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.vertex3d;

import android.content.Context;

import android.opengl.GLSurfaceView;

import android.os.Build;

import android.util.AttributeSet;

import android.view.MotionEvent;

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

class Vertex3DSurfaceView extends GLSurfaceView

  {

  private int mX, mY;

  private Vertex3DRenderer mRenderer;

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

  public Vertex3DSurfaceView(Context c, AttributeSet attrs)

    {

    super(c, attrs);

    if(!isInEditMode())

      {

      setEGLContextClientVersion(2);

      if( Build.FINGERPRINT.startsWith("generic") )

        {

        setEGLConfigChooser(8, 8, 8, 8, 16, 0);

        }

      mRenderer = new Vertex3DRenderer(this);

      setRenderer(mRenderer);

      }

    }

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

  @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);

                                        }

                                      }

                                    break;

      case MotionEvent.ACTION_UP  : mX = -1;

                                    mY = -1;

                                    float qx = mRenderer.mQuat1.getX();

                                    float qy = mRenderer.mQuat1.getY();

                                    float qz = mRenderer.mQuat1.getZ();

                                    float qw = mRenderer.mQuat1.getW();

                                    float rx = mRenderer.mQuat2.getX();

                                    float ry = mRenderer.mQuat2.getY();

                                    float rz = mRenderer.mQuat2.getZ();

                                    float rw = mRenderer.mQuat2.getW();

                                    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);

                                    break;

      }

    return true;

    }

}