Saturday, March 30, 2013

could not run Android's adb on Linux 64bit

I tried to install Android ADT and SDK on 64bit Linux (CrunchBang linux).  Once it's all downloaded and installed, Eclipse said it could not run adb.

To get it going, I found on stackoverflow that you will need to install ia32-libs package.

# apt-get install ia32-libs

However, when I tried, it failed.  apt-get reported that ia32-libs depends on ia32-libs-i386, but ia32-libs-i386 can not be installed.

To make ia32-libs to install, i386 arch has to be added first.

# dpkg --add-architecture i386
# apt-get update

After that, installing ia32-libs should go though.

Wednesday, March 27, 2013

cocos2d-html5 setOpacity doesn't work?

I am trying out cocos2d-html5 and implementing a game similar to Word Drift so people can try it on the web.  At one point I want to make a sprite transparent initially.  So I do this: = cc.Sprite.create("res/select.png");, 65/2);;

but it doesn't work.  The sprite is still showing on screen.  Turn out that, to make it works, the image has to be preloaded.  That is, if you using the project template bundled within cocos2d-html5 package,  you will have to put this image in g_resource in resource.js

var s_select = "res/select.png";
var g_ressources = [ {type:"image", src:s_select} ];

The images in g_resources get loaded in main.js


and that makes setOpacity() works.

I'm sure there are documents somewhere explaining why the images needs to be preloaded, but I'm too lazy to find it out for now.  It's more fun coding than hunting for document :)  Anyway if you know why please post it in the comment.

Thursday, March 14, 2013

Basic momentum scrolling implementation with AndEngine

This is the simple implementation of momentum scrolling with AndEngine I did for Word Drift, a word puzzle game I made a few months ago.

It is working OK, so if you want to use it as-is, feel free to do so.  If you want to modify it, please do, but if possible, please post the modify code in the comment so everybody can benefit.

If you are actually thinking about modifying it, please do low/high pass filter to smooth out the accel value.  Currently I just average out the accel value with its previous two values.

Once that's done, maybe a rubber-band effect or something similar to it.

Here's how it looks.

Here's the code.

public class MainActivity extends SimpleBaseGameActivity implements IScrollDetectorListener, IOnSceneTouchListener {
 private static final float FREQ_D = 120.0f;
 private static final int STATE_WAIT = 0;
 private static final int STATE_SCROLLING = 1;
 private static final int STATE_MOMENTUM = 2;
 private static final int STATE_DISABLE = 3;
 private static final int WRAPPER_HEIGHT = 1260;
 private static final float MAX_ACCEL = 5000;

 private static final double FRICTION = 0.96f;
 private TimerHandler thandle;
 private int mState = STATE_DISABLE;
 private double accel, accel1, accel0;
 private float mCurrentY;
 private IEntity mWrapper;
 private SurfaceScrollDetector mScrollDetector;
 private long t0;
 public EngineOptions onCreateEngineOptions() {
  final Camera camera = new Camera(0, 0, 480, 800);
  final EngineOptions eo = new EngineOptions(true, ScreenOrientation.PORTRAIT_SENSOR, 
       new RatioResolutionPolicy(480, 800), camera);
  return eo;

 protected void onCreateResources() {
  thandle = new TimerHandler(1.0f / FREQ_D, true, new ITimerCallback() {
   public void onTimePassed(final TimerHandler pTimerHandler) {

 protected Scene onCreateScene() {
  Scene scene = new Scene();
  scene.setBackground(new Background(0.1f, 0.1f, 0.1f));
  mScrollDetector = new SurfaceScrollDetector(this);
  mWrapper = new Entity(0, 0);
  for (int i = 0; i < 20; i++) {
   Rectangle r = new Rectangle(17.5f, i * 100 + 20, 445, 80, getVertexBufferObjectManager());
  mState = STATE_WAIT;
  return scene;

 public boolean onSceneTouchEvent(Scene pScene, TouchEvent pSceneTouchEvent) {
  if (mState == STATE_DISABLE)
   return true;
  if (mState == STATE_MOMENTUM) {
   accel0 = accel1 = accel = 0;
   mState = STATE_WAIT;

  return true;

 public void onScrollStarted(ScrollDetector pScollDetector, int pPointerID, float pDistanceX, float pDistanceY) {
  t0 = System.currentTimeMillis();

 public void onScroll(ScrollDetector pScollDetector, int pPointerID, float pDistanceX, float pDistanceY) {
  long dt = System.currentTimeMillis() - t0;
  if (dt == 0)
  double s =  pDistanceY / (double)dt * 1000.0;  // pixel/second
  accel = (accel0 + accel1 + s) / 3;
  accel0 = accel1;
  accel1 = accel;
  t0 = System.currentTimeMillis();

 public void onScrollFinished(ScrollDetector pScollDetector, int pPointerID, float pDistanceX, float pDistanceY) {

 protected synchronized void doSetPos() {
  if (accel == 0) {
  if (mCurrentY > 0) {
   mCurrentY = 0;
   mState = STATE_WAIT;
   accel0 = accel1 = accel = 0;
  if (mCurrentY < -WRAPPER_HEIGHT) {
   mCurrentY = -WRAPPER_HEIGHT;
   mState = STATE_WAIT;
   accel0 = accel1 = accel = 0;
  mWrapper.setPosition(0, mCurrentY);

  if (accel < 0 && accel < -MAX_ACCEL)
   accel0 = accel1 = accel = - MAX_ACCEL;
  if (accel > 0 && accel > MAX_ACCEL)
   accel0 = accel1 = accel = MAX_ACCEL;
  double ny = accel / FREQ_D;
  if (ny >= -1 && ny <= 1) {
   mState = STATE_WAIT;
   accel0 = accel1 = accel = 0;
  if (! (Double.isNaN(ny) || Double.isInfinite(ny)))
   mCurrentY += ny;
  accel = (accel * FRICTION);


Thursday, March 7, 2013

PicSlide - picture sliding puzzle

This is a third game running on the same engine, the previous two are Word Drift and wordest.  However, this one is not a word game.  It is a classic sliding game, sometimes called 15-puzzle.  However, instead of rearrange the numbers, it use pictures instead.  I have been taking pictures for years, and finally I found the way to put those pictures to work :)

The sliding puzzle is a good little game to kill time.  You can get it at