1. 
   
2. // use an arrayList to store a list of objects
3. ArrayList<Missile> missiles = new ArrayList<Missile>(); 
4. 
   
5. void setup() {
6.   size(1000,700);
7.   background(192,64,0);
8.   launchmissiles(5); // launch five missiles (change this number to whatever you want)
9. }
10. 
    
11. void draw() {
12.   // this is an enhanced for loop. it's fairly new to Java/Processing.
13.   // read it as "for every Missile m in the arrayList "missiles", do the shown things with it"
14.   for (Missile m: missiles) {
15.     m.fly(); // call the "fly" method of the missile
16.     m.display(); // call the "display" method of the missile
17.   }
18. }
19. 
    
20. void launchmissiles(int num) {
21.   for(int i=0; i<num; i+=1) {    
22.     // this is where every missile object is created and added to the missiles arrayList
23.     // every missile is created with a random start position, a random x-velocity and a random y-velocity
24.     missiles.add( new Missile(random(width), random(-.5,.5), random(.2, .5))); // 
25.   }
26. }
27. 
    
28. void mousePressed() {  
29.   launchmissiles(5); // if you click the mouse, launch another five missiles
30. }
31. 
    
32. 
    
33. 
    
34. class Missile {
35.   float startloc;
36.   float x, y;
37.   float xvel, yvel;
38. 
    
39.   // contructor
40.   Missile(float _startloc, float _xvel, float _yvel) {
41.     startloc = _startloc;
42.     x = startloc;
43.     y = 0;
44.     xvel = _xvel;
45.     yvel = _yvel;
46.   }
47. 
    
48.   void display() {
49.     stroke(255);
50.     line(startloc, 0, x, y);
51.   }
52. 
    
53.   void fly() {
54.     x += xvel;
55.     y += yvel;
56.   } 
57. }

Well apparently not supposed to classes or objects lol. A challenge of sorts lul.

Update: Okay, well now my current things to do:

I don't know the game but I made some changes.

you click the mouse and there the missiles start.

they collide (explode) at screen boundary.

1. // use an arrayList to store a list of objects
2. ArrayList<Missile> missiles = new ArrayList<Missile>();
3. // have rects insted of lines for Missile: their size
4. final int sizeMissileAtBegin=2;
5. void setup() {
6.   size(1000, 700);
7.   background(192, 64, 0);
8.   // launch five missiles (change this number to whatever you want)
9.   // launchmissiles(5);
10. }
11. void draw() {
12.   background(192, 64, 0);
13.   println ("count "+missiles.size()+" missiles.");
14.   // this is an enhanced for loop. it's fairly new to Java/Processing.
15.   // read it as "for every Missile m in the arrayList "missiles", do the
16.   // shown things with it"
17.   for (Missile m: missiles) {
18.     m.decreaseLife(); // call the decrease life (for explosion)
19.     m.fly(); // call the "fly" method of the missile
20.     m.display(); // call the "display" method of the missile
21.   }
22.   //
23.   // remove dead ones (you need to have a conventional for-loop here)
24.   for (int i=missiles.size()-1; i>=0; i--) {
25.     Missile m = (Missile) missiles.get(i);
26.     if (m.offScreen() || m.dead) {
27.       missiles.remove(i);
28.     }
29.     m.collideScreenBoundary(); // explosion
30.   }
31. }
32. // --------------------------------------------------------------
33. void mousePressed() { 
34.   launchmissiles(5); // if you click the mouse, launch five missiles
35. }
36. //
37. void launchmissiles(int num) {
38.   for (int i=0; i<num; i++) {   
39.     // this is where every missile object is created and added to the missiles arrayList
40.     // every missile is created with a random start position, a random x-velocity and a random y-velocity
41.     // missiles.add( new Missile(random(width), random(-.5, .5), random(.2, .5))); //
42.     // missiles.add( new Missile(mouseX, mouseY, random(-.5, .5), random(.2, .5))); //
43.     missiles.add( new Missile(mouseX, mouseY,
44.     random(-.5, .5), random(-.5, .5),
45.     sizeMissileAtBegin, 0.0, true)); //
46.   }
47. }
48. // =========================================================================
49. class Missile {
50.   float startlocX, startlocY; // start pos
51.   float x, y;          // pos
52.   float xvel, yvel;    // vel
53.   float sizeMissile ;  // size for rect
54.   float life=20;       // how much lifes does it have
55.   float lifeDecrease;  // remove lifes
56.   boolean dead=false;  // is it alive?
57.   boolean withLine;    // draw line? Exlosion has none
58.   //
59.   // contructor
60.   Missile(
61.   float _startlocX, float _startlocY,
62.   float _xvel, float _yvel,
63.   float _size, float _lifeDecrease,
64.   boolean _withLine) {
65.     startlocX = _startlocX;
66.     startlocY = _startlocY;   
67.     x = startlocX;
68.     y = _startlocY;
69.     sizeMissile = _size;
70.     lifeDecrease=_lifeDecrease;
71.     xvel = _xvel;
72.     yvel = _yvel;
73.     withLine=_withLine;
74.   }  // contructor
75.   //
76.   void display() {
77.     stroke(255);
78.     if (withLine) {
79.       line(startlocX, startlocY, x, y);
80.     }
81.     rect(x, y, sizeMissile, sizeMissile);
82.   } // method
83.   //
84.   void fly() {
85.     x += xvel;
86.     y += yvel;
87.   } // method
88.   //
89.   void collideScreenBoundary() {
90.     // check screen boundary and explode
91.     if (x<30 || x>width-30 || y <30 || y > height-30) {
92.       //sizeMissile+=.1;
93.       if (sizeMissile>=sizeMissileAtBegin) {
94.         dead=true;
95.         // explode!
96.         for (int i=0; i<6; i+=1) {   
97.           // this is where explode missile object is created and added to the missiles arrayList
98.           // it is smaller (1) and life decrease is 1, no Line (false).
99.           missiles.add( new Missile(x, y, random(-.5, .5), random(-.5, .5), 1, 1, false)); //
100.         }
101.       }
102.     }
103.   } // method
104.   //
105.   void decreaseLife() {
106.     life-=lifeDecrease;
107.     if (life<=0) {
108.       dead=true;
109.     }
110.   } // method
111.   //
112.   boolean offScreen() {
113.     // is it off screen?
114.     if (x<1 || x>width || y <1 || y > height) {
115.       return(true);
116.     }
117.     else
118.     {
119.       return(false);
120.     }
121.   } // method
122. } // class

