TheGameCreators - CodeBase - Hypnotic particles and gravity wells

Category: 2D Effects

Version: 1.0

Information

Uploaded: 6th Mar 2005 06:10

Modified: 30th Oct 2006 21:20

Author: flibX0r

Summary

One fine evening I was rather bored, and whipped up this little effect. Don't stare at it for too long, it tends to have a hypnotic effect

Full Description

DarkBASIC Professional Source Code

` This code was downloaded from The Game Creators

` It is reproduced here with full permission

` http://www.thegamecreators.com

` me so bored, dunno what to do tonight

` set teh display mode

set display mode 640, 480, 32

` define teh constants

#constant TOTAL_PARTICLE_COUNT   1023

#constant GRAVITY_CONSTANT       20

#constant BOUNCEREDUCTION        0.5

sync on

sync rate 60

randomize timer()

hide mouse

type Particle

x as float

y as float

vx as float

vy as float

mass as float

colour

endtype

dim p(TOTAL_PARTICLE_COUNT+1) as Particle

dim c(10) as integer

c(0) = rgb(255,0,0)

c(1) = rgb(255,128,0)

c(2) = rgb(255,255,0)

c(3) = rgb(128,255,0)

c(4) = rgb(0,255,0)

c(4) = rgb(0,255,128)

c(5) = rgb(0,255,255)

c(6) = rgb(0,128,255)

c(7) = rgb(0,0,255)

c(8) = rgb(0,128,0)

c(9) = 0

`INITILISATION

`for i=0 to TOTAL_PARTICLE_COUNT

for i=0 to 31

for j=0 to 31

p(i+j*32).x = rnd(100) + 270.5

p(i+j*32).y = rnd(100) + 190.5

p(i+j*32).vx = 0

p(i+j*32).vy = 0

p(i+j*32).mass = 4

p(i+j*32).colour = 0

next j

next i

make memblock 1, 640*480*4+12

write memblock dword 1, 0, 640

write memblock dword 1, 4, 480

write memblock dword 1, 8, 32

for i=12 to (640*480*4+11) step 4

write memblock byte 1, i, 0         :`Blue

write memblock byte 1, i+1, 0       :`Green

write memblock byte 1, i+2, 0       :`Red

write memblock byte 1, i+3, 10      :`Alpha

next i

make image from memblock 1, 1

`MAIN LOOP

`This is the part to edit. basically it just applies

`forces to the particles, draws them, and repeats

`cls

`Apply forces

if inkey$()<>" "

FORCE_GRAV_POINT(-1, 100, 100)

FORCE_GRAV_POINT(-1, 540, 100)

FORCE_GRAV_POINT(-1, 100, 380)

FORCE_GRAV_POINT(-1, 540, 380)

`Update positions

for i=0 to TOTAL_PARTICLE_COUNT

p(i).x = p(i).x + p(i).vx

p(i).y = p(i).y + p(i).vy

next i

endif

`No going outside the screen

`if one does, then its back to the start

for i=0 to TOTAL_PARTICLE_COUNT

if (p(i).vx*p(i).vx)+(p(i).vy*p(i).vy)>36

p(i).x = rnd(100) + 270.5

p(i).y = rnd(100) + 190.5

p(i).vx = 0

p(i).vy = 0

p(i).colour = p(i).colour+1

if p(i).colour=9

p(i).colour=0

p(i).x = rnd(100) + 270.5

p(i).y = rnd(100) + 190.5

endif

next i

`Draw the particles

for i=0 to TOTAL_PARTICLE_COUNT

ink c(p(i).colour), 0

dot p(i).x, p(i).y

next i

`draw the image to create the trail effect

paste image 1, 0, 0, 1

sync

loop

`Functions

`Gravity Point

function FORCE_GRAV_POINT(particle, gx, gy)

ink RGB(255,255,255), 0

circle gx, gy, 10

dist as float

accel as float

if particle = -1

for i=0 to TOTAL_PARTICLE_COUNT

dist = (gx-p(i).x)*(gx-p(i).x) + (gy-p(i).y)*(gy-p(i).y)

accel = GRAVITY_CONSTANT*(p(i).mass)/dist

dist = sqrt(dist)

p(i).vx = p(i).vx + accel*(gx-p(i).x)/dist

p(i).vy = p(i).vy + accel*(gy-p(i).y)/dist

next i

else

dist = (gx-p(particle).x)*(gx-p(particle).x) + (gy-p(particle).y)*(gy-p(particle).y)

CodeBase - Hypnotic particles and gravity wells

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DarkBASIC Professional Source Code

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Author Name:	flibX0r
CodeBase Entries:	2