Distorted Android

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// 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/>.                            //

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package org.distorted.library;

import android.graphics.Bitmap;

import android.graphics.Matrix;

import android.opengl.GLES30;

import android.opengl.GLUtils;

import java.util.Iterator;

import java.util.LinkedList;

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/**

 * Class which represents a OpenGL Texture object.

 * <p>

 * Create a Texture of arbitrary size and feed some pixels to it via the setTexture() method.

 * <p>

 * Keep all objects created in a static LinkedList. The point: we need to be able to mark

 * Textures for deletion, and delete all marked objects later at a convenient time (that's

 * because we can only delete from a thread that holds the OpenGL context so here we provide a

 * framework where one is able to mark for deletion at any time and actual deletion takes place

 * on the next render).

 */

public class DistortedTexture extends DistortedRenderable

  {

  private static boolean mListMarked = false;

  private static LinkedList<DistortedTexture> mList = new LinkedList<>();

  private static int mTextureH;

  private boolean mMarked;

  private Bitmap mBmp= null;

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

// We have to flip vertically every single Bitmap that we get fed with.

//

// Reason: textures read from files are the only objects in OpenGL which have their origins at the

// upper-left corner. Everywhere else the origin is in the lower-left corner. Thus we have to flip.

// The alternative solution, namely inverting the y-coordinate of the TexCoord does not really work-

// i.e. it works only in case of rendering directly to the screen, but if we render to an FBO and

// then take the FBO and render to screen, (DistortedTree does so!) things get inverted as textures

// created from FBO have their origins in the lower-left... Mindfuck!

  private static Bitmap flipBitmap(Bitmap src)

    {

    Matrix matrix = new Matrix();

    matrix.preScale(1.0f,-1.0f);

    return Bitmap.createBitmap(src,0,0,src.getWidth(),src.getHeight(), matrix,true);

    }

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

// must be called from a thread holding OpenGL Context

  void create()

    {

    if( mBmp!=null && mColorH !=null )

      {

      if( mColorH[0]==0 )

        {

        GLES30.glGenTextures(1, mColorH, 0);

        GLES30.glBindTexture(GLES30.GL_TEXTURE_2D, mColorH[0]);

        GLES30.glTexParameteri ( GLES30.GL_TEXTURE_2D, GLES30.GL_TEXTURE_MIN_FILTER, GLES30.GL_LINEAR );

        GLES30.glTexParameteri ( GLES30.GL_TEXTURE_2D, GLES30.GL_TEXTURE_MAG_FILTER, GLES30.GL_LINEAR );

        GLES30.glTexParameteri ( GLES30.GL_TEXTURE_2D, GLES30.GL_TEXTURE_WRAP_S, GLES30.GL_CLAMP_TO_EDGE );

        GLES30.glTexParameteri ( GLES30.GL_TEXTURE_2D, GLES30.GL_TEXTURE_WRAP_T, GLES30.GL_CLAMP_TO_EDGE );

        GLUtils.texImage2D(GLES30.GL_TEXTURE_2D, 0, flipBitmap(mBmp), 0);

        }

      else

        {

        GLES30.glBindTexture(GLES30.GL_TEXTURE_2D, mColorH[0]);

        GLUtils.texSubImage2D(GLES30.GL_TEXTURE_2D, 0,0,0,flipBitmap(mBmp));

        }

      mBmp = null;

      }

    }

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

// must be called from a thread holding OpenGL Context

  private void delete()

    {

    if( mColorH !=null && mColorH[0]>0 )

      {

      GLES30.glDeleteTextures(1, mColorH, 0);

      mColorH[0] = 0;

      }

    mMarked = false;

    }

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

  static void getUniforms(int mProgramH)

    {

    mTextureH= GLES30.glGetUniformLocation( mProgramH, "u_Texture");

    GLES30.glActiveTexture(GLES30.GL_TEXTURE0);

    GLES30.glUniform1i(mTextureH, 0);

    }

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

  static synchronized void onDestroy()

    {

    mListMarked = false;

    mList.clear();

    }

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

// must be called form a thread holding OpenGL Context

  static synchronized void deleteAllMarked()

    {

    if( mListMarked )

      {

      DistortedTexture tmp;

      Iterator<DistortedTexture> iterator = mList.iterator();

      while(iterator.hasNext())

        {

        tmp = iterator.next();

        if( tmp.mMarked )

          {

          tmp.delete();

          iterator.remove();

          }

        }

      mListMarked = false;

      }

    }

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// PUBLIC API

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

/**

 * Create empty texture of given dimensions.

 */

  public DistortedTexture(int width, int height)

    {

    mSizeX    = width ;

    mSizeY    = height;

    mColorH[0]= 0;

    mBmp      = null;

    mMarked   = false;

    mList.add(this);

    }

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

/**

 * Mark the underlying OpenGL object for deletion. Actual deletion will take place on the next render.

 */

  public void markForDeletion()

    {

    mListMarked = true;

    mMarked     = true;

    }

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

/**

 * Sets the underlying android.graphics.Bitmap object.

 * <p>

 * You can only recycle() the passed Bitmap once the OpenGL context gets created (i.e. after call

 * to GLSurfaceView.onSurfaceCreated) because only after this point can the Library upload it to the GPU!

 *

 * @param bmp The android.graphics.Bitmap object to apply effects to and display.

 */

  public void setTexture(Bitmap bmp)

    {

    mBmp= bmp;

    }

  }