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;
  
  /**
   * The haze filter can be used to add or remove haze.
   *
   * This is similar to a UV filter.
   */
  public class GPUImageHazeFilter extends GPUImageFilter {
      public static final String HAZE_FRAGMENT_SHADER = "" +
              "varying highp vec2 textureCoordinate;\n" +
              "\n" +
              "uniform sampler2D inputImageTexture;\n" +
              "\n" +
              "uniform lowp float distance;\n" +
              "uniform highp float slope;\n" +
              "\n" +
              "void main()\n" +
              "{\n" +
              "	//todo reconsider precision modifiers	 \n" +
              "	 highp vec4 color = vec4(1.0);//todo reimplement as a parameter\n" +
              "\n" +
              "	 highp float  d = textureCoordinate.y * slope  +  distance; \n" +
              "\n" +
              "	 highp vec4 c = texture2D(inputImageTexture, textureCoordinate) ; // consider using unpremultiply\n" +
              "\n" +
              "	 c = (c - d * color) / (1.0 -d);\n" +
              "\n" +
              "	 gl_FragColor = c; //consider using premultiply(c);\n" +
              "}\n";
  
      private float mDistance;
      private int mDistanceLocation;
      private float mSlope;
      private int mSlopeLocation;
  
      public GPUImageHazeFilter() {
          this(0.2f, 0.0f);
      }
  
      public GPUImageHazeFilter(float distance, float slope) {
          super(NO_FILTER_VERTEX_SHADER, HAZE_FRAGMENT_SHADER);
          mDistance = distance;
          mSlope = slope;
      }
  
      @Override
      public void onInit() {
          super.onInit();
          mDistanceLocation = GLES20.glGetUniformLocation(getProgram(), "distance");
          mSlopeLocation = GLES20.glGetUniformLocation(getProgram(), "slope");
      }
  
      @Override
      public void onInitialized() {
          super.onInitialized();
          setDistance(mDistance);
          setSlope(mSlope);
      }
  
      /**
       * Strength of the color applied. Default 0. Values between -.3 and .3 are best.
       *
       * @param distance -0.3 to 0.3 are best, default 0
       */
      public void setDistance(float distance) {
          mDistance = distance;
          setFloat(mDistanceLocation, distance);
      }
  
      /**
       * Amount of color change. Default 0. Values between -.3 and .3 are best.
       *
       * @param slope -0.3 to 0.3 are best, default 0
       */
      public void setSlope(float slope) {
          mSlope = slope;
          setFloat(mSlopeLocation, slope);
      }
  }
  