Vertically ripples a 640x480 2D image with an almost water like effect

                                    ` This code was downloaded from The Game Creators
                                    ` It is reproduced here with full permission
                                    ` http://www.thegamecreators.com
                                    
                                    `	------------------------------------------------------------------------
`	DarkRipples                                DarkForge Snippet (10/2/2001)
`	------------------------------------------------------------------------
`	Vertically ripples a 640x480 2D image with an almost water like effect

sync rate 0
sync on
hide mouse

load bitmap "tmk-blue.bmp",1
create bitmap 2,640,480

set current bitmap 1
for i=1 to 480
	get image i,0,i-1,640,i
next i

`	Change the waves and speed values for smoother/faster waves

step#=3 : sx=0 : speed=3 : waves = 10

`	Makes the little graphic at the bottom

cls 0
set text font "Terminal"
set text size 14
set text to bold
ink rgb(10,10,10),0
center text 320,446,"- DarkForge 2001 -"
center text 320,460,"Press cursor keys to change wave pattern"
ink rgb(255,255,255),0
center text 321,447,"- DarkForge 2001 -"
center text 321,461,"Press cursor keys to change wave pattern"
get image 500,200,446,450,479

`	The main loop - it's just another sine wave trick basically

do

	set current bitmap 2

	for i=1 to 480
		paste image i,0,i+sin(sx+i*step#)*waves
	next i

	inc sx,speed

	if upkey() then step#=3 : speed=3 : waves=10
	if downkey() then step#=1.5 : speed=4 : waves=16
	if leftkey() then step#=3 : speed=6 : waves=10
	if rightkey() then step#=0.5 : speed=2 : waves=14

	paste image 500,200,446,1
	copy bitmap 2,0

	sync

loop