Distorted Android

///////////////////////////////////////////////////////////////////////////////////////////////////

// Copyright 2016 Leszek Koltunski                                                               //

//                                                                                               //

// This file is part of Distorted.                                                               //

//                                                                                               //

// Distorted is free software: you can redistribute it and/or modify                             //

// it under the terms of the GNU General Public License as published by                          //

// the Free Software Foundation, either version 2 of the License, or                             //

// (at your option) any later version.                                                           //

//                                                                                               //

// Distorted is distributed in the hope that it will be useful,                                  //

// but WITHOUT ANY WARRANTY; without even the implied warranty of                                //

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                                 //

// GNU General Public License for more details.                                                  //

//                                                                                               //

// You should have received a copy of the GNU General Public License                             //

// along with Distorted.  If not, see <http://www.gnu.org/licenses/>.                            //

///////////////////////////////////////////////////////////////////////////////////////////////////

package org.distorted.examples.flag;

import android.app.ActivityManager;

import android.content.Context;

import android.content.pm.ConfigurationInfo;

import android.opengl.GLSurfaceView;

import android.util.AttributeSet;

import android.view.MotionEvent;

///////////////////////////////////////////////////////////////////////////////////////////////////

class FlagSurfaceView extends GLSurfaceView

{

    private final static int DIRECTION_SENSITIVITY=  12;

    private int mX, mY;

    private FlagRenderer mRenderer;

///////////////////////////////////////////////////////////////////////////////////////////////////

    public FlagSurfaceView(Context context, AttributeSet attrs)

      {

      super(context,attrs);

      mX = -1;

      mY = -1;

      if(!isInEditMode())

        {

        mRenderer = new FlagRenderer(this);

        final ActivityManager activityManager     = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);

        final ConfigurationInfo configurationInfo = activityManager.getDeviceConfigurationInfo();

        setEGLContextClientVersion( (configurationInfo.reqGlEsVersion>>16) >= 3 ? 3:2 );

        setRenderer(mRenderer);

        }

      }

///////////////////////////////////////////////////////////////////////////////////////////////////

    public FlagRenderer getRenderer()

      {

      return mRenderer;

      }

///////////////////////////////////////////////////////////////////////////////////////////////////

    private void resetQuats()

      {

      float qx = mRenderer.mQuat1.get0();

      float qy = mRenderer.mQuat1.get1();

      float qz = mRenderer.mQuat1.get2();

      float qw = mRenderer.mQuat1.get3();

      float rx = mRenderer.mQuat2.get0();

      float ry = mRenderer.mQuat2.get1();

      float rz = mRenderer.mQuat2.get2();

      float rw = mRenderer.mQuat2.get3();

      float tx = rw*qx - rz*qy + ry*qz + rx*qw;

      float ty = rw*qy + rz*qx + ry*qw - rx*qz;

      float tz = rw*qz + rz*qw - ry*qx + rx*qy;

      float tw = rw*qw - rz*qz - ry*qy - rx*qx;

      mRenderer.mQuat1.set(0f, 0f, 0f, 1f);

      mRenderer.mQuat2.set(tx, ty, tz, tw);

      }

///////////////////////////////////////////////////////////////////////////////////////////////////

    @Override public boolean onTouchEvent(MotionEvent event) 

      {

      int action = event.getAction();

      int x = (int)event.getX();

      int y = (int)event.getY();

      switch(action)

         {

         case MotionEvent.ACTION_DOWN: mX = x;

                                       mY = y;

                                       break;

         case MotionEvent.ACTION_MOVE: if( mX>=0 && mY>= 0 )

                                         {

                                         float px = mY-y;

                                         float py = mX-x;

                                         float pz = 0;

                                         float plen = (float)Math.sqrt(px*px + py*py + pz*pz);

                                         if( plen>0 )

                                           {

                                           px /= plen;

                                           py /= plen;

                                           pz /= plen;

                                           float cosA = (float)Math.cos(plen*3.14f/mRenderer.mScreenMin);

                                           float sinA = (float)Math.sqrt(1-cosA*cosA);

                                           mRenderer.mQuat1.set(px*sinA, py*sinA, pz*sinA, cosA);

                                           }

                                         }

                                       if( (mX-x)*(mX-x) + (mY-y)*(mY-y) > mRenderer.mScreenMin*mRenderer.mScreenMin/(DIRECTION_SENSITIVITY*DIRECTION_SENSITIVITY) )

                                         {

                                         mX = x;

                                         mY = y;

                                         resetQuats();

                                         }

                                       break;

         case MotionEvent.ACTION_UP  : mX = -1;

                                       mY = -1;

        	                             resetQuats();

                                       break;

         }

      return true;

      }

}