Jump to content
  • Advertisement
Sign in to follow this  
Ilici

OpenGL Cloud Rendering Demo, Testing Needed (new ver)

This topic is 4838 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

New version uploaded Fixes: 1. Ugly rotating is now gone 2. Impostor/3D blending is smoother ---------------------------------- Hi guys, I've been writing an article on 3D volumetric cloud rendering with realistic shading using OpenGL and it will be online real soon now. There is also a demo which I'd like to get some feedback on, mostly if everything works and what performance you get. You can download the demo here. The FPS counter is quite shoddy (i just take 1 over the frame time) but mostly I'm interested in the amount of slow down when switching from impostors to 3d models of the clouds (this should be fairly obvious). Here's a screenshot as a reference to what it should look like. There's no error logging, if anything goes wrong (missing files) it will simply quit, but there shouldn't be any problems since no extensions are used. On my Radeon 7200 it works fine but when going in clouds the performance drops well down (5-10 fps). On a Geforce 2 MX I've encountered some problems with the clouds being simply grey and I'm not sure what to blame. [Edited by - Ilici on August 18, 2005 1:27:54 PM]

Share this post


Link to post
Share on other sites
Advertisement
Seems to be about the same on my GeForce FX 5700LE. 80+ fps nowhere near the clouds (probably refresh rate limited). When I get near the clouds the number of particles soard to over 10000 and the frame rate drops to 5 fps or so. Looks very nice apart from one thing: when I turn the clouds seems to turn with me, although I'm guessing this is just in the nature of the system rather than a bug per se.

Share this post


Link to post
Share on other sites
If you're looking for just performance tweeks, it runs fine on a Radeon 9800 pro.

A few notes:

The load time is a bit long (20 seconds), but, depending on the code necessary to do this, it might be expected.

The clouds rotate depending on your orientation. Not sure if this was what you were going for.

The clouds look nice. Although, they have a bit of that freshly picked cotton bits on the edges. Perhaps alpha transparency levels should be increased on the little bits? Then I think it would look a bit more natural (sort of running through the gin look).

It's a bit disorienting to start the application looking down. You may want to add a plane with a bit of flat shading just so people can know what they're looking at. Also, starting by looking toward the sun would be nice.

You may want to get rid of the pointer as well. It's a bit distracting.

The layperson wouldn't be able to tell the difference between fake and fully rendered clouds, so you have that going for you.

Good luck with what you're doing, the clouds look great!

Patrick

Share this post


Link to post
Share on other sites
Very nice work!

Did you roughly follow the technique in this article?

I ask because the clouds are composed of particles and I would like to know if the trick to making them look real is in the lighting or the particle system or both.

Share this post


Link to post
Share on other sites
Quote:
Original post by InterGeek
The load time is a bit long (20 seconds), but, depending on the code necessary to do this, it might be expected.


I have to do read-back from the framebuffer for each particle (a cloud can have thousands). Also the particles must be sorted and there are some more complex operations done inside a loop over all the particles. But you are right, slow loading times are a drawback of this method and I've mentioned it in the article.

Quote:

The clouds rotate depending on your orientation. Not sure if this was what you were going for.


Hmm, well the impostors are regenerated when the angle between the current and previous camera position, from the cloud center, is greater than some value. Tweaking this value will result in a balance between obvious popping and performance. I'll try to work on it, maybe make it adjustable since graphics card performance varies a lot.

Quote:

The clouds look nice. Although, they have a bit of that freshly picked cotton bits on the edges. Perhaps alpha transparency levels should be increased on the little bits? Then I think it would look a bit more natural (sort of running through the gin look).


I see what you mean, I'll try that idea out. The sizes of the particles are stored in the cloud models which I took from the original implementation by Harris.

Quote:

It's a bit disorienting to start the application looking down. You may want to add a plane with a bit of flat shading just so people can know what they're looking at. Also, starting by looking toward the sun would be nice.

You may want to get rid of the pointer as well. It's a bit distracting.



I'm such a lazy programmer :D. I'll fix that.

Quote:
by skittleo
Did you roughly follow the technique in this article?


Both mine and that article are based on the same paper.

I'm a little worried about the 5fps when going into the cloud, that's a fairly big problem, can anyone try to replicate that kind of performance and tell me how many particles there were rendered?

Share this post


Link to post
Share on other sites
It sounds like I was being nit-picky. Like I said, the program looks professional. Those are some great looking clouds!

Patrick

Share this post


Link to post
Share on other sites
hmm... can´t tell anything about the performance since it is constantly running at 59.9 fps, which is obviously due to my 60 Hz desktop refresh rate. Turning off VSync would really help to tell you something about the performance.

My hardware specs:
AMD Barton 2500+ @ 3200+
GeForce 6800 GT 256 MB
1024 MB RAM

The rotation of the clouds is quite obvious, depends on what you plan to do with those clouds, but if you want them to be close to the camera, you should try to hide it better. Otherwise the clouds look great I think, although they could benefit from more variation inside them. I think the clouds have too less variations in their shade closer to their center. Perhaps adding some lens flare would be nice, too.

Share this post


Link to post
Share on other sites
Quote:
Original post by matches81
Turning off VSync would really help to tell you something about the performance.
You can change the VSync setting in the Advanced Settings of your Display Properties.

Share this post


Link to post
Share on other sites
Quote:
Original post by matches81
hmm... can´t tell anything about the performance since it is constantly running at 59.9 fps, which is obviously due to my 60 Hz desktop refresh rate. Turning off VSync would really help to tell you something about the performance.

My hardware specs:
AMD Barton 2500+ @ 3200+
GeForce 6800 GT 256 MB
1024 MB RAM

The rotation of the clouds is quite obvious, depends on what you plan to do with those clouds, but if you want them to be close to the camera, you should try to hide it better. Otherwise the clouds look great I think, although they could benefit from more variation inside them. I think the clouds have too less variations in their shade closer to their center. Perhaps adding some lens flare would be nice, too.


I saw the same thing while standing still and moving the camera. As you move in towards the clouds and back away from the clouds the effect is hardly noticable though.

I get 75 fps with 12 imposters, 0 particles, but as low as 12.5 fps using around 13000 particles when I get right next to a cloud

Pentium 4, 2.40 GHz
GeForce FX 5600
512 MB RAM

Share this post


Link to post
Share on other sites
I get about 2 FPS average on this machine, but the app runs fine (no graphical glitches). 32MB GeForce2. I'll try it on my own card (128MB 9550) tonight.

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!