Distorted Android

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

// 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 android.content.res.Resources;

import android.opengl.GLES30;

import org.distorted.library.R;

import org.distorted.library.main.Distorted;

import org.distorted.library.main.DistortedFramebuffer;

import org.distorted.library.main.DistortedRenderState;

import org.distorted.library.program.DistortedProgram;

import org.distorted.library.program.FragmentCompilationException;

import org.distorted.library.program.FragmentUniformsException;

import org.distorted.library.program.LinkingException;

import org.distorted.library.program.VertexCompilationException;

import org.distorted.library.program.VertexUniformsException;

import org.distorted.library.type.Data1D;

import java.io.InputStream;

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

public class PostprocessEffectBlur extends PostprocessEffect

  {

  private static final int MAX_HALO = 50;    // Support effects creating up to MAX_HALO pixels wide 'halo' around the object.

  private Data1D mBlurRadius;

  private static final float GAUSSIAN[] =   // G(0.00), G(0.03), G(0.06), ..., G(3.00), 0

    {                                       // where G(x)= (1/(sqrt(2*PI))) * e^(-(x^2)/2). The last 0 terminates.

    0.398948f, 0.398769f, 0.398231f, 0.397336f, 0.396086f, 0.394485f, 0.392537f, 0.390247f, 0.387622f, 0.384668f,

    0.381393f, 0.377806f, 0.373916f, 0.369733f, 0.365268f, 0.360532f, 0.355538f, 0.350297f, 0.344823f, 0.339129f,

    0.333229f, 0.327138f, 0.320868f, 0.314436f, 0.307856f, 0.301142f, 0.294309f, 0.287373f, 0.280348f, 0.273248f,

    0.266089f, 0.258884f, 0.251648f, 0.244394f, 0.237135f, 0.229886f, 0.222657f, 0.215461f, 0.208311f, 0.201217f,

    0.194189f, 0.187238f, 0.180374f, 0.173605f, 0.166940f, 0.160386f, 0.153951f, 0.147641f, 0.141462f, 0.135420f,

    0.129520f, 0.123765f, 0.118159f, 0.112706f, 0.107408f, 0.102266f, 0.097284f, 0.092461f, 0.087797f, 0.083294f,

    0.078951f, 0.074767f, 0.070741f, 0.066872f, 0.063158f, 0.059596f, 0.056184f, 0.052920f, 0.049801f, 0.046823f,

    0.043984f, 0.041280f, 0.038707f, 0.036262f, 0.033941f, 0.031740f, 0.029655f, 0.027682f, 0.025817f, 0.024056f,

    0.022395f, 0.020830f, 0.019357f, 0.017971f, 0.016670f, 0.015450f, 0.014305f, 0.013234f, 0.012232f, 0.011295f,

    0.010421f, 0.009606f, 0.008847f, 0.008140f, 0.007483f, 0.006873f, 0.006307f, 0.005782f, 0.005296f, 0.004847f,

    0.004432f, 0.000000f

    };

  private static final int NUM_GAUSSIAN = GAUSSIAN.length-2;

  // The (fixed-function-sampled) Gaussian Blur kernels are of the size k0=1, k1=2, k2=2, k3=3, k4=3, k5=4, k6=4,...

  // i.e. k(i)=floor((i+3)/2).  (the 'i' in k(i) means 'blur taking into account the present pixel and 'i' pixels

  // in all 4 directions)

  // We need room for MAX_BLUR of them, and sum(i=0...N, floor((i+3)/2)) = N + floor(N*N/4)

  private static float[] weightsCache = new float[MAX_HALO + MAX_HALO*MAX_HALO/4];

  private static float[] offsetsCache = new float[MAX_HALO + MAX_HALO*MAX_HALO/4];

  private static DistortedProgram mBlur1Program, mBlur2Program;

  private static int mRadius1H,mOffsets1H,mWeights1H,mDepth1H, mColorTexture1H;

  private static int mRadius2H,mOffsets2H,mWeights2H,mDepth2H, mColorTexture2H;

  private static float[] mWeights = new float[MAX_HALO];

  private static float[] mOffsets = new float[MAX_HALO];

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

/**

 * Blur the object.

