Custom SpeedTree shader

Unity Engine
1

I have a shader I built in Shader Forge that I’m trying to apply to a SpeedTree. SpeedTrees use a special, kind of complex shader that applies things like vertex-baked AO and wind animations. I’ve been digging in the source (Download Archive) and trying work in my shader, but it’s just not going well. Does anyone have any pointers? Shader scripts are kind of alien to me (hence Shader Forge).

Edit:
I did some more research on how shaders work and was able to make some progress. Here’s some helpful resources:

2

Hello. Any progress on this?

3

I’d be interested in this also. Changing the existing values at run-time is as far as i’ve got so far. http://www.nuzly.com/changing-the-color-of-speedtree-materials-at-runtime-in-unity3d/

4

I recently did this – take a look at the SpeedTreeCommon.cginc – you can rip most of it out and put it into your own shader file. That shader file should be based on the speed tree shader you want to change. The fragment shader in that cginclude file is where you should modify your colors – you can also add your own texture or color property for more customization.

5

hey here’s a version i made as an alternative to the SpeedTree shader

Shader "Custom/Wind_HueVariation" {
    Properties{
        _Color("Main Color", Color) = (1,1,1,1)
        _MainTex("Base (RGB) Trans (A)", 2D) = "white" {}
        _BumpMap("Normalmap", 2D) = "bump" {}
        _Cutoff("Alpha cutoff", Range(0,1)) = 0.5
        [Toggle(HUE)]_Hue("Hue Variation", int) = 0
        _HueVariation("", Color) = (1,0.25,0,0.1)
        [Toggle(POSITION_BASED)]_Positioned("Based on Position", int) = 0
        [Toggle(ACTIVATE_WIND)]_ActivateWind("Activate Wind", int) = 1
        _WindStrength("Wind Strength", Range(0,1)) = 0.25
        _WindSpeed("Wind Speed", Range(0,100)) = 0.25
        _NoiseStrength("Noise Strength", Range(0,1)) = 0.25
        _NoiseSpeed("Noise Speed", Range(0,10)) = 0.25
        _WindYShake("Wind Y Shake", Range(0,10)) = 5
        /*[HideInInspector]*/_WindVector("Wind Vector", Vector) = (1,1,1,0)
        /*[HideInInspector]*/_WindFreq("Wind Frequency", Vector) = (1,1,1,0)
    }

    SubShader{
        Tags{ "Queue" = "AlphaTest" "IgnoreProjector" = "True" "RenderType" = "TransparentCutout" }
        LOD 200
        Cull Off
        CGPROGRAM
        #pragma surface surf Lambert alphatest:_Cutoff vertex:vert addshadow
        #pragma shader_feature ACTIVATE_WIND
        #pragma shader_feature POSITION_BASED
        #pragma shader_feature HUE
        sampler2D _MainTex;
        sampler2D _BumpMap;
        fixed4 _Color;
        fixed4 _HueVariation;
        half _WindStrength;
        half _NoiseStrength;
        half _WindSpeed;
        half _NoiseSpeed;
        half _WindYShake;
        fixed4 _WindVector;
        fixed4 _WindFreq;

        struct Input
        {
            float2 uv_MainTex;
            float2 uv_BumpMap;
            float3 pos;
        };

        float rand(float3 myVector)
        {
            return frac(sin(dot(myVector, float3(12.9898, 78.233, 45.5432))) * 43758.5453);
        }

        void vert(inout appdata_full v, out Input o)
        {
            UNITY_INITIALIZE_OUTPUT(Input, o);
            #ifdef HUE
            half r = frac(mul(unity_ObjectToWorld, v.vertex).y * v.vertex.y * rand(mul(unity_ObjectToWorld, v.vertex).xyz));
            half g = frac(mul(unity_ObjectToWorld, v.vertex).y * v.vertex.y * rand(mul(unity_ObjectToWorld, v.vertex).xyz));
            half b = frac(mul(unity_ObjectToWorld, v.vertex).y * v.vertex.y * rand(mul(unity_ObjectToWorld, v.vertex).xyz));
            o.pos = half3(r,g,b) * _HueVariation.rgb;
            //o.pos = mul(unity_ObjectToWorld, v.vertex).xyz * step(_HueVariation.r+ _HueVariation.g+ _HueVariation.b,rand(mul(unity_ObjectToWorld, v.vertex).yyy))* _HueVariation.rgb;
            #endif
            #ifdef POSITION_BASED
                o.pos *= saturate(rand(mul(unity_ObjectToWorld, float4(0, 0, 0, 1))));
            #endif
                half gradient = _WindYShake - mul(unity_ObjectToWorld, v.vertex).y;
           
            #ifdef ACTIVATE_WIND   
                v.vertex.x += ((((_WindVector.x + rand(v.color.rgb)) * sin(_WindFreq.x * (_Time.y *_WindSpeed + v.vertex.y)))*(rand(v.color.rgb) * _WindStrength*0.1)) + (sin(_Time.y *_NoiseSpeed + v.vertex.z)*(rand(v.color.rgb) * _NoiseStrength*0.1))) * (v.vertex.y - _WindYShake);
                v.vertex.y += ((((_WindVector.y + rand(v.color.rgb)) * sin(_WindFreq.y * (_Time.x *_WindSpeed + v.vertex.x)))*(rand(v.color.rgb) * _WindStrength*0.1)) + (cos(_Time.y *_NoiseSpeed + v.vertex.z)*(rand(v.color.rgb) * _NoiseStrength*0.1))) * (v.vertex.y - _WindYShake);
                v.vertex.z += ((((_WindVector.z + rand(v.color.rgb)) * cos(_WindFreq.z * (_Time.x *_WindSpeed + v.vertex.y)))*(rand(v.color.rgb) * _WindStrength*0.1)) + (cos(_Time.y *_NoiseSpeed + v.vertex.x)*(rand(v.color.rgb) * _NoiseStrength*0.1))) * (v.vertex.y - _WindYShake);
            #endif
           

        }

        void surf(Input IN, inout SurfaceOutput o)
        {
            fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
            o.Albedo = c.rgb + (IN.pos * _HueVariation.a);
            o.Alpha = c.a;
            o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));
        }
        ENDCG
    }
    FallBack "Legacy Shaders/Transparent/Cutout/Diffuse"
}
2 Likes
6

Hello folks,

Has any of you been able to add global transparency (without the X-ray effect, so not applied to the individual textures) on Speedtree’s shader ? (I asked the same question here but we may as well keep this thread documented…)