how to use android sensors

8/13/2019 How to Use Android Sensors

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How to use Android sensors? This article teaches how to use Android sensors.

The Android sensors are hardware devices. Android provides a manager to control the

devices.User should register the devices you want to use by the manager. And implements the

callback functions for the sensor event alert.

Step1:We create a new class for the sensors. This is a reusable class.

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public class SensorController implements SensorEventListener{ public SensorController(Context context) { } @Override public void onAccuracyChanged(Sensor arg0, int arg1){

// TODO Auto-generated method stub } @Override public void onSensorChanged(SensorEvent arg0){ // TODO Auto-generated method stub } }

Step2:The class implements two interface for the sensor events.In the class constructor

we need the Context to get the sensor manager.

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private SensorManager mSensorManager = null;

public SensorController(Context context) { mSensorManager =

(SensorManager)context.getSystemService(context.SENSOR_SERVICE); registerSensor();

}

Step3:Create the registerSensor() function to register the sensors.At this example i

register the magnetic and accelerometer. These two sensor can combined to create a compass on

Android.

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private Boolean sensorRegisteredFlag = false; private void registerSensor() { if(mSensorManager != null) { List<sensor> sensors = mSensorManager.getSensorList(Sensor.TYPE_MAGNETIC_FIELif(sensors.size() > 0) { Sensor sensor = sensors.get(0); //if(!mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DE

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if(!mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAYSENSOR_DELAY_NORMAL

{ return; } } sensors = mSensorManager.getSensorList(Sensor.TYPE_ACCELEROMETER); if(sensors.size() > 0) { Sensor sensor = sensors.get(0); //if(!mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DE

if(!mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAYSENSOR_DELAY_NORMAL

{ return; } } sensorRegisteredFlag = true;

} }

</sensor> Step4:The onAccuracyChanged() method is called when the sensor accuracy has changed. The

first parameter is the sensor of the registered. And the other parameter is the new accuracy

of the sensor.There are four value of the accuracy.At this example we does not care thechanges.

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SensorManager.SENSOR_STATUS_ACCURACY_HIGH// This sensor is reporting data with maximum accuracy

SensorManager.SENSOR_STATUS_ACCURACY_MEDIUM// This sensor is reporting data with an average level of accuracy,

// calibration with the environment may improve the readings

SensorManager.SENSOR_STATUS_ACCURACY_LOW// This sensor is reporting data with low accuracy,// calibration with the environment is needed

SensorManager.SENSOR_STATUS_UNRELIABLE// The values returned by this sensor cannot be trusted,// calibration is needed or the environment doesn't allow readings

Step5:The onSensorChanged() method is whole thing we want.We collect the magnetic and

accelerometer values and convert to the human readable values.

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private final double RADIANS_TO_DEGREES = 180/Math.PI; private final float[] sZVector = { 0, 0, 1, 1 }; private float R[] = new float[16]; private float remapR[] = new float[16]; private float remapR_inv[] = new float[16]; private float AccelerometerValues_last[] = new float[3]; private float MagneticFieldValues_last[] = new float[3]; private float orientationValues[] = new float[3];









private float orientationVector[] = new float[4]; private float azimuthVector[] = new float[4]; boolean bHaveAccelerometer = false; boolean bHaveMagneticField = false; private float orientation;//up direction private float azimuth;//aim to north private float pitch;

public void onSensorChanged(SensorEvent event){ if(event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) { MagneticFieldValues_last[0] = event.values[0]; MagneticFieldValues_last[1] = event.values[1]; MagneticFieldValues_last[2] = event.values[2];

bHaveMagneticField = true; } if(event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) { AccelerometerValues_last[0] = event.values[0]; AccelerometerValues_last[1] = event.values[1]; AccelerometerValues_last[2] = event.values[2];

bHaveAccelerometer = true; } if(bHaveMagneticField && bHaveAccelerometer) { if(SensorManager.getRotationMatrix(R, null, AccelerometerValues_last,

MagneticFieldValues_last)) { SensorManager.remapCoordinateSystem(R, SensorManager.AXIS_Y, SensorManager.AX

remapR);

SensorManager.getOrientation(remapR, orientationValues);

