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 Rotating Particle (Flamethrower) Tower Spawn Acceleration  (Read 2293 times) 0 Members and 1 Guest are viewing this topic.
Slyth2727
 « Posted 2013-04-10 23:33:49 »

Right, in my Java2d TD Game I have set on making a tower that has 3 barrels which spin around and, using my particle engine, spew out fire particles at the direction the barrels are pointing. I have no trouble with the rotation, and I can set the acceleration vector by saying particle.setAcc(X, Y). If the Y value is positive, the particle will go down by that many pixels per tick. Negative, opposite. Same thing for X, just on the X axis. My only problem is if I have the rotation method going like this:

 1  2  3  4  5  6 `            if (rotateT >= rotateS) {               rotation++;               rotateT = 0;            } else {               rotateT++;            }`

and my method for spawning in particles is this:

 1 `            Screen.addOverParticle(X, Y, velocityx, velocityy, size, amount, life, image);`

how would I get it so it the spawning of the particles spins around in a circle as if a flamethrower is turning around in a continuous circle, firing. I have a few ideas, but I think it will be very CPU intensive the ways I am thinking. Thanks -cMp
relminator
 « Reply #1 - Posted 2013-04-11 00:46:45 »

 1  2  3 `float ang = (float)Math.toRadians(rotation);velocityx = (float)Math.cos(ang) * speed; velocityy = (float)Math.sin(ang) * speed;`

Slyth2727
 « Reply #2 - Posted 2013-04-11 01:02:08 »

I get an interesting effect with this. The particles spawn like a box and the width gets bigger than smaller while the height gets smaller than bigger in an indirect variation, if you will. Not the effect I was looking for and still am but a nice one..
StumpyStrust
 « Reply #3 - Posted 2013-04-11 02:02:18 »

If you get a box it is because you are using different speeds for x and y.

If you want it so it looks like someone with a water hose spinning in a circle with flames instead of water, then what relminator said is right. You might be doing something different in your particle system.

Here is how my emitters do this

 1  2  3  4  5  6  7  8  9  10  11  12  13 `float temp = angle2 - angle1;                   float newAngle = (float) (((Rnd.randomPlus(temp))+angle1) * Math.PI/180);         newAngle *= -1;         if(randomV)         {            float v = Rnd.randomPlus(vel);            x.setVel((float)(v*FastMath.cos(newAngle)),(float) (v*FastMath.sin(newAngle)));         }         else         {            x.setVel((float)(vel*FastMath.cos(newAngle)),(float) (vel*FastMath.sin(newAngle)));         }`

Note in this I have extra options like random vel and emitting particles between 2 angles but the key is the x.setVel

Slyth2727
 « Reply #4 - Posted 2013-04-11 23:33:05 »

Ok I see now! Works like a charm, thank you very much
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