// Draw an ellipse with the specified semi-major axis and eccentricity. The orbit is drawn over a single period,
// fading from full brightness at the given eccentric anomaly.
//
// In order to match exactly the position at which a planet is drawn, the planet's position at the current time
// must be passed as a parameter. positionNow is in the current coordinate system of the render context, not the
// translated and rotated system of the orbital plane.
public static void DrawEllipse(RenderContext11 renderContext, double semiMajorAxis, double eccentricity, double eccentricAnomaly, Color color, Matrix3d worldMatrix, Vector3d positionNow)
{
if (ellipseShader == null)
{
ellipseShader = new EllipseShader11();
}
if (ellipseVertexBuffer == null)
{
ellipseVertexBuffer = CreateEllipseVertexBuffer( 500);
}
Matrix3d savedWorld = renderContext.World;
renderContext.World = worldMatrix;
renderContext.devContext.InputAssembler.PrimitiveTopology = SharpDX.Direct3D.PrimitiveTopology.LineStrip;
renderContext.SetVertexBuffer(ellipseVertexBuffer);
ellipseShader.UseShader(renderContext, semiMajorAxis, eccentricity, eccentricAnomaly, new SharpDX.Color(color.R, color.G, color.B, color.A), savedWorld, positionNow);
renderContext.devContext.Draw(ellipseVertexBuffer.Count, 0);
renderContext.World = savedWorld;
}
static void initialize()
{
instance = new EllipseShader11();
instance.CompileShader(RenderContext11.VertexProfile, RenderContext11.PixelProfile);
contantBuffer = new SharpDX.Direct3D11.Buffer(RenderContext11.PrepDevice, Utilities.SizeOf<EllipseShaderConstants>(), ResourceUsage.Default, BindFlags.ConstantBuffer, CpuAccessFlags.None, ResourceOptionFlags.None, 0);
}
// This version of DrawEllipse works without a 'head' point
public static void DrawEllipse(RenderContext11 renderContext, double semiMajorAxis, double eccentricity, double eccentricAnomaly, Color color, Matrix3d worldMatrix)
{
if (ellipseShader == null)
{
ellipseShader = new EllipseShader11();
}
if (ellipseWithoutStartPointVertexBuffer == null)
{
ellipseWithoutStartPointVertexBuffer = CreateEllipseVertexBufferWithoutStartPoint(360);
}
var savedWorld = renderContext.World;
renderContext.World = worldMatrix;
renderContext.devContext.InputAssembler.PrimitiveTopology = PrimitiveTopology.LineStrip;
renderContext.SetVertexBuffer(ellipseWithoutStartPointVertexBuffer);
ellipseShader.UseShader(renderContext, semiMajorAxis, eccentricity, eccentricAnomaly, new SharpDX.Color(color.R, color.G, color.B, color.A), savedWorld, new Vector3d(0.0, 0.0, 0.0));
renderContext.devContext.Draw(ellipseWithoutStartPointVertexBuffer.Count, 0);
renderContext.World = savedWorld;
}