Matrix.multiplyMV(orientationVector, 0, remapR, 0, sZVector, 0); pitch = (float) (-Math.atan2(orientationVector[1], orientationVector[2]) *

RADIANS_TO_DEGREES);

Matrix.multiplyMV(orientationVector, 0, remapR, 0, sZVector, 0); orientation = (float) (-Math.atan2(orientationVector[0], orientationVector[1]

RADIANS_TO_DEGREES);

Matrix.invertM(remapR_inv, 0, remapR, 0); Matrix.multiplyMV(azimuthVector, 0, remapR_inv, 0, sZVector, 0); azimuth = (float) (180 + Math.atan2(azimuthVector[0], azimuthVector[1]) *

RADIANS_TO_DEGREES); } } }

Step6:Three important values we want are ready. Provide get method for the other class.

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public boolean getNowOrientation(float [] retValues){ retValues[0] = pitch; retValues[1] = orientation; retValues[2] = azimuth; return true; }

Step7:Implement the on action methods.

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public void onResume() { registerSensor(); }

public void onPause() { if(mSensorManager != null && sensorRegisteredFlag) { mSensorManager.unregisterListener(this); } }

Step8:Back to the main activity class.Create a thread to get the values and refresh the

values periodically.

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public class MySensors extends Activity{

private SensorController MySensors = null; private Handler mHandler = new Handler(Looper.getMainLooper()); private TextView NowText = null;

@Override public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.main);

MySensors = new SensorController(this);

NowText = (TextView)findViewById(R.id.TextView01);

mHandler.postDelayed(ReadSensorValues, 300); }

private Runnable ReadSensorValues = new Runnable(){ float orientationValues[] = new float[3]; public void run(){









MySensors.getNowOrientation(orientationValues);

NowText.setText("pitch:" + orientationValues[0] + "\n" + "orientation:" + orientationValues[1] + "\n" + "azimuth:" + orientationValues[2]);

mHandler.postDelayed(ReadSensorValues, 100); }}; protected void onResume() { super.onResume(); MySensors.onResume(); }

protected void onPause() { super.onPause(); MySensors.onPause();

}}

Step9:Run the application, you should see the values beat in the TextView.

How to use camera in Android? This article teaches how to use Android camera.

Step1:Camera preview needs a surface to show.And needs some callback function to handle

the take picture processes.We create a class named CameraPreivew, and implement the SurfaceHolder.Callback and

CameraPreviewCallback.

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http://ibuzzlog.blogspot.com/2012/08/how-to-use-camera-in-android.html




http://4.bp.blogspot.com/-cqh4QpYw-h4/UCHZiLE-oaI/AAAAAAAAAOs/UrU46Y_PRJg/s1600/device.png





public class CameraPreview implements SurfaceHolder.Callback,Camera.PreviewCallback {

public CameraPreview(int PreviewlayoutWidth, int PreviewlayoutHeight) { // TODO }@Override public void onPreviewFrame(byte[] arg0, Camera arg1){ // At preview mode, the frame data will push to here. // But we do not want these data. }

@Override public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3)

{ // TODO Auto-generated method stub }

@Override public void surfaceCreated(SurfaceHolder arg0){ // TODO Auto-generated method stub }

@Override public void surfaceDestroyed(SurfaceHolder arg0){

// TODO Auto-generated method stub }

// Take picture interface public void CameraTakePicture(String FileName) { // TODO}

// Set auto-focus interface public void CameraStartAutoFocus() { // TODO

} }

Step2: At the class constructor, we set the preview size.

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public CameraPreview(int PreviewlayoutWidth, int PreviewlayoutHeight) { PreviewSizeWidth = PreviewlayoutWidth; PreviewSizeHeight = PreviewlayoutHeight; }

Step3:At the SurfaceHolder callback functions, we handle the camera instance.

