Terrain PBR?

Now that Unity 5 has switched to PBR, are you going to be updating the terrain shader? I see that it still only has Diffuse and Normal inputs, ideally I'd like to see Diffuse, Specular, and Normal so I can properly integrate terrain in a PBR-shaded scene.

 

My hunch is that built in solutions for this will be later in the 5.x cycle along with other improvements to the terrain system. But in the meantime I would hope that 3rd parties will provide solutions in the coming months, e.g. with nice asset store terrain stuff.

 

I tried Relief Terrain Pack, which turned out to be a horribly buggy mess. I could develop my own hacky workarounds I suppose (maybe have extra inputs for specular in the shader which are assigned through custom script), although I have no idea how to integrate my own shaders with Unity's PBR (the Universal shader is no help here, I can't for the life of me make heads or tails of it).

 

Yeah RTP is a disaster right now. A real shame, because terrains made with it in U4 kind of look better than the flat ones in u5 now.

 

There are some terrain shaders in Lux you could try, but I have no idea what results you'll get with it in Unity5.

 

Nah, that wouldn't work (because ofc it doesn't integrate with Unity's new deferred pipeline).

As far as I can tell, the meat of deferred shaders is a vertex fragment shader, the vert and frag functions look something like this:

Code (csharp):

1.  
2. VertexOutputDeferred vertDeferred (VertexInput v)
3. {
4. // stuff...
5. }
6.  
7. void fragDeferred (
8.    VertexOutputDeferred i,
9.    out half4 outDiffuse : SV_Target0,       // RT0: diffuse color (rgb), --unused-- (a)
10.    out half4 outSpecRoughness : SV_Target1,   // RT1: spec color (rgb), roughness (a)
11.    out half4 outNormal : SV_Target2,       // RT2: normal (rgb), --unused-- (a)
12.    out half4 outEmission : SV_Target3       // RT3: emission (rgb), --unused-- (a)
13. )
14. {
15. // more stuff...
16. }
17.  

So it looks like we need a terrain shader that uses these in order to work with Unity's new deferred pipeline. Although we still need to hack the specular map input somehow... perhaps with a custom script that assigns them to the material.

 

Yeah, this has kind of been overlooked. I'm very surprised by this. The ground is a pretty big thing to leave out of your PBR pipeline.

 

Agreed.
I'd really like to get an official UT response on this. Are they just going to neglect terrain for Unity 5, are we going to get an updated terrain shader, etc...?

 

a Unity Technologies official?

 

You don't need a script for that, just use a custom terrain material that uses the new shader, and assign them in the material inspector.

 

Any update on the likelihood of this making it to 5.0?

 

this is good news...

 

this is news from october

this would be really great, even if it's just 4 textures first pass.


also, there was a terrain shader that was shared on the forums recently,
http://forum.unity3d.com/threads/so-i-created-this-pbr-terrain-shader.281658/#post-1878021

I haven't tried it yet, but it may be worth looking into

 

We'd love it to self optimise in the same way. I appreciate its a lot of extra work on your part. Also a variant which uses vertex colour for splatting would be nice since we could use those on normal meshes as well.

 

Perhaps we could implement the Unity 5 BRDF shading model from the UnityUniversalBRDF.cginc (comes in the built-in shaders.zip for unity 5) into a custom terrain shader. I have been trying but I haven't been very successful since I am a bit of a beginner (I have had some decent progress but I broke something) perhaps somebody with a more extensive knowledge of shader programing could come up with a better solution. This is what I have so far for the terrain basemap shader: (There are Errors and it is a work-in-progress)

Code (CSharp):

