From FreeSpace Wiki
add-background-bitmap add-background-bitmap Adds a background bitmap to the sky. Returns an integer that is stored in a variable so it can be deleted using remove-background-bitmap Takes 9 arguments... 1: Background bitmap name 2: Pitch 3: Bank 4: Heading 5: X scale (expressed as a percentage of the original size of the bitmap) 6: Y scale (expressed as a percentage of the original size of the bitmap) 7: X divisions. 8: Y divisions. 9: Variable in which to store result
- You must have at least one variable in the mission to choose this SEXP.
- The variable that stores the background information must be a number, not a string. Otherwise FRED will return an error message when it saves the mission.
- Notice that items #5 and #6 are percentages, whereas in the background editor, you work with concrete numbers. If the dimension of your bitmap is 1.5, it should be 150 with this SEXP.