Stylized Grass Shader [URP] ☘️

With Map Magic 2 you can place grass as detail meshes with a node like this (color doesn't do anything in this case).
Since the Unity terrain doesn't support LODs on mesh details you have to extract one LOD level mesh from the prefabs Staggart mentioned as an own prefab and plug it in there.



You can also use the Grass Mode on this node, but then you have to set the terrain grass material to one from this asset. So far some external tools worked for that (Nature Renderer doesn't support Unity 2021 anymore), but apparently Unity 2021 can do that somehow (my previous question is about trying to find out how).

 

Been having an issue with the colormap renderer since switching to unity 2021lts though I am not 100% certain that is the cause. When I render the map it ends up like this. Am I missing something?

 

Normally, if you were to use a prefab using a custom mesh/material the grass would appear as red geometry on the terrain. As of 2021.2, the terrain handles this properly and actually uses the material from the prefab for rendering.

I see despite this, the terrain still doesn't support LOD Groups for grass. Guess that'll have to wait another 5 years

I've updated the documentation here, to clarify the differences in 2021.2+. I'll see to making some variants of the prefabs without any LOD groups, which could be used with the terrain now.

I've attached them as a package here.

@rh4unity These prefabs could also be used with MapMagic or Gaia, since they used the terrain's vegetation system as well [Attachment removed, terrain-specific prefabs are now included in the asset]

 

Based on your screenshot, it looks like the color map is being applied correctly. Though I assume those long lines aren't intended. Are you also seeing these in the texture preview?


I can't quite make out if they're also visible on the terrain itself.

 

Yes the lines are unintentional and they do show in the image preview after rendering but not on my terrain at all besides affecting the colormap. If I change the color map resolution it affects the lines but they never go away.

Also in my preview it seems to show a low number for textels per meter I think 1.25 or something (not too sure what that means tbh lol).

 

Hi @StaggartCreations, sorry for the delayed response. So I found one thing that was severely making this issue worse (the white outline around materials) was using .PSD files instead of .PNGs. Even attempting the Unity importer setting 'Remove Matte' didn't help.

That said, I do still see the issue on .pngs to much lesser extent. It's much more noticeable if I drop the rendering resolution. At first I thought it might be something with my projects settings but I see the same issue on a completely fresh Unity project. I'll prep some sample assets for you in a bit.

On another note, I love that you've added an 'invert' option for the distance fading. I know this is a stretch, but would it be possible to have a near AND distant fading option on the material? If it's too difficult or costly that's fine, I can use two separate materials for this, but doing it in one shader would be awesome.

--------------------
Edit:

Ah! Figured it out, so... not sure what about the shader changed that made this noticeable, but the issue seems to be with Unity's 'Max Size' on image import. I was dropping a 4k image to 1k via this setting and it was causing the odd fringing in the shader. Manually dropping the resolution in Photoshop and not having Unity do any scaling fixed it.

Sorry for runaround and thanks for looking into it. If you have any response for the distance fading I'd love to hear it though, thanks.

 

That's definitely strange, I can't think of a good reason why streaks would appear here. The moment when the color map is being rendered, that's how the terrain appears to the renderer.

You could try to enable the "Using non-standard terrain shader" option, then try rendering. When it's disabled, the materials on all terrains are temporarily swapped out with an unlit terrain shader. It could be that this shader broke in 2021.3, but I'm not seeing a difference compared to 2021.2.

What may be is that your texture has foliage on a white background. As the resolution gets lower the white pixels start to bleed over onto the UV shells. If you were to disable mipmaps on the texture in question, and the bright spots go away, that hints at a color bleeding issue.

The way around this is to use flood filling on textures. Off the bat, I don't know how this is done in Photoshop, but in Substance Designer the "Distance" node achieves this. This is usually necessary for textures used with alpha clipping materials, more often than not.

An example of a texture using flood filling:


An alternative is to paint a matching color around the edges of the UV shells manually, or shrink the shells down a bit. This adds a safe margin.

Combining near and far distance fading is definitely possible and can replace the "invert" option, which probably makes more sense too. I'll jolt this down for the v1.3.0 update so I can hit 5 birds with one stone

 

Hi I am getting a warning while building,


Stylized Grass Shader\Scripts\GrassBender.cs(56,35): warning CS0109: The member 'GrassBender.particleSystem' does not hide an accessible member. The new keyword is not required.

Any fix for this?

 

The warning can safely be ignored. It's related to a MonoBehaviour field that was deprecated in Unity a long long time ago, but was actually never removed. Removing the 'new' keyword otherwise makes it appear in the editor, so it kind of swings both ways unfortunately.

 

Thank you.
On another note, I am using WebGL and Nature renderer 2020, and within that I am receiving an error that says it does not support procedural instancing on WebGL. Does that affect your stylized grass shader? Or will the materials still instance regardless?
And one more question if thats ok? It appears Angle fading prevents the shader from rendering on WebGL, is that a known limitation?

