public HitboxArmorMarker(HitboxPolygon hitbox, Armor arg_armor, float displacement, float segment_separation)
{
// we need to construct the lines to represent our armor segments.
// We have to project the armors angular system onto the hitbox.
armor = arg_armor;
nodes = new List<Vector2>[armor.segment_count];
int count = hitbox.count;
Vector2[] corners = new Vector2[count];
Vector2[] displacements = new Vector2[count];
Vector2 last = hitbox.corners.Last();
for (int i = 0; i < count; i++)
{
Vector2 p = hitbox.corners[i];
Vector2 delta = last - p;
delta.Normalize();
displacements[i] = Utility.RotateNeg(delta) * displacement / 2.0f;
corners[i] = p;
last = p;
}
for (int i = 0; i < count; i++)
{
int k = (i == count - 1) ? 0 : i + 1;
corners[i] += displacements[i];
corners[i] += displacements[k];
}
Vector2 p1 = corners[0];
int first_segment = armor.GetSegmentLocal(p1);
int segment = first_segment;
nodes[segment] = new List<Vector2>();
List<Vector2> popped = null;
for (int j = 0; j < count; j++)
{
// iterate through all hitbox segments
int i = j + 1;
if (i == count) { i = 0; }
Vector2 p2 = corners[i];
// if this line has crossed an armor intersection
int new_segment = armor.GetSegmentLocal(p2);
if (new_segment != segment)
{
// We find the midpoint of the the line where it croses the armor angle
Vector2 cossin = Utility.CosSin(-armor.GetSegmentStartAngle(segment));
float p1ry = p1.X * cossin.Y + p1.Y * cossin.X;
float p2ry = p2.X * cossin.Y + p2.Y * cossin.X;
float alpha = p1ry / (p1ry - p2ry);
Vector2 mid = ((p2 - p1) * alpha) + p1;
if (new_segment == first_segment)
{
// this segment already has data in it.
// we will add this back in later.
popped = nodes[new_segment];
}
// the new segment starts at the midpoint
nodes[new_segment] = new List<Vector2>();
nodes[new_segment].Add(mid);
nodes[new_segment].Add(p2);
// the previous segment ends at the midpoint
nodes[segment].Add(mid);
segment = new_segment;
}
else
{
nodes[segment].Add(p2);
}
p1 = p2;
}
if (popped != null)
{
// We popped some of the data from the first segment, time to get it back
foreach (Vector2 pt in popped)
{
nodes[first_segment].Add(pt);
}
}
float sep = segment_separation / 2.0f;
foreach (List<Vector2> node in nodes)
{
trim(node, 1, sep);
trim(node, -1, sep);
}
}
Intersection IntersectPolygonHalf(HitboxPolygon hitbox)
{
Intersection best_sect = null;
// checks each point in the hitbox
for (int i = 0; i < count; i++)
{
// shift the point into global frame
Vector2 point = pos + Utility.Rotate(corners[i], angle);
// we then see to if any of the points lie inside this polygon
Intersection sect = hitbox.Intersect(point);
if (sect != null)
{
// the intersection with the biggest overlap is the most important to service
if (best_sect == null || sect.overlap > best_sect.overlap)
{
// we average the surface normal and the corner normal
// To provide a better approximation of the impact normal
float corner_normal = corner_normals[i] + angle;
float delta = Utility.AngleDelta(corner_normal + MathHelper.Pi, sect.surface_normal);
sect.surface_normal = Utility.WrapAngle(sect.surface_normal + delta / 2.0f);
//sect.surface_normal = Utility.Angle(hitbox.pos - pos); // COM approx. A backup solution.
best_sect = sect;
}
}
}
return best_sect;
}
// Returns the intersection of two HitboxPolygons
public Intersection IntersectPolygon(HitboxPolygon hitbox)
{
//TODO: abstract the two point test loops out.
Intersection best_sect = this.IntersectPolygonHalf(hitbox);
Intersection next_sect = hitbox.IntersectPolygonHalf(this);
if (next_sect != null)
{
next_sect.surface_normal = Utility.WrapAngle(next_sect.surface_normal + MathHelper.Pi);
}
else { return best_sect; }
if (best_sect == null) { return next_sect; }
return (best_sect.overlap > next_sect.overlap) ? best_sect : next_sect;
}
public HitboxPolygon( HitboxPolygon clone )
{
corners = clone.corners;
count = clone.count;
segment_normals = clone.segment_normals;
corner_normals = clone.corner_normals;
radius = clone.radius;
radius_sq = clone.radius_sq;
size = clone.size;
}