demos/luashooter/scripts/backgrounds.lua

   1 --[[
   2 File: backgrounds.lua
   3 Author: Brett Lajzer
   4 Date: 5.25.2006
   5
   6 About:
   7 This file contains various functions that draw backgrounds.
   8 --]]
   9
  10 backgrounds = {}
  11
  12 --background images
  13 backgrounds.star_bg = get_image("img/star_bg.bmp")
  14
  15
  16 --background variables
  17 backgrounds.offset = 0
  18
  19
  20 --background-drawing functions
  21
  22 function backgrounds.stars_fixed()
  23
  24   local wide = math.ceil(s_width/128)
  25   local tall = math.ceil(s_height/128)
  26
  27   for i = 0, wide do
  28     for j = 0, tall do
  29       display(backgrounds.star_bg, 128 * i, 128 *j,0,1,1)
  30     end
  31   end
  32
  33 end
  34
  35
  36 function backgrounds.stars_scrolling(speed)
  37
  38   local wide = math.ceil(s_width/128)
  39   local tall = math.ceil(s_height/128)
  40
  41   for i = 0, wide do
  42     for j = -1, tall do
  43       display(backgrounds.star_bg, 128 * i, 128 *j + backgrounds.offset,0,1,1)
  44     end
  45   end
  46   backgrounds.offset = backgrounds.offset + (speed or 4)
  47   if backgrounds.offset >= 128 then backgrounds.offset = 0 end
  48 end