Return a 15-bit integer pixel value given separate red, green, and blue values.

Each r, g, b value is an integer between 0 and 255.

You probably want to use TargaBase#get_row_rgb or TargaBase#get_row_rgba instead.

You probably want to use TargaBase#put_row_rgb or TargaBase#put_row_rgba instead.

Given a 15-bit integer colour value, return separate [r, g, b] values.

Each r, g, b value is an integer between 0 and 255.