Author Topic: removing flicker from JPCT applet with AWT graphics  (Read 6949 times)

Offline dmouse

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removing flicker from JPCT applet with AWT graphics
« on: August 14, 2008, 06:06:49 pm »
Hi all,

I was wondering if anyone knows how to remove the flickering when using standard Java AWT methods for displaying images and text (ie g.drawImage and drawString ) on top of a JPCT FrameBuffer software  rendered 3d scene. The usual double buffering approach does not seem to work, the 3D scene renders smoothly but any text/graphics drawn on top flicker very badly. Am I perhaps missing something?

Does anyone know how to remove this flickering?

Thanks in advance, for any help/advice that anyone can offer.


Offline EgonOlsen

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #1 on: August 14, 2008, 06:09:11 pm »
Draw into the rendered image instead. You can get the graphics context from the framebuffer. This won't work in Java 1.1 though...

Offline dmouse

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #2 on: August 14, 2008, 06:20:53 pm »
Egon,

Thanks you for your nearly instantaneous reply!

OK, using "buffer.getGraphics().drawString (" display text here ",200,200);" works very well, the flickering is gone.

Is there a solution that will work for 1.1 compatible applets, as this is essential for me?

Thanks again.

Offline EgonOlsen

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #3 on: August 14, 2008, 08:20:53 pm »
The problem with 1.1 is, that it has to use MemoryImageSource, which doesn't provide a graphics context. If the text/image is static, use textures instead and blit those. If it isn't, you can draw the rendered image into another one, draw your text/images onto that and draw the whole bunch to screen. That will be slower of course, which is why i would limit it to 1.1. and use another pipeline for higher versions.
You can also access the pixels-array directly, but i doubt that this will be very helpful in this case.

Offline fireside

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #4 on: August 15, 2008, 09:18:31 pm »
As long as we're on this topic.  I can't seem to set the font when I get the graphics context from the framebuffer for some reason.  It just gets ignored.  The same code works when I use g, but then I get flicker.  I can paint a string with graphics from framebuffer, but only in one type of font.  I'm compiling for 1.2.
« Last Edit: August 15, 2008, 09:21:21 pm by fireside »
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Offline EgonOlsen

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #5 on: August 16, 2008, 12:02:39 am »
I guess that Graphics should be Graphics...i don't see why one should ignore the font while the other doesn't. All i'm doing is returning the Graphics from the BufferedImage that holds the pixel data. Nothing special, no magic involved... ???

Offline fireside

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #6 on: August 16, 2008, 04:43:44 am »
Here's a screen shot:


Here's the code with just switching the commented lines:
Code: [Select]
        buffer.clear(java.awt.Color.getHSBColor(-100, -100, 130));
        if(lives > 1)buffer.blit(mLife, 0, 0,0,0,16,50,true);       
        if(lives > 2)buffer.blit(mLife, 0, 0,32,0,16,50,true);
        if(hasCheese)buffer.blit(cheese, 0, 0,440,0,32,32,true);       
         world.renderScene(this.buffer);
        world.draw(this.buffer);
        buffer.update();       
        buffer.display(g);
//        if(win){buffer.getGraphics().setFont(myFont);g.drawString("Level Complete", 100, 175);}
        if(win){g.setFont(myFont);g.drawString("Level Complete", 100, 175);} 
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Offline EgonOlsen

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #7 on: August 16, 2008, 10:16:35 am »
You are setting the font on the buffer's Graphics instance, but are rendering it into the screen's one. That can't work...

Offline fireside

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #8 on: August 16, 2008, 11:21:26 am »
Not sure what you mean.  I had it above the world.renderScene(), and it did the same thing. 
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Offline EgonOlsen

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #9 on: August 16, 2008, 11:24:29 am »
I mean this:

Code: [Select]
if(win){buffer.getGraphics().setFont(myFont);g.drawString("Level Complete", 100, 175);}
You are setting the font in another context than the screen's, but you are drawing to the screen.

It should be something like:

Code: [Select]
if(win){buffer.getGraphics().setFont(myFont);buffer.getGraphics().drawString("Level Complete", 100, 175);}

Offline fireside

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #10 on: August 16, 2008, 02:59:20 pm »
It's still little, but now it's white with this code:
Code: [Select]
world.renderScene(this.buffer);
 world.draw(this.buffer);
 if(true){buffer.getGraphics().setFont(myFont);buffer.getGraphics().drawString("Level Complete", 100, 175);}         
 buffer.update();       
  buffer.display(g);

It seems to ignore the font.  I tried setting myFont to public, but it didn't help.
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Offline EgonOlsen

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #11 on: August 16, 2008, 05:29:22 pm »
What can i say...it's just using normal Java2D methods on a normal Graphics-context of a normal BufferedImage. It should work fine. Maybe myFont is not what it is suspected to be?
« Last Edit: August 17, 2008, 12:23:38 am by EgonOlsen »

Offline fireside

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #12 on: August 16, 2008, 08:48:20 pm »
I just copied it from some tutorial.  It's at the top with the other class variables.
 public Font myFont = new Font("SansSerif", Font.BOLD, 30);

Well, maybe it will come clear later.  For now I'll just use graphics g and let it flicker if I have to change the font.
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Offline dmouse

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #13 on: August 17, 2008, 12:09:36 pm »
Hi,

I just wanted to say thank you to Egon again for his help with my original question in this thread.

I have decided to blit text and graphics over the the 3d scene, as this method will clearly work for 1.1 applets, 1.2+ applets and hardware accelerated applications, all with the same code. I initially thought this might be slower than g.drawString etc.., but isn't noticiably so, particularly with only a limited amount text being displayed (such as game menus and such).

Thanks again.

Offline AGP

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Re: removing flicker from JPCT applet with AWT graphics
« Reply #14 on: August 18, 2008, 07:30:22 am »
Fireside, I'm almost certain that if you do
Code: [Select]
Graphics g = buffer.getGraphics(); g.setFont(myFont); g.drawString("My String."); it'll work like a charm. Try it out and let us know.