content: /*
   * Copyright (C) 2011 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.filterpacks.imageproc;
  
  import android.filterfw.core.Filter;
  import android.filterfw.core.FilterContext;
  import android.filterfw.core.Frame;
  import android.filterfw.core.FrameFormat;
  import android.filterfw.core.GenerateFieldPort;
  import android.filterfw.core.Program;
  import android.filterfw.core.ShaderProgram;
  import android.filterfw.format.ImageFormat;
  
  import java.util.Date;
  import java.util.Random;
  
  public class GrainFilter extends Filter {
  
      private static final int RAND_THRESHOLD = 128;
  
      @GenerateFieldPort(name = "strength", hasDefault = true)
      private float mScale = 0f;
  
      @GenerateFieldPort(name = "tile_size", hasDefault = true)
      private int mTileSize = 640;
  
      private Program mGrainProgram;
      private Program mNoiseProgram;
  
      private int mWidth = 0;
      private int mHeight = 0;
      private int mTarget = FrameFormat.TARGET_UNSPECIFIED;
  
      private Random mRandom;
  
      private final String mNoiseShader =
              "precision mediump float;\n" +
              "uniform vec2 seed;\n" +
              "varying vec2 v_texcoord;\n" +
              "float rand(vec2 loc) {\n" +
              "  float theta1 = dot(loc, vec2(0.9898, 0.233));\n" +
              "  float theta2 = dot(loc, vec2(12.0, 78.0));\n" +
              "  float value = cos(theta1) * sin(theta2) + sin(theta1) * cos(theta2);\n" +
              // keep value of part1 in range: (2^-14 to 2^14).
              "  float temp = mod(197.0 * value, 1.0) + value;\n" +
              "  float part1 = mod(220.0 * temp, 1.0) + temp;\n" +
              "  float part2 = value * 0.5453;\n" +
              "  float part3 = cos(theta1 + theta2) * 0.43758;\n" +
              "  return fract(part1 + part2 + part3);\n" +
              "}\n" +
              "void main() {\n" +
              "  gl_FragColor = vec4(rand(v_texcoord + seed), 0.0, 0.0, 1.0);\n" +
              "}\n";
  
      private final String mGrainShader =
              "precision mediump float;\n" +
              "uniform sampler2D tex_sampler_0;\n" +
              "uniform sampler2D tex_sampler_1;\n" +
              "uniform float scale;\n" +
              "uniform float stepX;\n" +
              "uniform float stepY;\n" +
              "varying vec2 v_texcoord;\n" +
              "void main() {\n" +
              "  float noise = texture2D(tex_sampler_1, v_texcoord + vec2(-stepX, -stepY)).r * 0.224;\n" +
              "  noise += texture2D(tex_sampler_1, v_texcoord + vec2(-stepX, stepY)).r * 0.224;\n" +
              "  noise += texture2D(tex_sampler_1, v_texcoord + vec2(stepX, -stepY)).r * 0.224;\n" +
              "  noise += texture2D(tex_sampler_1, v_texcoord + vec2(stepX, stepY)).r * 0.224;\n" +
              "  noise += 0.4448;\n" +
              "  noise *= scale;\n" +
              "  vec4 color = texture2D(tex_sampler_0, v_texcoord);\n" +
              "  float energy = 0.33333 * color.r + 0.33333 * color.g + 0.33333 * color.b;\n" +
              "  float mask = (1.0 - sqrt(energy));\n" +
              "  float weight = 1.0 - 1.333 * mask * noise;\n" +
              "  gl_FragColor = vec4(color.rgb * weight, color.a);\n" +
              "}\n";
  
      public GrainFilter(String name) {
          super(name);
          mRandom = new Random(new Date().getTime());
      }
  
      @Override
      public void setupPorts() {
          addMaskedInputPort("image", ImageFormat.create(ImageFormat.COLORSPACE_RGBA));
          addOutputBasedOnInput("image", "image");
      }
  
      @Override
      public FrameFormat getOutputFormat(String portName, FrameFormat inputFormat) {
          return inputFormat;
      }
  
      public void initProgram(FilterContext context, int target) {
          switch (target) {
              case FrameFormat.TARGET_GPU:
                  ShaderProgram shaderProgram = new ShaderProgram(context, mNoiseShader);
                  shaderProgram.setMaximumTileSize(mTileSize);
                  mNoiseProgram = shaderProgram;
  
                  shaderProgram = new ShaderProgram(context, mGrainShader);
                  shaderProgram.setMaximumTileSize(mTileSize);
                  mGrainProgram = shaderProgram;
                  break;
  
              default:
                  throw new RuntimeException("Filter Sharpen does not support frames of " +
                      "target " + target + "!");
          }
          mTarget = target;
      }
  
      private void updateParameters() {
          float seed[] = { mRandom.nextFloat(), mRandom.nextFloat() };
          mNoiseProgram.setHostValue("seed", seed);
  
          mGrainProgram.setHostValue("scale", mScale);
      }
  
      private void updateFrameSize(int width, int height) {
          mWidth = width;
          mHeight = height;
  
          if (mGrainProgram != null) {
              mGrainProgram.setHostValue("stepX", 0.5f / mWidth);
              mGrainProgram.setHostValue("stepY", 0.5f / mHeight);
              updateParameters();
          }
      }
  
      @Override
      public void fieldPortValueUpdated(String name, FilterContext context) {
          if (mGrainProgram != null && mNoiseProgram != null) {
              updateParameters();
          }
      }
  
      @Override
      public void process(FilterContext context) {
          // Get input frame
          Frame input = pullInput("image");
          FrameFormat inputFormat = input.getFormat();
  
          FrameFormat noiseFormat = ImageFormat.create(inputFormat.getWidth() / 2,
                                                       inputFormat.getHeight() / 2,
                                                       ImageFormat.COLORSPACE_RGBA,
                                                       FrameFormat.TARGET_GPU);
  
          // Create noise frame
          Frame noiseFrame = context.getFrameManager().newFrame(inputFormat);
  
          // Create output frame
          Frame output = context.getFrameManager().newFrame(inputFormat);
  
          // Create program if not created already
          if (mNoiseProgram == null || mGrainProgram == null || inputFormat.getTarget() != mTarget) {
              initProgram(context, inputFormat.getTarget());
              updateParameters();
          }
  
          // Check if the frame size has changed
          if (inputFormat.getWidth() != mWidth || inputFormat.getHeight() != mHeight) {
              updateFrameSize(inputFormat.getWidth(), inputFormat.getHeight());
          }
  
          Frame[] empty = {};
          mNoiseProgram.process(empty, noiseFrame);
  
          // Process
          Frame[] inputs = {input, noiseFrame};
          mGrainProgram.process(inputs, output);
  
          // Push output
          pushOutput("image", output);
  
          // Release pushed frame
          output.release();
          noiseFrame.release();
      }
  }
  