 *

 * @param blurRadius The 'strength' if the effect, in pixels. 0 = no blur, 10 = when blurring a given pixel,

 *                   take into account 10 pixels in each direction.

 */

  public PostprocessEffectBlur(Data1D blurRadius)

    {

    super(EffectName.BLUR);

    mBlurRadius = blurRadius;

    }

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

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

    {

    return mBlurRadius.get(uniforms,index,currentDuration,step);

    }

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

  public int apply(float[] uniforms, int index, float qualityScale, DistortedFramebuffer buffer)

    {

    buffer.setAsOutput();

    float w1  = buffer.getWidth();

    float h1  = buffer.getHeight();

    float near= 1.0f - buffer.getNear();

    int radius = (int)(uniforms[index]*qualityScale);

    if( radius>=MAX_HALO ) radius = MAX_HALO-1;

    computeGaussianKernel(radius);

    int offset = radius + radius*radius/4;

    radius = (radius+1)/2;

    // horizontal blur

    GLES30.glViewport(0, 0, (int)w1, (int)h1);

    mBlur1Program.useProgram();

    buffer.bindForOutput(1);

    buffer.setAsInput(0);

    GLES30.glUniform1fv( mWeights1H, radius+1, weightsCache,offset);

    GLES30.glUniform1i( mRadius1H, radius);

    GLES30.glUniform1f( mDepth1H , near);

    GLES30.glUniform1i( mColorTexture1H , 0 );

    for(int i=0; i<=radius; i++) mOffsets[i] = offsetsCache[offset+i]/h1;

    GLES30.glUniform1fv( mOffsets1H ,radius+1, mOffsets,0);

    GLES30.glVertexAttribPointer(mBlur1Program.mAttribute[0], POS_DATA_SIZE, GLES30.GL_FLOAT, false, 0, mQuadPositions);

    GLES30.glVertexAttribPointer(mBlur1Program.mAttribute[1], TEX_DATA_SIZE, GLES30.GL_FLOAT, false, 0, mQuadTexture);

    DistortedRenderState.useStencilMark();

    GLES30.glDrawArrays(GLES30.GL_TRIANGLE_STRIP, 0, 4);

    DistortedRenderState.unuseStencilMark();

    GLES30.glActiveTexture(GLES30.GL_TEXTURE0);

    GLES30.glBindTexture(GLES30.GL_TEXTURE_2D, 0);

    // vertical blur

    mBlur2Program.useProgram();

    buffer.bindForOutput(0);

    buffer.setAsInput(1);

    GLES30.glColorMask(true,true,true,true);

    GLES30.glClearColor(0.0f,0.0f,0.0f,0.0f);

    GLES30.glClear(GLES30.GL_COLOR_BUFFER_BIT);

    GLES30.glUniform1fv( mWeights2H, radius+1, weightsCache,offset);

    GLES30.glUniform1i( mRadius2H, radius);

    GLES30.glUniform1f( mDepth2H , near);

    GLES30.glUniform1i( mColorTexture2H , 0 );

    for(int i=0; i<=radius; i++) mOffsets[i] = offsetsCache[offset+i]/w1;

    GLES30.glUniform1fv( mOffsets2H ,radius+1, mOffsets,0);

    GLES30.glVertexAttribPointer(mBlur2Program.mAttribute[0], POS_DATA_SIZE, GLES30.GL_FLOAT, false, 0, mQuadPositions);

    GLES30.glVertexAttribPointer(mBlur2Program.mAttribute[1], TEX_DATA_SIZE, GLES30.GL_FLOAT, false, 0, mQuadTexture);

    DistortedRenderState.useStencilMark();

    GLES30.glDrawArrays(GLES30.GL_TRIANGLE_STRIP, 0, 4);

    DistortedRenderState.unuseStencilMark();

    GLES30.glActiveTexture(GLES30.GL_TEXTURE0);

    GLES30.glBindTexture(GLES30.GL_TEXTURE_2D, 0);

    return 2;

    }

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

  public static void createProgram(Resources resources)

  throws FragmentCompilationException,VertexCompilationException,VertexUniformsException,FragmentUniformsException,LinkingException

    {

    int gl             = Distorted.getGlVersion();

    int GLSL           = (gl==3 ? 300:100);

