[SOLVED] How to convert screen's color image to grayscale

compvis · Post by **compvis** » Thu Mar 12, 2015 9:57 am

Hi,

In my project, i need to simulate an infrared-nigh camera image for aircraft so i want to convert color image on buffer to grayscale before it is rendered on screen.
Could you pls point me some hints?

Thank you in advance,

Zonder · Post by **Zonder** » Thu Mar 12, 2015 10:34 am

Here you go http://www.ogre3d.org/tikiwiki/tiki-ind ... Compositor

Some other reading on screen effects http://www.ogre3d.org/tikiwiki/tiki-ind ... +Rendering

areay · Post by **areay** » Fri Mar 13, 2015 1:30 am

Yeah, there's an Ogre SampleBrowser Sample that shows compositor that does exactly this.

compvis · Post by **compvis** » Fri Mar 13, 2015 2:56 am

Zonder wrote:Here you go http://www.ogre3d.org/tikiwiki/tiki-ind ... Compositor

Some other reading on screen effects http://www.ogre3d.org/tikiwiki/tiki-ind ... +Rendering

Thanks, these are great links. I learn it very much.

areay wrote:Yeah, there's an Ogre SampleBrowser Sample that shows compositor that does exactly this.

Thanks,

But is it possible to processing in real time by coding (not by scripts)? For example, image processing on buffer before it is rendered on screen? Which event i should inject my codes and how to handle image from buffer?

Post by **dark_sylinc** » Fri Mar 13, 2015 4:13 am

compvis wrote:But is it possible to processing in real time by coding (not by scripts)? For example, image processing on buffer before it is rendered on screen? Which event i should inject my codes and how to handle image from buffer?

What the Compositor sample does is to run pixel shaders, which is your own programmable code running on the GPU.
If what you're looking is to use a routine writen by you in C++ (instead of hlsl or glsl), even though it can be done, it will be extremely slow.

compvis · Post by **compvis** » Fri Mar 13, 2015 4:23 am

dark_sylinc wrote:
compvis wrote:But is it possible to processing in real time by coding (not by scripts)? For example, image processing on buffer before it is rendered on screen? Which event i should inject my codes and how to handle image from buffer?
What the Compositor sample does is to run pixel shaders, which is your own programmable code running on the GPU.
If what you're looking is to use a routine writen by you in C++ (instead of hlsl or glsl), even though it can be done, it will be extremely slow.

I don't want to dive into Hlsl or Glsl because I'm not familiar (not expert) with it and my application is small so i want to convert buffer data to work with opencv image (cv::Mat image) with C++ interface. Could you pls tell me some hints?

Or Could someone help me to create scripts (compositor) ?
Thanks

areay · Post by **areay** » Tue Mar 17, 2015 4:29 am

>> Or Could someone help me to create scripts (compositor) ?

We've told you where to find this, in the source (and material samples) for the SampleBrowser that comes as part of Ogre.

The other, slow, way to do it would be using a RTT and then doing your processing on the RenderTexture that it writes to. There is an example of how to use RTT in the Ogre tutorials. After you've done the tutorial you can change the RenderTexture to be read/write and then process that.

compvis · Post by **compvis** » Wed Mar 18, 2015 4:29 am

Dear all,

My problem resolved in Compositors sample.

Than you very much,

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