TheGameCreators - CodeBase - Water Wave Effect

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Category: 2D Effects

Version: 2.0

Information

Uploaded: 25th Sep 2003 18:25

Modified: 2nd Oct 2003 18:00

Author: skovron

Summary

Use your mouse and LMB to generate water waves...

Full Description

This code loads some image, than for each pixel position it calculates displacement. Displacement points to pixel which replaces current pixel. It could produce very chaotic bitmaps but displacement is calculatet with use of heightmaps. Each coord of heightmap holds wave amplitude at that position so calculationg difference between neighbor amplitudes (along each axis) we simply calculate displacement for pixel position It's hard for me to explain it in more detail becouse my english is very bad. Well, sorry for that. Now prepare some image, but remember it should be very small, the bigger the bitmap is the more loops have to execute I use 320x240, with 640x480 my computer has a little troubles Move mouse and use left button, than try to change some properties inside the code Well enjoy! New version 2.0 has some optimalizations made by D Man

DarkBASIC Professional Source Code

` This code was downloaded from The Game Creators

` It is reproduced here with full permission

` http://www.thegamecreators.com

remstart

Water Wave Effect

by Mariusz Skowronski (2003)

optimalized by D Man

remend

rem global vars

rem bitmap size and color depth

global g_bmpWidth as integer

global g_bmpHeight as integer

global g_bmpBpp as integer

global g_bytesPerPixel as integer

rem memblock pointers (for faster access)

global g_srcMemPtr as dword

global g_dstMemPtr as dword

rem screen dimensions

global g_scrWidth as integer

global g_scrHeight as integer

rem height array swap index (current and new)

global g_ch as integer

global g_nh as integer

rem properties

rem wave amplitude

global g_waveForce as integer

rem drop size

global g_dropRadius as integer

rem damping value (the smaller value the faster waves disappear) 1 - 100

global g_waveDamp as integer

rem init vars

g_scrWidth = 640

g_scrHeight = 480

g_waveForce = 300

g_dropRadius = 8

g_waveDamp = 20 : rem DON'T USE ZERO

rem begin

set display mode g_scrWidth, g_scrHeight, 16

sync rate 0: sync on

rem load bitmap (remember the smaller bitmap the faster it runs)

load bitmap "example1.jpg", 1

g_bmpWidth = bitmap width(1)

g_bmpHeight = bitmap height(1)

g_bmpBpp = bitmap depth(1)

g_bytesPerPixel = g_bmpBpp/8

rem create 2 bitmap memblocks

make memblock from bitmap 1, 1

make memblock from bitmap 2, 1

rem get memblock addresses

g_srcMemPtr = get memblock ptr(2)

g_dstMemPtr = get memblock ptr(1)

rem dont need this bitmap anymore

delete bitmap 1

rem allocate 2 height maps

dim g_heightMap(1, g_bmpWidth-1, g_bmpHeight-1) as integer

rem clear height maps

ClearHeights()

rem set current height map to 0

g_ch = 0: g_nh = 1

rem main loop

set current bitmap 0

rem update heights

UpdateHeights()

rem update bitmap

UpdateBitmap()

rem uncomment following lie and rem this above to see it in greyscale

rem DrawHeights()

rem create bitmap form memblock

make bitmap from memblock 0, 1

sync

if mouseclick()=1

rem make wave at point mx, my

MakeWave(mousex(), mousey(), g_dropRadius, g_waveForce)

endif

loop

delete memblock 1

delete memblock 2

rem that's all

end

rem this clears height maps

function ClearHeights()

local x, y

for y=0 to g_bmpHeight-1

for x=0 to g_bmpWidth-1

g_heightMap(0, x, y) = 0

g_heightMap(1, x, y) = 0

next x

next y

endfunction

rem this makes a new wave

function MakeWave(x, y, radius, mul)

local u, v, sqru, sqrv, sqrr

sqrr = radius*radius

rem check if not out of bitmap boundary

if (x>radius) and (x<g_bmpWidth-1-radius) and (y>radius) and (y<g_bmpHeight-1-radius)

for v=y-radius to y+radius

sqrv = (v-y)*(v-y)