    String GLSL_VERSION= (gl==3 ? "#version 300 es\n" : "#version 100\n");

    final InputStream blur1VertexStream   = resources.openRawResource(R.raw.blur_vertex_shader);

    final InputStream blur1FragmentStream = resources.openRawResource(R.raw.blur1_fragment_shader);

    try

      {

      mBlur1Program = new DistortedProgram(blur1VertexStream,blur1FragmentStream,

                                          GLSL_VERSION, GLSL_VERSION + "#define MAX_BLUR "+MAX_HALO, GLSL);

      }

    catch(Exception e)

      {

      android.util.Log.e("EFFECTS", "exception trying to compile BLUR1 program: "+e.getMessage());

      throw new RuntimeException(e.getMessage());

      }

    int blur1ProgramH = mBlur1Program.getProgramHandle();

    mRadius1H       = GLES30.glGetUniformLocation( blur1ProgramH, "u_Radius");

    mOffsets1H      = GLES30.glGetUniformLocation( blur1ProgramH, "u_Offsets");

    mWeights1H      = GLES30.glGetUniformLocation( blur1ProgramH, "u_Weights");

    mDepth1H        = GLES30.glGetUniformLocation( blur1ProgramH, "u_Depth");

    mColorTexture1H = GLES30.glGetUniformLocation( blur1ProgramH, "u_ColorTexture");

    final InputStream blur2VertexStream   = resources.openRawResource(R.raw.blur_vertex_shader);

    final InputStream blur2FragmentStream = resources.openRawResource(R.raw.blur2_fragment_shader);

    try

      {

      mBlur2Program = new DistortedProgram(blur2VertexStream,blur2FragmentStream,

                                          GLSL_VERSION, GLSL_VERSION + "#define MAX_BLUR "+MAX_HALO, GLSL);

      }

    catch(Exception e)

      {

      android.util.Log.e("EFFECTS", "exception trying to compile BLUR2 program: "+e.getMessage());

      throw new RuntimeException(e.getMessage());

      }

    int blur2ProgramH = mBlur2Program.getProgramHandle();

    mRadius2H       = GLES30.glGetUniformLocation( blur2ProgramH, "u_Radius");

    mOffsets2H      = GLES30.glGetUniformLocation( blur2ProgramH, "u_Offsets");

    mWeights2H      = GLES30.glGetUniformLocation( blur2ProgramH, "u_Weights");

    mDepth2H        = GLES30.glGetUniformLocation( blur2ProgramH, "u_Depth");

    mColorTexture2H = GLES30.glGetUniformLocation( blur2ProgramH, "u_ColorTexture");

    }

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

// This implements the 'Better separable implementation using GPU fixed function sampling' from

// https://software.intel.com/en-us/blogs/2014/07/15/an-investigation-of-fast-real-time-gpu-based-image-blur-algorithms

  private void computeGaussianKernel(int radius)

    {

    int offset = radius + radius*radius/4;

    if( weightsCache[offset]==0.0f )

      {

      float z, x= 0.0f, P= (float)NUM_GAUSSIAN / (radius>3 ? radius:3);

      mWeights[0] = GAUSSIAN[0];

      float sum   = GAUSSIAN[0];

      int j;

      for(int i=1; i<=radius; i++)

        {

        x += P;

        j = (int)x;

        z = x-j;

        mWeights[i] = (1-z)*GAUSSIAN[j] + z*GAUSSIAN[j+1];

        sum += 2*mWeights[i];

        }

      for(int i=0; i<=radius; i++) mWeights[i] /= sum;

      int numloops = radius/2;

      weightsCache[offset] = mWeights[0];

      offsetsCache[offset] = 0.0f;

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

        {

        offsetsCache[offset+i+1] = mWeights[2*i+1]*(2*i+1) + mWeights[2*i+2]*(2*i+2);

        weightsCache[offset+i+1] = mWeights[2*i+1] + mWeights[2*i+2];

        offsetsCache[offset+i+1]/= weightsCache[offset+i+1];

        }

      if( radius%2 == 1 )

        {

        int index = offset + radius/2 +1;

        offsetsCache[index]=radius;

        weightsCache[index]=mWeights[radius];

        }

      }

    }

  }