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.library.main;

import android.opengl.GLES31;

import android.opengl.Matrix;

import org.distorted.library.effect.EffectQuality;

import java.util.ArrayList;

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

/**

 * This is not really part of the public API.

 *

 * @y.exclude

 */

public abstract class DistortedOutputSurface extends DistortedSurface implements DistortedMaster.Slave

{

/**

 * Do not create DEPTH or STENCIL attachment

 */

  public static final int NO_DEPTH_NO_STENCIL = 0;

/**

 * Create DEPTH, but not STENCIL

 */

  public static final int DEPTH_NO_STENCIL    = 1;

/**

 * Create both DEPTH and STENCIL

 */

  public static final int BOTH_DEPTH_STENCIL  = 2;

  private static final int ATTACH = 0;

  private static final int DETACH = 1;

  private static final int DETALL = 2;

  private static final int SORT   = 3;

  private ArrayList<DistortedNode> mChildren;

  private int mNumChildren;   // ==mChildren.length(), but we only create mChildren if the first one gets added

  private class Job

    {

    int type;

    DistortedNode node;

    Job(int t, DistortedNode n)

      {

      type = t;

      node = n;

      }

    }

  private ArrayList<Job> mJobs = new ArrayList<>();

  // Global buffers used for postprocessing.

  private static DistortedOutputSurface[] mBuffer = new DistortedOutputSurface[EffectQuality.LENGTH];

  private long mTime;

  private float mFOV;

  float mDistance, mNear;

  float[] mProjectionMatrix;

  int mDepthStencilCreated;

  int mDepthStencil;

  int[] mDepthStencilH = new int[1];

  int[] mFBOH          = new int[1];

  private float mClearR, mClearG, mClearB, mClearA;

  private float mClearDepth;

  private int mClearStencil;

  private int mClear;

  float mMipmap;

  int mRealWidth;   // the Surface can be backed up with a texture that is

  int mRealHeight;  // larger than the viewport we have to it.

                    // mWidth,mHeight are the sizes of the Viewport, those -

                    // sizes of the backing up texture.

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

  DistortedOutputSurface(int width, int height, int createColor, int numcolors, int depthStencil, int fbo, int type)

    {

    super(width,height,createColor,numcolors,type);

    mRealWidth = width;

    mRealHeight= height;

    mProjectionMatrix = new float[16];

    mFOV = 60.0f;

    mNear=  0.5f;

    mDepthStencilCreated= (depthStencil== NO_DEPTH_NO_STENCIL ? DONT_CREATE:NOT_CREATED_YET);

    mDepthStencil = depthStencil;

    mFBOH[0]         = fbo;

    mDepthStencilH[0]= 0;

    mTime = 0;

    mClearR = 0.0f;

    mClearG = 0.0f;

    mClearB = 0.0f;

    mClearA = 0.0f;

    mClearDepth = 1.0f;

    mClearStencil = 0;

    mClear = GLES31.GL_DEPTH_BUFFER_BIT | GLES31.GL_COLOR_BUFFER_BIT;

    mMipmap = 1.0f;

    createProjection();

    }

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

  private void createProjection()

    {

    if( mWidth>0 && mHeight>1 )

      {

      if( mFOV>0.0f )  // perspective projection

        {

        float a = 2.0f*(float)Math.tan(mFOV*Math.PI/360);

        float q = mWidth*mNear;

        float c = mHeight*mNear;

        float left   = -q/2;

        float right  = +q/2;

        float bottom = -c/2;

        float top    = +c/2;

        float near   =  c/a;

        mDistance    = mHeight/a;

        float far    = 2*mDistance-near;

        Matrix.frustumM(mProjectionMatrix, 0, left, right, bottom, top, near, far);

