/// <summary>
/// Create a triangle primitive.
/// </summary>
/// <param name="p1">Fist point, in pixels.</param>
/// <param name="p2">Second point, in pixels.</param>
/// <param name="p3">Third point, in pixels.</param>
private void CreateTriangle(Vector2 p1, Vector2 p2, Vector2 p3)
{
VectorList.Add(p1);
VectorList.Add(p2);
VectorList.Add(p3);
VectorList.Add(p1);
}
/// <summary>
/// Create a square primitive.
/// </summary>
/// <param name="topLeft">Top left hand corner of the square.</param>
/// <param name="bottomRight">Bottom right hand corner of the square.</param>
private void CreateSquare(Vector2 topLeft, Vector2 bottomRight)
{
VectorList.Add(topLeft);
VectorList.Add(new Vector2(topLeft.X, bottomRight.Y));
VectorList.Add(bottomRight);
VectorList.Add(new Vector2(bottomRight.X, topLeft.Y));
VectorList.Add(topLeft);
}
/// <summary>
/// draw a pie shape
/// </summary>
/// <param name="Position">location to draw the pie</param>
/// <param name="radius">the radius of the pie</param>
/// <param name="startAngle">the angle to start the pie</param>
/// <param name="sweepAngle">the sweep angle of the pie</param>
/// <param name="color">color dat pie</param>
public void Pie(Vector2 position, float radius, float startAngle, float sweepAngle, Color color)
{
Clear();
Position = position;
Color = color;
VectorList.Add(Vector2.Zero);
CreateArc(radius, NumCircleSegments, startAngle, sweepAngle);
VectorList.Add(Vector2.Zero);
RenderLinePrimitive();
}
/// <summary>
/// Creates an ellipse starting from (0, 0) with the given width and height.
/// Vectors are generated using the parametric equation of an ellipse.
/// </summary>
/// <param name="semiMajorAxis">The width of the ellipse at its center.</param>
/// <param name="semiMinorAxis">The height of the ellipse at its center.</param>
/// <param name="sides">The number of sides on the ellipse. (64 is average).</param>
private void CreateEllipse(float semiMajorAxis, float semiMinorAxis, int sides)
{
// Local variables.
float fMax = (float)MathHelper.TwoPi;
float fStep = fMax / (float)sides;
// Create full ellipse.
for (float fTheta = fMax; fTheta >= -1; fTheta -= fStep)
{
VectorList.Add(new Vector2((float)(semiMajorAxis * Math.Cos(fTheta)),
(float)(semiMinorAxis * Math.Sin(fTheta))));
}
}
/// <summary>
/// Creates a circle starting from (0, 0).
/// </summary>
/// <param name="radius">The radius (half the width) of the circle.</param>
/// <param name="sides">The number of sides on the circle. (64 is average).</param>
private void CreateArc(float radius, int sides, float startAngle, float sweepAngle)
{
float step = sweepAngle / (float)sides;
// Create the full circle.
var numSteps = 0;
var theta = startAngle;
while (numSteps < sides + 1)
{
VectorList.Add(new Vector2(radius * (float)Math.Cos(theta),
radius * (float)Math.Sin(theta)));
numSteps++;
theta += step;
}
}
public void SineWave(Vector2 start, Vector2 end, float frequency, float amplitude, Color color)
{
Clear();
Color = color;
//get the length of the sine wave
var length = (end - start).Length();
//lay out all the points
float segmentLength = 5f;
float xPos = 0f;
float mid = length / 2f;
while ((xPos + segmentLength) < length)
{
var ratio = 1f - (Math.Abs(mid - xPos) / mid);
VectorList.Add(new Vector2(xPos, ratio * (float)(Math.Sin(frequency * xPos) * amplitude)));
//VectorList.Add(new Vector2(xPos, 0));
xPos += segmentLength;
}
//add the last line segment at the end
VectorList.Add(new Vector2(length, 0f));
//create the rotaion matrix
Matrix mat = Matrix.CreateRotationZ((end - start).Angle());
//multiply the rotaion by the translation matrices
mat *= Matrix.CreateTranslation(start.X, start.Y, 0f);
//multiply each point by the combined matrix
for (int i = 0; i < VectorList.Count; i++)
{
VectorList[i] = MatrixExtensions.MatrixExt.Multiply(mat, VectorList[i]);
}
RenderLinePrimitive();
}
/// <summary>
/// Create a line primitive.
/// </summary>
/// <param name="start">Start of the line, in pixels.</param>
/// <param name="end">End of the line, in pixels.</param>
private void CreateLine(Vector2 start, Vector2 end)
{
VectorList.Add(start);
VectorList.Add(end);
}