PixelShaderEffect Class

[NoComposition] Custom image effect which uses a pixel shader to apply arbitrary user-defined processing.

Inheritance Hierarchy

SystemObject
Microsoft.Graphics.Canvas.EffectsPixelShaderEffect

Namespace: Microsoft.Graphics.Canvas.Effects
Assembly: Microsoft.Graphics.Canvas (in Microsoft.Graphics.Canvas.dll) Version: 0.0.0.0

Syntax

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public sealed class PixelShaderEffect : ICanvasEffect, 
	IGraphicsEffect, IGraphicsEffectSource, ICanvasImage, IDisposable

The PixelShaderEffect type exposes the following members.

Constructors

	Name	Description
	PixelShaderEffect	Initializes a new instance of the PixelShaderEffect class.

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Properties

	Name	Description
	BufferPrecision	Specifies what precision to use for intermediate buffers when drawing this effect.
	CacheOutput	Enables caching the output from drawing this effect.
	MaxSamplerOffset	Describes the maximum offset the shader will add to or subtract from a texture coordinate when sampling from an input that uses Offset coordinate mapping mode.
	Name	Attaches a user-defined name string to the effect.
	Properties	Collection of properties configures the constant buffer that will be passed to the custom pixel shader.
	Source1	Gets or sets the first input source for the custom pixel shader.
	Source1BorderMode	Sets the border mode used when sampling the first input texture.
	Source1Interpolation	Sets the interpolation mode used when sampling the first input texture.
	Source1Mapping	Describes what texture coordinates the shader will use when sampling its first input texture.
	Source2	Gets or sets the second input source for the custom pixel shader.
	Source2BorderMode	Sets the border mode used when sampling the second input texture.
	Source2Interpolation	Sets the interpolation mode used when sampling the second input texture.
	Source2Mapping	Describes what texture coordinates the shader will use when sampling its second input texture.
	Source3	Gets or sets the third input source for the custom pixel shader.
	Source3BorderMode	Sets the border mode used when sampling the third input texture.
	Source3Interpolation	Sets the interpolation mode used when sampling the third input texture.
	Source3Mapping	Describes what texture coordinates the shader will use when sampling its third input texture.
	Source4	Gets or sets the fourth input source for the custom pixel shader.
	Source4BorderMode	Sets the border mode used when sampling the fourth input texture.
	Source4Interpolation	Sets the interpolation mode used when sampling the fourth input texture.
	Source4Mapping	Describes what texture coordinates the shader will use when sampling its fourth input texture.
	Source5	Gets or sets the fifth input source for the custom pixel shader.
	Source5BorderMode	Sets the border mode used when sampling the fifth input texture.
	Source5Interpolation	Sets the interpolation mode used when sampling the fifth input texture.
	Source5Mapping	Describes what texture coordinates the shader will use when sampling its fifth input texture.
	Source6	Gets or sets the sixth input source for the custom pixel shader.
	Source6BorderMode	Sets the border mode used when sampling the sixth input texture.
	Source6Interpolation	Sets the interpolation mode used when sampling the sixth input texture.
	Source6Mapping	Describes what texture coordinates the shader will use when sampling its sixth input texture.
	Source7	Gets or sets the seventh input source for the custom pixel shader.
	Source7BorderMode	Sets the border mode used when sampling the seventh input texture.
	Source7Interpolation	Sets the interpolation mode used when sampling the seventh input texture.
	Source7Mapping	Describes what texture coordinates the shader will use when sampling its seventh input texture.
	Source8	Gets or sets the eighth input source for the custom pixel shader.
	Source8BorderMode	Sets the border mode used when sampling the eighth input texture.
	Source8Interpolation	Sets the interpolation mode used when sampling the eighth input texture.
	Source8Mapping	Describes what texture coordinates the shader will use when sampling its eighth input texture.

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Methods

	Name	Description
	Dispose	Releases all resources used by the effect.
	GetBounds(ICanvasResourceCreator)	Retrieves the bounds of this PixelShaderEffect.
	GetBounds(ICanvasResourceCreator, Matrix3x2)	Retrieves the bounds of this PixelShaderEffect.
	GetInvalidRectangles	Queries what regions of the effect output have changed since it was last drawn.
	GetRequiredSourceRectangle	Queries what part of an effect source image is needed to draw an output region.
	GetRequiredSourceRectangles	Queries what parts of the effect source images are needed to draw an output region.
	InvalidateSourceRectangle	Notifies the effect that one of its source images has changed.
	IsSupported	Checks whether the pixel shader used by this effect is compatible with the Direct3D feature level of the specified device.

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Remarks

Supported by Win2D but not Windows.UI.Composition.

This effect renders graphics using a custom pixel shader. Depending on the chosen shader, it supports from 0 to 8 sources. These can be any ICanvasImage, and are passed into the shader as input textures.

Steps to use a custom pixel shader:

Write a pixel shader in HLSL
Compile it using fxc.exe
Include the resulting .bin file with your app (you do not need to ship the source .hlsl file)
Load the .bin file and pass it to the PixelShaderEffect(Byte) constructor
If your shader uses non 1:1 texture coordinate mapping (sampling at different locations from the pixel being shaded), make sure the appropriate SamplerCoordinateMapping is set (eg. Source1Mapping)
Set from 0 to 8 source properties (eg. Source1) as required by the shader
Configure any constant buffer Properties required by the shader
Draw the effect!

See the PixelShaderEffect(Byte) constructor documentation for more details about steps #1 and #2.

Note that custom pixel shaders work in units of pixels rather than dips. For instance the value returned by D2DGetScenePosition (from d2d1effecthelpers.hlsli) is in pixels. If your shader manipulates position or size values, you have two options:

Have the shader work in pixels. In your CPU program code, convert all position and size values from dips to pixels (eg. using ConvertDipsToPixels(Single, CanvasDpiRounding)) before setting them as effect properties.
Or have the shader work in dips. Pass the current Dpi value as an effect property, and in your HLSL shader code, scale the result of D2DGetScenePosition by 96/dpi to convert it from pixels to dips.

Examples

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var effect = new PixelShaderEffect(File.ReadAllBytes("MyShader.bin"))
{
    Source1 = tigerBitmap
};

effect.Properties["tint"] = new Vector4(0.5f, 1, 0, 1);

drawingSession.DrawImage(effect);

Reference

Microsoft.Graphics.Canvas.Effects Namespace