// HelloOpenGL.java


package com.rvasolutions.helloopengl;

import android.app.Activity;
import android.content.Context;
import android.opengl.GLSurfaceView;
import android.os.Bundle;
import android.view.MotionEvent;

public class HelloOpenGL extends Activity {

    private GLSurfaceView mGLView;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Create a GLSurfaceView instance and set it
        // as the ContentView for this activity
        mGLView = new HelloOpenGLSurfaceView(this);
        setContentView(mGLView);
    }

    @Override
    protected void onPause() {
        super.onPause();
        // The following call pauses the rendering thread.
        // If your OpenGL application is memory intensive,
        // you should consider de-allocating objects that
        // consume significant memory here.
        mGLView.onPause();
    }

    @Override
    protected void onResume() {
        super.onResume();
        // The following call resumes a paused rendering thread.
        // If you de-allocated graphics objects for onPause()
        // this is a good place to reallocate them.
        mGLView.onResume();
    }
}

class HelloOpenGLSurfaceView extends GLSurfaceView {

    private final float TOUCH_SCALE_FACTOR = 180.0f / 320;
    private HelloOpenGLRenderer mRenderer;
    private float mPreviousX;
    private float mPreviousY;

    public HelloOpenGLSurfaceView(Context context){
        super(context);

        // Create an OpenGL ES 2.0 Context
        setEGLContextClientVersion(2);

        // set the mRenderer member
        mRenderer = new HelloOpenGLRenderer();
        setRenderer(mRenderer);

        // Render the view only when there is a change
        setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
    }

    @Override
    public boolean onTouchEvent(MotionEvent e) {
        // MotionEvent reports input details from the touch screen
        // and other input controls. In this case, you are only
        // interested in events where the touch position changed.

        float x = e.getX();
        float y = e.getY();

        switch(e.getAction()) {
            case MotionEvent.ACTION_MOVE:

                float dx = x - mPreviousX;
                float dy = y - mPreviousY;

                // reverse direction of rotation above the midline
                if ( y > getHeight() /2) {
                    dx = dx * -1;
                }

                // reverse direction of rotation to left of the midline
                if ( x < getWidth() /2) {
                    dy = dy * -1;
                }

                mRenderer.mAngle += (dx + dy) * TOUCH_SCALE_FACTOR;
                requestRender();
        }

        mPreviousX = x;
        mPreviousY = y;
        return true;
    }
}