Distorted Android

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// Copyright 2017 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.effect;

import org.distorted.library.type.Data2D;

import org.distorted.library.type.Data3D;

import org.distorted.library.type.Data4D;

import org.distorted.library.type.Static4D;

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

/**

 * Pull all points around the center of the Effect towards a line passing through the center

 * (that's if degree>=1) or push them away from the line (degree<=1).

 *

 * Note: this is not a fully 3D effect - the pinching is always within the XY plane; z coordinates

 * of all vertices remain unaffected. If someone wants a fully 3D Pinch effect, we'd probably need

 * to write another VertexEffectPinch3D with 2 more arguments (latitude and longitude angles defining

 * the plane the pinching works on).

 */

public class VertexEffectPinch extends VertexEffect

  {

  private Data2D mPinch;

  private Data3D mCenter;

  private Data4D mRegion;

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

/**

 * 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);

    mRegion.get(uniforms,index+REGION_OFFSET,currentDuration,step);

    boolean ret = mPinch.get(uniforms,index,currentDuration,step);

    uniforms[index+1] = (float)(Math.PI*uniforms[index+1]/180);

    uniforms[index+REGION_OFFSET+1] =-uniforms[index+REGION_OFFSET+1];  // region's y

    return ret;

    }

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

// PUBLIC API

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

// Pull P=(v.x,v.y) towards the line that

// a) passes through the center of the effect

// b) forms angle defined in the 2nd interpolated value with the X-axis

// with P' = P + (1-h)*dist(line to P)

// when h>1 we are pushing points away from S: P' = P + (1/h-1)*dist(line to P)

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

/**

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

 */

  public static void enable()

    {

    addEffect(EffectName.PINCH,

        "vec3 center = vUniforms[effect+1].yzw; \n"

      + "vec3 ps = center-v.xyz; \n"

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

      + "float t = degree(vUniforms[effect+2],center,ps) * (1.0-h)/max(1.0,h); \n"

      + "float angle = vUniforms[effect].y; \n"

      + "vec2 dir = vec2(sin(angle),-cos(angle)); \n"

      + "v.xy += t*dot(ps.xy,dir)*dir;"

      );

    }

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

/**

 * Pull all points around the center of the Effect towards a line passing through the center

 * (that's if degree>=1) or push them away from the line (degree<=1)

 *

 * @param pinch  The current degree of the Effect + angle the line forms with X-axis

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

 * @param region Region that masks the Effect.

 */

  public VertexEffectPinch(Data2D pinch, Data3D center, Data4D region)

    {

    super(EffectName.PINCH);

    mPinch  = pinch;

    mCenter = center;

    mRegion = (region==null ? new Static4D(0,0,0, Float.MAX_VALUE) : region);

    }

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

/**

 * Pull all points around the center of the Effect towards a line passing through the center

 * (that's if degree>=1) or push them away from the line (degree<=1)

 *

 * @param pinch  The current degree of the Effect + angle the line forms with X-axis

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

 */

  public VertexEffectPinch(Data2D pinch, Data3D center)

    {

    super(EffectName.PINCH);

    mPinch  = pinch;

    mCenter = center;

    mRegion = new Static4D(0,0,0, Float.MAX_VALUE);

    }

  }