//returns true if the polygons passed as parameters intersect
int PolyInPoly(const POLY * t1, const POLY * t2)
{
int i, j;
LINE l1, l2;
if(!t1 || !t2)
return 0;
if(PointInPoly(&t1->p[0], t2) || PointInPoly(&t1->p[1], t2) || PointInPoly(&t1->p[2], t2))
return 1; //if any of the points of t1 are in t2
for(i = 0; i < 3; i++)
{
l1.a.x = t1->p[i].x;
l1.a.y = t1->p[i].y;
l1.b.x = t1->p[(i + 1) % 3].x;
l1.b.y = t1->p[(i + 1) % 3].y;
for(j = 0; j < 3; j++)
{
l2.a.x = t2->p[j].x;
l2.a.y = t2->p[j].y;
l2.b.x = t2->p[(j + 1) % 3].x;
l2.b.y = t2->p[(j + 1) % 3].y;
if(LinesIntersect(&l1, &l2)) //if the line intersects any line in t2
return 1;
}
}
return 0; //no intersection
}
//returns true if the point is contained within the polygon
int PointInPoly(const POINT2 * p, const POLY * t)
{
int i, intersections = 0;
LINE l1, l2;
if(!p || !t)
return 0;
l1.a.x = -1.0f;
l1.a.y = -1.0f;
l1.b.x = p->x;
l1.b.y = p->y;
for(i = 0; i < 3; i++)
{
l2.a.x = t->p[i].x;
l2.a.y = t->p[i].y;
l2.b.x = t->p[(i + 1) % 3].x;
l2.b.y = t->p[(i + 1) % 3].y;
if(LinesIntersect(&l1, &l2))
intersections++;
}
return (intersections & 1); //returns 1 if odd, 0 if even # intersections
}
bool Collider::CollidePolygonPolygon(PolygonCollider* a, PolygonCollider* b)
{
//If the polygons aren't even close to eachother, don't bother
if (a->GetLeftmost() > b->GetRightmost())
return false;
if (a->GetRightmost() < b->GetLeftmost())
return false;
if (a->GetTopmost() > b->GetBottommost())
return false;
if (a->GetBottommost() < b->GetTopmost())
return false;
//Check if the first point of either polygon is inside the other
//(accounts for the case where one poly is completely inside the other)
if (a->IntersectsPoint(b->GetPoint(0)) || b->IntersectsPoint(a->GetPoint(0)))
return true;
//Compare lines, looking for an intersection
int totalA = a->GetPointCount();
int totalB = b->GetPointCount();
for (int i = 0; i < totalA; ++i)
{
Vector2 startA = a->GetPoint(i);
Vector2 endA = a->GetPoint((i + 1) % totalA);
for (int j = 0; j < totalB; ++j)
{
Vector2 startB = b->GetPoint(j);
Vector2 endB = b->GetPoint((j + 1) % totalB);
if (LinesIntersect(startA, endA, startB, endB))
return true;
}
}
return false;
}
std::vector<IntResult> SimpleIntersector::Intersects(FastCurve* curve1, FastCurve* curve2)
{
std::vector<IntResult> ret;
bool swap=false;
FastLine* line1 = dynamic_cast<FastLine*>(curve1);
if(line1)
{
FastLine* line2 = dynamic_cast<FastLine*>(curve2);
if(line2)
ret = LinesIntersect((FastLine*)curve1,(FastLine*)curve2);
else
{
FastArc* arc2 = dynamic_cast<FastArc*>(curve2);
if(arc2)
{
ret = LineArcIntersect(line1,arc2);
}
}
}
else
{
FastArc* arc1 = dynamic_cast<FastArc*>(curve1);
if(arc1)
{
FastLine* line2 = dynamic_cast<FastLine*>(curve2);
if(line2)
{
ret = LineArcIntersect(line2,arc1);
swap = true;
}
else
{
FastArc* arc2 = dynamic_cast<FastArc*>(curve2);
ret = ArcsIntersect(arc1,arc2);
}
}
}
if(swap)
{
for(unsigned int i=0; i < ret.size(); i++)
{
ret[i].Swap();
}
}
return ret;
}
// ignores radius for now
bool PathCollider::IntersectsLine(const Vector2& start, const Vector2& end, float radius, CollisionData *collisionData)
{
Node *node = startNode;
while(node)
{
Node *next = node->GetNext();
if (next)
{
if (node->variant != -1)
{
if (LinesIntersect(node->GetWorldPosition(), next->GetWorldPosition(), start, end, collisionData))
{
collisionData->collider = this;
return true;
}
}
}
node = next;
}
return false;
}
bool Collider::CollideRectPolygon(RectangleCollider* a, PolygonCollider* b, CollisionData *collisionData)
{
//TODO: store data in collisionData!
//Check if it's even possible for them to collide
if (a->GetLeft() > b->GetRightmost())
return false;
if (a->GetRight() < b->GetLeftmost())
return false;
if (a->GetTop() > b->GetBottommost())
return false;
if (a->GetBottom() < b->GetTopmost())
return false;
//Check if the first point of either is inside the other
//(accounts for the case where one is completely inside the other)
if (a->IntersectsPoint(b->GetPoint(0)) || b->IntersectsPoint(a->GetTopLeft()))
return true;
//Compare lines for intersections
Vector2 rectPoints[4];
rectPoints[0] = a->GetTopLeft();
rectPoints[1] = a->GetTopRight();
rectPoints[2] = a->GetBottomRight();
rectPoints[3] = a->GetBottomLeft();
int totalB = b->GetPointCount();
for (int i = 0; i < totalB; ++i)
{
Vector2 startB = b->GetPoint(i);
Vector2 endB = b->GetPoint((i + 1) % totalB);
for (int j = 0; j < 4; ++j)
{
if (LinesIntersect(startB, endB, rectPoints[j], rectPoints[(j + 1) % 4]))
return true;
}
}
return false;
}
