Eeeew, my grass looks like ****

bitplane · Post by **bitplane** » Sun Jan 08, 2006 1:54 am

the hardware vertex buffers wont help with billboards, only static meshes (i think) cos you need to change them to face the camera every frame

krama757 · Post by **krama757** » Sun Jan 08, 2006 2:03 am

Hmm. If you were to write the grass, would you use a billboarding effect?

bitplane · Post by **bitplane** » Sun Jan 08, 2006 11:23 am

well i tried it and billboards look pretty good so far. getting a reasonable frame rate anyway.

shame the distant ones are black instead of fading out.

download here

if you change some parameters and want to regenerate the grass, just delete the files out of /grass/ and they'll be recreated next time you start

dawasw · Post by **dawasw** » Sun Jan 08, 2006 7:47 pm

Bitplane I've tried your grass and it's great !

But I don't know If I will use any grass in my project anyway , I'm afraid of low speed. (when I would add grass, many trees and later player with enemies it would work fast enough)

krama757 · Post by **krama757** » Sun Jan 08, 2006 8:13 pm

Damn! Very nice. So what did you do that made yours speed up? (Havent read the code yet)

======

Wow, using a particle system for each grass billboard eh. That works. Has irrlicht got special optimizations for using particles instead of regular billboards then?

bitplane · Post by **bitplane** » Sun Jan 08, 2006 11:12 pm

what you've got there is a 10x10 grid of grass nodes, each one contains a particle system. turn debug data on to see whats going on.
it will only calculate particles if its near to the screen, and it will only draw particles that are within a certain range. what it needs next is a daddy node that spawns and destroys grass nodes as the camera moves around. there's no need for 100 grass nodes, a 3x3 grid around the camera at all times would be good for seamless worlds.
I think this calls for some showing off in the project announcements forum!

krama757 · Post by **krama757** » Sun Jan 08, 2006 11:28 pm

Agreed completely! Very well done.

Bit, why does the grass shake? Is that the particle system refreshing the grass?

bitplane · Post by **bitplane** » Sun Jan 08, 2006 11:55 pm

thats my 'wind' example. I've made a function that will (one day) provide the wind speed at a given position and time, but i'm crap at fancy wave-like movement.
download from here instead for *slightly* better wind (still doesnt use time)
http://gdlib.net/index.php?name=Downloa ... ails&id=64

krama757 · Post by **krama757** » Sun Jan 08, 2006 11:59 pm

Well, thanks a bunch for the scene node. I will soon write the tree tutorial as I promised

Xaron · Post by **Xaron** » Mon Jan 09, 2006 7:58 am

Thanks bitplane, this looks really great!

Regards - Xaron

Electron · Post by **Electron** » Mon Jan 09, 2006 8:58 pm

Nice, Very similar technique to parts of what's described in a GPU Gems 2 article

MindGames · Post by **MindGames** » Wed Jan 11, 2006 7:48 am

Thanks a lot, I just tried your demo and it looks pretty good. One problem I had was that if you rotate the view, the bilboards rotate too and this is quite noticable.

Have you any ideas about how to get around this problem?

krama757 · Post by **krama757** » Wed Jan 11, 2006 7:15 pm

Well thats the problem with billboards, they rotate

If you just made them all meshes that didnt rotate then you would get some wierd looking grass when you looked at the meshes from the side...So this is the ideal solution.

Guest · Post by **Guest** » Sat Jan 14, 2006 11:54 pm

Dug out this old link from an OGRE shot:

http://img180.imageshack.us/my.php?image=grassy25na.jpg

Generally a star-shaped geometry approach with height variations, normals that face upward for lighting and shaders for waving. You could implement the same in Irrlicht, OGRE has a demo of this IIRC if you want to see it in action.