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@Override public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3){ Parameters parameters; mSurfHolder = arg0;

parameters = mCamera.getParameters(); // Set the camera preview size parameters.setPreviewSize(PreviewSizeWidth, PreviewSizeHeight); // Set the take picture size, you can set the large size of the camera

supported. parameters.setPictureSize(PreviewSizeWidth, PreviewSizeHeight);

// Turn on the camera flash.String NowFlashMode = parameters.getFlashMode(); if ( NowFlashMode != null ) parameters.setFlashMode(Parameters.FLASH_MODE_ON); // Set the auto-focus.String NowFocusMode = parameters.getFocusMode (); if ( NowFocusMode != null ) parameters.setFocusMode("auto");

mCamera.setParameters(parameters);

mCamera.startPreview(); }

@Override public void surfaceCreated(SurfaceHolder arg0){ mCamera = Camera.open(); try { // If did not set the SurfaceHolder, the preview area will be black. mCamera.setPreviewDisplay(arg0); mCamera.setPreviewCallback(this);

}catch (IOException e) { mCamera.release(); mCamera = null; } }

@Override public void surfaceDestroyed(SurfaceHolder arg0)






{ mCamera.setPreviewCallback(null); mCamera.stopPreview(); mCamera.release(); mCamera = null; }

Step4:In the PreviewCallback, we call the myAutoFocusCallback to handle the take picture

processes after the auto-focus.

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// Take picture interface public void CameraTakePicture(String FileName) {

TakePicture = true; NowPictureFileName = FileName; mCamera.autoFocus(myAutoFocusCallback); }

// Set auto-focus interface public void CameraStartAutoFocus() { TakePicture = false; mCamera.autoFocus(myAutoFocusCallback); }

Step5:Create a instance to implement the AutoFocusCallback.

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AutoFocusCallback myAutoFocusCallback = new AutoFocusCallback() { public void onAutoFocus(boolean arg0, Camera NowCamera){ if ( TakePicture ) { NowCamera.stopPreview();//fixed for Samsung S2 NowCamera.takePicture(shutterCallback, rawPictureCallback,

jpegPictureCallback);

TakePicture = false; } } };

Step6:Implement 3 callback instance to handle the takepicture processes.

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ShutterCallback shutterCallback = new ShutterCallback() { public void onShutter(){ // Just do nothing. } };

PictureCallback rawPictureCallback = new PictureCallback() { public void onPictureTaken(byte[] arg0, Camera arg1){ // Just do nothing. } };

PictureCallback jpegPictureCallback = new PictureCallback() { public void onPictureTaken(byte[] data, Camera arg1){ // Save the picture. try { Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0,data.length); FileOutputStream out = new FileOutputStream(NowPictureFileName); bitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);

}catch (IOException e){ e.printStackTrace();

} }

};

Step7:The camera basic function we all implemented, now we go back to the main activity

to use the CameraPreview.

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public class MyCamera extends Activity { private CameraPreview camPreview;private FrameLayout mainLayout;

private Handler mHandler = new Handler(Looper.getMainLooper());

@Override public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); //Set this SPK Full screen getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);






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//Set this APK no title requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.main);

SurfaceView camView = new SurfaceView(this); SurfaceHolder camHolder = camView.getHolder();

camPreview = new CameraPreview(640, 480);

camHolder.addCallback(camPreview); camHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

mainLayout = (FrameLayout) findViewById(R.id.frameLayout1); mainLayout.addView(camView, new LayoutParams(640, 480)); }

@Override public boolean onTouchEvent(MotionEvent event){if (event.getAction() == MotionEvent.ACTION_DOWN)

{int X = (int)event.getX();if ( X >= 640 ) mHandler.postDelayed(TakePicture, 300); else camPreview.CameraStartAutoFocus();

} return true; };

private Runnable TakePicture = new Runnable(){ String extStorageDirectory =

Environment.getExternalStorageDirectory().toString(); String MyDirectory_path = extStorageDirectory; String PictureFileName; public void run(){ File file = new File(MyDirectory_path); if (!file.exists())file.mkdirs(); PictureFileName = MyDirectory_path + "/MyPicture.jpg"; camPreview.CameraTakePicture(PictureFileName);

} };}

Step8:The code is all done here, now is to setup the Android configuration to active the

Camera hardware.Edit AndroidManifest.xml to active the function we need.

