Distorted Android

  PIPE             ( EffectType.VERTEX  ,   new float[] {1,0f}           , 5, 0,     3    , VertexEffectPipe.class         ),

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

// Copyright 2023 Leszek Koltunski  leszek@koltunski.pl                                          //

//                                                                                               //

// This file is part of Distorted.                                                               //

//                                                                                               //

// This library is free software; you can redistribute it and/or                                 //

// modify it under the terms of the GNU Lesser General Public                                    //

// License as published by the Free Software Foundation; either                                  //

// version 2.1 of the License, or (at your option) any later version.                            //

//                                                                                               //

// This library 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                             //

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

//                                                                                               //

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

// License along with this library; if not, write to the Free Software                           //

// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA                //

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

package org.distorted.library.effect;

import org.distorted.library.type.Data3D;

import org.distorted.library.type.Data5D;

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

/**

 * Pull all points around the center of the Effect towards the center point (if degree>=1) or push them

 * away from it (degree<=1).

 */

public class VertexEffectPipe extends VertexEffect

  {

  private static final EffectName NAME = EffectName.PIPE;

  private final Data5D mPipe;

  private final Data3D mCenter;

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

/**

 * Only for use by the library itself.

 *

 * @y.exclude

 */

  public boolean compute(float[] uniforms, int index, long currentDuration, long step )

    {

    mCenter.get(uniforms,index+CENTER_OFFSET,currentDuration,step);

    return mPipe.get(uniforms,index+VALUES_OFFSET,currentDuration,step);

    }

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

// here, if one tests this with the 'Generic' examples app - and chooses the 'Cubes 3x3x3' mesh,

// then adds an 'empty' PIPE effect - then two corners of the mesh turn bright.

// It turns out this is because the points at those corners are very close to being on the

// line defined by 'center' and 'vect' (so 'ps' is very small)

// Then by means of some miracle we have

// dot_ps>0, (sign_ps-1.0)==0.0 and dot_ps-(sign_ps-1.0) == 0.0 !! so n_ps - undef.

  static String code()

    {

    return

        "vec3 pc = vUniforms[effect+1].yzw - v;            \n"

      + "vec3 vect = vUniforms[effect].yzw;                \n"

      + "vec3 ps = pc - dot(pc,vect)*vect;                 \n"

      + "float radius = vUniforms[effect+1].x;             \n"

      + "float deg = max( 0.0, 1.0 - length(ps)/radius );  \n"

      + "float h = vUniforms[effect].x;                    \n" // from this point on, having calculated

      + "float tmp = (1.0-h)*deg;                          \n" // ps and deg, proceed just like in Sink

      + "float t1 = tmp*(deg+1.0)/h;                       \n"

      + "float t2 = tmp/(0.618*(0.618+deg));               \n"

      + "float t = t2 + (t1-t2)*((sign(h-1.0)+1.0)/2.0);   \n"

      + "v += t*ps;                                        \n"

      + "const float A = 1.6;                              \n"

      + "const float B = 10.0;                             \n"

      + "vec3 n_ps = dot(ps,n)*ps;                         \n"

      + "float dot_ps = dot(ps,ps);                        \n"

      + "float sign_ps= sign(dot_ps);                      \n"

      + "n_ps = (sign_ps*n_ps)/(dot_ps-(sign_ps-1.0));     \n"

      + "float move = deg*(h-1.0)/(h/B+1.0/A);             \n"

      + "n += move*n_ps;                                   \n"

      + "n = normalize(n);";

    }

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

// PUBLIC API

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

/**

 * Have to call this before the shaders get compiled (i.e before DistortedLibrary.onCreate()) for the Effect to work.

 */

  public static void enable()

    {

    addEffect(NAME, code() );

    }

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

/**

 * Pull (degree>1) or push away from (degree<1) all points of an infinite 'pipe' shaped region. We

 * pull (or push) each point in space towards a point in the center of the pipe which is closest to it.

 * Points located outside of the pipe are not affected (thus this acts kind of like a 'region')

 *

 * @param pipe   5-dimensional data describing the effect and kind of including the region in it as well.

 *               1st: the degree of pull (similar to the one in the sink effect)

 *               (2nd,3rd,4th) -> the vector along which the 'pipe' points to.

 *               5th: the radius of the pipe.

 * @param center 3-dimensional Data that, at any given time, returns the Center of the Effect.

 */

  public VertexEffectPipe(Data5D pipe, Data3D center)

    {

    super(NAME);

    mPipe   = pipe;

    mCenter = center;

    }

  }

      + "float h = vUniforms[effect].x;                    \n"