        }

      else             // parallel projection

        {

        float left   = -mWidth/2.0f;

        float right  = +mWidth/2.0f;

        float bottom = -mHeight/2.0f;

        float top    = +mHeight/2.0f;

        float near   = mWidth+mHeight-mHeight*(1.0f-mNear);

        mDistance    = mWidth+mHeight;

        float far    = mWidth+mHeight+mHeight*(1.0f-mNear);

        Matrix.orthoM(mProjectionMatrix, 0, left, right, bottom, top, near, far);

        }

      }

    }

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

  private static void createPostprocessingBuffers(int width, int height, float near)

    {

    float mipmap=1.0f;

    for (int j=0; j<EffectQuality.LENGTH; j++)

      {

      mBuffer[j] = new DistortedFramebuffer(2, BOTH_DEPTH_STENCIL, TYPE_SYST, (int) (width * mipmap), (int) (height * mipmap));

      mBuffer[j].mMipmap = mipmap;

      mBuffer[j].mNear = near;  // copy mNear as well (for blitting- see PostprocessEffect.apply() )

      mBuffer[j].glClearColor(1.0f, 1.0f, 1.0f, 0.0f);

      mipmap *= EffectQuality.MULTIPLIER;

      }

    DistortedObject.toDo(); // create the FBOs immediately. This is safe as we must be holding the OpenGL context now.

    GLES31.glStencilMask(0xff);

    GLES31.glDepthMask(true);

    GLES31.glColorMask(true, true, true, true);

    GLES31.glClearColor(1.0f, 1.0f, 1.0f, 0.0f);

    GLES31.glClearDepthf(1.0f);

    GLES31.glClearStencil(0);

    for (int j=0; j<EffectQuality.LENGTH; j++)

      {

      mBuffer[j].setAsOutput();

      GLES31.glFramebufferTexture2D(GLES31.GL_FRAMEBUFFER, GLES31.GL_COLOR_ATTACHMENT0, GLES31.GL_TEXTURE_2D, mBuffer[j].mColorH[1], 0);

      GLES31.glClear(GLES31.GL_COLOR_BUFFER_BIT | GLES31.GL_DEPTH_BUFFER_BIT | GLES31.GL_STENCIL_BUFFER_BIT);

      GLES31.glFramebufferTexture2D(GLES31.GL_FRAMEBUFFER, GLES31.GL_COLOR_ATTACHMENT0, GLES31.GL_TEXTURE_2D, mBuffer[j].mColorH[0], 0);

      GLES31.glClear(GLES31.GL_COLOR_BUFFER_BIT);

      }

    }

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

  static synchronized void onDestroy()

    {

    for(int j=0; j<EffectQuality.LENGTH; j++)

      {

      mBuffer[j] = null;

      }

    }

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

// The postprocessing buffers mBuffer[] are generally speaking too large (there's just one static

// set of them) so before we use them for output, we need to adjust the Vieport as if they were

// smaller. That takes care of outputting pixels to them. When we use them as input, we have to

// adjust the texture coords - see the get{Width|Height}Correction functions.

  private static void clonePostprocessingViewport(DistortedOutputSurface from)

    {

    if( mBuffer[0].mWidth != from.mWidth || mBuffer[0].mHeight != from.mHeight )

      {

      DistortedOutputSurface surface;

      for(int i=0; i<EffectQuality.LENGTH; i++)

        {

        surface = mBuffer[i];

        surface.mWidth  = (int)(from.mWidth *surface.mMipmap);

        surface.mHeight = (int)(from.mHeight*surface.mMipmap);

        surface.mNear   = from.mNear;  // Near plane is independent of the mipmap level

        //android.util.Log.e("surface", "viewport "+i+" to ("+from.mWidth+"x"+from.mHeight+")");

        surface.createProjection();

        int maxw = surface.mWidth  > surface.mRealWidth  ? surface.mWidth  : surface.mRealWidth;

        int maxh = surface.mHeight > surface.mRealHeight ? surface.mHeight : surface.mRealHeight;

        if (maxw > surface.mRealWidth || maxh > surface.mRealHeight)