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<manifest android:versioncode="1" android:versionname="1.0" package="my.project.Mxmlns:android="http://schemas.android.com/apk/res/android">

<uses -sdk="-sdk" android:minsdkversion="8"> <uses -feature="-feature" android:name="android.hardware.camera">

<uses -feature="-feature" android:name="android.hardware.camera.autofocus">

<uses -permission="-permission" android:name="android.permission.CAMERA"></us<uses -permission="-permission" android:name="android.permission.WRITE_EXTERNAL_

<uses -permission="-permission" android:name="android.permission.FLASHLIGHT">

<application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:label="@string/app_name" android:name=".MyCamera" andro

<intent -filter="-filter"> <action android:name="android.intent.action.MAIN"> <category android:name="android.intent.category.LAUNCHER">

</category></action></intent> </activity>

</application> </uses></uses></uses></uses></manifest>

Step9:And the layout file main.xml should be simple like this.

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<framelayout android:id="@+id/frameLayout1" android:layout_height="fill_parent" andrxmlns:android="http://schemas.android.com/apk/res/android"> </framelayout>

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Labels: Android

2012/08/01

How to use Runnable in Android? This article teaches how to use Runnable class in Android.

There are two ways to use thread class.

One is directly used in the Thread.

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new Thread(new Runnable(){

@Override public void run(){

//Do things. }

}).start();

http://schemas.android.com/apk/res/android





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Clicking finish button. A new project in the workspace.

http://4.bp.blogspot.com/-VYWuWnP5xJQ/UBH5eBIN7tI/AAAAAAAAAOA/6JK0Oc_yUIU/s1600/MyFirstJNI_2.PNG



Step3:Manually create 2 directories in the project directory, JNI and libs.

Step4:Creating Andoird.mk file in the JNI directory.Android.mk is just a text file.

Android.mk file contents:

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LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := first-jni LOCAL_SRC_FILES := first-jni.cpp include $(BUILD_SHARED_LIBRARY)

Step5:Creating your jni C/C++ file in the JNI directory.Aftercompile the jni code

successfully . There is a dynamatic link library(libfirst-jni.so) will be created in the libs

directory we create manually before.The jni code has two different type, C and C++.The difference is C++ file must export it's JNI

function to C.

The code explains it self.

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/* * first-jni.c */ #include <string.h>

#include <jni.h>

jstring Java_my_project_MyFirstJNI_MyFirstJNI_stringFromJNI( JNIEnv* env,

jobject thiz ) {

return (*env)->NewStringUTF(env, "My first JNI!"); }

<

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/*

* first-jni.cpp */ #include <string.h>#include <jni.h>

extern "C" jstring Java_my_project_MyFirstJNI_MyFirstJNI_stringFromJNI( JNIEnv* env,

jobject thiz ) {












return env->NewStringUTF("My first JNI!"); }

Step6:The JNI function name has rules.Refer to this link Naming_Functions.

Java_{Package name Replace dot with underline}_{Class name}_{function name}() ,

In my example will be the "Java_my_project_MyFirstJNI_MyFirstJNI_stringFromJNI","my_project_MyFirstJNI" is the package name, "package my.project.MyFirstJNI;""MyFirstJNI" is my jni file class name.

"stringFromJNI" is the jni function name for JAVA to call.

Step7:Now we had create our own jni function.Press F5 to refresh the Eclipse.

http://code.google.com/p/awesomeguy/wiki/JNITutorial#Naming_Functions


http://2.bp.blogspot.com/-Y2X7LiIKnAY/UBH5fCkudXI/AAAAAAAAAOI/C_FUuU0doTY/s1600/MyFirstJNI_3.PNG




Step8:Setup the Auto-build configuration, Please flow the steps in this article How

to install Android NDK on windows. Starting from Step11.

Step9:Modify the JAVA code to call our JNI function.

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package my.project.MyFirstJNI;

import android.app.Activity; import android.os.Bundle; import android.widget.TextView;

public class MyFirstJNI extends Activity{

// Called when the activity is first created. @Override public void onCreate(Bundle savedInstanceState){

super.onCreate(savedInstanceState); TextView tv = new TextView(this); tv.setText( stringFromJNI() ); setContentView(R.layout.main);

} // A native method that is implemented by the // 'first-jni' native library, which is packaged // with this application. //

public native String stringFromJNI();

// this is used to load the 'first-jni' library on application // startup. The library has already been unpacked into // /data/data/my.project.MyFirstJNI/libs/libfirst-jni.so at // installation time by the package manager. // static {

System.loadLibrary("first-jni"); }

}

http://ibuzzlog.blogspot.tw/2012/07/how-to-install-android-ndk-on-windows.html










Final Step:Run the project in emulator, the screen will show the string "My

first JNI!".

