Shader Model 4.0 and above not working in-game

[Gameslinx]

Hello, I'm developing a shader that requires the use of double precision values. To do this, I must use at least Shader Model (SM) 4.6.

SM 4.6 is supported by DX11, which is what KSP uses by default now.

Moving from SM 3.0 to SM 4.x was causing the shader to appear pink in-game, so I tested this on a completely default, fresh surface shader. I also tested it on a vert-frag shader to be sure. The results were the same - It wasn't working, even when I forced DX11. The shader works fine on SM 3.0. The line I'm referring to is #pragma target 4.6.

It's worth keeping in mind that SM 4.6 works fine in the Unity editor.

The code for the very basic shader is here:

Shader "Custom/Shader"
{
    Properties
    {
        _Color("Color", Color) = (1,1,1,1)
        _MainTex("Albedo (RGB)", 2D) = "white" {}
        _Glossiness("Smoothness", Range(0,1)) = 0.5
        _Metallic("Metallic", Range(0,1)) = 0.0
    }
    SubShader
    {
        Tags { "RenderType" = "Opaque" }
        LOD 200
        CGPROGRAM
        #pragma surface surf Standard fullforwardshadows
        #pragma target 4.6
        sampler2D _MainTex;
        struct Input
        {
            float2 uv_MainTex;
        };
        half _Glossiness;
        half _Metallic;
        fixed4 _Color;
        void surf(Input IN, inout SurfaceOutputStandard o)
        {
            fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
            o.Albedo = c.rgb;
        }
        ENDCG
    }
}

The code for the shader that I'll actually be moving over to SM 4.6 is here:

https://github.com/Gameslinx/Parallax-Occlusion/blob/master/Shaders/ParallaxOcclusion.shader

How come using SM 4.0 and above just doesn't work, even though it should be supported by KSP? Am I doing something wrong?

[blackrack]

Posting this here for future reference:

I managed to load a SM 4.0 shader in KSP, only I removed the #pragma target 4.0 line from the shader and used a SM 4.0 feature (in my case a geometry shader) and that gets the shader to load in KSP and force SM 4.0

The documentation seems to corroborate this: https://docs.unity.cn/560/Documentation/Manual/SL-ShaderCompileTargets.html

For forcing SM 4.6 use a tesselation shader anf make sure there is no #pragma target defined.

Edited August 6, 2020 by blackrack