Fastest way to set every pixel?

[dime]

I have a game board, let's say 1024x768.  Kind of like the game of life, but every cell will be it's own color.

What's the fastest way to do this?  I tried it though Slick 2d, but assuming there is probably some over head there.
I don't know OpenGL, so hopefully someone can guide me?

I've tried drawing fillRect and using an image (byte) buffer (ImageData.getImage() - involves lots of creating/destroying of an Image object)
I did it on different workstations, one has a way better CPU and the other has way better GPU.
It seems filling quads is heavy on the GPU and creating an image/byte buffer kills the cpu/memory.

Doing in direct in lwjgl will give better performance?  What would be a good approach and can someone point me in the right direction?

[gouessej]

Hi!

Slick2D already uses LWJGL. I'm not sure using OpenGL yourself would give better performance.

[moogie]

not sure why you would need to be constantly creating/destroying image objects when using a byte array to "blit" pixels.

I have used this in the past an achived reasonable frame rate:

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BufferedImage image = new BufferedImage(width,height,BufferedImage.INT_RGB); Int[] imagePixelData = ((DataBufferInt)image.getRaster().getDataBuffer()).getData(); ... // main loop start while (true) { /// do stuff... for (int y=0;y<height;y++) { for (int x=0;x<width;x++) { // get red, green, blue components however you like imagePixelData[y*width+x] = red<<16 | green <<8 | blue; } } // get graphic object of swing component to draw on and draw the image g.drawImage(image,0,0,null); // go back to start of main loop }

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[ShannonSmith]

Using any of the BufferedImage INT_ types:

Arrays.fill(((DataBufferInt)image.getData().getDataBuffer()).getData(),color);

Arrays.fill is much faster than a for loop.

[moogie]

true for a single color, however I was under the impression he wanted to manipulate the colour of individual pixels...

[ShannonSmith]

true for a single color, however I was under the impression he wanted to manipulate the colour of individual pixels...

Oh... I think your right, I read the title and thought he was talking about filling the whole image with a single colour.

[Momoko_Fan]

Probably just getting the pixels from the BufferedImage, modifying it, then drawing the image should be fastest.
Or you can go overboard and write a GPU shader that does this with OpenGL/OpenCL, it would be extremely fast but also hard to write.

[dime]

Probably just getting the pixels from the BufferedImage, modifying it, then drawing the image should be fastest.
Or you can go overboard and write a GPU shader that does this with OpenGL/OpenCL, it would be extremely fast but also hard to write.

I think that is what I want.  I'ved tried images and rects already, but pretty slow.
Any newbie articles to get started on shaders?

[moogie]

well, i knocked up a simple program which fills pixels of a 1024x768 image using a buffered image and on my atom net book it achieves 68 fps so on higher spec machines it should do better. what is your target frame rate?

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import java.awt.Graphics2D; import java.awt.image.BufferStrategy; import java.awt.image.BufferedImage; import java.awt.image.DataBufferInt; import javax.swing.JFrame; final public class a extends JFrame {    private static final int SCREEN_WIDTH = 1024;                     // Screen Width   private static final int SCREEN_HEIGHT = 768;                     // Screen Height   private static final int WIDTH_MUL_HEIGHT_MINUS_ONE=SCREEN_WIDTH*SCREEN_HEIGHT-1;         final public static  void main( String[] a) throws Exception     {          new a();     }             a() throws Exception     {          Graphics2D g;       final BufferedImage image= new BufferedImage(SCREEN_WIDTH,SCREEN_HEIGHT,BufferedImage.TYPE_INT_RGB);       /****************************************************************************************************************  * Initalize Screen  */       // the buffer strategey used for the video double buffer      BufferStrategy strategy;               setSize(SCREEN_WIDTH, SCREEN_HEIGHT);       show();             setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);             createBufferStrategy(2);       strategy = getBufferStrategy();              int frameCount=0;       long threashold=System.currentTimeMillis();       long time;       int i;             int[] pixelData=((DataBufferInt)image.getRaster().getDataBuffer()).getData();       /****************************************************************************************************************        * Game Loop        */       do       {                time=System.currentTimeMillis();   // the current timestamp         frameCount++;           if(time>threashold)           {              setTitle(""+frameCount);              frameCount=0;              threashold=time+1000-(time-threashold);           }                     for (i=WIDTH_MUL_HEIGHT_MINUS_ONE;i>=0;i--)           {              pixelData[i]=(i)&0xFFFFFF;           }                                          // Get hold of a graphics context for the accelerated surface           g = (Graphics2D) strategy.getDrawGraphics();          g.drawImage(image,0,0,null);                     strategy.show();             //    // give some cpu time to other processes          Thread.yield();       } while (true);               }     }

[dime]

well, i knocked up a simple program which fills pixels of a 1024x768 image using a buffered image and on my atom net book it achieves 68 fps so on higher spec machines it should do better. what is your target frame rate?

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import java.awt.Graphics2D; import java.awt.image.BufferStrategy; import java.awt.image.BufferedImage; import java.awt.image.DataBufferInt; import javax.swing.JFrame; final public class a extends JFrame {    private static final int SCREEN_WIDTH = 1024;                     // Screen Width   private static final int SCREEN_HEIGHT = 768;                     // Screen Height   private static final int WIDTH_MUL_HEIGHT_MINUS_ONE=SCREEN_WIDTH*SCREEN_HEIGHT-1;         final public static  void main( String[] a) throws Exception     {          new a();     }             a() throws Exception     {          Graphics2D g;       final BufferedImage image= new BufferedImage(SCREEN_WIDTH,SCREEN_HEIGHT,BufferedImage.TYPE_INT_RGB);       /****************************************************************************************************************  * Initalize Screen  */       // the buffer strategey used for the video double buffer      BufferStrategy strategy;               setSize(SCREEN_WIDTH, SCREEN_HEIGHT);       show();             setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);             createBufferStrategy(2);       strategy = getBufferStrategy();              int frameCount=0;       long threashold=System.currentTimeMillis();       long time;       int i;             int[] pixelData=((DataBufferInt)image.getRaster().getDataBuffer()).getData();       /****************************************************************************************************************        * Game Loop        */       do       {                time=System.currentTimeMillis();   // the current timestamp         frameCount++;           if(time>threashold)           {              setTitle(""+frameCount);              frameCount=0;              threashold=time+1000-(time-threashold);           }                     for (i=WIDTH_MUL_HEIGHT_MINUS_ONE;i>=0;i--)           {              pixelData[i]=(i)&0xFFFFFF;           }                                          // Get hold of a graphics context for the accelerated surface           g = (Graphics2D) strategy.getDrawGraphics();          g.drawImage(image,0,0,null);                     strategy.show();             //    // give some cpu time to other processes          Thread.yield();       } while (true);               }     }

Thanks, but I'm using Slick 2d; so would need to convert from AWT BufferedImage to Image:http://slick.cokeandcode.com/javadoc/org/newdawn/slick/Image.html

I'm assuming that would take a performance hit converting it every frame.

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[moogie]

well, i have never used slick2d before, however I would assume that you can do similar... i.e.

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ImageBuffer buffer = new ImageBuffer(1024,768); byte[] pixelData = buffer.getRGBA() ; Image image = buffer.getImage(); ... int index; // main loop while(true) { for (int y=0;y<height;y++) { for (int x=0;x<width;x++) {    index=(y*width+x)*4;    pixelData[index++]=red_component    pixelData[index++]=green_component    pixelData[index++]=blue_component    pixelData[index]=alpha_component } } ... draw image to canvas }