/// <summary>
/// Return a list of points forming a circle.
/// onPlane, X = Vertical, Y = Horizontal, Z = the other
/// </summary>
/// <param name="sides">The more sides the smoother the circle will appear</param>
/// <param name="colour">The colour e.g. Color.White or Color.Red</param>
public VertexPositionColor[] GetCircle(float radius, int sides, Color colour, Vector3 centre, string onPlane)
{
int points = sides + 1;
VertexPositionColor[] pointList = new VertexPositionColor[points];
// This function creates a circle so the maxArc is always 2PI (360 degrees)
float maxArc = 2 * (float)Math.PI; // in Radians
float fStep = maxArc / (float)sides;
float fAngle = 0;
for (int i = 0; i < sides; i++)
{
if (onPlane == "X")
{
// X plane Vertical forward
pointList[i] = new VertexPositionColor(
new Vector3(centre.X,
((float)Math.Sin(fAngle) * radius) + centre.Y,
((float)Math.Cos(fAngle) * radius) + centre.Z),
colour);
}
else if (onPlane == "Y")
{
// Y plane Horizontal
pointList[i] = new VertexPositionColor(
new Vector3(((float)Math.Sin(fAngle) * radius) + centre.X,
centre.Y,
((float)Math.Cos(fAngle) * radius) + centre.Z),
colour);
}
else
{
// Z plane Vertical side
pointList[i] = new VertexPositionColor(
new Vector3(((float)Math.Sin(fAngle) * radius) + centre.X,
((float)Math.Cos(fAngle) * radius) + centre.Y,
centre.Z),
colour);
}
// Move the point round by a segment of the circle
fAngle += fStep;
}
// Make sure the circle is complete the last point is the same as the first
pointList[sides] = pointList[0];
return(pointList);
}
/// <summary>
/// Return a list of points forming a vertical cylinder with only one edge
/// </summary>
/// <param name="radius">Radius</param>
/// <param name="hight">Height</param>
/// <param name="sides">The sides of the top and bottom circles
/// the more sides the smoother the circles will appear</param>
/// <param name="colour">The colour e.g. Color.White or Color.Red</param>
public VertexPositionColor[] GetCylinder(float radius, float height, int sides, Color colour)
{
// 2 circles and a line down one side
int points = (sides + 1) * 2;
VertexPositionColor[] pointList = new VertexPositionColor[points];
VertexPositionColor[] circleList = GetCircle(1.0f, sides, Color.Red, Vector3.Zero, "Y");
for (int i = 0; i < circleList.Length; i++)
{
// Add the top and bottom circles at the same time
pointList[i] = circleList[i];
pointList[i + circleList.Length] = circleList[i];
pointList[i + circleList.Length].Position.Y += height;
}
// Make sure the circle is complete the last point is the same as the first
return(pointList);
}
