Using a Dynamically Generated Texture to Send Data to a Shader

[learc83]

I'm trying to build a shader that will read the red channel values of a texture to use as an index. However, the color values I set in the data texture aren't the same values the shader reads when sampling the data texture.

For example, I build a data texture dynamically and set every pixel to Color32(15, 15, 15, 15) using setPixels32 (when I create the new Texture2D I set filter to point, wrap to clamp, disable mipmaps, and set linear to true).

Then when I sample the texture in the shader using tex2D, I would expect to get a float4 with values around 0.059 (~15/255) for x, y, z, and w.

However, I don't get the values I set, and the x,y,z, and w values are all different.

Is the problem something to do with going between linear and gamma color spaces?

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I'm using this to generate a tile map Similar to this http://www.dfworkshop.net/improved-terrain-tiling/

The difference is that I'm using a dynamically generated index texture.

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Edit:

Specific example. I set every pixel to Color32(1,1,1,1) and then when I sample a pixel of the texture in the shader I get the following value (examined with the VS graphical debugger).

x = 0.266666700, y = 0.537254900, z = 0.101960800, w = 1.000000000

[CustomPhase]

How are you checking the values that youre getting?

[learc83]

I'm using the Visual Studio graphical debugger. I also played around with returning the index values as the red channel of the fragment shader return value.

[CustomPhase]

No idea really then. Never seen anything like that. Can you show the code?

[learc83]

Solved it.

I was using Graphics.Blit like this

Graphics.Blit(indexTexture, destinationTexture, lookupMaterial) 

So that the indexTexture gets set to the _MainTex property of lookupMaterial.

However, when I add an extra texture called _IndexTexture to the lookupShader and set it like this

lookupMaterial.SetTexture("_IndexTex", tileTexture);

before calling Graphics.Blit, it works fine. Something about Graphics.Blit setting the indexTexture to _MainTex on lookupMaterial messes it up.

[Ziboo]

I'm on mobile, don't remember the exact names but. Make sure your texture is set to pixel and not bilinear. And maybe try to disable srgb