aparapi sample

Main.java

package example;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

import com.aparapi.Kernel;
import com.aparapi.Range;
/**
 * Required System Properties
 * 
 *-Dexample.useGPU: true of false.
 *-Dexample.inputFilePath: input file path str.
 *-Dexample.outputFilePath: output file path str.
 *-Djava.library.path: path to directory of aparapi_x86_64.dll
 *-Dcom.aparapi.enableShowGeneratedOpenCL: when you want detailed info, true.
 *-Dcom.aparapi.enableExecutionModeReporting: when you want detailed info, true.
 * */
public class Main {
  private int width;
  private int height;

  public static void main(String[] args) throws IOException {
    
    boolean useGPU = Boolean.getBoolean("example.useGPU");
    String inputFilePath = System.getProperty("example.inputFilePath");
    String outputFilePath = System.getProperty("example.outputFilePath");
    
    Main main = new Main();

    int[] pixels = main.loadFile(new File(inputFilePath));
    long start = System.currentTimeMillis();
    if (useGPU) {
      main.convertToGrayScaleInGpu(pixels);
    } else {
      main.convertToGrayScaleInJvm(pixels);
    }
    System.out.println("Convert Finished:" + (System.currentTimeMillis() - start) + "ms");
    
    File outFile = new File(outputFilePath);
    main.saveFile(outFile, pixels);
  }
  
  private void convertToGrayScaleInJvm(final int[] pixels) {
    for (int i = 0; i < pixels.length; i++) {
      int pixel = pixels[i];
      int alpha = pixel >> 24 & 0xFF;
      int red   = pixel >> 16 & 0xFF;
      int green = pixel >>  8 & 0xFF;
      int blue  = pixel & 0xFF;
      int y = (int)(0.298912 * red + 0.586611 * green + 0.114478 * blue);
      pixels[i] = alpha << 24  | y << 16 | y << 8 | y;
    }
  }
  
  private void convertToGrayScaleInGpu(final int[] pixels) {
    
    Kernel kernel = new Kernel() {
      @Override
      public void run() {
        //GPU world
        int i = getGlobalId();
        int pixel = pixels[i];
        int alpha = pixel >> 24 & 0xFF;
        int red   = pixel >> 16 & 0xFF;
        int green = pixel >>  8 & 0xFF;
        int blue  = pixel & 0xFF;
        int y = (int)(0.298912 * red + 0.586611 * green + 0.114478 * blue);
        pixels[i] = alpha << 24  | y << 16 | y << 8 | y;
      }};
      int size = pixels.length;
      kernel.execute(Range.create(size));
  }
  
  private int[] loadFile(File file) throws IOException {
    BufferedImage img = ImageIO.read(file);
    this.width = img.getWidth();
    this.height = img.getHeight();
    int[] pixels = new int[width*height];
    img.getRGB(0, 0, width, height, pixels, 0, width);
    return pixels;
  }
  
  private void saveFile(File file, int[] px) throws IOException {
    BufferedImage out = new BufferedImage(this.width, this.height, BufferedImage.TYPE_INT_RGB);
    out.setRGB(0, 0, this.width, this.height, px, 0, this.width);
    ImageIO.write(out, "jpg", file);
  }

}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>ka_ka_xyz</groupId>
  <artifactId>example.gpu</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>gpu_example</name>
  <dependencies>
    <dependency>
        <groupId>com.aparapi</groupId>
        <artifactId>aparapi</artifactId>
        <version>1.4.1</version>
    </dependency>
  </dependencies>
</project>