<compositor> Element (under map:options:terrain)

This element controls the method that osgEarth uses to composite image layers.

Values

auto	This mode is the default. osgEarth will automatically select an image composition method based on the available graphics hardware. It will test the hardware's ability to support the following techniques in the order of appearance below, and settle on the first supported technique.
multitexture_gpu	Assigns each image layer to its own texture image unit, and composites the layers on the GPU. The maximum number of allowable image layers is limited to the number of texture image units supported by your GPU hardware. (Note: modern GPUs expose more texture image units when using fragment shaders than they do in the fixed-function pipeline.)
multitexture_ffp	Assigns each image layer to its own texture image unit, and composites the layers using the OpenGL fixed-function pipeline.
texture_array	Composites image layers on the GPU, using a Texture2DArray construct. This technique effectively gives you unlimited image layers. It requires graphics hardware that supports the GL_TEXTURE_2D_ARRAY_EXT extension and GL_EXT_gpu_shader4 support.
multipass	Composites imagery by making multiple rendering passes over the scene graph. This technique places no limit on the number of image layers you can have, but can affect performance since each additional layer means another rendering pass over the scene graph.

Example

<map>
   <options>
      <terrain>
         <compositor>multitexture</compositor>
      </terrain>
      ...
   </options>
   ...  
</map>

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