/// <summary>
/// Draws an outline of a collision shape
/// </summary>
/// <param name="shape">shape to draw</param>
/// <param name="g">Graphics object</param>
/// <param name="transform">shape camera transform</param>
/// <param name="p">pen</param>
private static void DrawShape(this Shape shape, Graphics g, FarseerPhysics.Common.Transform transform, Pen p)
{
switch (shape.ShapeType)
{
case ShapeType.Circle:
CircleShape circle = shape as CircleShape;
g.DrawEllipse(p,
circle.Position.X - circle.Radius,
circle.Position.Y - circle.Radius,
circle.Position.X + circle.Radius,
circle.Position.Y + circle.Radius);
break;
case ShapeType.Chain:
ChainShape chain = shape as ChainShape;
IEnumerable <Vector2> verts = chain.Vertices;
g.DrawLines(
p,
chain.Vertices.Select((v) => v.Transform(transform)).ToDrawingPoints().ToArray()
);
break;
case ShapeType.Edge:
EdgeShape edge = shape as EdgeShape;
PointF p1 = edge.Vertex1.Transform(transform).ToDrawingPoint();
PointF p2 = edge.Vertex2.Transform(transform).ToDrawingPoint();
g.DrawLine(p, p1, p2);
break;
case ShapeType.Polygon:
PolygonShape poly = shape as PolygonShape;
g.DrawPolygon(p, poly.Vertices.Select((v) => v.Transform(transform)).ToDrawingPoints().ToArray());
break;
}
}
public override Atom.Math.RectangleF GetBounds()
{
if (this.fixtures == null)
{
return(new Atom.Math.RectangleF());
}
var trans = new FarseerPhysics.Common.Transform();
Fixture fixture = this.fixtures[0];
fixture.Body.GetTransform(out trans);
FarseerPhysics.Collision.AABB fullAabb;
fixture.Shape.ComputeAABB(out fullAabb, ref trans, 0);
for (int i = 1; i < this.fixtures.Count; ++i)
{
fixture = this.fixtures[i];
fixture.Body.GetTransform(out trans);
FarseerPhysics.Collision.AABB aabb;
fixture.Shape.ComputeAABB(out aabb, ref trans, 0);
fullAabb.Combine(ref aabb);
}
var corner = fullAabb.LowerBound;
var extends = fullAabb.Extents;
return(new Atom.Math.RectangleF(corner.X, corner.Y, extends.X * 2.0f, extends.Y * 2.0f));
}
// v2 = A.R' * (B.R * v1 + B.p - A.p) = (A.R' * B.R) * v1 + (B.p - A.p)
public static void MultiplyT(ref Transform A, ref Transform B, out Transform C)
{
C = new Transform();
MultiplyT(ref A.R, ref B.R, out C.R);
C.Position.x = B.Position.x - A.Position.x;
C.Position.y = B.Position.y - A.Position.y;
}
public static Vector2 MultiplyT(ref Transform T, ref Vector2 v)
{
Vector2 tmp = Vector2.zero;
tmp.x = v.x - T.Position.x;
tmp.y = v.y - T.Position.y;
return(MultiplyT(ref T.R, ref tmp));
}
/// <summary>
/// Get the interpolated transform at a specific time.
/// </summary>
/// <param name="xf">The transform.</param>
/// <param name="beta">beta is a factor in [0,1], where 0 indicates alpha0.</param>
public void GetTransform(out Transform xf, float beta)
{
xf = new Transform();
xf.Position.x = (1.0f - beta) * C0.x + beta * C.x;
xf.Position.y = (1.0f - beta) * C0.y + beta * C.y;
float angle = (1.0f - beta) * A0 + beta * A;
xf.R.Set(angle);
// Shift to origin
xf.Position -= MathUtils.Multiply(ref xf.R, ref LocalCenter);
}
/// <summary>
/// Build vertices to represent an oriented box.
/// </summary>
/// <param name="hx">the half-width.</param>
/// <param name="hy">the half-height.</param>
/// <param name="center">the center of the box in local coordinates.</param>
/// <param name="angle">the rotation of the box in local coordinates.</param>
public static Vertices CreateRectangle(float hx, float hy, Vector2 center, float angle)
{
Vertices vertices = CreateRectangle(hx, hy);
Transform xf = new Transform();
xf.Position = center;
xf.R.Set(angle);
// Transform vertices
for (int i = 0; i < 4; ++i)
{
vertices[i] = MathUtils.Multiply(ref xf, vertices[i]);
}
return(vertices);
}
public override Atom.Math.RectangleF GetBounds()
{
if (this.fixture == null)
{
return(new Atom.Math.RectangleF());
}
var trans = new FarseerPhysics.Common.Transform();
fixture.Body.GetTransform(out trans);
FarseerPhysics.Collision.AABB aabb;
fixture.Shape.ComputeAABB(out aabb, ref trans, 0);
var corner = aabb.LowerBound;
var extends = aabb.Extents;
return(new Atom.Math.RectangleF(corner.X, corner.Y, extends.X * 2.0f, extends.Y * 2.0f));
}
public override void DrawTransform(ref Transform transform)
{
// TODO: implement
}
public static Vector2 MultiplyT(ref Transform T, Vector2 v)
{
return(MultiplyT(ref T, ref v));
}
public static Vector2 Multiply(ref Transform T, ref Vector2 v)
{
return(new Vector2(T.Position.x + T.R.Col1.x * v.x + T.R.Col2.x * v.y,
T.Position.y + T.R.Col1.y * v.x + T.R.Col2.y * v.y));
}
/// <summary>
/// Build vertices to represent an oriented box.
/// </summary>
/// <param name="hx">the half-width.</param>
/// <param name="hy">the half-height.</param>
/// <param name="center">the center of the box in local coordinates.</param>
/// <param name="angle">the rotation of the box in local coordinates.</param>
public static Vertices CreateRectangle(float hx, float hy, Vector2 center, float angle)
{
Vertices vertices = CreateRectangle(hx, hy);
Transform xf = new Transform();
xf.Position = center;
xf.R.Set(angle);
// Transform vertices
for (int i = 0; i < 4; ++i)
{
vertices[i] = MathUtils.Multiply(ref xf, vertices[i]);
}
return vertices;
}
