ShaderEffect Class

Reference

Definition

Namespace:: System.Windows.Media.Effects

Assembly:: PresentationCore.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Provides a custom bitmap effect by using a PixelShader.

public ref class ShaderEffect abstract : System::Windows::Media::Effects::Effect

public abstract class ShaderEffect : System.Windows.Media.Effects.Effect

type ShaderEffect = class
    inherit Effect

Public MustInherit Class ShaderEffect
Inherits Effect

Inheritance: Object

DispatcherObject

DependencyObject

Freezable

Animatable

Effect
ShaderEffect

Examples

The following code example shows how to derive from the ShaderEffect class.

using System;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Effects;
using System.Reflection;

namespace ShaderEffectDemo
{

    public class ThresholdEffect : ShaderEffect
    {
        private static PixelShader _pixelShader =
            new PixelShader() { UriSource = MakePackUri("ThresholdEffect.fx.ps") };

        public ThresholdEffect()
        {
            PixelShader = _pixelShader;

            UpdateShaderValue(InputProperty);
            UpdateShaderValue(ThresholdProperty);
            UpdateShaderValue(BlankColorProperty);
        }

        // MakePackUri is a utility method for computing a pack uri
        // for the given resource. 
        public static Uri MakePackUri(string relativeFile)
        {
            Assembly a = typeof(ThresholdEffect).Assembly;

            // Extract the short name.
            string assemblyShortName = a.ToString().Split(',')[0];

            string uriString = "pack://application:,,,/" +
                assemblyShortName +
                ";component/" +
                relativeFile;

            return new Uri(uriString);
        }

        ///////////////////////////////////////////////////////////////////////
        #region Input dependency property

        public Brush Input
        {
            get { return (Brush)GetValue(InputProperty); }
            set { SetValue(InputProperty, value); }
        }

        public static readonly DependencyProperty InputProperty =
            ShaderEffect.RegisterPixelShaderSamplerProperty("Input", typeof(ThresholdEffect), 0);

        #endregion

        ///////////////////////////////////////////////////////////////////////
        #region Threshold dependency property

        public double Threshold
        {
            get { return (double)GetValue(ThresholdProperty); }
            set { SetValue(ThresholdProperty, value); }
        }

        public static readonly DependencyProperty ThresholdProperty =
            DependencyProperty.Register("Threshold", typeof(double), typeof(ThresholdEffect),
                    new UIPropertyMetadata(0.5, PixelShaderConstantCallback(0)));

        #endregion

        ///////////////////////////////////////////////////////////////////////
        #region BlankColor dependency property

        public Color BlankColor
        {
            get { return (Color)GetValue(BlankColorProperty); }
            set { SetValue(BlankColorProperty, value); }
        }

        public static readonly DependencyProperty BlankColorProperty =
            DependencyProperty.Register("BlankColor", typeof(Color), typeof(ThresholdEffect),
                    new UIPropertyMetadata(Colors.Transparent, PixelShaderConstantCallback(1)));

        #endregion
    }
}

The following code example shows a shader that corresponds to the previous ShaderEffect class.

// Threshold shader 

// Object Declarations

sampler2D implicitInput : register(s0);
float threshold : register(c0);
float4 blankColor : register(c1);

//--------------------------------------------------------------------------------------
// Pixel Shader
//--------------------------------------------------------------------------------------
float4 main(float2 uv : TEXCOORD) : COLOR
{
    float4 color = tex2D(implicitInput, uv);
    float intensity = (color.r + color.g + color.b) / 3;
    
    float4 result;
    if (intensity > threshold)
    {
        result = color;
    }
    else
    {
        result = blankColor;
    }
    
    return result;
}

The following XAML shows how to use the custom shader effect.

<Window x:Class="ShaderEffectDemo.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:ShaderEffectDemo"
    Title="Window1" Height="300" Width="300">
    <Window.Resources>
        <local:ThresholdEffect x:Key="thresholdEffect" Threshold="0.25" BlankColor="Orange" />
    </Window.Resources>
    
    <Grid Effect="{StaticResource thresholdEffect}">

    </Grid>
</Window>

Remarks

Derive from the ShaderEffect class to implement a custom effect based on a single pixel shader.

The following steps show how to create a custom effect.

Load a PixelShader from precompiled High Level Shading Language (HLSL) bytecode.
Define dependency properties that represent the parameters of the effect and the Brush-based surface inputs. Use one of the RegisterPixelShaderSamplerProperty overloads to associate these inputs with register numbers that are referenced in the HLSL bytecode.

The number of samplers is limited to 4.

The following restrictions apply when using a PS 3.0 shader.

