/// <summary>
/// Calculates all coordinate offsets for
/// both the X and Y blur pass in a single
/// pass and returns an object that allows
/// each pass to be handed to the render cycle
/// individually.
/// </summary>
/// <param name="textureWidth">The width of the texture to be blurred</param>
/// <param name="textureHeight">The height of the texture to be blurred</param>
/// <param name="radius">The blur radius</param>
/// <returns></returns>
private LinearOffsets ComputeOffsets(float textureWidth, float textureHeight, int radius)
{
var linearOffsets = new LinearOffsets()
{
X = new Vector2[radius * 2 + 1],
Y = new Vector2[radius * 2 + 1]
};
var index = 0;
float xOffset = 1.0f / textureWidth;
float yOffset = 1.0f / textureHeight;
for (int i = -radius; i <= radius; i++)
{
index = i + radius;
linearOffsets.X[index] = new Vector2(i * xOffset, 0f);
linearOffsets.Y[index] = new Vector2(0f, i * yOffset);
}
return(linearOffsets);
}
public void Initialize(GraphicsDevice device, Camera camera)
{
Width = device.PresentationParameters.BackBufferWidth;
Height = device.PresentationParameters.BackBufferHeight;
this.device = device;
spriteBatch = new SpriteBatch(this.device);
// load our fx
blur = FlatRedBallServices.Load <Effect>(@"Content\Shaders\Blur");
// calculate the effect blur radius using the array length
var radius = (blur.Parameters["Weights"].Elements.Count - 1) / 2;
// calculate kernal and offsets
kernal = ComputeKernal(radius, BlurAmount);
offsets = ComputeOffsets(Width, Height, radius);
blur.Parameters["Weights"].SetValue(kernal);
target2 = new RenderTarget2D(device, Width, Height);
initialized = true;
}