Java-Gaming.org Hi !
 Featured games (90) games approved by the League of Dukes Games in Showcase (753) Games in Android Showcase (228) games submitted by our members Games in WIP (842) games currently in development
 News: Read the Java Gaming Resources, or peek at the official Java tutorials
Pages: [1]
 ignore  |  Print
 Vector Maths  (Read 1274 times) 0 Members and 1 Guest are viewing this topic.
Stinine

Innocent Bystander

Java games rock!

 « Posted 2005-01-28 14:15:46 »

Hi Everyone,

I was wondering if anyone has any experience with vector maths espicially with J2ME?

Im currently stuck on two problems:

The first probelm is I need to classify if a point is to the front or backside of a 2D Plane.

Ive implemented it this way:

vect = planeOrign - point;
d = dot(vect,planeNormal)

if( d<-error) return PLANE_FRONT
else( d>error) return PLANE_BACKSIDE
return ON_PLANE

But this sometimes fails so i was wondering if there is an more accurate implementation for this problem.

The second problem is the working out a ray intercept with a 2D plane.

Ive implemented the ray intercept in the standard way:

d = -(planeNormal dot planeOrign);
numer = planeNormal dot rayOrign + d;
denom = planeNormal  dot rayDirection;

if denom== 0
return -1;

return -(numer/denom);

but I sometimes get funny results, with the rayDirection normalized or not)  where the treturned value is passed one when the should be an intercept

P.S if this helps the planeNormal was worked out by:

planeNormal= (pointOnPlane1 - pointOntplane2);
Normalise(planeNormal);
planeNormal
• =-planeNormal[y];
planeNormal[y]= planeNormal
• ;
Pages: [1]
 ignore  |  Print

 nelsongames (19 views) 2018-04-24 18:15:36 nelsongames (17 views) 2018-04-24 18:14:32 ivj94 (607 views) 2018-03-24 14:47:39 ivj94 (51 views) 2018-03-24 14:46:31 ivj94 (400 views) 2018-03-24 14:43:53 Solater (65 views) 2018-03-17 05:04:08 nelsongames (110 views) 2018-03-05 17:56:34 Gornova (175 views) 2018-03-02 22:15:33 buddyBro (746 views) 2018-02-28 16:59:18 buddyBro (93 views) 2018-02-28 16:45:17
 Java Gaming Resourcesby philfrei2017-12-05 19:38:37Java Gaming Resourcesby philfrei2017-12-05 19:37:39Java Gaming Resourcesby philfrei2017-12-05 19:36:10Java Gaming Resourcesby philfrei2017-12-05 19:33:10List of Learning Resourcesby elect2017-03-13 14:05:44List of Learning Resourcesby elect2017-03-13 14:04:45SF/X Librariesby philfrei2017-03-02 08:45:19SF/X Librariesby philfrei2017-03-02 08:44:05
 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