/// <summary>
/// Initializes a new instance of the <see cref="ProjectedShadowRenderer"/> class.
/// </summary>
/// <param name="graphicsService">The graphics service.</param>
public ProjectedShadowRenderer(IGraphicsService graphicsService)
{
if (graphicsService == null)
{
throw new ArgumentNullException("graphicsService");
}
_effect = new BasicEffect(graphicsService.GraphicsDevice)
{
DiffuseColor = Vector3.Zero,
LightingEnabled = false,
TextureEnabled = false
};
ShadowedPlane = new Plane(new Vector3(0, 1, 0), 0.01f);
LightPosition = new Vector4(1, 1, 1, 0);
}
/// <summary>
/// Creates the projection matrix for planar projected shadows.
/// </summary>
/// <param name="plane">The plane which receives the shadows.</param>
/// <param name="lightPosition">
/// The light position in homogeneous coordinates.
/// Set W to 1, to create a local light. Set W to 0, to create a directional light.
/// </param>
/// <returns>The shadow projection matrix.</returns>
public static Matrix CreateShadowMatrix(Plane plane, Vector4 lightPosition)
{
var planeEquation = new Vector4(plane.Normal, -plane.DistanceFromOrigin);
float a = planeEquation.X;
float b = planeEquation.Y;
float c = planeEquation.Z;
float d = planeEquation.W;
float lx = lightPosition.X;
float ly = lightPosition.Y;
float lz = lightPosition.Z;
float lw = lightPosition.W;
// Note: XNA matrix layout, not DigitalRune layout.
Matrix shadowMatrix = new Matrix(
b * ly + c * lz + d * lw, -a * ly, -a * lz, -a * lw,
-b * lx, a * lx + c * lz + d * lw, -b * lz, -b * lw,
-c * lx, -c * ly, a * lx + b * ly + d * lw, -c * lw,
-d * lx, -d * ly, -d * lz, a * lx + b * ly + c * lz);
return(shadowMatrix);
}
/// <summary>
/// Creates the projection matrix for planar projected shadows.
/// </summary>
/// <param name="plane">The plane which receives the shadows.</param>
/// <param name="lightPosition">
/// The light position in homogeneous coordinates.
/// Set W to 1, to create a local light. Set W to 0, to create a directional light.
/// </param>
/// <returns>The shadow projection matrix.</returns>
public static Matrix CreateShadowMatrix(Plane plane, Vector4F lightPosition)
{
var planeEquation = new Vector4F(plane.Normal, -plane.DistanceFromOrigin);
float a = planeEquation.X;
float b = planeEquation.Y;
float c = planeEquation.Z;
float d = planeEquation.W;
float lx = lightPosition.X;
float ly = lightPosition.Y;
float lz = lightPosition.Z;
float lw = lightPosition.W;
// Note: XNA matrix layout, not DigitalRune layout.
Matrix shadowMatrix = new Matrix(
b * ly + c * lz + d * lw, -a * ly, -a * lz, -a * lw,
-b * lx, a * lx + c * lz + d * lw, -b * lz, -b * lw,
-c * lx, -c * ly, a * lx + b * ly + d * lw, -c * lw,
-d * lx, -d * ly, -d * lz, a * lx + b * ly + c * lz);
return shadowMatrix;
}
//--------------------------------------------------------------
#region Creation & Cleanup
//--------------------------------------------------------------
/// <summary>
/// Initializes a new instance of the <see cref="ProjectedShadowRenderer"/> class.
/// </summary>
/// <param name="graphicsService">The graphics service.</param>
public ProjectedShadowRenderer(IGraphicsService graphicsService)
{
if (graphicsService == null)
throw new ArgumentNullException("graphicsService");
_effect = new BasicEffect(graphicsService.GraphicsDevice)
{
DiffuseColor = Vector3.Zero,
LightingEnabled = false,
TextureEnabled = false
};
ShadowedPlane = new Plane(new Vector3F(0, 1, 0), 0.01f);
LightPosition = new Vector4F(1, 1, 1, 0);
}
