RenderableFov class.

Intersections with planet and instrument FOV boundary vectors / boresight seem to be correct with a margin of error. This could be either due to
precision issues experienced at greater distances, light-time or stellar aberration correction methods, planetary radius etc etc.

shaders/pscstandard_fs.glsl

@@ -71,6 +71,7 @@ void main()
 	}
 	*/
 	diffuse = max(intensity * diffuse, ambient);
+	diffuse[3] = 0.8f;
 	//diffuse = vec4(1);
 
 	ABufferStruct_t frag = createGeometryFragment(diffuse, position, depth);