• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
Nick Karasch

[JAVA] image rotation

3 posts in this topic

How can I rotate an image in Java? I think I have AffineTransform pretty figured out but I can't figure out how to make a single image rotate without the entire JPanel rotating.

[CODE]
public void draw(Graphics2D g2d) {
rotate.translate(location.x, location.y);
rotate.rotate(rotation);
rotate.translate(-location.x,-location.y);

g2d.setTransform(rotate);
g2d.drawImage(currentAnimation.getCurrentFrame(), (int) location.x, (int) location.y, null);
}
[/CODE]

g2d is passed in from the paint method, it is obviously representing the entire contents of the panel. Should every image on the screen have it's own separate instance of graphics so I can only apply the AffineTranformation to it, without applying it to everything else?

Also, all of the coordinates are changing. The force applied by vectors rotate with the everything else. :\

Thanks. None of the search results could clarify this for me. Edited by nkarasch
0

Share this post


Link to post
Share on other sites
Inded the g2d object represents the entire contents of the JPanel - it's the canvas upon which everything is drawn.

Rather than everything having its own g2d object, everything should have its own AffineTransform object to define where it should be drawn on the canvas.

It's a good idea to reset the transformation after you've drawn your image (I think this will fix your problem) as follows:

[CODE]
public void draw(Graphics2D g2d) {
rotate.translate(location.x, location.y);
rotate.rotate(rotation);
rotate.translate(-location.x,-location.y);

// take a copy of the transformation that g2d is using
AffineTransform prevTransform = g2d.getTransform();

// apply the transformation for this object and draw
g2d.setTransform(rotate);
g2d.drawImage(currentAnimation.getCurrentFrame(), (int) location.x, (int) location.y, null);

// revert g2d back to the old transformation
g2d.setTransform(prevTransform);
}
[/CODE]

Matt Edited by de_mattT
1

Share this post


Link to post
Share on other sites
Thanks a ton, that is the best response I could have ask for.

Any idea how I can keep my entire coordinate system from changing in relation to the entity I rotated? I want right to continue to be right, up to continue to be up, etc. Even my screen boundaries are messed up for the rotated object. There has to be a way to do it.
0

Share this post


Link to post
Share on other sites
I'm not sure I understand your question sorry.

Are you saying you want to put something at a point on the screen and then rotate it around that point?
If you're translating it, then rotating it, the translation will be relative to the rotation, which sounds the problem you're describing.
The first three lines in the method are confusing me a bit.
If I've understood your problem correctly then the code below should fix it.

[CODE]
public void draw(Graphics2D g2d) {

// Reset the AffineTransform to an identity matrix
// do translation first and rotation second
// (this multiplies a translation matrix by a rotation matrix, which means that actually the rotation happens first)
rotate.setToIdentity();
rotate.translate(location.x, location.y);
rotate.rotate(rotation);

// take a copy of the transformation that g2d is using
AffineTransform prevTransform = g2d.getTransform(); // you might not need this anymore due to use of different drawImage method

// call draw and pass in the affine transformation to use
g2d.drawImage(currentAnimation.getCurrentFrame(), rotate, null);

// revert g2d back to the old transformation
g2d.setTransform(prevTransform); // you might not need this anymore due to use of different drawImage method
}
[/CODE]

Note the use of the other version of drawImage in the code above - we're not passing in the location. This means that the AffineTransform object contains all the transformation info, which makes it a bit easier to follow.

I hope this solves your problem :)

Matt
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0