _vertexIndex1;
uint16 _vertexIndex2;