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Homer_simpson

Sat Jan 03, 2009 6:01 pm


Particle system for newbies(rain,snow,smoke,etc)

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i've seen that a lot of you like to make animations with turing, so here's a little tutorial on how you can incorporate a particle system into your animations. you could use it to make rain, snow,smoke,etc


here's the steps to creating a particle system

set a type for particles with its required attributes in this example we're going to setup a rain system meaning every drop of rain will be a particle.
every drop of rain has a few attributes : x position, y position, falling speed
so we declare:

type Particle_Type :
    record
        x, y,speed : real
    end record

now we need a lot of these particles so we declare an array of this type 
so we declare an array of a 100 particles:

var Particles : array 1 .. 100  of Particle_Type 

now we have to give these particles their initial values :

for i : 1 .. 100
    Particles (i).x := Rand.Int (0, maxx) %randmize the x position of rain droplets from 0 to maxx
    Particles (i).y :=  Rand.Int (0, maxy) %randmize the y position
    Particles (i).speed :=  Rand.Int (3, 5) %randmize the speed of drops rain
end for


after we've setup all of our particles it's time to move them and draw them
so we start our animation loop like so:

loop
move particles 
draw particles
check to see if the particles need to be renewed
clear the screen
end loop

in code:

loop %main animation loop
    cls %clear the screen

    for i : 1 .. MaxParticles %inside this loop we go through all the particles 1 by 1
        Particles (i).y -= Particles (i).speed %move down the drop of rain

        if Particles (i).y