Java is both a popular object-oriented programming language and runtime environment which allows Java programs to run unchanged on most hardware and software platforms.

learn more… | top users | synonyms

1
vote
2answers
227 views

Circular dependency when creating entities

I have the following problem: I have a a class called Stage, that keeps an list of entities, which it iterates over every update loop, and updates them. One of these entities might be a weapon (PEW ...
2
votes
2answers
780 views

How can I create delays for sprite animations that work correctly when the application is killed and restored?

Please see my original question here: How should I use system time to compute delay times without stutters? In summary, I am attempting to to introduce a delay (say of 5 seconds or so) before a ...
1
vote
1answer
839 views

Fog Of War - Is looping over every tile inefficient?

I'm trying to optimize my static FOW code for my 2D tile-based game and the bottleneck seems to be in the rendering of the fog (rather than the circle drawing algorithm or other aspect of the code). ...
0
votes
1answer
199 views

Strange collision in Breakout [closed]

My Breakout game works fine so far, but I struggle with the collision detection... Well... just with the collision from the ball with the brick... Here's the relevant code: List<Brick> ...
2
votes
3answers
363 views

How do I implement Breakout's “multiball” powerup?

I'm just starting out and making a breakout clone as my first game. I'm implementing all kinds of powerups, but I'm stuck on multiball. The powerup adds additional bouncing balls to the game. So far, ...
0
votes
0answers
49 views

Java Angle Math: Calculate how near the player looks to an entity [duplicate]

I am programming a Minecraft Bukkit plugin and need a way to calculate an input number from 0 to 360 for displaying a custom compass / radar. So if the player directly looks at the object (shouldn't ...
0
votes
2answers
248 views

Slick2D: constructor vs. init method

What is the difference between the constructor of a BasicGameState and the init method? It appears that they are both called at the same time when the BasicGameState is registered in StateBasedGame, ...
0
votes
1answer
986 views

How do I double-buffer renders to a JPanel?

I'm trying to make a little breakout game with Java and Swing. The only issue so far is that drawing on the JPanel causes lots of flickering! The relevant code: JFrame frame = new ...
-2
votes
2answers
311 views

Why can't I set a single value in a game map Java 2D array? [closed]

I'm trying to set one character on 2D array. map[0][2] = "0"; However, I'm getting 11011 11011 11011 11011 ... I was expecting 11011 11111 11111 11111 ... What am I doing wrong? another ...
2
votes
2answers
323 views

Expandable 2d environment by spawning and controlling individual tiles

what is the best way to implement an environment that is "expandable" in every direction so that when the player moves in any direction a new row or column of tiles that can be manipulated ...
0
votes
0answers
323 views

LWJGL Rotating is moving

I am trying to rotate my QUAD even just a little bit. I have read pages like http://www.java-gaming.org/topics/lwjgl-tutorial-series-moving-and-rotating-triangle/30679/view.html In my render() ...
0
votes
1answer
143 views

What's the best way to time a character AI movement on android/java?

I'm creating an android game and I'm trying to figure out the best way to time a character position change, something like this: public void move() { //this.posX += 5; this.posY += 5; if ...
1
vote
1answer
141 views

Slick2D: Initializing graphics object before game loop

I'm using the Slick2D Java game library and I want to set the scale of the graphics object that gets passed to the render method in my game loop. I'd like to do this outside the render method, so ...
5
votes
3answers
2k views

How do I send multiple matrices to a vertex shader?

I'm practising animations using bones/skinning. I am trying to send the shader one matrix per vertex. I can think of these two approaches. Method 1 I have one uniform handle for each bone matrix ...
0
votes
1answer
87 views

One InputProcessor for two controllers

On my screen I want to display two controllers, one to turn around the character (We'll call itLook) and one to move the character (We'll call it Move). I have a line registering a ControllerListener ...
2
votes
2answers
159 views

How do I create a horizontally centered “gravity line”?

Here's my ideal scenario: A game object (in blue) can change its horizontal velocity, but it will be pulled back by gravity (dotted gray arrows) toward a central vertical line (in red). How can I ...
0
votes
1answer
379 views

Can I programmatically generate textures in java?

