OpenGLES2 and fixed1 mul(fixed4 v, fixed4x1 M)

Hi

I want to multiply two vectors (one transposed) and get scalar value.
Function fixed1 mul(fixed4 v, fixed4x1 M) is described here: http://http.developer.nvidia.com/Cg/mul.html
It works fine on Android phone with OpenGLES3 API, but when I switch to OpenGLES2 (in PlayerSettings/Other Settings/Graphics API) my shader doesn't work on Android device.

I made very simple shader, to prove this is the problem:

Code (csharp):

1. Shader "my/test" {
2.  
3.   Properties {
4.   }
5.   SubShader{
6.     Tags {
7.       "LightMode" = "ForwardBase"
8.     }
9.     Pass {
10.       Cull Off
11.        
12.       CGPROGRAM
13.      
14.       #pragma vertex   vert
15.       #pragma fragment frag
16.      
17.       struct VertIn {
18.         fixed4 posM : POSITION;
19.         fixed3 norm : NORMAL;
20.         fixed4 uv   : TEXCOORD0;
21.       };
22.      
23.       struct FragIn {
24.         fixed4 posP   : SV_POSITION;
25.       };
26.      
27.       FragIn vert ( VertIn i ) {
28.         FragIn o;
29.         o.posP       = mul(UNITY_MATRIX_VP, mul(unity_ObjectToWorld, i.posM));
30.         fixed test   = mul(fixed4(0,1,2,3),fixed4(1,0,2,1));
31.         return o;
32.       }
33.      
34.       float4 frag (FragIn i) : COLOR {
35.         return fixed4(1,1,1,1);
36.       }
37.      
38.       ENDCG
39.     }
40.   }
41.   //Fallback "Diffuse"
42. }
43.  

As you can see, it's super simple and returns white (fixed4(1,1,1,1)) for all fragments.
For some reason on Android device with OpenGLES2 it's pink.
It's white, when I comment line

Code (csharp):

1. fixed test   = mul(fixed4(0,1,2,3),fixed4(1,0,2,1));

What am I doing wrong?

Maybe I shouldn't use fixed4 like fixed1x4, but, to be honest, I don't know how to declare fixed1x4 value.
I tried fixed1x4(1,2,3,4) and transpose(fixed4(1,2,3,4)) and both do not compile.

 

OpenGLES 2.0 doesn't support non-square, non-power of 2 matrices. However it sounds like what you actually want is a dot product.

dot(fixed4(1,2,3,4),fixed4(1,2,3,4));

 

Thank you

 

I'm struggling to find link for this, so I'm going by memory, but:

While for most devices fixed and half are the same thing, some (older) devices, treat fixed (lowp) differently and it's generally clamped to -2 and 2, so you may get unpredictable results if you use values higher than that.