Greetings, Chrisir 

sorry, I hadn't seen your last post when I made mine...

That's actually an interesting effect you got there. But I don't think it's quite what tickerr has in mind.

Thanks for the try Chrisir lol. It was very interesting.

Okay...really got everything done with...

that's not too hard -
when the mouse is clicked,
store mouse pos:

1. xPos=mouseX;
2. yPos=mouseY;

then use xPos, yPos instead of mouseX and mouseY

In my Code I used a Arraylist to store the start points (mouseX,mouseY) in:

1.     missiles.add( new Missile(mouseX, mouseY,
2.     random(-.5, .5), random(-.5, .5),
3.     sizeMissileAtBegin, 0.0, true)); //

Lol, that's not working man. Look:

your Code is a bit unclear - maybe rethink what you want.

for example you call leftGunTower with
leftStartLocX - but this is a global var, so no
need to pass this var to leftGunTower,
because it's already known there.

xvel and yvel are not in use at all.

fired is not set back to false.

Question:
do you want the line come slowly out of your guntower and go to where the mouse has been pressed?

Because now it's there immediately.


Remark:
I think at the end of

1. void leftGunTower( float startLocX, float xEnd, float yEnd )

you want

1.   displayMissile( startLocX, xEnd, yEnd );

program
this program works a little better....

1. float StartLocY = 620;
2. float leftStartLocX = 335;
3. float x1 = leftStartLocX;
4. float y1 = StartLocY;
5. float rightStartLocX = 749;
6. float x2 = rightStartLocX;
7. float xVel = 0;
8. float yVel = 0;
9. boolean fired = true;
10. void setup()
11. {
12.   size( 1075, 700 );
13.   stroke( 255 );
14.   frameRate(2);
15. }
16. void leftGunTower( float startLocX, float xEnd, float yEnd )
17. {
18.   if ( x1 > xEnd )
19.   {
20.     x1 -= .8;
21.   }
22.   if ( x1 < xEnd )
23.   {
24.     x1 += .8;
25.   }
26.   if ( y1 > yEnd )
27.   {
28.     y1 -= .8;
29.   }
30.   if ( y1 < yEnd )
31.   {
32.     y1 += .8;
33.   }
34.   displayMissile( startLocX, xEnd, yEnd );
35. }
36. void displayMissile( float startLocX, float _x, float _y )
37. {
38.   line( startLocX, StartLocY, _x, _y );
39. }
40. void mouseClicked ()
41. {
42.   println("ssww");
43.   fired = true;
44.   fireMissile();
45. }
46. //
47. void fireMissile()
48. {
49.   if ( mouseButton == LEFT && fired ) {
50.     float xEnd = mouseX;
51.     float yEnd = mouseY;
52.     leftGunTower( leftStartLocX, xEnd, yEnd );
53.   }
54.   //
55.   else if ( mouseButton == RIGHT ) {
56.     float xEnd = mouseX;
57.     float yEnd = mouseY;
58.     //rightGunTower( rightStartLocX, xEnd, yEnd );
59.   }
60. }
61. //
62. //
63. void draw() {
64.   //
65.   background ( 192, 64, 0 );
66.   // mouseClicked();
67.   // displayMissile ( startLocX, startLocY, _x, _y );
68.   //
69. }
70. // -------------------------------------
71. //

You are a genius.

hello,

you have to distinguish between stages.

separate those stages.
You can even a var stageLeftBullet and stageRightBullet  and control the program by them.