When a PS 3.0 shader is assigned, the number of samplers increases to 8. Assign the PS 3.0 shader before other shaders to enable registering 8 samplers.
The full shader constant register limit of 224 for floats is used. For more information, see ps_3_0.
The following data types are supported in PS 3.0 shaders only. An exception is thrown if these are used in lower shader versions.
- int and types convertible to int: uint, byte, sbyte, long, ulong, short, ushort, char
- bool
If a valid PS 3.0 shader is loaded on a computer that does not have hardware support for PS 3.0, the shader is ignored. If the shader is invalid, no exception is thrown.
If a computer has more than one video card, the behavior is defined by the least capable video card. For example, if the computer has two video cards, one of which supports PS 3.0 and one of which does not, the behavior is the same as if the computer does not support PS 3.0.
If a computer supports rendering PS 3.0 in hardware, but an invalid PS 3.0 shader is assigned, the InvalidPixelShaderEncountered event is raised. An example of an invalid PS 3.0 shader is one compiled with the ps_3_sw flag. The ShaderEffect class accepts only PS 3.0 shaders that are compiled with the ps_3_0 flag passed to fxc.exe. For more information, see Effect-Compiler Tool.

Note

PS 2.0 shaders run when rendering in software. However, even if PS 3.0 is supported by the system's hardware, PS 3.0 shaders do not run during software rendering.

Constructors

ShaderEffect()

Initializes a new instance of the ShaderEffect class.

Fields

PixelShaderProperty

Identifies the PixelShader dependency property.

Properties

CanFreeze	Gets a value that indicates whether the object can be made unmodifiable. (Inherited from Freezable)
DdxUvDdyUvRegisterIndex	Gets or sets a value that indicates the shader register to use for the partial derivatives of the texture coordinates with respect to screen space.
DependencyObjectType	Gets the DependencyObjectType that wraps the CLR type of this instance. (Inherited from DependencyObject)
Dispatcher	Gets the Dispatcher this DispatcherObject is associated with. (Inherited from DispatcherObject)
EffectMapping	When overridden in a derived class, transforms mouse input and coordinate systems through the effect. (Inherited from Effect)
HasAnimatedProperties	Gets a value that indicates whether one or more AnimationClock objects is associated with any of this object's dependency properties. (Inherited from Animatable)
IsFrozen	Gets a value that indicates whether the object is currently modifiable. (Inherited from Freezable)
IsSealed	Gets a value that indicates whether this instance is currently sealed (read-only). (Inherited from DependencyObject)
PaddingBottom	Gets or sets a value indicating that the effect's output texture is larger than its input texture along the bottom edge.
PaddingLeft	Gets or sets a value indicating that the effect's output texture is larger than its input texture along the left edge.
PaddingRight	Gets or sets a value indicating that the effect's output texture is larger than its input texture along the right edge.
PaddingTop	Gets or sets a value indicating that the effect's output texture is larger than its input texture along the top edge.
PixelShader	Gets or sets the PixelShader to use for the effect.

