优化WPF 3D性能

原文: 优化WPF 3D性能

Maximize WPF 3D Performance

.NET Framework 4.5

As you use the Windows Presentation Foundation (WPF) to build 3D controls and include 3D scenes in your applications, it is important to consider performance optimization. This topic provides a list of 3D classes and properties that have performance implications for your application, along with recommendations for optimizing performance when you use them.

This topic assumes an advanced understanding of Windows Presentation Foundation (WPF) 3D features. The suggestions in this document apply to "rendering tier 2"—roughly defined as hardware that supports pixel shader version 2.0 and vertex shader version 2.0. For more details, see 

Graphics Rendering Tiers

.

Performance Impact: High

Property	Recommendation
Brush	Brush speed (fastest to slowest): SolidColorBrush LinearGradientBrush ImageBrush DrawingBrush  (cached) VisualBrush RadialGradientBrush  (uncached)
ClipToBoundsProperty	Set Viewport3D.ClipToBounds to false whenever you do not need to have Windows Presentation Foundation (WPF) explicitly clip the content of a  Viewport3D  to the Viewport3D’s rectangle. Windows Presentation Foundation (WPF) antialiased clipping can be very slow, and ClipToBounds is enabled (slow) by default on
IsHitTestVisible	Set Viewport3D.IsHitTestVisible to false whenever you do not need Windows Presentation Foundation (WPF) to consider the content of a   when performing mouse hit testing.  Hit testing 3D content is done in software and can be slow with large meshes.   is enabled (slow) by default on
GeometryModel3D	Create different models only when they require different Materials or Transforms. Otherwise, try to coalesce many   instances with the same Materials and Transforms into a few larger   and  MeshGeometry3D  instances.
	Mesh animation—changing the individual vertices of a mesh on a per-frame basis—is not always efficient in Windows Presentation Foundation (WPF).  To minimize the performance impact of change notifications when each vertex is modified, detach the mesh from the visual tree before performing per-vertex modification.  Once the mesh has been modified, reattach it to the visual tree.  Also, try to minimize the size of meshes that will be animated in this way.
3D Antialiasing	To increase rendering speed, disable multisampling on a   by setting the attached property  EdgeMode  to Aliased. By default, 3D antialiasing is disabled on Microsoft Windows XP and enabled on Windows Vista with 4 samples per pixel.
Text	Live text in a 3D scene (live because it’s in a   or  ) can be slow. Try to use images of the text instead (via  RenderTargetBitmap ) unless the text will change.
TileBrush	If you must use a   or a   in a 3D scene because the brush’s content is not static, try caching the brush (setting the attached property  CachingHint  to Cache). Set the minimum and maximum scale invalidation thresholds (with the attached properties  CacheInvalidationThresholdMinimum CacheInvalidationThresholdMaximum ) so that the cached brushes won’t be regenerated too frequently, while still maintaining your desired level of quality. By default,   are not cached, meaning that every time something painted with the brush has to be re-rendered, the entire content of the brush must first be re-rendered to an intermediate surface.
BitmapEffect	forces all affected content to be rendered without hardware acceleration. For best performance, do not use

Performance Impact: Medium

	When a mesh is defined as abutting triangles with shared vertices and those vertices have the same position, normal, and texture coordinates, define each shared vertex only once and then define your triangles by index with  TriangleIndices
	Try to minimize texture sizes when you have explicit control over the size (when you’re using a   and/or an  ). Note that lower resolution textures can decrease visual quality, so try to find the right balance between quality and performance.
Opacity	When rendering translucent 3D content (such as reflections), use the opacity properties on brushes or materials (via  Color ) instead of creating a separate translucent  by setting Viewport3D.Opacity to a value less than 1.
	Minimize the number of   objects you’re using in a scene. Put many 3D models in the same Viewport3D rather than creating separate Viewport3D instances for each model.
Freezable	Typically it’s beneficial to reuse  ,  , Brushes, and Materials. All are multiparentable since they’re derived from Freezable.
	Call the  Freeze  method on Freezables when their properties will remain unchanged in your application. Freezing can decrease working set and increase speed.
	Use   instead of   when the content of the brush will not change. 2D content can be converted to an  Image  via   and then used in an
BackMaterial	Don’t use   unless you actually need to see the back faces of your
Light	Light speed (fastest to slowest): AmbientLight DirectionalLight PointLight SpotLight
	Try to keep mesh sizes under these limits: Positions  : 20,001  Point3D  instances  : 60,003  Int32
Material	Material speed (fastest to slowest): EmissiveMaterial DiffuseMaterial SpecularMaterial
	Windows Presentation Foundation (WPF) 3D doesn't opt out of invisible brushes (black ambient brushes, clear brushes, etc.) in a consistent way.  Consider omitting these from your scene.
MaterialGroup	Each   in a   causes another rendering pass, so including many materials, even simple materials, can dramatically increase the fill demands on your GPU. Minimize the number of materials in your

Performance Impact: Low

Transform3DGroup	When you don’t need animation or data binding, instead of using a transform group containing multiple transforms, use a single  MatrixTransform3D , setting it to be the product of all the transforms that would otherwise exist independently in the transform group.
	Minimize the number of lights in your scene. Too many lights in a scene will force Windows Presentation Foundation (WPF) to fall back to software rendering.  The limits are roughly 110  objects, 70   objects, or 40   objects.
ModelVisual3D	Separate moving objects from static objects by putting them in separate   instances. ModelVisual3D is "heavier" than   because it caches transformed bounds. GeometryModel3D is optimized to be a model; ModelVisual3D is optimized to be a scene node. Use ModelVisual3D to put shared instances of GeometryModel3D into the scene.
	Minimize the number of times you change the number of lights in the scene. Each change of light count forces a shader regeneration and recompilation unless that configuration has existed previously (and thus had its shader cached).
	Black lights won’t be visible, but they will add to render time; consider omitting them.
	To minimize the construction time of large collections in Windows Presentation Foundation (WPF), such as a MeshGeometry3D’s  Normals TextureCoordinates , and , pre-size the collections before value population. If possible, pass the collections’ constructors prepopulated data structures such as arrays or Lists.