          {

          surface.mRealWidth = maxw;

          surface.mRealHeight = maxh;

          surface.recreate();

          surface.create();

          }

        }

      }

    }

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

  private static void oitClear(DistortedOutputSurface buffer)

    {

    DistortedEffects.zeroOutAtomic();

    DistortedEffects.oitClear(buffer);

    GLES31.glMemoryBarrier(GLES31.GL_SHADER_STORAGE_BARRIER_BIT|GLES31.GL_ATOMIC_COUNTER_BARRIER_BIT);

    }

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

  private int oitBuild(DistortedOutputSurface buffer)

    {

    GLES31.glViewport(0, 0, mWidth, mHeight);

    setAsOutput();

    GLES31.glActiveTexture(GLES31.GL_TEXTURE0);

    GLES31.glBindTexture(GLES31.GL_TEXTURE_2D, buffer.mColorH[0]);

    GLES31.glActiveTexture(GLES31.GL_TEXTURE1);

    GLES31.glBindTexture(GLES31.GL_TEXTURE_2D, buffer.mDepthStencilH[0]);

    //GLES31.glDisable(GLES31.GL_STENCIL_TEST);

    //GLES31.glStencilMask(0x00);

    DistortedRenderState.colorDepthStencilOn();

    DistortedRenderState.enableDepthTest();

    DistortedEffects.oitBuild(this, buffer.getWidthCorrection(), buffer.getHeightCorrection() );

    GLES31.glActiveTexture(GLES31.GL_TEXTURE0);

    GLES31.glBindTexture(GLES31.GL_TEXTURE_2D, 0);

    GLES31.glActiveTexture(GLES31.GL_TEXTURE1);

    GLES31.glBindTexture(GLES31.GL_TEXTURE_2D, 0);

    DistortedRenderState.colorDepthStencilRestore();

    DistortedRenderState.restoreDepthTest();

    return 1;

    }

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

// two phases: 1. collapse the SSBO 2. blend the ssbo's color

  private int oitRender(long currTime)

    {

    float corrW = getWidthCorrection();

    float corrH = getHeightCorrection();

    GLES31.glViewport(0, 0, mWidth, mHeight);

    // Do the Collapse Pass only if we do have a Depth attachment.

    // Otherwise there's no point (in fact we then would create a feedback loop!)

    if( mDepthStencilH[0] != 0 )

      {

      GLES31.glBindFramebuffer(GLES31.GL_FRAMEBUFFER, 0);

      GLES31.glActiveTexture(GLES31.GL_TEXTURE1);

      GLES31.glBindTexture(GLES31.GL_TEXTURE_2D, mDepthStencilH[0]);

      DistortedRenderState.switchOffColorDepthStencil();

      DistortedEffects.oitCollapse(this, corrW, corrH);

      GLES31.glBindTexture(GLES31.GL_TEXTURE_2D, 0);

      }

    setAsOutput(currTime);

    DistortedRenderState.switchColorDepthOnStencilOff();

    DistortedEffects.oitRender(this, corrW, corrH);

    DistortedRenderState.restoreColorDepthStencil();

    return 1;

    }

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

  private static void clearBuffer(DistortedOutputSurface buffer)

    {

    GLES31.glStencilMask(0xff);

    GLES31.glDepthMask(true);

    GLES31.glColorMask(true,true,true,true);

    GLES31.glClearColor(1.0f,1.0f,1.0f,0.0f);

    GLES31.glClearDepthf(1.0f);

    GLES31.glClearStencil(0);

    buffer.setAsOutput();

    GLES31.glFramebufferTexture2D(GLES31.GL_FRAMEBUFFER, GLES31.GL_COLOR_ATTACHMENT0, GLES31.GL_TEXTURE_2D, buffer.mColorH[buffer.mNumColors-1], 0);

