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;
  
  /**
   * Runs a 3x3 convolution kernel against the image
   */
  public class GPUImage3x3ConvolutionFilter extends GPUImage3x3TextureSamplingFilter {
      public static final String THREE_X_THREE_TEXTURE_SAMPLING_FRAGMENT_SHADER = "" +
              "precision highp float;\n" + 
              "\n" + 
              "uniform sampler2D inputImageTexture;\n" + 
              "\n" + 
              "uniform mediump mat3 convolutionMatrix;\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" + 
              "void main()\n" + 
              "{\n" + 
              "    mediump vec4 bottomColor = texture2D(inputImageTexture, bottomTextureCoordinate);\n" + 
              "    mediump vec4 bottomLeftColor = texture2D(inputImageTexture, bottomLeftTextureCoordinate);\n" + 
              "    mediump vec4 bottomRightColor = texture2D(inputImageTexture, bottomRightTextureCoordinate);\n" + 
              "    mediump vec4 centerColor = texture2D(inputImageTexture, textureCoordinate);\n" + 
              "    mediump vec4 leftColor = texture2D(inputImageTexture, leftTextureCoordinate);\n" + 
              "    mediump vec4 rightColor = texture2D(inputImageTexture, rightTextureCoordinate);\n" + 
              "    mediump vec4 topColor = texture2D(inputImageTexture, topTextureCoordinate);\n" + 
              "    mediump vec4 topRightColor = texture2D(inputImageTexture, topRightTextureCoordinate);\n" + 
              "    mediump vec4 topLeftColor = texture2D(inputImageTexture, topLeftTextureCoordinate);\n" + 
              "\n" + 
              "    mediump vec4 resultColor = topLeftColor * convolutionMatrix[0][0] + topColor * convolutionMatrix[0][1] + topRightColor * convolutionMatrix[0][2];\n" + 
              "    resultColor += leftColor * convolutionMatrix[1][0] + centerColor * convolutionMatrix[1][1] + rightColor * convolutionMatrix[1][2];\n" + 
              "    resultColor += bottomLeftColor * convolutionMatrix[2][0] + bottomColor * convolutionMatrix[2][1] + bottomRightColor * convolutionMatrix[2][2];\n" + 
              "\n" + 
              "    gl_FragColor = resultColor;\n" + 
              "}"; 
   
      private float[] mConvolutionKernel;
      private int mUniformConvolutionMatrix;
  
      /**
       * Instantiates a new GPUimage3x3ConvolutionFilter with default values, that
       * will look like the original image. 
       */
      public GPUImage3x3ConvolutionFilter() {
          this(new float[] {
                  0.0f, 0.0f, 0.0f,
                  0.0f, 1.0f, 0.0f,
                  0.0f, 0.0f, 0.0f
          });
      }
      
      /**
       * Instantiates a new GPUimage3x3ConvolutionFilter with given convolution kernel.
       *
       * @param convolutionKernel the convolution kernel
       */
      public GPUImage3x3ConvolutionFilter(final float[] convolutionKernel) {
          super(THREE_X_THREE_TEXTURE_SAMPLING_FRAGMENT_SHADER);
          mConvolutionKernel = convolutionKernel;
      }
  
      @Override
      public void onInit() {
          super.onInit();
          mUniformConvolutionMatrix = GLES20.glGetUniformLocation(getProgram(), "convolutionMatrix");
          setConvolutionKernel(mConvolutionKernel);
      }
  
      /**
       * Sets the convolution kernel.
       *
       * @param convolutionKernel the new convolution kernel
       */
      public void setConvolutionKernel(final float[] convolutionKernel) {
          mConvolutionKernel = convolutionKernel;
          setUniformMatrix3f(mUniformConvolutionMatrix, mConvolutionKernel);
      }
  }
  