Dynamic multiple image buffers?

Is it possible to create a image or image buffer dynamically with a reasonably large resolution? I would like to have a sort of second image buffer that could be drawn over the usual image. The problem of course is that there is no way to write the image using the per pixel writing commands. I would need to create and update a 640 by 480 image. This image would be used as a sort of overlay to the normal buffer. This extra image buffer is a way to store graphics data for later processing and drawing. Things like blurring and fading plasma effects can be done independently of the default back buffer.


I know the game development program 'Game Maker" called them surfaces but I have no idea how the initial creator implemented them.

IndiePath's render to texture module.

Render to texture really doesn't render to a texture, it renders to the backbuffer and grabs it into a texture.

To really render to a new targer you need something like a Frambuffer Object in OpenGL (if the extension is supported), which you can render to and then use as a texture. Otherwise you are left with something like the render-to-texture idea. Draw the texture grabbed from the previous frame to the backbuffer, modify it, re-grab it, draw the regular backbuffer, draw the grabbed texture on top, flip, clear the screen, repeat.

The DX code in the RTT module does.
For DX it creates a seperate texture which is set to the rendertarget rather than the backbuffer. The rendertarget is then reset to the backbuffer and the texture drawn.

Correct.
Its only the OpenGL one that uses the glcopy command.
Perhaps simpler as it is still worlds faster than the brute force approach with image -> pixmap ->image

Ahh, ok. Not cross-platform though ;-D

??

It is cross plattform.


On Windows you have both and on the other two operation systems you have the "crap compatible" approach with the glCopy
Most likely needed as crappies tend to have crappy GPU as well as they prefer "console" style, not? :)

I use Diablo's HighGFX for OpenGL which still seems to work after all the Bmax changes.

@tonyg , it seems like any of the threads with info on Diablos HighGFX the download links doesn't seem to work. If this is public domain could you either upload it to somewhere or send it to me on the mail shown in my profile?

There was only ever a download so not sure how Diablo meant for it to be distributed.

No problem, I have sent him an email to see if he responds.

I just mean that on OSX it doesn't render directly to the texture, there is an extra copy step.

@tonyg, I have recieved answer back from Diablo, and he writes:



I would have forwarded the mail recieved to you, but you do not have any contact info in your profile.

If you don't mind, I would appreciate if you would email me a copy, or if you could provide me with an email address where I could forward the answer from Diablo.

Hi, I have finally managed to upload highgfx.

You can download it from:
http://www.fallenmoon.net/dump/highgfx.mod.rar

And if anyone else wants to mirror it then please do :D

Thanks, I don't mind mirroring it.

http://zac-interactive.dk/mirror/highgfx.mod.rar