Partying on the bitmap...

Java 2D
#1

OK, I’ve googled a bit for this and haven’t found any leads. Any help would be appreciated…

How do I directly party on the bitmap in Java (i.e. draw arbitrary, dynamic stuff there)?

I’m trying to stay Java 1.1 compatible. I’m double-buffering, using an off-screen Image. Mostly, I want to blit other images into the main off-screen image, but the set of functions provided is rather limited, and so I’d like to do at least some stuff more dynamically (i.e. color-remapping as I blit, arbitrary rotation, etc…). I understand that this is likely to be somewhat slower than the provided drawImage functions - I can handle that. But of course I don’t want to have to drop all the way down to using 1 x 1 fillRects or the like.

In C, you can generally get a ptr to the dest bitmap (effectively as an array of bytes or DWORDs), then walk that array and do what you like - anything roughly comparable in Java?

I looked at BufferedImage, but that appears to require something higher than Java 1.1 (it’s an invalid type when I compile for 1.1 - I didn’t test it in 1.4, though).

I’ve seen the reference code here:
http://java.sun.com/j2se/1.4.2/docs/api/java/awt/image/MemoryImageSource.html
But this basically requires you to create a new image every time. So, for instance, if I had a slowly spinning ship sprite, then I’d have to create a new version of that sprite every frame. It’s doable, but not an ideal solution - what I’d like is to have my ship, in it’s normal non-rotated form, and dynamically blit it every frame at whatever the current rotation is.

Any thoughts and/or websites with reference code?

Thanks,
Phil

#2

You can use MemoryImageSource. You don’t have to create a new one every frame. There is a way to update the pixels.

#3

[quote]I’ve seen the reference code here:
http://java.sun.com/j2se/1.4.2/docs/api/java/awt/image/MemoryImageSource.html
But this basically requires you to create a new image every time. So, for instance, if I had a slowly spinning ship sprite, then I’d have to create a new version of that sprite every frame. It’s doable, but not an ideal solution - what I’d like is to have my ship, in it’s normal non-rotated form, and dynamically blit it every frame at whatever the current rotation is.
[/quote]
You could create your own version of this. Just create a class that implements the ImageProducer interface, then you control how the image is generated.

#4

But this is painfully slow! I would dual-implement one with PxelGrabber/ImageSource (for pre-1.2 platfroms) and completly rely on BufferedImage starting with 1.2 and later…

lg Clemens

#5

[quote]But this is painfully slow! I would dual-implement one with PxelGrabber/ImageSource (for pre-1.2 platfroms) and completly rely on BufferedImage starting with 1.2 and later…
[/quote]
BufferedImage is faster but I don’t think the differance is huge. The slow part is uploading the data to the card. Have you done any tests?

#6

yep, since 1.4 PixelGrabber’s performance is REALLY terrible.
It needs several (~7 with X11; 1,5min with OGL!!) seconds to completly grab an 1024x768 image…

There’s already a bug-report complaining about that…

lg Clemens