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;
  
  public class VignetteFilter extends Filter {
  
      @GenerateFieldPort(name = "scale", hasDefault = true)
      private float mScale = 0f;
  
      @GenerateFieldPort(name = "tile_size", hasDefault = true)
      private int mTileSize = 640;
  
      private Program mProgram;
  
      private int mWidth = 0;
      private int mHeight = 0;
      private int mTarget = FrameFormat.TARGET_UNSPECIFIED;
  
      private final float mSlope = 20.0f;
      private final float mShade = 0.85f;
  
      private final String mVignetteShader =
              "precision mediump float;\n" +
              "uniform sampler2D tex_sampler_0;\n" +
              "uniform float range;\n" +
              "uniform float inv_max_dist;\n" +
              "uniform float shade;\n" +
              "uniform vec2 scale;\n" +
              "varying vec2 v_texcoord;\n" +
              "void main() {\n" +
              "  const float slope = 20.0;\n" +
              "  vec2 coord = v_texcoord - vec2(0.5, 0.5);\n" +
              "  float dist = length(coord * scale);\n" +
              "  float lumen = shade / (1.0 + exp((dist * inv_max_dist - range) * slope)) + (1.0 - shade);\n" +
              "  vec4 color = texture2D(tex_sampler_0, v_texcoord);\n" +
              "  gl_FragColor = vec4(color.rgb * lumen, color.a);\n" +
              "}\n";
  
      public VignetteFilter(String name) {
          super(name);
      }
  
      @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, mVignetteShader);
                  shaderProgram.setMaximumTileSize(mTileSize);
                  mProgram = shaderProgram;
                  break;
  
              default:
                  throw new RuntimeException("Filter Sharpen does not support frames of " +
                      "target " + target + "!");
          }
          mTarget = target;
      }
  
      private void initParameters() {
          if (mProgram != null) {
              float scale[] = new float[2];
              if (mWidth > mHeight) {
                  scale[0] = 1f;
                  scale[1] = ((float) mHeight) / mWidth;
              } else {
                  scale[0] = ((float) mWidth) / mHeight;
                  scale[1] = 1f;
              }
              float max_dist = ((float) Math.sqrt(scale[0] * scale[0] + scale[1] * scale[1])) * 0.5f;
              mProgram.setHostValue("scale", scale);
              mProgram.setHostValue("inv_max_dist", 1f / max_dist);
              mProgram.setHostValue("shade", mShade);
  
              updateParameters();
          }
      }
  
      private void updateParameters() {
          // The 'range' is between 1.3 to 0.6. When scale is zero then range is 1.3
          // which means no vignette at all because the luminousity difference is
          // less than 1/256 and will cause nothing.
          mProgram.setHostValue("range", 1.30f - (float) Math.sqrt(mScale) * 0.7f);
      }
  
      @Override
      public void fieldPortValueUpdated(String name, FilterContext context) {
          if (mProgram != null) {
              updateParameters();
          }
      }
  
      @Override
      public void process(FilterContext context) {
          // Get input frame
          Frame input = pullInput("image");
          FrameFormat inputFormat = input.getFormat();
  
          // Create program if not created already
          if (mProgram == null || inputFormat.getTarget() != mTarget) {
              initProgram(context, inputFormat.getTarget());
          }
  
          // Check if the frame size has changed
          if (inputFormat.getWidth() != mWidth || inputFormat.getHeight() != mHeight) {
              mWidth = inputFormat.getWidth();
              mHeight = inputFormat.getHeight();
              initParameters();
          }
  
          // Create output frame
          Frame output = context.getFrameManager().newFrame(inputFormat);
  
          // Process
          mProgram.process(input, output);
  
          // Push output
          pushOutput("image", output);
  
          // Release pushed frame
          output.release();
      }
  }
  