    GLES31.glClear(GLES31.GL_COLOR_BUFFER_BIT|GLES31.GL_DEPTH_BUFFER_BIT|GLES31.GL_STENCIL_BUFFER_BIT);

    for(int i=buffer.mNumColors-2; i>=0; i--)

      {

      GLES31.glFramebufferTexture2D(GLES31.GL_FRAMEBUFFER, GLES31.GL_COLOR_ATTACHMENT0, GLES31.GL_TEXTURE_2D, buffer.mColorH[i], 0);

      GLES31.glClear(GLES31.GL_COLOR_BUFFER_BIT);

      }

    }

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

  void clear()

    {

    DistortedRenderState.colorDepthStencilOn();

    GLES31.glClearColor(mClearR, mClearG, mClearB, mClearA);

    GLES31.glClearDepthf(mClearDepth);

    GLES31.glClearStencil(mClearStencil);

    GLES31.glClear(mClear);

    DistortedRenderState.colorDepthStencilRestore();

    }

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

// Render all children, one by one. If there are no postprocessing effects, just render to THIS.

// Otherwise, render to a buffer and on each change of Postprocessing Bucket, apply the postprocessing

// to a whole buffer (lastQueue.postprocess) and merge it (this.oitBuild).

  int renderChildren(long time, int numChildren, ArrayList<DistortedNode> children)

    {

    int quality=0, internalQuality = 0, numRenders = 0, bucketChange = 0;

    DistortedNode child1, child2;

    EffectQueuePostprocess lastQueue=null, currQueue;

    long lastBucket=0, currBucket;

    oitClear(this);

    for(int i=0; i<numChildren; i++)

      {

      child1 = children.get(i);

      currQueue = child1.getPostprocessQueue();

      currBucket= currQueue.getID();

      if( currBucket==0 )

        {

        GLES31.glBindFramebuffer(GLES31.GL_FRAMEBUFFER, mFBOH[0]);

        numRenders += child1.draw(time, this);

        }

      else

        {

        if( mBuffer[0]==null ) createPostprocessingBuffers(mWidth,mHeight,mNear);

        if( lastBucket!=currBucket )

          {

          if( lastBucket==0 )

            {

            clonePostprocessingViewport(this);

            }

          else

            {

            for(int j=bucketChange; j<i; j++)

              {

              child2 = children.get(j);

              numRenders += child2.markStencilAndDepth(time,mBuffer[internalQuality],lastQueue);

              }

            numRenders += lastQueue.postprocess(mBuffer);

            numRenders += oitBuild(mBuffer[quality]);

            clearBuffer(mBuffer[quality]);

            }

          internalQuality = currQueue.getInternalQuality();

          quality         = currQueue.getQuality();

          bucketChange    = i;

          }

        mBuffer[quality].setAsOutput(time);

        child1.drawNoBlend(time,mBuffer[quality]);

        if( i==numChildren-1 )

          {

          for(int j=bucketChange; j<numChildren; j++)

            {

            child2 = children.get(j);

            numRenders += child2.markStencilAndDepth(time,mBuffer[internalQuality],currQueue);

            }

          numRenders += currQueue.postprocess(mBuffer);

          numRenders += oitBuild(mBuffer[quality]);

          GLES31.glMemoryBarrier(GLES31.GL_SHADER_STORAGE_BARRIER_BIT);

          numRenders += oitRender(time);  // merge the OIT linked list

          clearBuffer(mBuffer[quality]);

          }

        } // end else (postprocessed child)

      lastQueue = currQueue;

      lastBucket= currBucket;

      } // end main for loop

    return numRenders;

    }

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

  ArrayList<DistortedNode> getChildren()

    {

    return mChildren;

    }

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

/**

 * Not part of the Public API.

 *

 * @y.exclude

 */

  public float getWidthCorrection()

    {

    return (float)mWidth/mRealWidth;

    }

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

/**

 * Not part of the Public API.

