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19. December 2014

 

In this tutorial we look at the process of creating and using a Spritesheet in LibGDX.  This involves creating a series of sprites, putting them together with TexturePacker, then using a TextureAtlas and TextureRegion to display them with our Sprite.  We also quickly look at TexturePacker ( different product ) for those that prefer a UI.  Sample code and links to included assets below the video.

 

Once again, you can view the video in HD on YouTube by click here.

 

 

Example’s Source

package com.gamefromscratch;

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Input;
import com.badlogic.gdx.InputProcessor;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.g2d.TextureAtlas;
import com.badlogic.gdx.graphics.g2d.TextureRegion;

public class SpritesheetDemo extends ApplicationAdapter implements InputProcessor {
   SpriteBatch batch;
   TextureAtlas textureAtlas;
   Sprite sprite;
   TextureRegion textureRegion;
   int currentFrame = 1;
   int MAX_FRAMES = 19;
   
   @Override
   public void create () {
      batch = new SpriteBatch();
      textureAtlas = new TextureAtlas(Gdx.files.internal("ss.txt"));
      textureRegion = textureAtlas.findRegion("0001");
      sprite = new Sprite(textureRegion);
      sprite.setPosition(Gdx.graphics.getWidth()/2 - sprite.getWidth()/2,
            Gdx.graphics.getHeight()/2 - sprite.getHeight()/2);

      Gdx.input.setInputProcessor(this);
   }

   @Override
   public void render () {
      Gdx.gl.glClearColor(0, 0, 0, 1);
      Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
      batch.begin();
      sprite.draw(batch);
      batch.end();
   }

   @Override
   public boolean keyDown(int keycode) {
      if(keycode == Input.Keys.UP){
         currentFrame++;
         if(currentFrame > MAX_FRAMES)
            currentFrame = 1;
         sprite.setRegion(textureAtlas.findRegion(String.format("%04d",currentFrame)));
      }
      if(keycode == Input.Keys.DOWN){
         currentFrame--;
         if(currentFrame < 1)
            currentFrame = MAX_FRAMES;

         sprite.setRegion(textureAtlas.findRegion(String.format("%04d",currentFrame)));
      }
      return true;
   }

   @Override
   public boolean keyUp(int keycode) {
      return false;
   }

   @Override
   public boolean keyTyped(char character) {
      return false;
   }

   @Override
   public boolean touchDown(int screenX, int screenY, int pointer, int button) {
      return false;
   }

   @Override
   public boolean touchUp(int screenX, int screenY, int pointer, int button) {
      return false;
   }

   @Override
   public boolean touchDragged(int screenX, int screenY, int pointer) {
      return false;
   }

   @Override
   public boolean mouseMoved(int screenX, int screenY) {
      return false;
   }

   @Override
   public boolean scrolled(int amount) {
      return false;
   }
}

 

The sprite art used for this example was rendered using this Blender file.

The texture packing application (near the end) was CodeAndWeb’s TexturePacker.

Programming


16. December 2014

 

This video tutorial covers handling gestures in LibGDX, this includes:

  • pinch
  • zoom
  • tap
  • pan
  • long press

 

You can view the video in full resolution on Youtube here.  The source is included below.

 

Source from this tutorial example:

package com.gamefromscratch;

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.input.GestureDetector;
import com.badlogic.gdx.math.MathUtils;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.math.Vector3;

public class GestureDemo extends ApplicationAdapter implements GestureDetector.GestureListener {
   SpriteBatch batch;
   Sprite sprite;
   OrthographicCamera camera;
   GestureDetector gestureDetector;
   
   @Override
   public void create () {
      batch = new SpriteBatch();
      sprite = new Sprite(new Texture(Gdx.files.internal("storm_trooper.png")));
      sprite.setPosition(-sprite.getWidth()/2,-sprite.getHeight()/2);
      sprite.setCenter(0.5f,0.5f);

      camera = new OrthographicCamera(1280,720);
      camera.update();

      gestureDetector = new GestureDetector(this);
      Gdx.input.setInputProcessor(gestureDetector);
   }

   @Override
   public void render () {
      Gdx.gl.glClearColor(0, 0, 0, 1);
      Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
      batch.setProjectionMatrix(camera.combined);
      batch.begin();
      sprite.draw(batch);
      batch.end();
   }

   @Override
   public boolean touchDown(float x, float y, int pointer, int button) {
      return false;
   }

