I am trying to modify an existing, multi-pass shader into a single surface shader for batching/instancing capabilities. Unfortunately, the single pass version doesnt seem to render the mesh elements in the same order, causing some weird transparency issues.
Here is what the multi-pass shader renders (properly):
(notice the foliage at the bottom appears in front of the plant stems)
Here is the shader code:
Shader "2Sided_ColorMask" {
Properties{
_Color("Color", Color) = (1,1,1,1)
_MainTex("Albedo (RGB)", 2D) = "white" {}
_MaskTex("Color Mask", 2D) = "white"{}
_Cutoff("Alpha Cutoff", Range(0.0, 1.0)) = 0.5
}
SubShader{
Tags { "Queue" = "Transparent" "RenderType" = "TransparentCutout" "IgnoreProjector" = "True" }
Blend SrcAlpha OneMinusSrcAlpha
LOD 200
Cull Off
// this is the vert/frag shader pass - this pass does not seem to batch properly but renders well
Pass {
CGPROGRAM
#pragma vertex vert fullforwardshadows alpha
#pragma fragment frag fullforwardshadows alpha
#include "UnityCG.cginc"
struct v2f {
float4 vertex : SV_POSITION;
float2 texcoord : TEXCOORD0;
};
sampler2D _MainTex;
sampler2D _MaskTex;
fixed _Cutoff;
v2f vert(appdata_img v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.texcoord = v.texcoord;
return o;
}
fixed4 frag(v2f i) : SV_Target
{
clip(c.a - _Cutoff);
return c;
}
ENDCG
}
// surface shader that handles color masking
CGPROGRAM
#pragma surface surf Standard fullforwardshadows alpha:fade vertex:vert
#pragma target 3.0
#include "UnityCG.cginc"
sampler2D _MainTex;
sampler2D _MaskTex;
float _Cutoff;
struct Input {
float2 uv_MainTex, uv_MaskTex;
};
struct v2f {
float4 vertex : SV_POSITION;
float2 texcoord : TEXCOORD0;
};
// Add instancing support for this shader.
UNITY_INSTANCING_CBUFFER_START(Props)
// put more per-instance properties here
UNITY_DEFINE_INSTANCED_PROP(fixed4, _Color)
UNITY_INSTANCING_CBUFFER_END
void vert(inout appdata_full v)
{
// blank since we're not using it in this test
}
// color masking surface function
void surf(Input IN, inout SurfaceOutputStandard o)
{
// Albedo comes from a texture tinted by color
float4 c = tex2D(_MainTex, IN.uv_MainTex);
float mask = tex2D(_MaskTex, IN.uv_MainTex).r;
c.rgb = c.rgb * (1 - mask) + UNITY_ACCESS_INSTANCED_PROP(_Color) * mask;
clip(c.a - _Cutoff);
o.Albedo = c.rgb;
o.Alpha = c.a;
}
ENDCG
}
FallBack "VertexLit"
}
If I only use the surface shader from above (i.e, exclude the Pass), it renders it like this:
The plant stems are always in front, regardless of camera angle.
Im not sure if this is just an OIT issue or something that cannot be addressed in a single surface shader but it seems like it should be straightforward to fix.
Any help would be greatly appreciated!
Thanks