Shader Fails on Intel HD Graphics Cards

So I'm having a bit of an odd issue... It's hard to test myself since I don't have access to a computer with this video adapter, but a number of people trying to run my game on Intel HD Graphics 4000 and similar cards are reporting that this shader always shows solid black for them. The weirdest thing is that Shader.isSupported returns true, the cards report supporting shader 3.0, and the fallback is never invoked.

Here's the shader code:

Code (csharp):

1. Shader "Custom/Unlit Transparent Colored"
2. {
3.     Properties
4.     {
5.         _Color ("Blending Color", Color) = (0.5,0.5,0.5,1)
6.         _MainTex ("Base (RGB), Alpha (A)", 2D) = "white" {}
7.         _BlendTex ("Blend (RGB), Alpha (A)", 2D) = "grey" {}
8.         _SecondBlend ("Use Second Blend", Range (0, 1)) = 0
9.         _Desaturate ("Use Desaturation", Range (0, 1)) = 0
10.         _SepiaMode ("Use Really Colors", Range (0, 1)) = 0
11.     }
12.  
13.     SubShader
14.     {
15.         LOD 200
16.  
17.         Tags
18.         {
19.             "Queue" = "Transparent"
20.             "IgnoreProjector" = "True"
21.             "RenderType" = "Transparent"
22.         }
23.  
24.         Pass {
25.  
26.             Blend SrcAlpha OneMinusSrcAlpha
27.  
28.             ZTest Always Cull Off ZWrite Off
29.             Fog { Mode off }      
30.  
31.             CGPROGRAM
32.  
33.             #pragma fragmentoption ARB_precision_hint_fastest
34.             #pragma vertex vert
35.             #pragma fragment frag
36.             #pragma target 2.0
37.  
38.  
39.             // vertex input: position, UV
40.             struct appdata {
41.                 float4 vertex : POSITION;
42.                 float4 texcoord : TEXCOORD0;
43.             };
44.  
45.             struct v2f {
46.                 float4 pos : POSITION;
47.                 float2 uv : TEXCOORD0;
48.             };
49.  
50.             sampler2D _MainTex;
51.             sampler2D _BlendTex;
52.  
53.             fixed4 _Color;
54.             //fixed4 _Color2;
55.             half _Desaturate;
56.             half _SecondBlend;
57.             half _SepiaMode;
58.  
59.             v2f vert( appdata v ) {
60.                 v2f o;
61.                 o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
62.                 o.uv = v.texcoord.xy;
63.                 return o;
64.             }
65.            
66.             fixed4 frag(v2f i) : COLOR {
67.                 fixed4 color = tex2D (_MainTex, i.uv);
68.                
69.                 fixed alpha = color.a;
70.                 fixed power = (color.r + color.g + color.b) / 3;
71.  
72.                 color = color * lerp(_Color * 2, 1, power);
73.                
74.                 if(_SecondBlend > 0.5)
75.                 {
76.                     fixed4 color2 = tex2D (_BlendTex, i.uv);
77.  
78.                     color = (color * (1 - color2.a)) + (color * color2 * color2.a); // * lerp(color2, float4(1,1,1,1), color2.a);
79.                 }
80.  
81.                 if(_Desaturate < 0.5)
82.                 {
83.                     fixed des = (color.r + color.g + color.b) / 3;
84.                     color.r = des;
85.                     color.g = des;
86.                     color.b = des;
87.                 }
88.  
89.                 if(_SepiaMode > 0.5)
90.                 {
91.                     color = color * float4(0.76, 0.59, 0.37, 1);
92.                 }
93.  
94.                 color.a = alpha;
95.  
96.                 return color;
97.             }
98.  
99.             ENDCG
100.         }
101.     }
102.  
103.     Fallback "Unlit/Transparent"
104. }
105.  

 

Could it be the target 2.0 doing it?
Maybe they only have 3.0 but not 2.0? (is such a thing possible?)

also you have ifs

 

I don't think such a thing is possible. Also on the ifs, I use them to enable/disable certain features. Is there an issue with that approach?

 

I don't know, but on some older cards if statements do tend to cause issues. But usually there performance based not black screen based

 

Try 3.0. also check that DX11 (if you're using it, that is) isn't screwing with the shader syntax, as DX11 often does this dopey syntax rubbish that causes 3.0 shaders to show up black.

 

Based on ZephyrSys's suggestion, I removed the if statements and replaced them with #pragma multi_compile keywords, which appears to have fixed the issue. It's concerning that the shader would silently fail rather than fallback, but I guess some cards won't do if's (or that many if's).

Thanks for the help everyone.

 

You're welcome.