 

I believe Nature Renderer's procedural instancing relies on compute shader support, which WebGL in turn as a platform does not support. I assume NR will automatically fall back to regular instancing if procedural instancing isn't supported. If the NR integration is enabled, yet procedural instancing is not, everything will still renderer properly. So it's all totally safe.

I'm pretty sure I know why this may be breaking on WebGL, since it technically affects mobile platforms as well. I've meanwhile fixed this, but the change is part of a larger update. In the LightingPass.hlsl file on line 187 you can replace the word SafeNormalize with normalize, then save it. Please let me know if this also pans out for you!

 

Hi, in my scene I need to use Ambient occlusion , but I want to exclude the grass because it will not look good if it has dark areas.

I have set the "Ambient occlusion" of the material to 0, but I still can't eliminate the effect of AO on the grass.
How do I need to exclude the grass and use AO?

By the way, I have used Screen Space Ambient Occlusion (SSAO) and a third party plugin "HBAO", both of which have the above problem.

Please help me, thanks.

 

The parameter on the grass material itself acts more as a fake AO, where the base of the mesh gets a darker tint. The naming is perhaps a bit ambiguous.

The Ambient Occlusion effect that gets applied through the SSAO render feature is something that's part of URP's lighting model, hence it can't be controlled on a per-material basis.

You can however remove SSAO support from the grass shader itself. In the StylizedGrassShader.shader file you can comment out this line, which will do just that.


After which the SSAO effect will no longer draw on grass geometry. However, grass will "cast" ambient occlusion on the terrain, that in itself is unavoidable.

 

Thank you so much, what a legend you are.
I am only really using nature renderer to allow a custom terrain grass shader. Would I be better off using something else? I wasn't sure if vegetation studio did the same thing or not.

 

No problem!

While both assets are different in their own right, they're both built around Unity's direct rendering API. Meaning, no GameObjects are involved, nor Unity's native render loop, which is part of the reason why performance is much better over using vanilla Unity. Though as of Unity 2021.2 the terrain grass system now also accepts custom grass shaders.

I've attempted to cover the difference between different systems on this page of the documentation, which may be worth looking over.

 

In your opinion would it still be beneficial using nature renderer over the native renderer in 2021.2, even if I cant use streaming and procedural instancing?
Also, does vegetation studio align grass meshes to the terrain like nature renderer?

 

I'd say so, procedural instancing is often faster than regular instancing, particularly since culling is done on the GPU instead.

Vegetation Studio also supports rotations on the XZ axis, so aligning the vegetation to the terrain slope is possible (but optional).

 

Thanks

So that normalize fix you gave me for the alpha fading doesn't seem to help for WebGL. Any other ideas?

 

I had a better look at it, and it turns out that particular change is unrelated to the edge fading functionality

I can verify this change works in a build (specifically the OpenGLES graphics API)


Note that in Unity 2019 enabling this feature won't appear to have any effect on WebGL, even in the editor, this is due to a bug in Unity's shader compiler, which meanwhile's been fixed in 2020.3.

 

Thank you so much. You're a legend, that worked great!
I have an issue again, sorry xD
I have managed to solved a lag/stuttering issue in WebGL by disabling GPU instancing on all the materials. But it has caused another issue. Grass rendered with Nature renderer as a terrain detail doesn't render in the WebGL build (with GPU instancing in the material off)
It renders fine as a gameobject however. Is there a reason for this that I can solve?
Nature Renderers procedural instancing is off by default on WebGL, and it renders fine with GPU instancing turned on, so I don't think it's related to nature renderer exactly.

PS If it helps, I just bought your water and underwater asset

 

Great, thanks for the feedback!

Nature Renderer hinges on the use GPU Instancing, so that it can render a whole bunch of individual grass meshes in one go. If it's disabled on the material in question its safe to assume that rendering will no longer work as expected, Unity's rendering API will basically bail out. Why exactly there's stuttering is best pinpointed by attaching the Profiler to a development build.

In any event, you'd have to make sure you are targeting WebGL 2.0 in the player settings. That's probably default nowadays, but worth checking. WebGL 1.0 is one of the few platforms that doesn't support GPU Instancing.

 

Version 1.2.2 is now available, some minor changes. Asset store link

Fixed:
- Grass bending appearing flipped in Unity 2022.1
- Edge fading being inverted when using the OpenGLES graphics API

Version 1.3.0

This is currently under development and mainly revolves around reworking the bending feature on a technical level. The reason being is that it was developed in late 2019, based on little to no information about how the render pipeline works or how to incorporate custom rendering. I now realize it's rather hacky and goes against the grain to some extent. Currently, a 2nd hidden camera is used, which involves a lot of overhead as it normally does. This is in fact not necessary.