Is it possible to programmatically generate textures in Java, textures that could then be used to cover in game objects?
2
votes
2answers
1k views

Should game objects draw themselves? [duplicate]

Assuming you have classes like Player, Enemy, Map and Tile. The first approach to structuring rendering code would be to give each a render() method and let it draw itself: void render(){ ...
0
votes
1answer
131 views

Calculate The Proper X and Y Coordinate

I have a class called Tile, the constructor takes an integer that represents the tile's type. You can load a tileset ( via loadTileset() ) which initalizes the fields - tileset numOfTiles tileWidth ...
0
votes
1answer
286 views

Grid collision - finding the location of an entity in each box

I am trying to implement grid-based collision in a 2d game with moving circles. The canvas is 400x400 pixels. Below you can see the code for my Grid class. What I want it to do is check inside which ...
0
votes
2answers
613 views

Create a tornado like particle movement, based on velocity

For context i'm using Java and Minecraft Forge, however the concept should be fairly standard. To spawn particles you use this function... world.spawnParticle("largesmoke", posX, posY, posZ, ...
-2
votes
2answers
956 views

How to calculate a bounding rectangle of a polygon?

Polygon poly = new Polygon(); poly.getPoints().setAll(5d, 15d, 15d, 25d, 5d, 30d); How do I calculate the Polygon's height and width? There is no poly.getWidth() or poly.getHeight() method in ...
-1
votes
2answers
117 views

LWJGL Jumping Down [closed]

I'm currently building a little game using LWJGL, and I got a Game class which contains my game loop, instances etc... And a Player class which contains a constructor (for x and y coords), logic ...
0
votes
1answer
1k views

How do I move the camera in 2D LWJGL openGL?

I am making a top-down rpg game with the LWJGL but I can't figure out how to make the camera follow the player. I've tryed using GLU.gluLookAt() but it seems to be designed for 3D and when I try it ...
0
votes
1answer
647 views

Game Structure in depth [closed]

I've been curious about game structure for some time now. Does everyone who is a game programmer come up with there own approach to structure there game, or is there like some sort of defined layout. ...
0
votes
0answers
71 views

Lateral Friction Phisics

I am trying to create a physics engine for my game, and need to cancel out any lateral velocity for when entities turn. I have tried to mimic this page's example, but it is not working. I have objects ...
0
votes
2answers
128 views

Algorithmic error in tile engine? [closed]

I'm toying with creating a tile-based 2D java game engine. I can render the "local" area without issues(I.E. deciding which local tiles to render). The problem came when I introduced floating point ...
-2
votes
1answer
214 views

What do the 6 points stand for in Polygon().getPoints().setAll?

I have the following code to create a polygon: Polygon poly = new Polygon(); poly.getPoints().setAll(14d, 17d, 26d, 17d, 20d, 27d); // What do these mean? What do these 6 points stand for?
0
votes
3answers
87 views

Getting entity type object [closed]

I have a custom entity class and what it does is create a SQUARE object. public class Entity { Rectangle rect; public Entity() { this.rect = new Rectangle(20,20); rect.relocate(200,200); ...
1
vote
1answer
346 views

Get Tile Location On Screen (Java Slick and Tiled2D)

I want to create a rectangle around each tile that's blocked value = true. How can I find the X and Y (on screen) coords of the each individual Tile?
-3
votes
1answer
173 views

How do you divide the screen into tiles? [closed]

I have been reading alot on tile-based game programming but i could not find a satisfying answer to this question. I want to know how i can divide the screen into tiles of a size like 32? I am doing ...
2
votes
1answer
712 views

3d Water Simulation formula questions

I have created a Grid: At each point along the grid, is a vertex (Intersection Points): Each of these points has an x,y,z position. Vector3f(x,y,z). In an attempt to animate the grid into a group ...
1
vote
3answers
302 views

What caused rotation in exported blender model to jMonkey? (OGRE)

First off, I am very new to jMonkeyEngine 3 and still learning. Not exactly sure what could be causing my snowman to have already been rotated before import. I created him in blender and it was facing ...
5
votes
2answers
1k views

How does this formula for generating water waves work?