 *

 * @y.exclude

 */

  public float getHeightCorrection()

    {

    return (float)mHeight/mRealHeight;

    }

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

// PUBLIC API

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

/**

 * Draws all the attached children to this OutputSurface.

 * <p>

 * Must be called from a thread holding OpenGL Context.

 *

 * @param time Current time, in milliseconds. This will be passed to all the Effects stored in the children Nodes.

 * @return Number of objects rendered.

 */

  public int render(long time)

    {

    // change tree topology (attach and detach children)

/*

    boolean changed1 =

*/

    DistortedMaster.toDo();

/*

    if( changed1 )

      {

      for(int i=0; i<mNumChildren; i++)

        {

        mChildren.get(i).debug(0);

        }

      DistortedNode.debugMap();

      }

*/

    // create and delete all underlying OpenGL resources

    // Watch out: FIRST change topology, only then deal

    // with OpenGL resources. That's because changing Tree

    // can result in additional Framebuffers that would need

    // to be created immediately, before the calls to drawRecursive()

/*

    boolean changed2 =

*/

    toDo();

/*

    if( changed2 )

      {

      DistortedObject.debugLists();

      }

*/

    // mark OpenGL state as unknown

    DistortedRenderState.reset();

    int numRenders=0;

    for(int i=0; i<mNumChildren; i++)

      {

      numRenders += mChildren.get(i).renderRecursive(time);

      }

    setAsOutput(time);

    numRenders += renderChildren(time,mNumChildren,mChildren);

    return numRenders;

    }

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

/**

 * Bind this Surface as a Framebuffer we can render to.

 *

 * @param time Present time, in milliseconds. The point: looking at this param the library can figure

 *             out if this is the first time during present frame that this FBO is being set as output.

 *             If so, the library, in addition to binding the Surface for output, also clears the

 *             Surface's color and depth attachments.

 */

  public void setAsOutput(long time)

    {

    GLES31.glBindFramebuffer(GLES31.GL_FRAMEBUFFER, mFBOH[0]);

    if( mTime!=time )

      {

      mTime = time;

      clear();

      }

    }

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

/**

 * Bind this Surface as a Framebuffer we can render to.

 * <p>

 * This version does not attempt to clear anything.

 */

  public void setAsOutput()

    {

    GLES31.glBindFramebuffer(GLES31.GL_FRAMEBUFFER, mFBOH[0]);

    }

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

/**

 * Return the Near plane of the Projection included in the Surface.

 *

 * @return the Near plane.

 */

  public float getNear()

    {

    return mNear;

    }

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

/**

 * Set mipmap level.

 * <p>

 * Trick for speeding up your renders - one can create a pyramid of OutputSurface objects, each next

 * one some constant FACTOR smaller than the previous (0.5 is the common value), then set the Mipmap

 * Level of the i-th object to be FACTOR^i (we start counting from 0). When rendering any scene into

 * such prepared OutputSurface, the library will make sure to scale any Effects used so that the end

 * scene will end up looking identical no matter which object we render to. Identical, that is, except

 * for the loss of quality and gain in speed associated with rendering to a smaller Surface.

 * <p>

 * Example: if you create two FBOs, one 1000x1000 and another 500x500 in size, and set the second one

 * mipmap to 0.5 (the first one's is 1.0 by default), define Effects to be a single move by (100,100),

 * and render a skinned Mesh into both FBO, the end result will look proportionally the same, because

 * in the second case the move vector (100,100) will be auto-scaled to (50,50).

 *

 * @param mipmap The mipmap level. Acceptable range: 0<mipmap<infinity, although mipmap>1

 *               does not make any sense (that would result in loss of speed and no gain in quality)

 */

  public void setMipmap(float mipmap)

    {

    mMipmap = mipmap;

    }

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

/**

 * Set the (R,G,B,A) values of GLES31.glClearColor() to set up color with which to clear

 * this Surface at the beginning of each frame.

