Eeeew, my grass looks like ****

[krama757]

Guys how do you work with billboarded grass? I cant seem to get good results.

My grass texture is:


And my grass turns out to look like:


A desired effect would be like:
[IMG]http://www.kjapi.com/images/screenshots ... t0.jpg[IMG]

Code:

Code: Select all

IBillboardSceneNode* grass[100][100];
	ITexture* grassTex = driver->getTexture("./data/Trial Grass 1/Trial5.bmp");

	driver->makeColorKeyTexture(grassTex, (SColor)(255,0,0,0));
	grassTex->regenerateMipMapLevels();

	int g = 0;

	for(i = 0; i<60; i++){
		for(int j = 0; j<60; j++){
			//g = i;
			//if(i%2 == 0)
			//	g = i+1;
			grass[i][j] = smgr->addBillboardSceneNode(0, dimension2d<f32>(1.0f,0.5f));		
			grass[i][j]->setMaterialTexture(0,grassTex);
			grass[i][j]->setMaterialFlag(EMF_LIGHTING, false);
			grass[i][j]->setMaterialFlag(EMF_BACK_FACE_CULLING, false);
			grass[i][j]->setMaterialType(EMT_TRANSPARENT_ALPHA_CHANNEL_REF);
			grass[i][j]->setPosition(vector3df(i*0.5, -0.5, j*0.5));
		}
	}

Any suggestions would be very appreciated!

(My return gift to the community will be a tree builders tutorial after I get this stuff done )

[master123467]

well ok i thnk i could give it a try

[Guest]

it's very cool!
i am looking forward your tutorial.

[krama757]

master123.4567 do you have any suggestions? I have no clue what you are trying

[bitplane]

billboard grass looks crappy man. (tho i also made the mistake of making the grass texture too dense)
ideally you want areas of mesh grass clumps that share the same mesh buffer, which create and fade in as you get close, and to know which ones are the top vertices so you can animate them blowing in the wind or being disturbed.

[krama757]

Well ignore the animation. I just want some good looking grass

The problem with rendering grass only at certain distances is that you would have to loop through all the nodes and check to see if they are close enough to the player. This used to lag truevision when I tried it there.


======

I wonder what causes things to lag. Is it the number of triangles rendered or is it just filling...how many pixels of the screen you fill. According to my video card specifications it can easily do 40 million triangles at 40 fps.

My bro says that rendering back to front is much slower than rendering front to back because lag is cause by filling in pixels. Does this ring a bell for someone? If its possible to do this please do tell me how.

Currently im using a nested for loops and am rendering front to back (or so I think...)

[bitplane]

the particle system node manages tons more billboards because they're all in the same mesh buffer, so they all draw at the same time instead of switching between them.
it still has to make each billboard face the camera every frame though, and upload the vertices to the graphics card. irrSpintz has hardware mesh buffers, which give an amazing performance boost.
if you want a lot of grass though, the only parts that exist should be near the camera. if you had a few types of plant that shared the same textures, you could copy lots of them in to one hardware buffer making a dense clump of plants. you create, fade in, fade out and destroy the clumps as you walk around.

[krama757]

Ah, so instead of managing each single grass billboard, you manage clumps of them, right?

(Along with using hardware buffers....I still need to get spintz up and running properly. I keep getting runtime errors )

[MikeR]

Your grass looks just like your texture. I saved a copy, and zoomed in a tad so I could see it better. To get the effect you are looking for, you are going to have to remove some of the light green. Making the blades thinner might help as well.

[omaremad]

http://mirror.ati.com/developer/samples/grass.html

same thing as the others (bad billboard)

but the shader also add realism

[krama757]

Do you guys have any good samples of grass textures or the like? A google search revealed nothing.

I think I might get better effects if I can apply better transparecies...I have 2 questions for you guys:
1) When I have a blurry texture, I get a really nastry black outline on all the grass because the colorkey only works on 100% black...is there a better way to do colorkeys?

2) How would I make an object progressively transparent. I took a look at the IMeshManipulator->setVertexColorAlpha(IMesh*, alpha) and it didnt do anything to my tree meshes....so anything else I can do?

[bitplane]

ideally you need new render mode (or fix the one my clouds use), transparrent alpha channel and transparrent vertex alpha together. spintz or hybrid may have one, i dunno, but i think i remember a discussion about it ages ago. otherwise, transparrent alpha add works with vertex colours but its a ghostly transparrent effect.
also you cant use vertex alpha for most meshes, it's slow, and all nodes that use that mesh will also fade. i think we need some fade-out material/shader for that instead.
all this talk about grass is getting me excited, i think i can feel a grass node coming on!

[Guest]

did you look at my link?

[bitplane]

yeah very nice omar! i'm still scared of shaders though. how about i make some particle system grass and you make it wiggle round with a shader. that would be cool

[krama757]

I dont mind Please do make some grass ^_^

Omaremand I had that link. They use billboards with one blade of grass per billboard. Then they place it in a random position on the heightmap--animating using a vertex shader and lighting using a pixel shader.

But, they are still using billboards. Thats the problem with mine...although I use billboarded grass it doesnt turn out as well. Mike's suggestions involve just chaning the texture.. Is that all there is to it?

I think using spintz's vertex buffers will help with speed...but what about quality?

=======
And what about those other two questions...if I understood your response then we would have to write a new material that allows progressively transparent stuff?