content: /*
   * Copyright (C) 2012 CyberAgent
   *
   * 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 jp.co.cyberagent.android.gpuimage;
  
  import android.opengl.GLES20;
  
  /**
   * This uses Sobel edge detection to place a black border around objects,
   * and then it quantizes the colors present in the image to give a cartoon-like quality to the image.
   */
  public class GPUImageToonFilter extends GPUImage3x3TextureSamplingFilter {
      public static final String TOON_FRAGMENT_SHADER = "" +
              "precision highp float;\n" +
              "\n" +
              "varying vec2 textureCoordinate;\n" +
              "varying vec2 leftTextureCoordinate;\n" +
              "varying vec2 rightTextureCoordinate;\n" +
              "\n" +
              "varying vec2 topTextureCoordinate;\n" +
              "varying vec2 topLeftTextureCoordinate;\n" +
              "varying vec2 topRightTextureCoordinate;\n" +
              "\n" +
              "varying vec2 bottomTextureCoordinate;\n" +
              "varying vec2 bottomLeftTextureCoordinate;\n" +
              "varying vec2 bottomRightTextureCoordinate;\n" +
              "\n" +
              "uniform sampler2D inputImageTexture;\n" +
              "\n" +
              "uniform highp float intensity;\n" +
              "uniform highp float threshold;\n" +
              "uniform highp float quantizationLevels;\n" +
              "\n" +
              "const highp vec3 W = vec3(0.2125, 0.7154, 0.0721);\n" +
              "\n" +
              "void main()\n" +
              "{\n" +
              "vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);\n" +
              "\n" +
              "float bottomLeftIntensity = texture2D(inputImageTexture, bottomLeftTextureCoordinate).r;\n" +
              "float topRightIntensity = texture2D(inputImageTexture, topRightTextureCoordinate).r;\n" +
              "float topLeftIntensity = texture2D(inputImageTexture, topLeftTextureCoordinate).r;\n" +
              "float bottomRightIntensity = texture2D(inputImageTexture, bottomRightTextureCoordinate).r;\n" +
              "float leftIntensity = texture2D(inputImageTexture, leftTextureCoordinate).r;\n" +
              "float rightIntensity = texture2D(inputImageTexture, rightTextureCoordinate).r;\n" +
              "float bottomIntensity = texture2D(inputImageTexture, bottomTextureCoordinate).r;\n" +
              "float topIntensity = texture2D(inputImageTexture, topTextureCoordinate).r;\n" +
              "float h = -topLeftIntensity - 2.0 * topIntensity - topRightIntensity + bottomLeftIntensity + 2.0 * bottomIntensity + bottomRightIntensity;\n" +
              "float v = -bottomLeftIntensity - 2.0 * leftIntensity - topLeftIntensity + bottomRightIntensity + 2.0 * rightIntensity + topRightIntensity;\n" +
              "\n" +
              "float mag = length(vec2(h, v));\n" +
              "\n" +
              "vec3 posterizedImageColor = floor((textureColor.rgb * quantizationLevels) + 0.5) / quantizationLevels;\n" +
              "\n" +
              "float thresholdTest = 1.0 - step(threshold, mag);\n" +
              "\n" +
              "gl_FragColor = vec4(posterizedImageColor * thresholdTest, textureColor.a);\n" +
              "}\n";
  
      float mThreshold;
      int mThresholdLocation;
      float mQuantizationLevels;
      int mQuantizationLevelsLocation;
  
      public GPUImageToonFilter() {
          this(0.2f, 10.0f);
      }
  
      public GPUImageToonFilter(float threshold, float quantizationLevels) {
          super(TOON_FRAGMENT_SHADER);
          mThreshold = threshold;
          mQuantizationLevels = quantizationLevels;
      }
  
      @Override
      public void onInit() {
          super.onInit();
          mThresholdLocation = GLES20.glGetUniformLocation(getProgram(), "threshold");
          mQuantizationLevelsLocation = GLES20.glGetUniformLocation(getProgram(), "quantizationLevels");
      }
  
      @Override
      public void onInitialized() {
          super.onInitialized();
          setThreshold(mThreshold);
          setQuantizationLevels(mQuantizationLevels);
      }
  
      /**
       * The threshold at which to apply the edges, default of 0.2.
       *
       * @param threshold default 0.2
       */
      public void setThreshold(final float threshold) {
          mThreshold = threshold;
          setFloat(mThresholdLocation, threshold);
      }
  
      /**
       * The levels of quantization for the posterization of colors within the scene, with a default of 10.0.
       *
       * @param quantizationLevels default 10.0
       */
      public void setQuantizationLevels(final float quantizationLevels) {
          mQuantizationLevels = quantizationLevels;
          setFloat(mQuantizationLevelsLocation, quantizationLevels);
      }
  }
  