 *

 * @param r the Red component. Default: 0.0f

 * @param g the Green component. Default: 0.0f

 * @param b the Blue component. Default: 0.0f

 * @param a the Alpha component. Default: 0.0f

 */

  public void glClearColor(float r, float g, float b, float a)

    {

    mClearR = r;

    mClearG = g;

    mClearB = b;

    mClearA = a;

    }

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

/**

 * Uses glClearDepthf() to set up a value with which to clear

 * the Depth buffer of our Surface at the beginning of each frame.

 *

 * @param d the Depth. Default: 1.0f

 */

  public void glClearDepthf(float d)

    {

    mClearDepth = d;

    }

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

/**

 * Uses glClearStencil() to set up a value with which to clear the

 * Stencil buffer of our Surface at the beginning of each frame.

 *

 * @param s the Stencil. Default: 0

 */

  public void glClearStencil(int s)

    {

    mClearStencil = s;

    }

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

/**

 * Which buffers to Clear at the beginning of each frame?

 * <p>

 * Valid values: 0, or bitwise OR of one or more values from the set GL_COLOR_BUFFER_BIT,

 *               GL_DEPTH_BUFFER_BIT, GL_STENCIL_BUFFER_BIT.

 * Default: GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT.

 *

 * @param mask bitwise OR of BUFFER_BITs to clear.

 */

  public void glClear(int mask)

    {

    mClear = mask;

    }

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

/**

 * Create new Projection matrix.

 *

 * @param fov Vertical 'field of view' of the Projection frustrum (in degrees).

 *            Valid values: 0<=fov<180. FOV==0 means 'parallel projection'.

 * @param near Distance between the screen plane and the near plane.

 *             Valid vaules: 0<near<1. When near==0 (illegal!), the Near Plane is exactly at the tip of

 *             the pyramid. When near==1 (illegal!) the near plane is equivalent to the screen plane.

 */

  public void setProjection(float fov, float near)

    {

    if( fov < 180.0f && fov >=0.0f )

      {

      mFOV = fov;

      }

    if( near<   1.0f && near> 0.0f )

      {

      mNear= near;

      }

    else if( near<=0.0f )

      {

      mNear = 0.01f;

      }

    else if( near>=1.0f )

      {

      mNear=0.99f;

      }

    createProjection();

    }

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

/**

 * Resize the underlying Framebuffer.

 * <p>

 * This method can be safely called mid-render as it doesn't interfere with rendering.

 *

 * @param width The new width.

 * @param height The new height.

 */

  public void resize(int width, int height)

    {

    if( mWidth!=width || mHeight!=height )

      {

      mWidth = mRealWidth = width;

      mHeight= mRealHeight= height;

      createProjection();

      if( mColorCreated==CREATED )

        {

        markForCreation();

        recreate();

        }

      }

    }

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

/**

 * Return true if the Surface contains a DEPTH attachment.

 *

 * @return <bold>true</bold> if the Surface contains a DEPTH attachment.

 */

  public boolean hasDepth()

    {

    return mDepthStencilCreated==CREATED;

    }

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

/**

 * Return true if the Surface contains a STENCIL attachment.

 *

 * @return <bold>true</bold> if the Surface contains a STENCIL attachment.

 */

  public boolean hasStencil()

    {

    return (mDepthStencilCreated==CREATED && mDepthStencil==BOTH_DEPTH_STENCIL);

    }

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

/**

 * Adds a new child to the last position in the list of our Surface's children.

 * <p>

 * We cannot do this mid-render - actual attachment will be done just before the next render, by the

 * DistortedMaster (by calling doWork())

 *

 * @param node The new Node to add.

 */

  public void attach(DistortedNode node)

    {

    mJobs.add(new Job(ATTACH,node));

    DistortedMaster.newSlave(this);

    }

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

/**

 * Adds a new child to the last position in the list of our Surface's children.

