czm_eyeToWindowCoordinates
        Transforms a position from eye to window coordinates.  The transformation
from eye to clip coordinates is done using czm_projection.
The transform from normalized device coordinates to window coordinates is
done using czm_viewportTransformation, which assumes a depth range
of near = 0 and far = 1.
This transform is useful when there is a need to manipulate window coordinates
in a vertex shader as done by BillboardCollection.
    
Parameters:
| Name | Type | Description | 
|---|---|---|
| position | vec4 | The position in eye coordinates to transform. | 
Returns:
	
	
		vec4 
		
		 The transformed position in window coordinates.
         
    
    
        Example
vec4 positionWC = czm_eyeToWindowCoordinates(positionEC);