I have been trying to implement the wave equation described in this paper ("Water Simulating in Computer Graphics," Kai Li and Liming Wu) in Java. Part of the paper discusses modeling waves as a sum ...
2
votes
1answer
2k views

Libgdx - Collision position - Box2D

I'm actually developping my own game but i'm facing a little problem. I trying to figured out how to get the position of a fixture (collision) between two entities. For example this : ...
2
votes
0answers
54 views

How should I model rotation caused by bounce friction? [duplicate]

In my Java2D simulation, I have a disc which, when it bounces off the boundary of a 2D region, begins to rotate, as if it had gotten some spin from the wall. I'm having trouble relating the ...
-1
votes
1answer
265 views

java tile based game :tile lag fix

hi I have a game where it reads a txt file and loads a map 0 represents air and 2 represents dirt I have a class for each tile as well as a tilemap I will show u my code. the problem is it lags like ...
-1
votes
1answer
504 views

Grid based Collision Detection between circles [duplicate]

I am working on a 2d arcade game where I have 5 types of circles with different sizes: The ship, the missiles, and 3 types of monsters. This is what it looks like: Currently I'm using brute force ...
3
votes
2answers
6k views

How to update libgdx scene2d Label text dynamically?

I display a BitmapFont on the screen, update its text and the font is updated dynamically on the screen as well. I seem to fail to do the same with a scene2d Label added as actor to a Stage. The ...
0
votes
0answers
47 views

Space invaders 2d array to represent scene [duplicate]

For code optimization purposes, I want to create a 2d array that contains 40 equal squares (10x10px). Each square represents 1\40 of the displayed window (400x400px). I populate the 2d array with the ...
0
votes
2answers
195 views

Game Design: Faction/Player circular relationship

For a Java game, say I have two classes: Player, representing a player in the game. Faction, representing a faction of players in the game. When the game starts up, all factions are loaded into some ...
12
votes
2answers
2k views

How do I create a World Healing Wave effect?

I want to change my dark and depressing background to a happy grassy background, in real-time, such that the happy background is shown in a radius around a game character. A forcefield of happiness, ...
3
votes
1answer
554 views

How to have the game world get rendered on just a part of the screen?

I am implementing a game on both Desktop and Android. The Desktop version will just rely on the keyboard to handle the user input on the game screen, whilst the Android one will have to have a set ...
4
votes
1answer
1k views

unable to launch LibGDX Particle Editor.jnlp

I am not able to launch LibGDX ParticleEditor.jnlp file on my system(win7 64 bit) with java7. when I execute this file with javaws.exe in jre7/bin folder, it displays splash screen of badlogic games ...
0
votes
1answer
138 views

Game states vs calling new activities

I am trying to decide what the best method is to call "level complete-screen" and "game over-screen" in my real-time android 2d game. Currently I am using game-states and only updating my game when ...
2
votes
1answer
369 views

Invert Alpha on Image

I'm making a lighting system right now, and the last part I have to do is to invert the alpha channel on the final light map. My previous code that used to work was DataBufferByte buf = ...
-1
votes
1answer
194 views

How to swap the position of two sprites? [closed]

I'm making a game like Candy Crush with Cocos2D in Android. I've made the sprites but I want to swap to sprites by touch . How to swap the position of two sprites?
0
votes
2answers
179 views

How do I show a Quit button on Desktop but don't show it on Android with libgdx?

So I would like to display a Quit button on the Desktop main menu screen, but I wouldn't want to have it on Android too. What is the correct approach to achieve this? Do I have to check the ...
3
votes
2answers
267 views

Why aren't resources such as Pixmap disposed on finalization in LibGDX?

I've been looking at the LibGDX framework, and certain classes such as Pixmap require to be disposed manually when you are no longer using them (call the dispose method). I'm wondering, since this is ...
1
vote
1answer
160 views

Universal Tween Engine: are accessor hierarchies possible?

Background: I'm using Universal Tween Engine, which allows generic accessors to be implemented to permit tweening of arbitrary atttributes. I have a hierarchy of game entity classes that share a ...