Cant find suitable example for android 2d opengl s

Question

As SpriteMethodTest says there are many ways for drawing sprites. First i tried canvas and had some performance problems. Than i decided to learn opengl. I made my first achievements using GL11Ext extension. but you know by default when you draw textures they are flipped and the x and y axis have zero on the bottom left corner of device screen (in landscape mode) not like the canvas and you cant rotate sprites.

Than i tried to affect this axis view using GLU look at. But had not effect.

Than i wanted to rotate my sprites and had not effect cause of GL11Ext as they say.

So i have the major stackoverflow condition now and the basic question is:

1. Which method to use to achieve ZOOMING, ROTATING and BOUNCING effects on sprites and for LOOKING AT X AND Y AXIS IN OLD SWEET WAY [(0,0) IS ON TOP LEFT IN LANDSCAPE MODE] ?

2. AND IS THERE SOME SPRITE CLASS EXAMPLE IN THE UNIVERSE WICH USES ONLY 1 GOOD WAY OF SPRITE RENDERING ? (SpriteMethodTest confuses me much)

Answer 1

EVRIKA !!!

I was allmost killing myself ! after 3 days of leaving Canvas and learning OpenGL methods to implement game engine.

The web is full of OpenGL tutorials full of trash and many of them are unfinished and many of them lead to wrong way for 2D OpenGL game engine implementation methotds. The big wrong point is using G11Ext for making games. AS THEY DONT ROTATE : D

Annd annd then i found this tutorial from other tutorial which i found from youtube game sample video link lol:

not to confuse viewers here is

Chapter 1: http://obviam.net/index.php/opengl-es-with-android-switching-from-canvas-to-opengl/

Chapter 2: http://obviam.net/index.php/opengl-es-android-displaying-graphical-elements-primitives/

Chapter 3: http://obviam.net/index.php/texture-mapping-opengl-android-displaying-images-using-opengl-and-squares/

Annd just 15 minutes ago I discovered the way I can ROTATE, MOVE AND RESIZE shapes with its sprites ! ! ! hahah

So as many of readers are asking after reading this GREAT tutorial how to move and resize and rotate sprites. So i worked out some code from this mess of examples and tutorials:

This class is used for some vertex manipulations

public class Vertex
{
    public FloatBuffer buffer; // buffer holding the vertices
    public float vertex[];
    public Vertex (float[] vertex)
    {
        this.vertex = vertex;
        this.prepare ();
    }
    private void prepare ()
    {
        // a float has 4 bytes so we allocate for each coordinate 4 bytes
        ByteBuffer factory = ByteBuffer.allocateDirect (vertex.length * 4);
        factory.order (ByteOrder.nativeOrder ());
        // allocates the memory from the byte buffer
        buffer = factory.asFloatBuffer ();
        // fill the vertexBuffer with the vertices
        buffer.put (vertex);
        // set the cursor position to the beginning of the buffer
        buffer.position (0);        
    }
}

and this class is used for drawing shape with texture able to move rotate and position

public class Square
{
    Vertex shape,texture;
    int corner=0;
    float x=0;

    public Square()
    {
        shape = new Vertex (new float[]
                {
                1f,1f,0f,
                0f,1f,0f,
                1f,0f,0f,
                0f,0f,0f,
                });

        texture = new Vertex (new float[]
                {
                1.0f, 0.0f,
                0.0f, 0.0f,
                1.0f, 1.0f,
                0.0f, 1.0f,
                });     
    }

    /** The draw method for the square with the GL context */
    public void draw (GL10 gl, int image, float x, float y, float width, float height, float corner)
    {
        if (corner>=0)
        {
            corner += 1;    
        }
        if (corner>360)
        {
            corner = -1;
        }
        gl.glPushMatrix();

        x += 1f;
        if (x>800)
        {
            x = 0;
        }

        position (gl, 0, 0, width, height, corner);

        // bind the previously generated texture
        gl.glBindTexture(GL10.GL_TEXTURE_2D, image);

        // Point to our buffers
        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

        // set the colour for the square
        gl.glColor4f (0.0f, 1.0f, 0.0f, 0.5f);

        // Set the face rotation
        gl.glFrontFace(GL10.GL_CW);     

        // Point to our vertex buffer
        gl.glVertexPointer (3, GL10.GL_FLOAT, 0, shape.buffer);
        gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, texture.buffer);

        // Draw the vertices as triangle strip
        gl.glDrawArrays (GL10.GL_TRIANGLE_STRIP, 0, shape.vertex.length / 3);

        // Disable the client state before leaving
        gl.glDisableClientState (GL10.GL_VERTEX_ARRAY);
        gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

        gl.glPopMatrix();       
    }

    public void position (GL10 gl, float x, float y, float width, float height, float corner)
    {
        gl.glTranslatef (x, y, 0f); //MOVE !!! 1f is size of figure if called after scaling, 1f is pixel if called before scaling

        if (corner>0)
        {
            gl.glTranslatef (width/2, height/2, 0f);
            gl.glRotatef (corner, 0f, 0f, 1f); // ROTATE !!!
            gl.glTranslatef (-width/2, -height/2, 0f);          

        }

        gl.glScalef (width, height, 0f); // ADJUST SIZE !!!

