The trick is to double buffer and use two image components, by-reference
textures and y-up. Then you can update the buffered image attached to the
backbuffer between frames and just set the texture's imagecomponent to the
back buffer in one command. Here is a bunch of fairly relevent source:
class SubOverlay {
private static final boolean debug = false;
int lx,ly,ux,uy; // which part of the parent image does this
represent
int texWidth; // the width of the texture (power of 2)
int texHeight; // the height of the texture (power of 2)
int width; // width of the sub-overlay
int height; // height of the sub-overlay
BufferedImage a; // buffered image used for icA
BufferedImage b; // buffered image used for icB
ImageComponent2D icA; // one of the double buffers
ImageComponent2D icB; // the other one of the double buffers
Shape3D shape; // textured quad used to hold geometry
Texture2D tex; // texture mapped to icA or icB
Appearance ap; // appearance for this sub-overlay
Overlay overlay; // the owner of this sub-overlay
boolean frontBuffer; // true if icA is the current texture, false if
its icB
int transferBuffer[]; // used for transferring scan lines from main
image to sub-image
/**
* Creates the sub overlay for the specified region.
*/
protected SubOverlay( Overlay overlay, int lx, int ly, int ux, int uy) {
this.overlay = overlay;
// save the screen location
this.lx = lx;
this.ly = ly;
this.ux = ux;
this.uy = uy;
// caclulate the sub overlay size
width = ux-lx+1;
height = uy-ly+1;
// now we need to calculate the texture size needed to contain this
// size sub-overlay. Find the smallest power of two that works
texWidth = smallestPower(width);
texHeight = smallestPower(height);
// create the two buffers
boolean hasAlpha = (overlay.getBlendAlpha() ||
overlay.getClipAlpha());
if (hasAlpha) {
a = CustomBufferedImage.getCustomRGBA(texWidth,texHeight);
b = CustomBufferedImage.getCustomRGBA(texWidth,texHeight);
} else {
a = CustomBufferedImage.getCustomRGB(texWidth,texHeight);
b = CustomBufferedImage.getCustomRGB(texWidth,texHeight);
}
// determine a compatible by-ref image type
int icType;
if (hasAlpha)
icType = ImageComponent2D.FORMAT_RGBA;
else
icType = ImageComponent2D.FORMAT_RGB;
// create two by-reference image components
icA = new ImageComponent2D(icType,a,true,true);
icB = new ImageComponent2D(icType,b,true,true);
// create a transfer buffer for one scan line
transferBuffer = new int[texWidth];
// create the shape
buildShape();
// define the texture
int texType;
if (hasAlpha) texType = Texture.RGBA;
else texType = Texture.RGB;
if (debug)
System.out.println("Sub-overlay : "+width+","+height+" ->
"+texWidth+","+texHeight+ " : "+
lx+","+ly+" - "+ux+","+uy);
tex = new Texture2D(Texture.BASE_LEVEL,texType,texWidth,texHeight);
tex.setBoundaryModeS(Texture.CLAMP);
tex.setBoundaryModeT(Texture.CLAMP);
tex.setMagFilter(Texture.FASTEST);
tex.setMinFilter(Texture.FASTEST);
tex.setImage(0,icA);
tex.setCapability(Texture.ALLOW_IMAGE_WRITE);
ap.setTexture(tex);
frontBuffer = true;
}
/**
* Transfers the scan lines from the full image to the sub-image. The
* scan lines are applied in reverse order so that it is compatible with
* that silly Y-up thing (grrr).
*/
protected void updateBackBuffer( BufferedImage fullImage ) {
BufferedImage backBuffer;
if (frontBuffer) backBuffer = b;
else backBuffer = a;
/*
Graphics g = backBuffer.getGraphics();
g.setColor(Color.pink);
g.fillRect(0,0,texWidth-1,texHeight-1);
g.dispose();
*/
int w = fullImage.getWidth();
for (int i=0;i<height;i++) {
int y = overlay.height-uy+i-1;
fullImage.getRGB(lx,y,width,1,transferBuffer,0,w);
backBuffer.setRGB(0,texHeight-i-1-(texHeight-height),width,1,transferBuffer,
0,texWidth);
}
/*
Graphics g = backBuffer.getGraphics();
g.setColor(Color.pink);
g.drawRect(0,0,width,height);
g.dispose();
*/
}
/**
* Swaps the buffers
*/
protected void swap() {
if (frontBuffer) tex.setImage(0,icB);
else tex.setImage(0,icA);
frontBuffer = !frontBuffer;
}
----- Original Message -----
From: Karsten Fries <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, January 21, 2002 1:43 PM
Subject: Re: [JAVA3D] Dynamic Textures?
Hi Joachim,
actually I made some experience with updating texture content quite
recently.
The approach i finally came up with is quite similar to that one you
described,
but
you don't have to recreate the Texture2D instance all the time.
The texture is only created once, and during update you just replace the
ImageComponent (which unfortunately
must be created again and again from the BufferedImage, which is certainly
rigid.
The Texture capabilites must contain ALLOW_TEXTURE_WRITE to reset the image
component (setImage( 0, imageComponent) ).
This still doesn't help! The texture seems to be not updated and the results
are kind of arbitrary, especially if you
update the texture several times with many small changes.
The final trick you need, and this is something the sun guys could check
back,
is that you should not just
replace or modify the appearance associated with the texture shape, but set
the
appearance explicilty to null and than create
a new texture appearance. The problem is (as it seems) that the system
doesn't
recognize the change the way the
update was done.
Hope this workaround works,
Karsten
PS: if you finally come up with a better solution (that especially is Java3D
1.2.1_3 compatible), you can do me a great favour
in letting me know.
Joachim Diepstraten wrote:
> Hi Alex
>
> Hmm thanks for the answer and thanks for the source
> but I'm not sure if that's actually the thing I'm
> searching for, well I still will have a look on it.
> Cause I'm not planing to do something with JMF but
> rather my textures are textures coming from an
> offScreen rendering pass.
>
> --
> Explore SRT with the help of Java3D
> (http://wwwvis.informatik.uni-stuttgart.de/relativity/minkowski)
> (http://www.antiflash.net/java3d/relativity (mirror)
>
>
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