Methods

ApplyAnimationClock(DependencyProperty, AnimationClock)	Applies an AnimationClock to the specified DependencyProperty. If the property is already animated, the SnapshotAndReplace handoff behavior is used. (Inherited from Animatable)
ApplyAnimationClock(DependencyProperty, AnimationClock, HandoffBehavior)	Applies an AnimationClock to the specified DependencyProperty. If the property is already animated, the specified HandoffBehavior is used. (Inherited from Animatable)
BeginAnimation(DependencyProperty, AnimationTimeline)	Applies an animation to the specified DependencyProperty. The animation is started when the next frame is rendered. If the specified property is already animated, the SnapshotAndReplace handoff behavior is used. (Inherited from Animatable)
BeginAnimation(DependencyProperty, AnimationTimeline, HandoffBehavior)	Applies an animation to the specified DependencyProperty. The animation is started when the next frame is rendered. If the specified property is already animated, the specified HandoffBehavior is used. (Inherited from Animatable)
CheckAccess()	Determines whether the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject)
ClearValue(DependencyProperty)	Clears the local value of a property. The property to be cleared is specified by a DependencyProperty identifier. (Inherited from DependencyObject)
ClearValue(DependencyPropertyKey)	Clears the local value of a read-only property. The property to be cleared is specified by a DependencyPropertyKey. (Inherited from DependencyObject)
Clone()	Creates a modifiable clone of this ShaderEffect object, making deep copies of this object's values. When copying this object's dependency properties, this method copies resource references and data bindings (which may no longer resolve), but not animations or their current values.
CloneCore(Freezable)	Makes the instance a clone (deep copy) of the specified Freezable using base (non-animated) property values.
CloneCurrentValue()	Creates a modifiable clone of this ShaderEffect object, making deep copies of this object's current values. Resource references, data bindings, and animations are not copied, but their current values are copied.
CloneCurrentValueCore(Freezable)	Makes the instance a modifiable clone (deep copy) of the specified Freezable using current property values.
CoerceValue(DependencyProperty)	Coerces the value of the specified dependency property. This is accomplished by invoking any CoerceValueCallback function specified in property metadata for the dependency property as it exists on the calling DependencyObject. (Inherited from DependencyObject)
CreateInstance()	Initializes a new instance of the Freezable class. (Inherited from Freezable)
CreateInstanceCore()	Creates a new instance of the Freezable derived class.
Equals(Object)	Determines whether a provided DependencyObject is equivalent to the current DependencyObject. (Inherited from DependencyObject)
Freeze()	Makes the current object unmodifiable and sets its IsFrozen property to `true`. (Inherited from Freezable)
FreezeCore(Boolean)	Makes this Animatable object unmodifiable or determines whether it can be made unmodifiable. (Inherited from Animatable)
GetAnimationBaseValue(DependencyProperty)	Returns the non-animated value of the specified DependencyProperty. (Inherited from Animatable)
GetAsFrozen()	Creates a frozen copy of the Freezable, using base (non-animated) property values. Because the copy is frozen, any frozen sub-objects are copied by reference. (Inherited from Freezable)
GetAsFrozenCore(Freezable)	Makes the instance a frozen clone of the specified Freezable using base (non-animated) property values.
GetCurrentValueAsFrozen()	Creates a frozen copy of the Freezable using current property values. Because the copy is frozen, any frozen sub-objects are copied by reference. (Inherited from Freezable)
GetCurrentValueAsFrozenCore(Freezable)	Makes the current instance a frozen clone of the specified Freezable. If the object has animated dependency properties, their current animated values are copied.
GetHashCode()	Gets a hash code for this DependencyObject. (Inherited from DependencyObject)
GetLocalValueEnumerator()	Creates a specialized enumerator for determining which dependency properties have locally set values on this DependencyObject. (Inherited from DependencyObject)
GetType()	Gets the Type of the current instance. (Inherited from Object)
GetValue(DependencyProperty)	Returns the current effective value of a dependency property on this instance of a DependencyObject. (Inherited from DependencyObject)
InvalidateProperty(DependencyProperty)	Re-evaluates the effective value for the specified dependency property. (Inherited from DependencyObject)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
OnChanged()	Called when the current Freezable object is modified. (Inherited from Freezable)
OnFreezablePropertyChanged(DependencyObject, DependencyObject)	Ensures that appropriate context pointers are established for a DependencyObjectType data member that has just been set. (Inherited from Freezable)
OnFreezablePropertyChanged(DependencyObject, DependencyObject, DependencyProperty)	This member supports the Windows Presentation Foundation (WPF) infrastructure and is not intended to be used directly from your code. (Inherited from Freezable)
OnPropertyChanged(DependencyPropertyChangedEventArgs)	Overrides the DependencyObject implementation of OnPropertyChanged(DependencyPropertyChangedEventArgs) to also invoke any Changed handlers in response to a changing dependency property of type Freezable. (Inherited from Freezable)
PixelShaderConstantCallback(Int32)	Associates a dependency property value with a pixel shader's float constant register.
PixelShaderSamplerCallback(Int32)	Associates a dependency property value with a pixel shader's sampler register.
PixelShaderSamplerCallback(Int32, SamplingMode)	Associates a dependency property value with a pixel shader's sampler register and a SamplingMode.
ReadLocalValue(DependencyProperty)	Returns the local value of a dependency property, if it exists. (Inherited from DependencyObject)
ReadPreamble()	Ensures that the Freezable is being accessed from a valid thread. Inheritors of Freezable must call this method at the beginning of any API that reads data members that are not dependency properties. (Inherited from Freezable)
RegisterPixelShaderSamplerProperty(String, Type, Int32)	Associates a dependency property with a shader sampler register.
RegisterPixelShaderSamplerProperty(String, Type, Int32, SamplingMode)	Associates a dependency property with a shader sampler register and a SamplingMode.
SetCurrentValue(DependencyProperty, Object)	Sets the value of a dependency property without changing its value source. (Inherited from DependencyObject)
SetValue(DependencyProperty, Object)	Sets the local value of a dependency property, specified by its dependency property identifier. (Inherited from DependencyObject)
SetValue(DependencyPropertyKey, Object)	Sets the local value of a read-only dependency property, specified by the DependencyPropertyKey identifier of the dependency property. (Inherited from DependencyObject)
ShouldSerializeProperty(DependencyProperty)	Returns a value that indicates whether serialization processes should serialize the value for the provided dependency property. (Inherited from DependencyObject)
ToString()	Returns a string that represents the current object. (Inherited from Object)
UpdateShaderValue(DependencyProperty)	Notifies the effect that the shader constant or sampler corresponding to the specified dependency property should be updated.
VerifyAccess()	Enforces that the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject)
WritePostscript()	Raises the Changed event for the Freezable and invokes its OnChanged() method. Classes that derive from Freezable should call this method at the end of any API that modifies class members that are not stored as dependency properties. (Inherited from Freezable)
WritePreamble()	Verifies that the Freezable is not frozen and that it is being accessed from a valid threading context. Freezable inheritors should call this method at the beginning of any API that writes to data members that are not dependency properties. (Inherited from Freezable)

Events

Changed

Occurs when the Freezable or an object it contains is modified.

(Inherited from Freezable)

Applies to

Del via