1. Shader "Nature/Terrain/Terrain_PBR LightingBase" {
2. Properties {
3.     _Color ("Main Color", Color) = (1,1,1,1)
4.     _SpecColor ("Specular Color", Color) = (0.5, 0.5, 0.5, 1)
5.     _Shininess ("Shininess", Range (0.03, 1)) = 0.078125
6.     _MainTex ("Base (RGB) Gloss (A)", 2D) = "white" {}
7.     _BumpMap ("Normalmap", 2D) = "bump" {}
8. }
9.  
10. CGINCLUDE
11. #include "UnityCG.cginc"
12. #include "UnityUniversalBRDF.cginc"
13. #include "UnityUniversalUtils.cginc"
14.  
15. sampler2D _MainTex;
16. sampler2D _BumpMap;
17. fixed4 _Color;
18. half _Shininess;
19.  
20. struct Input {
21.     float2 uv_MainTex;
22.     float2 uv_BumpMap;
23. };
24.  
25. void surf (Input IN, inout SurfaceOutput o) {
26.  
27.  
28.     fixed4 tex = tex2D(_MainTex, IN.uv_MainTex);
29.     o.Albedo = tex.rgb * _Color.rgb;
30.     o.Gloss = tex.a;
31.     o.Alpha = tex.a * _Color.a;
32.     o.Specular = _Shininess;
33.     o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));
34. }
35.  
36. half4 LightingTerrainBRDF (SurfaceOutput s, fixed3 lightDir, half3 viewDir, half3 specGI, half4 light)
37. {
38.     half3 h = normalize (lightDir + viewDir);
39.  
40.  
41.     half reflectivity = RGBToLuminance(s.Specular);
42.     half roughness = 1 - _Shininess;
43.     s.Albedo = s.Albedo * (1 - reflectivity);
44.  
45.     half nl = DotClamped (s.Normal, lightDir);
46.     half nh = BlinnTerm (s.Normal, h);
47.     half nv = DotClamped (s.Normal, viewDir);
48.     half vh = DotClamped (viewDir, h);
49.     half lv = DotClamped (lightDir, viewDir);
50.     half lh = DotClamped (lightDir, h);
51.  
52.     half F = FresnelTerm (reflectivity, vh);
53.     half G = GeometricTerm (nl, nh, nv, vh);
54.     half R = BlinnPhongNormalizedTerm (nh, RoughnessToSpecPower (roughness));
55.     R = max (0, R);
56.  
57.     half nlPow = pow((1.00001-nl), 5);
58.     half nvPow = pow((1.00001-nv), 5);
59.  
60.  
61.     half Fd90 = 0.5 + 2 * pow(lh, 2) * roughness;
62.  
63.     half disneydiffuse = (1 +(Fd90 - 1)*nlPow) * (1 + (Fd90 - 1)*nvPow);
64.  
65.     half spec = max(0, (F * G * R) / (4 * nv + 1e-5f) );
66.     //float spec = pow (nh, s.Specular*128.0) * s.Gloss;
67.     half diff = disneydiffuse * nl;
68.  
69.     half fresnel = FresnelTerm(0, nv);
70.  
71.     fixed4 c;
72.     //c.rgb = (s.Albedo * _LightColor0.rgb * diff + _LightColor0.rgb * _SpecColor.rgb * spec) * (atten * 2);
73.  
74.     c.rgb = s.Albedo * (light.ambient + light.color * diff) + s.Specular * (specGI + (light.color * spec)) + (1-reflectivity) * (1-roughness) * specGI;
75.  
76.     //c.rgb = combinedcolor, fresnel(0, nv) * (1-roughness));
77.  
78.     return c;
79. }
80.  
81.  
82. ENDCG
83.  
84. SubShader {
85.     Tags { "RenderType"="Opaque" }
86.     LOD 400
87.  
88.     CGPROGRAM
89.     #pragma surface surf TerrainBRDF
90.     #pragma target 3.0
91.     ENDCG
92. }
93.  
94. SubShader {
95.     Tags { "RenderType"="Opaque" }
96.     LOD 400
97.  
98.     CGPROGRAM
99.     #pragma surface surf TerrainBRDF nodynlightmap
100.     ENDCG
101. }
102.  
103. //FallBack "Legacy Shaders/Specular"
104. }
105.  

 

We've recently added a PBR terrain shader to the Alloy 3 alpha for Unity 5. Just in case anyone is interested.

 

Hello Unity, are there any plans for parallax occlusion mapping in your standard shader? Very interested in it. It adds this very convincing depth effect to textures, with good texture it can look like real 3d geometry. Current parallax is at least S***ty(if it works at all).

 

There is a tesselation shader out there already. You can try looking that up

 

As I see some promotional entries above I feel encouraged to inform:

My RTP3.2 terrain shading package works now with U5 (beta19 at least but will be adjusting this when needed).

Tom

P.S. And there is PBR present since RTP3.1 (Unity4)