Java-Gaming.org    
Featured games (79)
games approved by the League of Dukes
Games in Showcase (477)
Games in Android Showcase (109)
games submitted by our members
Games in WIP (536)
games currently in development
News: Read the Java Gaming Resources, or peek at the official Java tutorials
 
    Home     Help   Search   Login   Register   
Pages: [1]
  ignore  |  Print  
  area of an Area for Qix  (Read 644 times)
0 Members and 1 Guest are viewing this topic.
Offline pin_kushn

Senior Newbie




Java games rock!


« Posted 2006-05-17 14:45:39 »

I am emulating an old arcade game: I think it was called Qix.  The player gradually "fills in" the game screen.  I have instances of both Polygon and Area that encapsulate the area that the player has filled in, but I can't figure out how to get an int or a double that represent the actual number of pixels contained by an Area or Polygon instance.  Any pointers?
Offline ryanm

Senior Member


Projects: 1
Exp: 15 years


Used to be bleb


« Reply #1 - Posted 2006-05-17 16:44:36 »

Once you know how to compute the area of a triangle, you can subdivide your polygon to find the total area.

Basically, take one vertex A, and for each edge B->C in the polygon, compute the area of the triangle formed by ABC, and sum the results.

This, however, will only work for convex polygons. To handle concave polygons you need to do a bit more work. For each edge B->C, you check which side A falls on, and either add or subtract the area of the triangle to the total.

For instance, assuming you are iterating through the edges in a counter-clockwise direction, if A lies on the left hand side of B->C, you add the area of the triangle ABC, if on the right hand side, you subtract.
Offline pin_kushn

Senior Newbie




Java games rock!


« Reply #2 - Posted 2006-05-17 16:58:58 »

Excellent.  Thanks.  The link to the Line2D static method is a nice added bonus: didn't know about that.
Pages: [1]
  ignore  |  Print  
 
 
You cannot reply to this message, because it is very, very old.

 

Add your game by posting it in the WIP section,
or publish it in Showcase.

The first screenshot will be displayed as a thumbnail.

CogWheelz (18 views)
2014-07-30 21:08:39

Riven (26 views)
2014-07-29 18:09:19

Riven (15 views)
2014-07-29 18:08:52

Dwinin (13 views)
2014-07-29 10:59:34

E.R. Fleming (34 views)
2014-07-29 03:07:13

E.R. Fleming (12 views)
2014-07-29 03:06:25

pw (44 views)
2014-07-24 01:59:36

Riven (44 views)
2014-07-23 21:16:32

Riven (30 views)
2014-07-23 21:07:15

Riven (31 views)
2014-07-23 20:56:16
List of Learning Resources
by SilverTiger
2014-07-31 18:29:50

List of Learning Resources
by SilverTiger
2014-07-31 18:26:06

List of Learning Resources
by SilverTiger
2014-07-31 13:54:12

HotSpot Options
by dleskov
2014-07-08 03:59:08

Java and Game Development Tutorials
by SwordsMiner
2014-06-14 00:58:24

Java and Game Development Tutorials
by SwordsMiner
2014-06-14 00:47:22

How do I start Java Game Development?
by ra4king
2014-05-17 11:13:37

HotSpot Options
by Roquen
2014-05-15 09:59:54
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
Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines | Managed by Enhanced Four Valid XHTML 1.0! Valid CSS!