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;
  
  /**
   * Adjusts the shadows and highlights of an image
   * shadows: Increase to lighten shadows, from 0.0 to 1.0, with 0.0 as the default.
   * highlights: Decrease to darken highlights, from 0.0 to 1.0, with 1.0 as the default.
   */
  public class GPUImageHighlightShadowFilter extends GPUImageFilter {
      public static final String HIGHLIGHT_SHADOW_FRAGMENT_SHADER = "" +
              " uniform sampler2D inputImageTexture;\n" +
              " varying highp vec2 textureCoordinate;\n" +
              "  \n" +
              " uniform lowp float shadows;\n" +
              " uniform lowp float highlights;\n" +
              " \n" +
              " const mediump vec3 luminanceWeighting = vec3(0.3, 0.3, 0.3);\n" +
              " \n" +
              " void main()\n" +
              " {\n" +
              " 	lowp vec4 source = texture2D(inputImageTexture, textureCoordinate);\n" +
              " 	mediump float luminance = dot(source.rgb, luminanceWeighting);\n" +
              " \n" +
              " 	mediump float shadow = clamp((pow(luminance, 1.0/(shadows+1.0)) + (-0.76)*pow(luminance, 2.0/(shadows+1.0))) - luminance, 0.0, 1.0);\n" +
              " 	mediump float highlight = clamp((1.0 - (pow(1.0-luminance, 1.0/(2.0-highlights)) + (-0.8)*pow(1.0-luminance, 2.0/(2.0-highlights)))) - luminance, -1.0, 0.0);\n" +
              " 	lowp vec3 result = vec3(0.0, 0.0, 0.0) + ((luminance + shadow + highlight) - 0.0) * ((source.rgb - vec3(0.0, 0.0, 0.0))/(luminance - 0.0));\n" +
              " \n" +
              " 	gl_FragColor = vec4(result.rgb, source.a);\n" +
              " }";
  
      private int mShadowsLocation;
      private float mShadows;
      private int mHighlightsLocation;
      private float mHighlights;
  
      public GPUImageHighlightShadowFilter() {
          this(0.0f, 1.0f);
      }
  
      public GPUImageHighlightShadowFilter(final float shadows, final float highlights) {
          super(NO_FILTER_VERTEX_SHADER, HIGHLIGHT_SHADOW_FRAGMENT_SHADER);
          mHighlights = highlights;
          mShadows = shadows;
      }
  
      @Override
      public void onInit() {
          super.onInit();
          mHighlightsLocation = GLES20.glGetUniformLocation(getProgram(), "highlights");
          mShadowsLocation = GLES20.glGetUniformLocation(getProgram(), "shadows");
      }
  
      @Override
      public void onInitialized() {
          super.onInitialized();
          setHighlights(mHighlights);
          setShadows(mShadows);
      }
  
      public void setHighlights(final float highlights) {
          mHighlights = highlights;
          setFloat(mHighlightsLocation, mHighlights);
      }
      
      public void setShadows(final float shadows) {
          mShadows = shadows;
          setFloat(mShadowsLocation, mShadows);
      }
  }
  