for u=x-radius to x+radius

sqru = (u-x)*(u-x)

rem for speed reasons check (dx^2 + dy^2) <= r^2

rem instead of real formula: sqrt(dx^2 + dy^) < r

if (sqru+sqrv)<=sqrr:

g_heightMap(g_ch,u,v) = mul*int(radius - sqrt(sqru+sqrv)+1)

endif

next u

next v

endif

endfunction

rem this is only for debug (shows waves in grayscale)

function DrawHeights()

local x, y, height, color

local dstAddr as dword

rem for each height

for y=0 to g_bmpHeight-1

for x=0 to g_bmpWidth-1

height = g_heightMap(g_ch, x, y)/10

rem prepare gray color

color = rgb(height+128, height+128, height+128)

rem dont need this if useing one color depth

select g_bytesPerPixel

case 2: dstAddr = g_dstMemPtr +12+(y*g_bmpWidth+x)*2: endcase

case 4: dstAddr = g_dstMemPtr +12+(y*g_bmpWidth+x)*4: endcase

endselect

*dstAddr = color

next x

next y

endfunction

rem the meat. this updates height map

function UpdateHeights()

local x, y,  height, temp

rem we need skip bitmap edges couse we're making kind of area sampling

for y=2 to g_bmpHeight-3

for x=2 to g_bmpWidth-3

rem calculate height difference

rem read 12 height values surrounding (x,y), divide by 6 so we've got twice as much as average value

rem and then subtract current height at (x, y)

height = g_heightMap(g_ch,x-1,y)

height = height + g_heightMap(g_ch,x-2,y)

height = height + g_heightMap(g_ch,x+1,y)

height = height + g_heightMap(g_ch,x+2,y)

height = height + g_heightMap(g_ch,x,y-1)

height = height + g_heightMap(g_ch,x,y-2)

height = height + g_heightMap(g_ch,x,y+1)

height = height + g_heightMap(g_ch,x,y+2)

height = height + g_heightMap(g_ch,x-1,y-1)

height = height + g_heightMap(g_ch,x+1,y-1)

height = height + g_heightMap(g_ch,x-1,y+1)

height = height + g_heightMap(g_ch,x+1,y+1)

height = int(height/6) - g_heightMap(g_nh,x,y)

rem add some dampig reducing amplitudes

height = height - int(height/g_waveDamp + 1)

g_heightMap(g_nh, x, y) = height

next x

next y

rem swap height maps

temp = g_ch

g_ch = g_nh

g_nh = temp

endfunction

rem this creates waved bitmap

function UpdateBitmap()

local x, y, tx, ty, color

local srcAddr, dstAddr as dword

rem skip bitmap edges

for y=1 to g_bmpHeight-1

for x=1 to g_bmpWidth-1

rem calculate pixel displacements based on height difference

tx = x + (g_heightMap(g_ch, x-1, y) - g_heightMap(g_ch, x, y))/10: rem divide couse height values are too high

ty = y + (g_heightMap(g_ch, x, y-1) - g_heightMap(g_ch, x, y))/10

rem if (tx, ty) still inside bitmap bounds

if tx>=0 and tx<g_bmpWidth and ty>=0 and ty<g_bmpHeight

rem read color from coords we've calculated

select g_bytesPerPixel

case 2: srcAddr = g_srcMemPtr+12+(ty*g_bmpWidth+tx)*2: endcase

case 4: srcAddr = g_srcMemPtr+12+(ty*g_bmpWidth+tx)*4: endcase

endselect

color = *srcAddr

else

rem if out of bitmap bounds let the color be black

color = 0

endif

rem store this color at current position

select g_bytesPerPixel

case 2: dstAddr = g_dstMemPtr+12+(y*g_bmpWidth+x)*2: endcase

case 4: dstAddr = g_dstMemPtr+12+(y*g_bmpWidth+x)*4: endcase

endselect

*dstAddr = color

next x

next y

endfunction

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Author Name:	skovron
CodeBase Entries:	1

CodeBase - Water Wave Effect

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DarkBASIC Professional Source Code

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