   @Override
   public boolean tap(float x, float y, int count, int button) {
      if(count > 1){
         sprite.setPosition(-sprite.getWidth()/2,-sprite.getHeight()/2);
         sprite.setSize(256f,256f);
         sprite.setRotation(0f);
      }
      else {
         Vector3 touchPos = new Vector3(x, y, 0);
         camera.unproject(touchPos);
         sprite.setPosition(touchPos.x, touchPos.y);
      }
      return true;
   }

   @Override
   public boolean longPress(float x, float y) {

      Vector3 touchPos = new Vector3(x,y,0);
      camera.unproject(touchPos);

      if(sprite.getBoundingRectangle().contains(touchPos.x,touchPos.y)) {
         float alpha = sprite.getColor().a;

         if (alpha >= 0.f)
            sprite.setAlpha(alpha - 0.25f);
         else
            sprite.setAlpha(1f);
      }
      return true;
   }

   @Override
   public boolean fling(float velocityX, float velocityY, int button) {
      return false;
   }

   @Override
   public boolean pan(float x, float y, float deltaX, float deltaY) {
      Vector3 touchPos = new Vector3(x,y,0);
      camera.unproject(touchPos);

      sprite.setPosition(touchPos.x - sprite.getWidth()/2,touchPos.y - sprite.getHeight()/2);

      return true;
   }

   @Override
   public boolean panStop(float x, float y, int pointer, int button) {
      return false;
   }

   @Override
   public boolean zoom(float initialDistance, float distance) {
      sprite.setSize(distance,distance);
      return true;
   }

   @Override
   public boolean pinch(Vector2 initialPointer1, Vector2 initialPointer2, Vector2 pointer1, Vector2 pointer2)
{
float deltaX = pointer2.x - pointer1.x; float deltaY = pointer2.y - pointer1.y; float angle = (float)Math.atan2((double)deltaY,(double)deltaX) * MathUtils.radiansToDegrees; angle += 90f; if(angle < 0) angle = 360f - (-angle); sprite.setRotation(-angle); return true; } }

Programming


9. December 2014

 

In this video tutorial we look at using the different types of Cameras available, using a Camera to position your world in a device independent way.  Next we discuss the various Viewport options available for making your render results look best across a number of devices.  Since this video was released at the same time as the text version of the tutorial, I will be linking to those tutorials for code examples.

 

You can see the full 1080p video directly on YouTube or embedded below.

 

 

For the text tutorials, or for the code or assets used in this tutorial, check this tutorial on Cameras and this tutorial on Viewports.

 

Additionally, the text only tutorial also covers converting coordinates too and from your world coordinates, something I forgot to do in the video tutorial.

Programming


24. November 2014

 

In this video tutorial, we look at handling Keyboard, Mouse and Touch input in LibGDX.  We look at both handling input via polling as well as an event driven approach.

 

You can see the video in full 1080p definition here.  Once again, all the code included in the video is available below:

 

 

Polled Input Sample

package com.gamefromscratch;

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Input;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;

public class PolledInputDemo extends ApplicationAdapter {
   SpriteBatch batch;
   Texture img;
   Sprite sprite;
   
   @Override
   public void create () {
      batch = new SpriteBatch();
      img = new Texture("badlogic.jpg");
      sprite = new Sprite(img);
      sprite.setPosition(Gdx.graphics.getWidth()/2 - sprite.getWidth()/2,
            Gdx.graphics.getHeight()/2 - sprite.getHeight()/2);
   }

   @Override
   public void render () {

      // Keyboard events
      if(Gdx.input.isKeyPressed(Input.Keys.LEFT))
         sprite.translateX(-1f);
      if(Gdx.input.isKeyPressed(Input.Keys.RIGHT))
         sprite.translateX(1f);
      if(Gdx.input.isKeyPressed(Input.Keys.SPACE))
         sprite.setPosition(Gdx.graphics.getWidth()/2 - sprite.getWidth()/2,
               Gdx.graphics.getHeight()/2 - sprite.getHeight()/2);

      if(Gdx.input.isButtonPressed(Input.Buttons.RIGHT))
         sprite.setPosition(Gdx.input.getX(),Gdx.graphics.getHeight() - Gdx.input.getY());


      Gdx.gl.glClearColor(0, 0, 0, 1);
      Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
      batch.begin();
      batch.draw(sprite, sprite.getX(), sprite.getY());
      batch.end();
   }

   @Override
   public void dispose(){
      img.dispose();
   }
}

Event Driven Input Sample

package com.gamefromscratch;