 * <p>

 * We cannot do this mid-render - actual attachment will be done just before the next render, by the

 * DistortedMaster (by calling doWork())

 *

 * @param surface InputSurface to initialize our child Node with.

 * @param effects DistortedEffects to initialize our child Node with.

 * @param mesh MeshObject to initialize our child Node with.

 * @return the newly constructed child Node, or null if we couldn't allocate resources.

 */

  public DistortedNode attach(DistortedInputSurface surface, DistortedEffects effects, MeshObject mesh)

    {

    DistortedNode node = new DistortedNode(surface,effects,mesh);

    mJobs.add(new Job(ATTACH,node));

    DistortedMaster.newSlave(this);

    return node;

    }

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

/**

 * Removes the first occurrence of a specified child from the list of children of our Surface.

 * <p>

 * A bit questionable method as there can be many different Nodes attached as children, some

 * of them having the same Effects but - for instance - different Mesh. Use with care.

 * <p>

 * We cannot do this mid-render - actual detachment will be done just before the next render, by the

 * DistortedMaster (by calling doWork())

 *

 * @param effects DistortedEffects to remove.

 */

  public void detach(DistortedEffects effects)

    {

    long id = effects.getID();

    DistortedNode node;

    boolean detached = false;

    for(int i=0; i<mNumChildren; i++)

      {

      node = mChildren.get(i);

      if( node.getEffects().getID()==id )

        {

        detached = true;

        mJobs.add(new Job(DETACH,node));

        DistortedMaster.newSlave(this);

        break;

        }

      }

    if( !detached )

      {

      // if we failed to detach any, it still might be the case that

      // there's an ATTACH job that we need to cancel.

      int num = mJobs.size();

      Job job;

      for(int i=0; i<num; i++)

        {

        job = mJobs.get(i);

        if( job.type==ATTACH && job.node.getEffects()==effects )

          {

          mJobs.remove(i);

          break;

          }

        }

      }

    }

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

/**

 * Removes the first occurrence of a specified child from the list of children of our Surface.

 * <p>

 * We cannot do this mid-render - actual attachment will be done just before the next render, by the

 * DistortedMaster (by calling doWork())

 *

 * @param node The Node to remove.

 */

  public void detach(DistortedNode node)

    {

    mJobs.add(new Job(DETACH,node));

    DistortedMaster.newSlave(this);

    }

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

/**

 * Removes all children Nodes.

 * <p>

 * We cannot do this mid-render - actual attachment will be done just before the next render, by the

 * DistortedMaster (by calling doWork())

 */

  public void detachAll()

    {

    mJobs.add(new Job(DETALL,null));

    DistortedMaster.newSlave(this);

    }

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

/**

 * This is not really part of the public API. Has to be public only because it is a part of the

 * DistortedSlave interface, which should really be a class that we extend here instead but

 * Java has no multiple inheritance.

 *

 * @y.exclude

 */

  public void doWork()

    {

    int num = mJobs.size();

    Job job;

    for(int i=0; i<num; i++)

      {

      job = mJobs.remove(0);

      switch(job.type)

        {

        case ATTACH: if( mChildren==null ) mChildren = new ArrayList<>(2);

                     job.node.setSurfaceParent(this);

                     DistortedMaster.addSorted(mChildren,job.node);

                     mNumChildren++;

                     break;

        case DETACH: if( mNumChildren>0 && mChildren.remove(job.node) )

                       {

                       job.node.setSurfaceParent(null);

                       mNumChildren--;

                       }

                     break;

        case DETALL: if( mNumChildren>0 )

                       {

                       DistortedNode tmp;

                       for(int j=mNumChildren-1; j>=0; j--)

                         {

                         tmp = mChildren.remove(j);

                         tmp.setSurfaceParent(null);

                         }

                       mNumChildren = 0;

                       }

                     break;

        case SORT  : mChildren.remove(job.node);

                     DistortedMaster.addSorted(mChildren,job.node);

                     break;

        }

      }

    }

}