There's still a bug in URP that prevents Trails and Particles from properly rendering, I gave up on reporting it as a bug . The current workaround is to convert them to meshes every frame, and rendering those instead. This can quickly start to hammer performance in some cases (up to 10ms with 8 trails active).

I've meanwhile found a way around both of these issues, making the rendering of bending information as fast as rendering mesh/trails/particles normally is.

Pros:
- Minimal CPU overhead, 0.01ms as opposed to 0.12ms for one particle system.
- Benders can benefit from the SRP Batcher and frustum/occlusion culling (basically all native rendering features)
- Having Alpha blending enabled on a grass bender no longer breaks the height-checking capabilities (eg. a mesh floating over the grass, yet still pushing it down)

Cons:
- Breaking change for any mesh that's currently both used as both a bender and a normal renderer. These now have to be separate.
- Sorting layer and Alpha blending options won't be functional if the SRP Batcher is disabled (it can't be as of 2021.2+ anyway!)

Other changes:
- Reworked Material UI to support Material Variants (introduced in Unity 2022.1). This will unfortunately reset some material parameters to their default values, a necessary evil.
- Adding prefabs specific to the terrain vegetation system (no LODs)
- Support for dynamic wind speeds
- Added normal maps for all the included grass textures
- Improved grass meshes. Doing away with the traditional cross-shape
- Options to choose which vertex color channels are used for wind or bending.

Not yet sure if this update requires a clean install, but I'll be sure to prepare an update guide once it's released.

 

Hi, may i ask if the grass bending feature works for WebGL? (ie does it use geometry shader / compute shader to achieve the feature?)
I'm looking to implement this feature in my WebGL game and want to find out if i should get this asset.

 

Looking forward to the 1.3.0 update, @StaggartCreations. Curious about how not requiring the second camera will work for benders but sounds like a plus! Dynamic wind would be great as well, right now I do a weird calming of wind before changing directions.

Also making sure you've still got combined near/far distance fading in the pipeline, thanks!

 

Yes, just the same! The rendering involved is pretty generic so has no platform limitations.

Happy to hear it! I've meanwhile implemented near/far fading which works as you would expect. The UI needs a little more polishing for the settings

 

@StaggartCreations Thanks for the info!

 

Hey. First of all. I absolutely love this shader. I have used it in an old project of mine. Now I am working on a different project using HDRP. Will there ever be HDRP support in the future? ~ Julian

 

Q: Importing the asset. Unity 2021.3 LTS, URP with VSP.

Demo scene grass is "invisible" until i select them in the hierachy.
Once selected it shows up on camera and in scene, as soon as i unselect it disappears again.

Followed the instructions from the doc, including the troubleshooting where it's reimport the asset.

Still no luck, any ideas?

I tried moving 2 patches out of the meshes sub gameobjects to see if it makes a difference, still the same see screenshot.

 

Ah never mind, a little investigation and experimentation, it appears to be the LOD groups not working,
disabling the LOD's all works.. It's a Unity issue, not a asset issue.

 

Appreciate the interest! I personally have little to no experience with HDRP, which doesn't provide solid foundations to develop and support an asset for it. URP has proven to be a handful in terms of breaking changes and updates, so I'm also hesitant to throw another render pipeline into the mix.

It may be that the "LOD Bias" setting in your Quality Settings is very low. By default it's '0.2' on the 'Very Low' setting, causing the grass to cull really early. If it's 0, then the grass will never be visible.

The LOD distances on all the grass prefabs are tuned based on a LOD Bias on 1.0. But you can definitely edit them to draw out the distances further.

 

Hi! Awesome work! I'm currently trying to make dynamic wind work with this shader. I updated it since I saw in the 'other changes' section that it supports dynamic wind speeds. At the moment I'm having an issue where changing the wind speeds changes the overall offset rather than the rate of offset for the gusts and their tints.

After updating I see the math for the Wind.hlsl is the same. I've tried to edit it myself but I'm having trouble adjusting the math. The goal is to store the previous offset so that every calculation boils down to

Code (CSharp):

1. currentOffset = PreviousOffset + offsetStep

If I can break down the offsets into steps, instead of it being set by speed * time, then I can fix this issue.

To explain it another way, if speed is 5 and time is 100, and the next frame speed it 4.9, the offset will shift by ~10 units(100 * 0.1) from what I understand.

This means that while I'm adjusting the direction of the wind as well, the entire gust map will slide separate from the direction of the wind.

Thanks again for your work, I love this shader and your stylized water shader, you've inspired me to dip my toes into tech art just a little

 

Thanks! In the asset's current version this is indeed the case where changing the wind speed dynamically causes jittering to occur until the wind speed settles again on a fixed value. The solution here involves passing the time difference between the last/current frame to shaderland, and using that instead. But all the related changes will be part of version 1.3.0.

