'
' This example creates a spotlight with a realistic light emission 
' by adding a spotlight to the scene, applying a volume shader to the 
' default pass, and then connecting it to the spotlight. 
'
NewScene , false
' Get a pointer to the default pass
Set oDefPass = GetValue( "Passes.Default_Pass" )
' Here we are using a utility function that will set up the spotlights
' connected to the volume shader on the default pass. The function
' passes back the names for the spotlight and the connection point.
aSpotInfo = setUpSpots( "Spot1", oDefPass, false )
' The 2nd time around we don't need the info, so we won't use another
' array of returned values
setUpSpots "Spot2", oDefPass, true
' Render a single frame of the default pass just to see both spotlights
' after connecting them to the volume shader: you can see that both spots
' emit their own spotlight beam (from opposite sides)
RenderPasses oDefPass, 1, 1
' Now remove the first spot from the light list and render another frame
' to see the effect. 
RemoveObjectsFromShader aSpotInfo(0), aSpotInfo(1)
' Render a single frame of the default pass: you can see that since the
' first one was removed from the volume shader, it does not appear to 
' emit a spotlight beam
RenderPasses oDefPass, 1, 1
' --------------------------------------------------------------------------
function setUpSpots( in_spot_name, in_pass, in_move_me )
        ' Define these locally only
        Dim oSpotObj, oRetValue, oLightShader, sVolShader, sLightCnxPnt
        ' Get a spot light
        GetPrimLight "Spot", in_spot_name, , , oSpotObj
        ' This is just a cheat to make sure we translate only one of the spots
        If in_move_me Then
                Translate  oSpotObj, -7, 1, 0
        End If 
        ' Apply a light shader and get an object pointer to it (the returned
        ' value is an XSICollection containing the shader as its only member)
        Set oRetValue = SIApplyShader( "Fast_light_effects.Preset", oSpotObj )
        Set oLightShader = oRetValue(0)
        ' Add a volume shader on the default pass and save its fullname
        sVolShader = SIApplyShaderToCnxPoint( "Fast_volume_effects.Preset", _
                        in_pass & ".VolumeShaderStack", , false )
        sLightCnxPnt = sVolShader & ".Lights"
        ' Now add the Spot to the Volume shader light list
        AddObjectsToShader oSpotObj, sLightCnxPnt
        ' Return the array of names we will need later
        setUpSpots = Array( oSpotObj, sLightCnxPnt )
end function