GetManagerFromContext: pointer to object of manager 'RenderSettings' crash in Unity3d

I recently encountered an issue using Unity3d where I was unable to create a build of a client's project because of a crash that occurred in the Unity Editor during build publishing.  Unfortunately I don't have an image of the crash message dialog, but essentially it said:

"Fatal error! GetManagerFromContext: pointer to object manager 'RenderSettings' is NULL"

which wasn't the most helpful message in the world.  I spent some time trying to track down any obvious issue in the code with no luck, so start looking on the Unity forum and found This forum post which described a very similar issue I was seeing.

Luckily it seems this was a known issue, apparently caused by assigning ProceduralMaterials to Material properties inside scripts.  There have been a couple of fixes for this particular problem recently, the Unity 4.5.4 release notes and Unity 4.5.4p2 release notes both mention fixes related to this issue.

Updating to the vanilla Unity 4.5.4 release from 4.5.3 fixed my particular crash.

TL;DR
If you're seeing a crash similar to what I posted above, and you use procedural materials in the project, try to update to Unity 4.5.4 or one of the patch releases and see if that fixes the issue

Handling Texture Tiling and Offset in a Unity3d Vertex and Fragment Shader using TRANSFORM_TEX macro

When doing some test work, I found my Cg shader wasn't handling texture offset and tiling properly, resulting in distortion such as below:

The Unity shader on the left properly handles a 3x tiling factor for the texture, while my shader on the right doesn't properly handle the same 3x tiling factor

My shader setup was pretty simple, here's a snippet of the important parts:

#include "UnityCG.cginc"

sampler2D _MainTex;
float4 _Color;

v2f vert ( appdata_base v )
{
    v2f o; 

    o.pos = mul (UNITY_MATRIX_MVP, v.vertex);

    // Texture offset - BAD
    o.uv = v.texcoord;
    return o;
}

half4 frag (v2f i) : COLOR
{    
    return tex2D(_MainTex, i.uv) * _Color;
}

I bolded the problematic part, which is the Texture UV handling in the 'vert' program.  Simply grabbing the v.texcoord will work when there is not tiling or offsets in the texture, but breaks once those elements are introduced

After snooping around, I found the solution is to use the TRANSFORM_TEX macro in the UnityCG.cginc to make sure the texture's offset and tiling are properly applied.  A small caveat to this is you must, "declare float4 properties for each texture before the vertex program, with _ST appended" (Quoted from Unity3d shader docs).

Here's a snippet of my shader with the new changes:

#include "UnityCG.cginc"

sampler2D _MainTex;
float4 _Color;
uniform float4 _MainTex_ST; // Needed for TRANSFORM_TEX(v.texcoord, _MainTex)

v2f vert ( appdata_base v )
{
    v2f o; 

    o.pos = mul (UNITY_MATRIX_MVP, v.vertex);

    // Texture offset - GOOD
    o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
    return o;
}

half4 frag (v2f i) : COLOR
{    
    return tex2D(_MainTex, i.uv) * _Color;
}

With this happy little change, our shader now properly handles the tiling and offsets of the texture.

 

For those curious, I gleaned this information from the Unity3D Vertex and Fragment Programs and the ancient Unity 2.x Shader Conversion Guide.  The info pulled from the Shader conversion guide regards the _MainTex_ST property needed for TRANSFORM_TEX to work. 

UPDATE - Dec 1, 2013 - The Unity 2.x Shader Conversion Guide seems to have disappeared from the internet.  This information is all still relevant for Unity 4.x release versions