Changing the wind direction, however, is still something I'm dabbling with. Specifically for wind gusts, for ambient wind it works smoothly.

 

Hi there, I am using your underwater shader 2 with planar reflection. The grass shader has a blue tint in the reflections. Is there a way I can fix this?
I have tested with other shaders and it seems to just be the grass shader that is tinted.

Thanks

 

Ah, I've encountered this before here. The blue tint comes from the environment reflections. For some reason Unity's lighting model doesn't entirely respect alpha clipping when it comes down to a mirrored projection. This also happens with Shader Graphs, not sure why the Lit shader is unaffected.

In the Stylized Grass Shaders/Shaders/Libraries/LightingPass.hlsl file you can replace
surfaceData.alpha = albedoAlpha.a; with surfaceData.alpha = 1.0; to remedy this.

You can see the difference here, the grass renders correctly while the shrub/tree don't:

 

Will this affect anything else? Looks like that worked great otherwise. Thanks.

 

Great! And not as far as I can tell.

 

Awesome thanks.
I have an issue i've just noticed with the scale map functionality of the Colormap Renderer.
Is there a max amount of layers you can use before it starts breaking? Im on my 10th texture and the scaling of that layer doesn't appear to work.
These darker greens are all set to the same 100% as the main colour, and yet they are scaling differently. Changing the slider doesn't do anything for those colors, the only slider that affects the darker greens is the main green, in which it seems to behave inverted. Ie scaling down the main green to 1% makes them pop back up.

 

hey! so after I bake the color renderer I'm getting a lot of different colors and shadows. I assume I'm doing something wrong here haha.

Thanks!

 

Try lowering the resolution of the color renderer. It's picking all the detail of your ground texture.

 

I checked it out, and that indeed seems to be the case. There's no artificial limit on the amount of layers but it seems like anything beyond #8 is not configurable in strength. I have found a fix though:

In the ColorMapEditor.cs file (at the bottom). This function:

Code (CSharp):

1. public static int GetSplatmapID(int layerID)
2. {
3.     if (layerID > 3) return 1;
4.     if (layerID > 7) return 2;
5.     if (layerID > 11) return 3;
6.  
7.     return 0;
8. }

should be

Code (CSharp):

1. public static int GetSplatmapID(int layerID)
2. {
3.     if (layerID > 11) return 3;
4.     if (layerID > 7) return 2;
5.     if (layerID > 3) return 1;
6.  
7.     return 0;
8. }

 

It's definitely a little better! But I'm not seeing that nice blend between the grass and ground. Also is it possible to turn off the cast shadows?

 

Thanks. What is the chance of this getting ported to HDRP at some point by the way?
We could probably pay for the time it took too.

 

Yes, you need to turn off "cast shadows" in the mesh renderer of the grass asset you are using (on all the LODs).

It looks like you may have some other settings (maybe smoothness and/or AO/normals interfering with the blend.
But ignoring that for now, the main issue is the detailed ground texture.
This grass is very well optimised, you might be better to rely on the grass models to give detail to your ground rather than using a busy material. Maybe turn down the normal map and/or simplify the grass main texture like in the demo scene.
Here is an example of what I mean. This is the demo grass'ish. If I turn the normal map to add more detail it breaks the illusion.


So start with just a simple colour for now, then work your way back up.
And you really can increase the grass numbers a bit

 

Can I ask how you made the background mountains for your demo? The normal map works really well with the art style.

 

The backdrop mountain mesh (and albedo/normal map) come out of World Creator 2 (the standalone edition). It's my go-to terrain generator, but it also has a mesh- and texture exporter.

 

Yeah thats what im using. Did you do anything to the maps afterwards?
Do you still have the files? I'd be happy to pay you. Just wanna see what you did, coz I'm clearly missing something.

 

I don't mind! You can grab the project here: https://1drv.ms/u/s!AlkpXXlKu-02xd83dnXOGgrfqZ_9TA?e=gjdtd0. Texture will likely be missing, since they're linked to my local files.

You may need to check the option to invert the green channel of the normal map if you're getting strange looking results.

 

How to bake colormap properly when terrains are in different additive scenes using gaia streaming.

 

In the editor you could load in all those scenes, containing the terrain tiles, then bake the color map. Terrains have to be present in order to include them in the render.

 

Does the color map adapt to dynamic day and night light or is this adaptation in the color that the engraving receives in another location?
What I mean is that I use Enviro Sky as a day/night weather system, my grass is perfect in the lighting from 10 am to 3 pm, after that with dusk or dawn they gain a strong glow / color with the environment almost all dark but the grass still with a lot of light.
I got this when I used the color map. Any tips?
I'm not sure if it's the light I have to move or the grass.
Does the color map saved with 12h light make a difference in color when the light is dimming?