public override Intersection Intersect(Vector2 point)
{
if (!this.WithinRadius(point) ) { return null; }
// the exclusion test is the same as the collision test
Intersection sect = new Intersection();
sect.surface_normal = Utility.Angle(point - pos);
sect.position = point;
return sect;
}
// Not totally stoaked with this implementation
public Intersection CalculateIntersection(Vector2 point)
{
Intersection sect = new Intersection();
sect.position = point;
// first shift the point into the reference frame of the hitbox
point = Utility.Rotate(point - pos, -angle);
float min_dist = float.MaxValue;
int best_segment = 0;
// look through every segment, finding the one closest to the point
for (int i = 0; i < count; i++)
{
Vector2 p1 = corners[i];
Vector2 p2 = (i == count-1) ? corners[0] : corners[i+1];
Vector2 pd = p2 - p1;
float t = Utility.Clamp( Vector2.Dot( point - p1, pd) / pd.LengthSquared() , 0.0f, 1.0f );
Vector2 projection = p1 + (t * pd);
float dist_sq = Vector2.DistanceSquared(projection, point);
if (dist_sq < min_dist)
{
min_dist = dist_sq;
best_segment = i;
}
}
// return the normal, and compensate for the hitbox rotation
sect.surface_normal = Utility.WrapAngle(segment_normals[best_segment] + angle);
sect.overlap = min_dist;
return sect;
}
public Intersection IntersectCircle(HitboxCircle hitbox)
{
// first shift the circle origin into the reference frame of the hitbox
Vector2 point = Utility.Rotate(hitbox.pos - pos, -angle);
for (int i = 0; i < count; i++)
{
// for each point we test if it falls into the circle
if ( Vector2.DistanceSquared(point, corners[i]) < hitbox.radius_sq )
{
// If one point falls in, we run with it.
Intersection sect = new Intersection();
// we take the corner, and shift it into global coordinate frame
sect.position = pos + Utility.Rotate(corners[i], angle);
// the surface normal is calculated like it is for a circle
sect.surface_normal = Utility.Angle(pos - hitbox.pos);
// Like a circle, again
sect.overlap = (hitbox.radius - (sect.position - hitbox.pos).Length()) * 2;
return sect;
}
}
return null;
}
public override Intersection Intersect(Hitbox hitbox)
{
if (!this.WithinRadius(hitbox)) { return null; }
if (hitbox is HitboxCircle)
{
// if both hitboxes are circles, then the ContainsExclusion test
// is the same as the collision test.
// So a collision has occurred
Intersection sect = new Intersection();
sect.position = ((hitbox.pos * radius) + (pos * hitbox.radius)) / (radius + hitbox.radius);
sect.surface_normal = Utility.Angle(pos - hitbox.pos);
sect.overlap = (radius - (sect.position - pos).Length())*2;
return sect;
}
if ( hitbox is HitboxPolygon )
{
// YEA. DO THAT.
return ((HitboxPolygon)hitbox).IntersectCircle(this);
}
return null;
}
