public bool PolygonAndLineContact(PolygonShape polygon, LineShape line)
{
var next = 0;
for (var current = 0; current < polygon.Points.Length; current++)
{
next = current + 1;
if (next == polygon.Points.Length)
{
next = 0;
}
var hit = LineAndLineContact(line,
new LineShape {
PointA = polygon.Points[current], PointB = polygon.Points[next]
});
if (hit)
{
return(true);
}
}
return(false);
}
public bool LineAndCircleContact(LineShape line, CircleShape circle)
{
var inside1 = PointAndCircleContact(line.PointA, circle);
var inside2 = PointAndCircleContact(line.PointB, circle);
if (inside1 || inside2)
{
return(true);
}
var distX = line.PointA.x - line.PointB.x;
var distY = line.PointA.y - line.PointB.y;
var len = (float)Math.Sqrt(distX * distX + distY * distY);
var dot = ((circle.Center.x - line.PointA.x) * (line.PointB.x - line.PointA.x)
+ (circle.Center.y - line.PointA.y) * (line.PointB.y - line.PointA.y))
/ (float)Math.Pow(len, 2);
var closestX = line.PointA.x + dot * (line.PointB.x - line.PointA.x);
var closestY = line.PointA.y + dot * (line.PointB.y - line.PointA.y);
var onSegment = LineAndPointContact(line, new Vector2(closestX, closestY));
if (!onSegment)
{
return(false);
}
distX = closestX - circle.Center.x;
distY = closestY - circle.Center.y;
var distance = (float)Math.Sqrt(distX * distX + distY * distY);
return(distance <= circle.Radius);
}
public LineShape CloneLine(LineShape original)
{
return(new LineShape
{
PointA = new Vector2(original.PointA.x, original.PointA.y),
PointB = new Vector2(original.PointB.x, original.PointB.y),
Center = new Vector2(original.Center.x, original.Center.y)
});
}
public bool LineAndPointContact(LineShape line, Vector2 point)
{
var d1 = Vector2.Distance(point, line.PointA);
var d2 = Vector2.Distance(point, line.PointB);
var lineLen = Vector2.Distance(line.PointA, line.PointB);
const float buffer = 0.1f;
return(d1 + d2 >= lineLen - buffer && d1 + d2 <= lineLen + buffer);
}
public bool LineAndLineContact(LineShape lineA, LineShape lineB)
{
var uA = ((lineB.PointB.x - lineB.PointA.x) * (lineA.PointA.y - lineB.PointA.y)
- (lineB.PointB.y - lineB.PointA.y) * (lineA.PointA.x - lineB.PointA.x))
/ ((lineB.PointB.y - lineB.PointA.y) * (lineA.PointB.x - lineA.PointA.x)
- (lineB.PointB.x - lineB.PointA.x) * (lineA.PointB.y - lineA.PointA.y));
var uB = ((lineA.PointB.x - lineA.PointA.x) * (lineA.PointA.y - lineB.PointA.y)
- (lineA.PointB.y - lineA.PointA.y) * (lineA.PointA.x - lineB.PointA.x))
/ ((lineB.PointB.y - lineB.PointA.y) * (lineA.PointB.x - lineA.PointA.x)
- (lineB.PointB.x - lineB.PointA.x) * (lineA.PointB.y - lineA.PointA.y));
return(uA >= 0 && uA <= 1 && uB >= 0 && uB <= 1);
}
public void RotateLine(ref LineShape line, float deltaAngle)
{
deltaAngle = (float)Math.PI * deltaAngle / 180f;
var cos = (float)Math.Cos(deltaAngle);
var sin = (float)Math.Sin(deltaAngle);
var xa = line.PointA.x - line.Center.x;
var ya = line.PointA.y - line.Center.y;
var xb = line.PointB.x - line.Center.x;
var yb = line.PointB.y - line.Center.y;
line.PointA.x = line.Center.x + xa * cos - ya * sin;
line.PointA.y = line.Center.y + xa * sin + ya * cos;
line.PointB.x = line.Center.x + xb * cos - yb * sin;
line.PointB.y = line.Center.y + xb * sin + yb * cos;
}
public void TranslateLine(ref LineShape line, Vector2 deltaPosition)
{
line.Center += deltaPosition;
line.PointA += deltaPosition;
line.PointB += deltaPosition;
}