How to convert the Raster image (.ras) into a series of three RGB grid

Hi everyone,
I used gmt2rgb and grd2rgb in versions 4 and 5 to read Sun raster image files to Red, Green and Blue bands. But I found this module lost in the gmt 6 version. How can I do that?
I want to drape an image to the perspective view with ‘grdview’ by the flag “-Gdrapegrid | -Ggrd_r -Ggrd_g -Ggrd_b”.
Thank you.

GMT can read regular images, e.g., geotiff, jpg for that purpose now. Sun raster files are a thing of the 1990s. For mixing images and rug,b components etc., see grdmix.

Thank you, Paul! I can do it now. Just use -Gfile.tif to drape the image on the perspective view.