public static Circular <V> Pie(float width, float height, float stepAngle,
float startAngle, float endAngle)
{
if (startAngle > endAngle)
{
throw new ArgumentException("Start angle must be bigger than end angle");
}
var fullCircle = startAngle == endAngle;
if (fullCircle)
{
endAngle += MathHelper.TwoPi;
}
var vertCount = (int)Math.Ceiling((endAngle - startAngle) / stepAngle) + (fullCircle ? 1 : 2);
var normal = new Vec3(0f, 0f, 1f);
var vertices = new V[vertCount];
vertices [0] = VertexHelpers.New <V> (new Vec3(0f), normal);
var angle = startAngle;
for (var i = 1; i < vertCount; i++)
{
var pos = new Vec3(width * (float)Math.Cos(angle), height * (float)Math.Sin(angle), 0f);
vertices [i] = VertexHelpers.New <V> (pos, normal);
angle = Math.Min(angle + stepAngle, endAngle);
}
return(new Circular <V> (vertices, fullCircle));
}
public static Triangle <V> Scalene(float leftOffset, float rightOffset, float height)
{
var normal = new Vec3(0f, 0f, 1f);
return(new Triangle <V> (new V[]
{
VertexHelpers.New <V> (new Vec3(0f, height, 0f), normal),
VertexHelpers.New <V> (new Vec3(rightOffset, 0f, 0f), normal),
VertexHelpers.New <V> (new Vec3(leftOffset, 0f, 0f), normal)
}));
}
public static Lathe <V> Turn <P> (Path <P, Vec3> path, Axis turnAxis, Vec3 offset,
float stepAngle, float startAngle, float endAngle)
where P : struct, IVertex <Vec3>
{
if (startAngle > endAngle)
{
throw new ArgumentException(
"Start angle must be less or equal than the end angle.If you want to turn " +
"the path a full circle, set the startAngle and endAngle to the same value.",
"startAngle");
}
var pathLen = path.Vertices.Length;
var fullCircle = startAngle == endAngle;
if (fullCircle)
{
endAngle += MathHelper.TwoPi;
}
if (stepAngle > (endAngle - startAngle))
{
throw new ArgumentException(
"StepAngle must to be less or equal than the sweep angle (endAngle - stargAngle)",
"stepAngle");
}
var radialCount = (int)Math.Ceiling((endAngle - startAngle) / stepAngle) * 2;
var vertices = new V [radialCount * (pathLen - 1) * 2];
var angle = startAngle;
var vertInd = 0;
var path1 = Positions(path, turnAxis, angle, offset);
var firstPos = path1;
for (var i = 0; i < radialCount; i += 2)
{
angle = Math.Min(angle + stepAngle, endAngle);
var path2 = fullCircle && i == radialCount - 2 ?
firstPos :
Positions(path, turnAxis, angle, offset);
for (int j = 0; j < pathLen - 1; j++)
{
var normal = path1[j].CalculateNormal(path2[j + 1], path1[j + 1]);
vertices[vertInd++] = VertexHelpers.New <V> (path1[j], normal);
vertices[vertInd++] = VertexHelpers.New <V> (path1[j + 1], normal);
vertices[vertInd++] = VertexHelpers.New <V> (path2[j + 1], normal);
vertices[vertInd++] = VertexHelpers.New <V> (path2[j], normal);
}
path1 = path2;
}
return(new Lathe <V> (vertices));
}
private static V[] GetVertices <V, P> (Path <P, Vec3> path, bool flipNormal)
where V : struct, IVertex3D
where P : struct, IVertex <Vec3>
{
var nodes = path.Vertices;
var pos1 = nodes[1].position;
var pos2 = nodes[0].position;
var pos3 = nodes.Skip(2).First(n => !pos1.AreCollinear(pos2, n.position)).position;
var normal = pos1.CalculateNormal(pos2, pos3);
if (flipNormal)
{
normal = -normal;
}
return(nodes.Select(n => VertexHelpers.New <V> (n.position, normal)).ToArray());
}
public static Quadrilateral <V> Trapezoid(float width, float height,
float topLeftOffset, float topRightOffset)
{
var bottomRight = width / 2f;
var topRight = bottomRight + topRightOffset;
var top = height / 2f;
var bottomLeft = -bottomRight;
var topLeft = bottomLeft + topLeftOffset;
var bottom = -top;
var normal = new Vec3(0f, 0f, 1f);
return(new Quadrilateral <V> (new V[]
{
VertexHelpers.New <V> (new Vec3(topRight, top, 0f), normal),
VertexHelpers.New <V> (new Vec3(bottomRight, bottom, 0f), normal),
VertexHelpers.New <V> (new Vec3(bottomLeft, bottom, 0f), normal),
VertexHelpers.New <V> (new Vec3(topLeft, top, 0f), normal)
}));
}
private static V SideVertex <V> (V vertex, Vec3 normal)
where V : struct, IVertex3D
{
return(VertexHelpers.New <V> (vertex.position, normal));
}
public static Polygon <V> FromPath <P> (Path <P, Vec3> Path)
where P : struct, IVertex <Vec3>
{
return(FromVertices(Path.Vertices.Select(n => VertexHelpers.New <V> (n.position, new Vec3(0f, 0f, 1f)))));
}
public static Polygon <V> FromVec2s(params Vec2[] vectors)
{
return(FromVertices(vectors.Select(vec => VertexHelpers.New <V> (new Vec3(vec, 0f), new Vec3(0f, 0f, 1f)))));
}