    }
}

and the main thing how to set camera so that 1 opengl unit == 1 pixel annd how to load textures

public class Scene implements Renderer
{
    public Context context;
    public Resources resources;
    public SparseIntArray images = new SparseIntArray ();
    public float width;
    public float height;

    public Scene (Context context)
    {
        this.context = context;
        this.resources = context.getResources ();
    }

    @Override
    public void onDrawFrame (GL10 gl)
    {
//      // clear Screen and Depth Buffer
        gl.glClear (GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
        gl.glMatrixMode(GL10.GL_MODELVIEW);
//      // Reset the Modelview Matrix
        gl.glLoadIdentity ();
        draw (gl);

    }

    @Override
    public void onSurfaceChanged (GL10 gl, int width, int height)
    {
        this.width = width;
        this.height = height;

        gl.glViewport (0, 0, width, height); // Reset The Current Viewport
        gl.glMatrixMode (GL10.GL_PROJECTION); // Select The Projection Matrix
        gl.glLoadIdentity (); // Reset The Projection Matrix

        gl.glOrthof (0, width, 0, height, -1f, 1f);
        //gl.glTranslatef (0f, -height/2, 0.0f); // move the camera !!


        gl.glMatrixMode (GL10.GL_MODELVIEW); // Select The Modelview Matrix
        gl.glLoadIdentity (); // Reset The Modelview Matrix

        load (gl);
    }

    public void onSurfaceCreated(GL10 gl, EGLConfig config) 
    {
        gl.glEnable(GL10.GL_TEXTURE_2D);            //Enable Texture Mapping ( NEW )
        gl.glShadeModel(GL10.GL_SMOOTH);            //Enable Smooth Shading
        gl.glClearColor(0.0f, 0.0f, 0.0f, 0.5f);    //Black Background
        gl.glClearDepthf(1.0f);                     //Depth Buffer Setup
        gl.glEnable(GL10.GL_DEPTH_TEST);            //Enables Depth Testing
        gl.glDepthFunc(GL10.GL_LEQUAL);             //The Type Of Depth Testing To Do

        gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);
        gl.glEnable(GL10.GL_BLEND);


        //Really Nice Perspective Calculations
        gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);

        init (gl);
    }


    public void init (GL10 gl)
    {

    }

    public void load (GL10 gl)
    {

    }

    public void draw (GL10 gl)
    {

    }

    private static int next (GL10 gl)
    {
        int[] temp = new int[1];
        gl.glGenTextures (1, temp, 0);
        return temp[0];
    }   

    public int image (GL10 gl, int resource)
    {
        int id = next (gl);
        images.put (resource, id);

        gl.glBindTexture (GL10.GL_TEXTURE_2D, id);

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

        gl.glTexParameterf (GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_CLAMP_TO_EDGE);
        gl.glTexParameterf (GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_CLAMP_TO_EDGE);

        gl.glTexEnvf (GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE, GL10.GL_REPLACE);

        BitmapFactory.Options options = new BitmapFactory.Options ();
        options.inScaled = false;

        InputStream input = resources.openRawResource (resource);
        Bitmap bitmap;
        try
        {
            bitmap = BitmapFactory.decodeStream (input, null, options);
        }
        finally
        {
            try
            {
                input.close ();
            }
            catch (IOException e)
            {
                // Ignore.
            }
        }

//       Matrix flip = new Matrix ();
//       flip.postScale (1f, -1f);
//       bitmap = Bitmap.createBitmap (bitmap, 0, 0, bitmap.getWidth (), bitmap.getHeight (), flip, true);

        GLUtils.texImage2D (GL10.GL_TEXTURE_2D, 0, bitmap, 0);      
        return id;
    }

}

and some usage

public class Scene2 extends Scene
{
    Square square1, square2;

    public Scene2(Context context)
    {
        super (context);
        // TODO Auto-generated constructor stub
    }

    public void init (GL10 gl)
    {
        square1 = new Square ();
        square2 = new Square ();
    }

    public void load (GL10 gl)
    {
        image (gl, R.drawable.s1_clouds);
        image (gl, R.drawable.s1_ground);
    }

    public void draw (GL10 gl)
    {
        square1.draw (gl, images.get(R.drawable.s1_clouds), 0, 0, width, height, 0);
        square1.draw (gl, images.get(R.drawable.s1_ground), 0, 0, width, height, 0);
    }

}

the main thing here i wanted to implement and implemented is that the X and Y axis are like in canvas:

(0,0)
 --------------------------------- X axis
|
|
|
|
|
|
|
|
Y axis

I ll write some full tutorial after this and I like to announce that i achieved all goals i wanted to achieve i.e: X axis on top, Y axis on left, opengl unit = pixel, set size of object in pixels, rotate object, move object everything in pixels. now i ll handle animating sprites and make them in finer classes and thats the new 2d opengl game framework basis...

discovering this functions helped me tutorial http://www.morrowland.com/apron/tutorials/gl/gl_matrix.php

So many thanks to this blog for pointing me out the only true way...

+1 android simpliest 2d opengl game engine in 1 week...

happy mind blowing...

:P

Edit: After year I have a nice framework https://github.com/hazardland/game.android using concepts described here and sample game with any possible framework usage examples here https://github.com/hazardland/ferry.android (view screens on market https://play.google.com/store/apps/details?id=hazardland.borani)