Ucupumar's hdr-2-rgbm allows you to use HDR textures by converting them to RGBM.
HDR 2 RGBM is addon for encoding HDR image to RGBM format. I created this addon because BGE or viewport cannot read HDR texture properly (RGB value always clamped at 1.0). RGBM format can encode any HDR image to standard 8-bit PNG image. This addon can decode RGBM in realtime too, so it can be useful for lightmap or environment map on viewport or BGE.
See video below to see this addon in action.