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 (406)
games submitted by our members
Games in WIP (290)
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  
  Rotate an image with AffineTransform without coordinate change.  (Read 1445 times)
0 Members and 1 Guest are viewing this topic.
Offline .

Junior Newbie





« Posted 2012-10-04 13:31:01 »



I have a game that i am making, where a ship is in the centre of the screen and planets scroll around it. The ship can rotate about it's centre, but can not change position.(the planets do that, for a scrolling effect) The problem is that I don't know how to move the planets in a certain direction based on where the ship is pointing. my first approach was to increment the planet's x and y coordinates based on where the ship was. example:
1  
2  
3  
4  
if(ships_rotation > 22.5 && ships rotation < 67.5){
            planet.x-= ship.y*speed;
            planet.y+= ship.y*speed;
            }
However this is very time-consuming because I have to write similar code for every direction the planet moves, as well as having very choppy movement. So I decided to attach a AffineTransform to the planet, because as i have found out earlier, AffineTransform can rotate coordinates. This next block of code shows an example of moving the ship diagonally just by incrementing x.
1  
2  
        aft.rotate(Math.toRadians(45));
        aft.translate(50,0);
However, there is one thing wrong with this code, and it is that the image rotates WITH the coordinates. My new approach is to rotate the image opposite the way I want it to go WITHOUT coordinate change, then rotate it back normally.(So the coordinates change) How can I accomplish this? I am open to other solutions, but NOT installing libraries. Thanks in advance.
Offline ReBirth
« Reply #1 - Posted 2012-10-04 15:04:01 »

Set/translate to the center of the image.

Offline Roquen

JGO Ninja


Medals: 66



« Reply #2 - Posted 2012-10-04 16:58:57 »

I'm not really understanding your description.  The ship can rotate, but is always "shown" at the center of the screen.  The ship moves, it's just the "camera" is always keeping it in the center (so planets don't move when the ship does).
Games published by our own members! Check 'em out!
Play the free demo of Revenge of the Titans!
Offline .

Junior Newbie





« Reply #3 - Posted 2012-10-04 21:51:03 »

I'm not really understanding your description.  The ship can rotate, but is always "shown" at the center of the screen.  The ship moves, it's just the "camera" is always keeping it in the center (so planets don't move when the ship does).
The ship turns, but stays in the center. The planets go past the ship to create a "moving" effect.
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 (64 views)
2013-05-17 21:29:12

alaslipknot (73 views)
2013-05-16 21:24:48

gouessej (104 views)
2013-05-16 00:53:38

gouessej (101 views)
2013-05-16 00:17:58

theagentd (111 views)
2013-05-15 15:01:13

theagentd (101 views)
2013-05-15 15:00:54

StreetDoggy (146 views)
2013-05-14 15:56:26

kutucuk (169 views)
2013-05-12 17:10:36

kutucuk (168 views)
2013-05-12 15:36:09

UnluckyDevil (177 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 0.108 seconds with 21 queries.