How to use OpenGL in Android This article teaches how to use OpenGL in Android phone.

There are two classes must be create and implement GLSurfaceView and Renderer.

The article OpenGL explains classes do. I just focus the implement step.

Step1:Create a new project in the Eclipse. I supposed that you already known how.

Step2:.Modify the layout file "main.xml".

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<?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" android:id="@+id/frameLayout1">

</FrameLayout>

Step3:Create a new class i named OpenGLRenderer.The class must implement the

Renderer class.

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package my.project.MyFirstOpenGL;

import javax.microedition.khronos.egl.EGLConfig;

import javax.microedition.khronos.opengles.GL10;

import android.content.Context; import android.opengl.GLSurfaceView.Renderer; import android.widget.FrameLayout;

public class OpenGLRenderer implements Renderer { public OpenGLRenderer(Context context, FrameLayout mainLayout) {

http://ibuzzlog.blogspot.com/2012/07/how-to-use-opengl-in-android.html


http://developer.android.com/guide/topics/graphics/opengl.html















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}

@Override public void onDrawFrame(GL10 arg0){ // TODO Auto-generated method stub

}

@Override public void onSurfaceChanged(GL10 arg0, int arg1, int arg2){ // TODO Auto-generated method stub

}

@Override public void onSurfaceCreated(GL10 arg0, EGLConfig arg1){

// TODO Auto-generated method stub

}

}

Step4:In the OpenGLRenderer constructor, we need the Context and FrameLayout

parameters. And create the GLSurfaceView add to the frameLayout.

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public OpenGLRenderer(Context context, FrameLayout mainLayout) {this.context = context; // // Create GLSurfaceView and set this class as the renderer. // GLSurfaceView glView = new GLSurfaceView(context); glView.setRenderer(this);

//put to Main layout mainLayout.addView(glView, new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT)); }






Step5:Put some basic OpenGL code to the other functions.

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public void onDrawFrame(GL10 gl){ // Clear the whole screen and depth. gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);

// Setting the GL_MODELVIEW matrix gl.glMatrixMode(GL10.GL_MODELVIEW);// Load the Identity matrix gl.glLoadIdentity(); }

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public void onSurfaceChanged(GL10 gl, int width, int height){ // Set OpenGL viewport gl.glViewport(0, 0, width, height);

// Setting the GL_PROJECTION matrix gl.glMatrixMode(GL10.GL_PROJECTION); // Load the Identity matrix gl.glLoadIdentity();

float ratio = (float) width / height; // Set the fovy to 45 degree. near depth is 0.1f and far depth is 100.f.

// And maintain the screen ratio. GLU.gluPerspective(gl, 45, ratio, 0.1f, 100.f); }

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public void onSurfaceCreated(GL10 gl, EGLConfig arg1){ // Set the background to black gl.glClearColor(0, 0, 0, 0); }

Step6:And now we can add OpenGLRenderer class to the main code.

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public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.main); FrameLayout mainLayout = (FrameLayout) findViewById(R.id.frameLayout1);















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// // Create OpenGL surface and render //OpenGLRenderer gl3DView = new OpenGLRenderer(this, mainLayout);

}

Step7:OK, We put the necessarily code to the project.Now we can run this

project on emulator.But there is nothing in the screen but the black.

Step8:At this stage, we create a OpenGL environment, but we did not put

things in there.

I want load a picture and map to a plane , then rotate it.

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http://4.bp.blogspot.com/-NSy_dK4PDlo/UA-lybNSx5I/AAAAAAAAAL4/jRkfI6A1180/s1600/MyFirstOpenGl_1.png




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// // Load the Texture // private void LoadTexture(GL10 gl, Context cont)

{ gl.glTexParameterf(GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MAG_FILTER,GL10.GL_LINEAR);

InputStream istream = cont.getResources().openRawResource(R.drawable.guam);

Bitmap bitmap; try{ bitmap = BitmapFactory.decodeStream(istream);

} finally{ try{ istream.close();

} catch(IOException e){} }gl.glGenTextures(MAX_TEXTURE, textureID, 0); gl.glBindTexture(GL10.GL_TEXTURE_2D, textureID[0]); GLUtils.texImage2D( GL10.GL_TEXTURE_2D, 0, bitmap, 0 );gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER,

