czm_windowToEyeCoordinates
        Transforms a position from window to eye coordinates.
The transform from window to normalized device coordinates is done using components
of (@link czm_viewport} and czm_viewportTransformation instead of calculating
the inverse of czm_viewportTransformation. The transformation from 
normalized device coordinates to clip coordinates is done using positionWC.w,
which is expected to be the scalar used in the perspective divide. The transformation
from clip to eye coordinates is done using czm_inverseProjection.
    
Parameters:
| Name | Type | Description | 
|---|---|---|
fragmentCoordinate | 
            
            
            vec4 | The position in window coordinates to transform. | 
Returns:
	
	
		vec4 
		
		 The transformed position in eye coordinates.
         
    
    
        Example
vec4 positionEC = czm_windowToEyeCoordinates(gl_FragCoord);
