Java-Gaming.org
Play Revenge of the Titans! The situation is critical. We need fancy commanders to defend Earth, the moon, Mars!
Featured games (78)
games approved by the League of Dukes
Games in Showcase (408)
games submitted by our members
Games in WIP (293)
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  
  Keeping two objects on the screen?  (Read 1060 times)
0 Members and 1 Guest are viewing this topic.
Offline CyanPrime
« Posted 2009-05-16 03:19:24 »

I'm trying to make it so that no matter how far apart two objects are they'll both remain on screen.
This is what I got so far:

float distance = (float) ((Math.sqrt((p1.x - p2.x) + (p1.y - p2.y))));
float camx = (float)((p1.x + p2.x) * 0.5);
float camy = (float)((p1.y + p2.y) * 0.5);
float camz = (float) (distance * 5);

What is the math I need so the Z zooms in and out correctly?
Offline lhkbob

JGO Knight


Medals: 32



« Reply #1 - Posted 2009-05-16 06:05:16 »

One that should help is that distance should be:
1  
float distance = (float) Math.sqrt( (p1.x - p2.x)*(p1.x - p2.x) + (p1.y - p2.y)*(p1.y - p2.y) );


To calculate the distance needed, try this:
1  
2  
3  
4  
5  
float width = Math.abs(p1.x - p2.x) + PADDING;
float camx = (float) ( (p1.x + p2.x) * .5);
float camy = (float) ( (p1.y + p2.y) * .5);

float camz = (float) (.5 * width * Math.tan(.5 * fov));


The only things I've added are PADDING (which would be a constant that just affects how much space between the edges of the screen you want), and the variable fov.  fov is the field of view angle that you're using when rendering.  If you're using JOGL, it's one of the values used in gluPerspective(), probably 60 degrees.

Pages: [1]
  ignore  |  Print  
 
 
You cannot reply to this message, because it is very, very old.

Play Revenge of the Titans! The situation is critical. We need fancy commanders to defend Earth, the moon, Mars!
 
Browse for soundtracks for your game!

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

The first screenshot will be displayed as a thumbnail.

The invasion has landed! On Mars! And you're there to beat 'em!
cubemaster21 (125 views)
2013-05-17 21:29:12

alaslipknot (133 views)
2013-05-16 21:24:48

gouessej (163 views)
2013-05-16 00:53:38

gouessej (155 views)
2013-05-16 00:17:58

theagentd (168 views)
2013-05-15 15:01:13

theagentd (153 views)
2013-05-15 15:00:54

StreetDoggy (197 views)
2013-05-14 15:56:26

kutucuk (221 views)
2013-05-12 17:10:36

kutucuk (220 views)
2013-05-12 15:36:09

UnluckyDevil (224 views)
2013-05-12 05:09:57
Complex number cookbook
by Roquen
2013-04-24 12:47:31

2D Dynamic Lighting
by Oskuro
2013-04-17 16:46:12

2D Dynamic Lighting
by Oskuro
2013-04-17 16:45:57

2D Dynamic Lighting
by Oskuro
2013-04-17 16:23:20

Noise (bandpassed white)
by Roquen
2013-04-05 17:36:01

Noise (bandpassed white)
by Roquen
2013-04-03 16:17:38

Java Data structures
by Roquen
2013-03-29 13:21:12

Topic Request
by kutucuk
2013-03-22 21:42:01
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!
Page created in 0.085 seconds with 20 queries.