GL10.GL_LINEAR);

bitmap.recycle(); mTextureBuffer = getNativeFloatBuffer(squTex); mVerticesBuffer = getNativeFloatBuffer(squVtx); mIndexBuffer = getNativeShortBuffer(squInx);

}

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// // Draw the scene // private void DrawTheScene(GL10 gl) {gl.glEnable( GL10.GL_TEXTURE_2D); gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

gl.glVertexPointer( 3, GL10.GL_FLOAT, 0, mVerticesBuffer); gl.glTexCoordPointer( 2, GL10.GL_FLOAT, 0, mTextureBuffer);

gl.glBindTexture(GL10.GL_TEXTURE_2D, textureID[0]);

gl.glDrawElements( GL10.GL_TRIANGLE_FAN, squInx.length,

GL10.GL_UNSIGNED_SHORT,mIndexBuffer);






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gl.glDisable(GL10.GL_TEXTURE_2D); gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); }

Step9:We need some variables.

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private float orientation = 0.0f;;

final int MAX_TEXTURE = 20;

private int[] textureID = new int[MAX_TEXTURE];

// UV Coordinates// _________// v0(0,0) | | v3(1,0)// | | // | | // v1(0,1) |_________| v2(1,1) // // // plane vertices // _________

// p0 | | p3// | | // | | // p1 |_________| p2 //

float squVtx[] = {-1.0f, 1.0f, 0.0f, //p0 Left-Top corner -1.0f, -1.0f, 0.0f, //p1 Left-bottom corner1.0f, -1.0f, 0.0f, //p2 Right-bottom corner1.0f, 1.0f, 0.0f };//p3 Right-top corner

// USE GL_TRIANGLE_FAN

short squInx[] = { 0, 1, 2, 3}; //0-1-2 first triangle //0-2-3 second trianglefloat squTex[] ={ 0.0f, 0.0f, //v0 Left-Top corner

0.0f, 1.0f, //v1 Left-bottom corner1.0f, 1.0f, //v2 Right-top corner 1.0f, 0.0f };//v3 Right-bottom corner

// Our UV texture buffer. private FloatBuffer mTextureBuffer;private FloatBuffer mVerticesBuffer;






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private ShortBuffer mIndexBuffer;

Step10:Add LoadTexture() and DrawTheScene() to the code.

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public void onSurfaceCreated(GL10 gl, EGLConfig arg1){ // Set the background to black gl.glClearColor(0, 0, 0, 0);

//Load the texture LoadTexture(gl, context);}

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public void onDrawFrame(GL10 gl){ // Clear the whole screen and depth. gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);

// Setting the GL_MODELVIEW matrix gl.glMatrixMode(GL10.GL_MODELVIEW);// Load the Identity matrix gl.glLoadIdentity();

// Move to Z = -10 gl.glTranslatef(0, 0, -10f); // Rotate y-asix gl.glRotatef(orientation, 0, 1.0f, 0);

//every time plus 1 defgee. orientation += 1.0f; if ( orientation >= 360 ) orientation = 0.0f;

// Draw the scene DrawTheScene(gl); }









Step11:Another functions.

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private FloatBuffer getNativeFloatBuffer(float[] buffer) { ByteBuffer ibb = ByteBuffer.allocateDirect(buffer.length*4); ibb.order(ByteOrder.nativeOrder()); FloatBuffer fbf = ibb.asFloatBuffer();

fbf.put(buffer); fbf.position(0); return fbf; }

private ShortBuffer getNativeShortBuffer(short[] buffer)

{ ByteBuffer ibb = ByteBuffer.allocateDirect(buffer.length*2); ibb.order(ByteOrder.nativeOrder()); ShortBuffer sbf = ibb.asShortBuffer();

sbf.put(buffer); sbf.position(0); return sbf; }

Step12:Finally, we put the picture to the OpenGL texture resources and

draw 2 triangles to show the picture. Then rotate it frame by fame.



http://4.bp.blogspot.com/-JDmdRWYBUo0/UA-5_F4HufI/AAAAAAAAAME/7CXSXDGK128/s1600/MyFirstOpenGL.gif


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