Material.SetTexture() applied per material instance but Material.SetFloat() is not

I'm trying to set shader parameters in a material at runtime and I would like them to be applied uniquely per instance of the material. I'm referencing the renderer and it's material so this should create a material instance when modifying these parameters.

Currently I am successfully able to use Material.SetTexture() to set a different texture per material instance but I am not able to do this with Material.SetFloat(). That will end up setting the float for all objects with that material rather than setting it per instance. How do I get Unity to set the float per instance rather than across all objects using that material?

Here is some of the code I'm using. I edited down the shader code to just show the more relevant parts:

Code (CSharp):

1. //In C# code
2. public void SetRiverTexture(bool bFlipX,bool bFlipY,Sprite riverSprite)
3. {
4.      spriteRenderer.material.SetTexture("_RiverTex",riverSprite.texture);
5.  
6.      if(bFlipX)
7.           spriteRenderer.material.SetFloat("_FlipX",1f);
8.  
9.      if(bFlipY)
10.           spriteRenderer.material.SetFloat("_FlipY",1f);
11. }
12.  
13. //In shader
14. Properties
15. {
16.      _RiverTex ("River Texture", 2D) = "white" {}
17.      [Toggle] _FlipX ("Flip River X", Float) = 0
18.      [Toggle] _FlipY ("Flip River Y", Float) = 0
19. }
20.  
21. CGPROGRAM
22. #pragma multi_compile _FLIPX_OFF _FLIPX_ON
23. #pragma multi_compile _FLIPY_OFF _FLIPY_ON
24.  
25. sampler2D _RiverTex;
26.  
27. void surf (Input IN, inout SurfaceOutput o)
28. {
29.     fixed2 uv = IN.uv_MainTex;
30.  
31.     #if _FLIPX_ON
32.         uv.x = 1.0 - uv.x;
33.     #endif
34.  
35.     #if _FLIPY_ON
36.         uv.y = 1.0 - uv.y;
37.     #endif
38.  
39.     fixed4 c = tex2D (_RiverTex, uv);
40.          
41.     o.Albedo = c.rgb * c.a;
42.     o.Alpha = c.a;
43. }
44. ENDCG

 

Is the problem unclear or need better explanation? Currently the only work around I have is to make a separate material for each customization of the shader that I want but I would much rather do this at runtime.

 

This should probably go into the graphics section...
To me what you describe sounds like a bug, but I'm no expert really.
Why don't you declare the floats normally for now (without multi_compile) and merge in the conditions like this :

Code (CSharp):

1. uv.x = 1.0 - flipX * uv.x;

?
I don't see how the performance of such a small shader can ever be an issue nowadays.

 

Well I took your idea of not using multi_compile and using SetFloat with a regular float in the CGPROGRAM and it does allow it to work properly. Here is what I'm using, I don't like it that much so if anyone knows why multi_compile floats are only being set globally and not per instance that would be helpful to know. Id much rather use them as booleans rather than actual floats.

Code (CSharp):

1. //Flip X and Y will either be 0 or 1.
2. uv.x = _FlipX - (uv.x * (-1 + _FlipX * 2));
3.  
4. uv.y = _FlipY - (uv.y * (-1 + _FlipY * 2));

 

Have you tried using Material.EnableKeyword? That was the way you would choose multi-compile paths in the past.

 

Aha, I had tried that before and it didn't work but I think I had been doing it wrong. I was trying to enable the material's reference to the float ("_FlipX") and not the actual key word ("_FLIPX_ON"). I just deleted the float toggle for the material since I don't actually need it and instead referenced the multi_compile's keyword. So this is the correct way:

Code (CSharp):

1. //In C#
2. spriteRenderer.material.EnableKeyword("_FLIPX_ON");
3.  
4. //In shader
5. #pragma multi_compile _FLIPX_OFF _FLIPX_ON
6.  
7. ...
8.  
9. #if _FLIPX_ON
10.      uv.x = 1 - uv.x;
11. #endif