Different shaders for iPad1 and iPad2

Graphics Shaders & Materials
1

Is it possible to write shaders so that they work on iPad 2/3 and fall back to another shader on iPad1? The 1st gen iPad isn’t fast enough to render my scenes with rim lighting and specular highlights, but the iPad 2 is. I suppose I can swap materials in code to replace low quality materials with better ones, but I wondered if it’s possible to do it directly in the shader.

I can use #pragma exclude_renderers to stop the shader being rendered on all iOS devices, but I haven’t found anything more granular than that.

2

It will be better to detect device in script and swap materials imho.

3

You could use custom keywords in custom shader then in game script call

Shader.EnableKeyword (“IPAD3_ON”);
Shader.DisableKeyword (“IPAD3_OFF”);

then in shader

#pragma multi_compile IPAD3_ON IPAD3_OFF

#if ( IPAD3_ON )
// do ipad 3 stuff
#else
// do non ipad3 stuff
#endif

// another method ================================

in game code set shader manually based on device ( i think the shaders all need to exist in scene to work on device like this )

Shader myshader = Shader.Find(“MyShaderName”)

gameobject.renderer.material.shader = myshader;

4

Thanks, echologin, #pragma multi_compile seems perfect!

5

Cool !, then call the Shader.enable(“keyword”) and disable at Start() + Awake(), ive seen examples where they call it every frame before rendering but Start + Awake seems to work for me.

6

I’m not having any luck. All of my shaders are surface shaders. Is the use of #pragma multi_compile and #ifdef not available inside surface shaders?

7

I don’t know i never wrote any surface shaders, only vertex/frag,

the #pragma has to go under the CGPROGRAM part ( maybe that is problem ? )

EDIT: i tried this and it seems to work as expected

Shader "Example/SurfaceTest	" 
{
	Properties 
 	{
 		_MainTex ("Texture", 2D) = "white" {}
 	}
    SubShader 
    {
      Tags { "RenderType" = "Opaque" }
      CGPROGRAM
      #pragma surface surf Lambert
      #pragma multi_compile IPAD3_ON IPAD3_OFF
      
      struct Input 
      {
          float2 uv_MainTex;
      };
      
      sampler2D _MainTex;
      
      void surf (Input IN, inout SurfaceOutput o) 
      {
          #ifndef IPAD3_OFF
	          o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb;
          #else
	          o.Albedo = fixed3 ( 1,0,0 );
          #endif
      }
      
      ENDCG
    } 
    
    Fallback "Diffuse"
  }

in unity shaders i do not think #ifdef works, it is #if and #ifndef

8

Aha, you’re right. It was the #ifdef which was causing me problems. Using #if and #ifndef works fine.

Thanks very much for the help.