bg_gradient (boolean, default: off) Controls whether or not the background is gradient colored. If yes, then bg_rgb_top and bg_rgb_bottom will be used to set the colors.

bg_image_filename (string, default: '') if set controls the image used in the background.

bg_image_linear (boolean, default: on) controls the sampling of the texture for the background image. If off, then the nearest pixel is set, otherwise, a linear interpolation is used.

bg_image_mode (integer, default: 0) Determines how the background image is drawn. 0 - stretched, 1 - centered, 2 - tiled, 3 - centered and repeated

bg_image_tilesize (vector, default: [100.0, 100.0, 0.0]) This setting is used when bg_image_mode=3 and defines the size of each tile (in x and y, z is not used).

bg_rgb (vector, default: [0.0,0.0,0.0]) controls the background rgb color.

bg_rgb_bottom (color, default: [0.2,0.2,0.5]) Controls bottom color when bg_gradient is set.

bg_rgb_top (color, default: [0.0,0.0,0.3]) Controls top color when bg_grdient is set.

depth_cue (boolean, default: on) controls whether or not a depth cue fog effect is used.

fog (float 0-1.0, default: 1.0) controls the fog density.

fog_start (float 0-1.0, default: 0.45) controls where fog starts.

opaque_background (boolean, default: on) controls whether or not the background is opaque.

show_alpha_checker (boolean, default: on) controls whether or not a checker pattern is shown in the background.