Really cool grass shader

[bitplane]

It doesn't look too hard to implement, doesn't alter the rendering pipeline, and the effect looks really good. The only down-side is that it requires quite a fast GPU, but it totally kicks the crap out of my mesh-based grass for draw distance, (not for realism though)

I thought I'd post this here in case it inspires someone to implement a nice free version

http://www.youtube.com/watch?v=yBIHr8kI3XA%20

[Virion]

cool, but when you look from the sky you can notice all the grids...

[JP]

It does look pretty cool from a shallow angle, obviously from above it's pretty terrible but most uses of grass will be from a shallow angle i guess...

Although if you're walking through it then you would see it from above as well if you looked near your feet... Maybe you could do some extra calculations so if it's a deep angle you're looking at then it would render differently...

[Klasker]

It looks cool - maybe we can use the ground's normal vector to make the grass semi-transparent depending on your angle of view. Speaking of normal-vectors, is it even possible to implement on a curved surface (ie. not flat)?

[BlindSide]

After following a few links I got to the HLSL version of the shader: http://www.cg.tuwien.ac.at/research/pub ... hader.HLSL

Might give it a go

[BlindSide]

Ok, heres an early test version for all you that can't wait (Requires PS 3.0)

http://irrlichtirc.g0dsoft.com/BlindSide/grass.zip

Screeny:

[JP]

didnt work for me, said it couldnt create the shader, i guess i don't have ps3!

[sRc]

Ok, heres an early test version for all you that can't wait (Requires PS 3.0)

http://irrlichtirc.g0dsoft.com/BlindSide/grass.zip

Screeny:
*snip*

Just tried it, looks pretty good the grid lines in the distance are a little distracting tho

[bitplane]

Yeah looks really nice apart from the edges, I fixed it like this-

Code: Select all

// line 177
			float4 biased;
			biased.xy = orthoLookup;
			biased.z = 0;
			biased.w = -100.0;
  			 
 	 		color += (1.0-color.w)*tex2Dbias(grassblades,biased);//orthoLookup);

But I doubt that's the best way to fix it! (still a shader newbie at the moment)

[Halifax]

Yeah those grid lines are getting a little bit annoying, I agree. Great shader though BlindSide! Keep up the good work.

I would like to maybe recommend doing an alpha blend pass, or maybe a blur pass to make the edges a little bit better.

*Halifax needs to learn how to do shaders, and get a better graphics card. :/

[BlindSide]

Yay, thanks for fixing the edges. Im not sure how you did that or what tex2Dbias does, but its looking great, heres a screenshot for Halifax and JP:






EDIT: Hmmm, It has to do with the mipmap levels eh? Lemme try disabling mipmaps on texture creation in the application itself...

[BlindSide]

Ok I updated the demo. I fixed the grid lines thing by disabling mipmaps on the "grassblades" image and I also added the choice for per-pixel lighting and how many ray-passes.

Same download link: http://irrlichtirc.g0dsoft.com/BlindSide/grass.zip

Screenshot of per-pixel lighting in action:

[Virion]

You are fast!

[sRc]

woah that made it freak out



color-changing where the texture starts freaking out (and that moves and changes when you move the camera), but the highlight is the console is absolutely wigging out with that error something like every frame!

[BlindSide]

Ok I fixed it... Same link.