SQL Server eliminates the function call and replaces the connection

I am trying to rewrite the "Request" part by removing this feature.
Since the table has more than 800K records, the function is called three times for all 800K pages.
I want to exclude a function and replace JOIN?

--Function
CREATE FUNCTION [dbo].[MapValue] 
(
    @ObjCode AS INT,
    @ObjName AS VARCHAR(50),
    @ObjValue AS INT
)
RETURNS VARCHAR(100)
AS
BEGIN
    DECLARE @returnValue AS VARCHAR(100)

    SELECT @returnValue = Value FROM dbo.tblMap
    WHERE ObjCode = @ObjCode AND ObjName = @ObjName AND ObjValue = @ObjValue

    -- Return the result of the function
    RETURN @returnValue

END

--Query
SELECT  ObjectId, ObjectTypeCode,
        dbo.MapValue(4, 'ACode', ACode) AS AType,
        dbo.MapValue(4, 'SCode', SCode) AS SCode,
        dbo.MapValue(4, 'PCode', PCode) AS PCode
FROM    dbo.APoint
WHERE   ObjectTypeCode = 1

      

        
        
        
      

    

Here is the query I came up with using JOIN.
Is there a better way to do this? Can I use just one connection instead of three?

--Modified query
SELECT  ObjectId, ObjectTypeCode,
        A.Value,
        s.Value,
        p.Value
FROM    dbo.APoint ap
    LEFT JOIN tblMap A ON A.ObjCode = 4 AND A.ObjName = 'ACode' AND A.ObjValue = ap.TypeCode
    LEFT JOIN tblMap s ON s.ObjCode = 4 AND s.ObjName = 'SCode' AND s.ObjValue = ap.TypeCode
    LEFT JOIN tblMap p ON p.ObjCode = 4 AND p.ObjName = 'PCode' AND p.ObjValue = ap.TypeCode
WHERE   ObjectTypeCode = 1