When you want to have more than 1 bullet at a time, use an Arraylist to store multiple in it. Then you need an object bullet.


new version of program...
we still aren't there....

1. // ***************************************
2. // program with two gun towers
3. // ***************************************
4. final float startLocY = 620;
5. final float leftStartLocX = 335;
6. final float rightStartLocX = 749;
7. // ---------------------------------
8. float shockwaveOneSize = 0;
9. float gShockwaveOneSize = 0;
10. float shockwaveTwoSize = 0;
11. float gShockwaveTwoSize = 0;
12. boolean shockwaveOne = true;
13. boolean shockwaveTwo = true;
14. boolean fireOneAlive = false;
15. boolean fireTwoAlive = false;
16. float xEnd ;
17. float yEnd ;
18. // ---------------------------------------------------------
19. void setup()
20. {
21.   size( 1075, 700 );
22.   stroke( 255 );
23. }
24. void displayMissile( float startLocX, float _x, float _y )
25. {
26.   if ( startLocX == leftStartLocX ) {
27.     if ( shockwaveOneSize < 25.0 && shockwaveOne == true ) {
28.       if ( shockwaveOneSize < 3 && shockwaveOne == true )
29.       {
30.         shockwaveOneSize += .5;
31.       }
32.       else {
33.         line( startLocX, startLocY, _x, _y ); 
34.         shockwaveOneSize += .5;
35.         gShockwaveOneSize = shockwaveOneSize;
36.         rectMode(CENTER);
37.         rect( _x, _y, shockwaveOneSize, shockwaveOneSize );
38.         println( "shockwaveOnesize: " + shockwaveOneSize );
39.       }
40.     }
41.     if ( shockwaveOneSize >= 25.0 ) {
42.       shockwaveOne = false;
43.       fireOneAlive = false;
44.       println( "fireOneAlive: " + fireOneAlive );
45.     }
46.   }
47.   if ( startLocX == rightStartLocX ) {
48.     if ( shockwaveTwoSize < 25.0 && shockwaveTwo == true ) {
49.       if ( shockwaveTwoSize < 3 && shockwaveTwo == true )
50.       {
51.         shockwaveTwoSize += .05;
52.       }
53.       else {
54.         line( startLocX, startLocY, _x, _y ); 
55.         shockwaveTwoSize += .5;
56.         gShockwaveTwoSize = shockwaveTwoSize;
57.         rectMode(CENTER);
58.         rect( _x, _y, shockwaveTwoSize, shockwaveTwoSize );
59.         println( "shockwaveTwoSize: " + shockwaveTwoSize );
60.       }
61.     }
62.     if ( shockwaveTwoSize >= 25.0 ) {
63.       println( ":O!!!" );
64.       shockwaveTwo = false;
65.       fireTwoAlive = false;
66.       println( "fireTwoAlive: " + fireTwoAlive );
67.     }
68.   }
69. }
70. void fireMissile()
71. {
72.   if ( mouseButton == LEFT ) {
73.     xEnd = mouseX;
74.     yEnd = mouseY;
75.     //displayMissile( leftStartLocX, xEnd, yEnd );
76.     fireOneAlive  = true;
77.   }
78.   else if ( mouseButton == RIGHT) {
79.     xEnd = mouseX;
80.     yEnd = mouseY;
81.     //displayMissile( rightStartLocX, xEnd, yEnd);
82.     fireTwoAlive  = true;
83.   }
84. }
85. void mouseClicked() {
86.   println("Mouse");
87.   //
88.   fireMissile();
89. }
90. void draw()
91. {
92.   background( 192, 64, 0 );
93.   //
94.   // towers
95.   fill(0);
96.   stroke( 255 ); 
97.   rectMode(CENTER);
98.   rect(leftStartLocX, startLocY+0, 30, 50);
99.   rect(rightStartLocX, startLocY+0, 30, 50 );
100.   // ------------------------------------
101.   fill(255);
102.   stroke( 255 ); 
103.   //
104.   if ( gShockwaveOneSize >= 25.0 || gShockwaveTwoSize >= 25.0 )
105.   {
106.     shockwaveOneSize = 0;
107.     shockwaveOne = true;
108.     shockwaveTwoSize = 0;
109.     shockwaveTwo = true;
110.     if ( fireTwoAlive ) {
111.       fireTwoAlive  = false;
112.     }
113.     if ( fireOneAlive ) {
114.       fireOneAlive = false;
115.     }
116.     gShockwaveOneSize = 0;
117.     gShockwaveTwoSize = 0;
118.   }
119.   if (fireOneAlive) {
120.     displayMissile( leftStartLocX, xEnd, yEnd );
121.   }
122.   if (fireTwoAlive) {
123.     displayMissile( rightStartLocX, xEnd, yEnd );
124.   } 
125.   // fireMissile();
126. } // func
127. //
128. //