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Input;
import com.badlogic.gdx.InputProcessor;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;

public class EventDrivenInputDemo extends ApplicationAdapter implements InputProcessor {
   SpriteBatch batch;
   Texture img;
   Sprite sprite;
   boolean movingRight = false;
   
   @Override
   public void create () {
      batch = new SpriteBatch();
      img = new Texture("badlogic.jpg");
      sprite = new Sprite(img);
      sprite.setPosition(Gdx.graphics.getWidth()/2-sprite.getWidth()/2,
            Gdx.graphics.getHeight()/2 - sprite.getHeight()/2);

      Gdx.input.setInputProcessor(this);
   }

   @Override
   public void render () {

      if(movingRight)
         sprite.translateX(1f);
      Gdx.gl.glClearColor(0, 0, 0, 1);
      Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
      batch.begin();
      batch.draw(sprite, sprite.getX(),sprite.getY());
      batch.end();
   }

   @Override
   public boolean keyDown(int keycode) {
      if(keycode == Input.Keys.RIGHT)
         movingRight = true;
      return true;
   }

   @Override
   public boolean keyUp(int keycode) {
      if(keycode == Input.Keys.LEFT)
         sprite.translateX(-1f);
      if(keycode == Input.Keys.RIGHT)
         movingRight = false;
      return true;
   }

   @Override
   public boolean keyTyped(char character) {
      return false;
   }

   @Override
   public boolean touchDown(int screenX, int screenY, int pointer, int button) {
      return false;
   }

   @Override
   public boolean touchUp(int screenX, int screenY, int pointer, int button) {
      return false;
   }

   @Override
   public boolean touchDragged(int screenX, int screenY, int pointer) {
      // If the user is holding down ( or was holding down, and hasnt released ) three fingers, move the sprite
      if(pointer ==2)
         sprite.setPosition(screenX,Gdx.graphics.getHeight()-screenY);
      return true;
   }

   @Override
   public boolean mouseMoved(int screenX, int screenY) {
      sprite.setPosition(screenX,Gdx.graphics.getHeight()-screenY);
      return true;
   }

   @Override
   public boolean scrolled(int amount) {
      if(amount > 0)
         sprite.translateY(1f);
      if(amount < 0)
         sprite.translateY(-1f);

      return true;
   }
}

Programming


21. November 2014

 

In the last video tutorial we used a graphic instead of text to create a Hello World.  This is because drawing text is actually a multi step process in LibGDX and not really appropriate for a first tutorial.  It is however perfect for a second tutorial, so here we are! ;)

 

In this video we explore the difference between TTF and Bitmap fonts, show how to run the Hiero font generation tool in both Eclipse and IntelliJ IDEA then create and save a bitmap font.  We then explore the code needed to show a bitmap font on screen, including how to measure the results, apply color and text justification.

 

The video is available in up to 1080P on YouTube by clicking here.

 

The source code:

Initial Example – Loading a font and drawing text:

package com.gamefromscratch;

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.g2d.BitmapFont;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;

public class gdxtext extends ApplicationAdapter {
   SpriteBatch batch;
    BitmapFont font;

   @Override
   public void create () {
      batch = new SpriteBatch();
        font = new BitmapFont(Gdx.files.internal("Papy.fnt"));
   }

   @Override
   public void render () {
      Gdx.gl.glClearColor(0, 0, 0, 1);
      Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
      batch.begin();

        //Example One -- Drawing Text
        font.draw(batch,"Hello World",Gdx.graphics.getWidth()/2,Gdx.graphics.getHeight()/2);

        batch.end();
   }
}

 

Example 2 – Measuring and centering text:

BitmapFont.TextBounds bounds = font.getBounds("Hello World");
font.draw(batch,"Hello World",
       Gdx.graphics.getWidth()/2 - bounds.width/2,
       Gdx.graphics.getHeight()/2 + bounds.height/2);

Example 3 – Multi-line Text

String debugString = "I took one, one cause you left me\n"
           + "Two, two for my family\n"
           + "Three, three for my heartache\n"
           + "Four, four for my headaches\n"
           + "Five, five for my sorrow\n";
   BitmapFont.TextBounds bounds = font.getMultiLineBounds(debugString);

 

Example 4 -- Center justified text in the colour purple

    font.setColor(Color.PURPLE);
    font.drawMultiLine(batch,
            debugString,
            0,
            Gdx.graphics.getHeight()/2 + bounds.height/2,
            Gdx.graphics.getWidth(),
            BitmapFont.HAlignment.CENTER
            );

Programming


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