Problems with transparent Vertex Shader

Graphics Shaders & Materials
1

Hi guys,

i have a problem with a transparent vertex shader written in CG.
On my computer and on a Samsung Galaxy Note 4 it works perfect but on my Xperia Z and the Xperia Z2 tablet it flickers.

As it should look like:
3023000--225882--Working.PNG

As it should not look like:

3023000--225881--Not Working.jpg
3023000--225881--Not Working.jpg1920×1080 367 KB

Here is my Shader Code:

Shader “Hologarfic” {
Properties {
_VertexColor (“Vertexcolor”, Color) = (1,1,1,1)
_FragmentColor (“Fragmentcolor”, Color) = (1,1,1,1)
_WireWidth (“Wire Width”, float) = 0
_Alpha (“Alpha”, float) = 0
}
SubShader {
Tags {“Queue”=“Transparent +1” “RenderType”=“Transparent”}
Blend SrcAlpha OneMinusSrcAlpha
Cull Off
ZWrite Off
LOD 200
Pass{
CGPROGRAM

//pragma
#pragma vertex vert
#pragma fragment frag

#include “UnityCG.cginc”
//user defined variables
uniform float4 _VertexColor;
uniform float4 _FragmentColor;
uniform float _WireWidth;
uniform float _Alpha;
float3 trianglecolor;
//base input structs
struct vertexInput{
float4 vertex : POSITION;
float4 color : COLOR;
};
struct vertexOutput{
float4 pos : SV_POSITION;
float4 color : COLOR;
};
//vertex funkction
vertexOutput vert(vertexInput v){
vertexOutput o;
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
o.color = v.color;
return o;
}
//fragment function
float4 frag(vertexOutput i) : COLOR{
float3 d = fwidth(i.color);
float3 tdist = smoothstep(float4(0,0,0,0), d*_WireWidth, i.color);
_FragmentColor = lerp(_VertexColor, _FragmentColor, min(min(tdist.x, tdist.y), tdist.z));
_FragmentColor = _FragmentColor * _Alpha;
return _FragmentColor;
}
ENDCG
}
}
}

Have anyone an idea how i could fix the problem?

2

Derivatives aren’t supported by all mobile hardware, or aren’t supported well. Those devices should be capable of it as it’s a requirement of OpenGL ES 3.0, but as you’re not specifying a shader level target it’s possible the devices are running the shader as es2.0 or es1.0(!).

Try adding:

#pragma target es3.0

3

Thank you for your reply.

I added #pragma target es3.0 under the #pragma fragment frag but it still doesn’t work. You say that derivatives aren’t supported well. Is there a way to write something like fwidth() what doesn’t use derivatives? Or would it help to wirte the shader in another language?

4

No, and no I’m afraid.

For mobile hardware I never use derivatives. Too unreliable. So it’s back to the drawing board I think. Just replace it with a texture lookup. When available derivatives will still be used for some proper texture filtering, but on other hardware the fallback is a bit friendlier.

5

You can imagine that i don’t know what i’m exactly do in shaders (I know that they show the grafik and compute textures and all this but i don’t know where i get things from and how i need to implement things that something else happens). I want that the underground have this wireframe. Until now i used the vertex colors red, green and blue and builded this shader with this as tamplate https://codea.io/talk/discussion/3170/render-a-mesh-as-wireframe.

My underground mesh is varying.

I would appreciate if you explain to me how I implement it with the texture lookup.

6

Thank you for your help i found a solution. I deleted the line where i declarate float d = fwidht(i.color); and changed the wirewidth. Now it works!