An Effect defines the render states required to render an object. An EffectBinding provides the logic that is required for using an effect at runtime.

Multiple EffectBindings can share the same Effect. An EffectBinding can in theory be shared by different graphics objects. But in most cases an EffectBinding belongs to a single object, such as a Mesh.

Technique and Parameter Bindings:
An effect may define one or more effect techniques. When rendering a certain object the correct technique needs to be chosen. In addition, an effect defines a set of effect parameters. An effect file (.fx) can define default values for effect parameters. However, most effect parameters need to be set at runtime. Static parameters (such as colors, textures, etc.) can be set when assets are loaded. Dynamic parameters (such as world matrix, view matrix, projection matrix, etc.) need to be updated, typically once per frame, when the associated objects are rendered.

Effect parameters belong to different categories, defined by EffectParameterHint. An EffectBinding can be used to manage all kinds of effect parameters, or only parameters of a certain type, e.g. only Material parameters. See also Hints.

DigitalRune Graphics introduces the concept of effect technique bindings and effect parameter bindings: The technique binding (see property TechniqueBinding) provides the logic for selecting a technique at runtime. Parameter bindings (stored in ParameterBindings) links a effect parameters to a certain values. By using a ConstParameterBindingT a parameter can be bound to a static value. By using a DelegateParameterBindingT a parameter can be dynamically updated when needed. Effect technique and parameter bindings are evaluated when the associated object (e.g. a mesh) needs to be rendered. Evaluation consists of two phases:

1. Update: The effect technique is selected; the new value of an effect parameter is calculated.
2. Apply: An effect technique is selected for rendering; the new value is applied to the effect parameter in Effect.

Initialization: When an effect binding is created all technique and parameter bindings are created automatically. This initialization involves two steps:

1. Interpretation: IEffectInterpreters are used to interpret the meaning of effect techniques and parameters. An IEffectInterpreter returns EffectTechniqueDescriptions and EffectParameterDescriptions which indicate how the effect should be used at runtime. This information is stored per effect and can also be queried using the methods GetTechniqueDescriptions(Effect) and GetParameterDescriptions(Effect).
2. Binding of Effect Parameters: IEffectBinders read the information provided in the previous step and create an EffectTechniqueBinding for the effect and EffectParameterBindings for all effect parameters.

Cloning:
EffectBindings need to be cloneable. The method Clone calls CreateInstanceCore and CloneCore(EffectBinding) which are responsible for creating a clone of the current instance. Classes that derive from EffectBinding need to provide the implementation for CreateInstanceCore and override CloneCore(EffectBinding) if necessary.

By default, when an EffectBinding is cloned all technique and parameter bindings are duplicated (deep copy). Any optional object stored in UserData is copied per reference (shallow copy).

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