Java-Gaming.org Hi !
 Featured games (84) games approved by the League of Dukes Games in Showcase (565) Games in Android Showcase (151) games submitted by our members Games in WIP (605) games currently in development
 News: Read the Java Gaming Resources, or peek at the official Java tutorials
Pages: [1]
 ignore  |  Print
 Line/Point Collsion?  (Read 862 times) 0 Members and 1 Guest are viewing this topic.
yoshidude

Junior Newbie

Java games rock!

 « Posted 2005-05-29 13:41:29 »

I am working on a game that's similar to Missile Command (in fact, it was supposed to be Missile Command, but I got stuck in a loop that wouldn't let me do anything else until the missile was done being drawn, and I'd have to re-do the whole game to fix that and I don't have time. If anyone wants to help me with that instead, that'd be awesome  ). Essentially, you click and a line appears, and everything that runs into it blows up. I'm not exactly sure how to do the collision there, because you need to follow up the slope of the line and I find the slope by y2-y1/x2-x1. By the end, the whole slope is found, but I'm not sure how to have it actually know where the line is, as opposed to a box with the line in it.

Here's my draw method:
 1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41 `      public void draw(int _x3,int x, int y, Graphics g){            double x3=(double)_x3;            MissileCommand Commander = new MissileCommand();            Graphics2D g2D=(Graphics2D)g;            if(x>=x3)            {                  m=((double)y/((double)x-x3)); //I have to parse it to a double for a true fraction.                  System.out.println("Slope: "+m+"X change?: "+x);                  double m2=m;            //      m+=100;                  x2=x3+1;                  x+=x3;                  while(m<=y && x2<=x )                  {                        //System.out.println("Slope: "+m+", "+m2+"\nX value: "+x+"\nY value: "+y);                        Shape liney = new Line2D.Double(x3,0,x2,m); //I draw to a double. Yay²! I saved Seth from having to do an algorithm.                        g2D.draw(liney);                        Commander.delay();                        x2++;                        m+=m2;                        System.out.println("Far: "+Far);                  }                  x-=x3;            }            if(x><=y && x2>=x)                  {                        //system.out.println("slope: "+m+", "+m2+"\nx value: "+x+"\ny value: "+y);                        shape liney = new line2d.double(x3,0,x2,m);                        g2d.draw(liney);                        commander.delay();                        //repaint();                        x2--;                        m+=m2;                        system.out.println("other far: "+far);                  }            }      }`

any help would be greatly appreciated, thanks.>
oNyx

JGO Coder

Medals: 2

pixels! :x

 « Reply #1 - Posted 2005-05-29 15:04:17 »

yoshidude

Junior Newbie

Java games rock!

 « Reply #2 - Posted 2005-05-29 15:07:28 »

Wow, I feel dumb. Especially because I use Line2D in my method.
Thanks so much though, I appreciate it.

Although, that is a boolean. I need the coordinate value of where it happens. Is there a way to get that?
oNyx

JGO Coder

Medals: 2

pixels! :x

 « Reply #3 - Posted 2005-05-29 15:50:01 »

>Is there a way to get that?

From that method? No.

Well, the changes between the frames are pretty small. I guess it's hard to spot the difference. I mean we're talking about 1-2 pixels here.

You could do that stuff with vector math. Basically you need to find the spot were those two linear graphs intersect. (Math from 8th grade is enough for that. Try to remember that stuff )

yoshidude

Junior Newbie

Java games rock!

 « Reply #4 - Posted 2005-05-29 15:57:38 »

I used a different method and got it, ptLineDist.

Thank you so much for pointing me there, you have no idea how awesome it is. I had so much done, but that wouldn't work, so it wasn't even a game. Thank you thank you thank you!

I did see an open-source Missile Command that used Vectors, but I wasn't sure how it worked and I really didn't have time to tear down my program and re-work it. Otherwise, I'd have done that instead.
Pages: [1]
 ignore  |  Print

You cannot reply to this message, because it is very, very old.

 theagentd (11 views) 2015-03-27 23:08:20 wxwsk8er (52 views) 2015-03-20 15:39:46 Fairy Tailz (46 views) 2015-03-15 21:52:20 Olo (28 views) 2015-03-13 17:51:59 Olo (30 views) 2015-03-13 17:50:51 Olo (37 views) 2015-03-13 17:50:16 Olo (43 views) 2015-03-13 17:47:07 ClaasJG (56 views) 2015-03-10 11:36:42 ClaasJG (41 views) 2015-03-10 11:33:01 Pippogeek (47 views) 2015-03-05 14:36:23
 LiquidNitrogen 23x BurntPizza 21x KevinWorkman 21x basil_ 21x EgonOlsen 17x theagentd 16x Roquen 16x princec 12x Riven 11x Varkas 10x SHC 9x Ashedragon 8x Ecumene 7x nsigma 7x wessles 7x phu004 7x
 How to: JGO Wikiby Mac702015-02-17 20:56:162D Dynamic Lighting2015-01-01 20:25:42How do I start Java Game Development?by gouessej2014-12-27 19:41:21Resources for WIP gamesby kpars2014-12-18 10:26:14Understanding relations between setOrigin, setScale and setPosition in libGdx2014-10-09 22:35:00Definite guide to supporting multiple device resolutions on Android (2014)2014-10-02 22:36:02List of Learning Resources2014-08-16 10:40:00List of Learning Resources2014-08-05 19:33:27
 java-gaming.org is not responsible for the content posted by its members, including references to external websites, and other references that may or may not have a relation with our primarily gaming and game production oriented community. inquiries and complaints can be sent via email to the info‑account of the company managing the website of java‑gaming.org