Dependent Texture Reads

Not dependent:
float3 nonDependentTextureRead = tex2D(_MainTexture, input.texcoord).xyz;

Dependent:
float3 DependentTextureRead = tex2D(_MainTexture, input.texcoord.zw).xyz;
float3 DependentTextureRead = tex2D(_MainTexture, input.texcoord.yx).xyz;
float3 DependentTextureRead = tex2D(_MainTexture, input.texcoord*2.0).xyz;

==========================

struct v2f{
 half2 uv : TEXCOORDn; //pass uvs direcly
 half4 packed2uvs : TEXCOORDn; //afraid of dependent texture read, avoid packing 2 uvs into 1 varying
 half4 packed4Scalars : TEXCOORDn; //for general purpose scalar packing
}

tex2D(_Texture,i.uv); //good, fastest
tex2D(_Texture,i.uv.xy); //afraid of dependent texture read, depends on driver?. avoid
tex2D(_Texture,i.uv.zw); //afraid of dependent texture read. avoid

Unity Shader Property Names

Legacy

• _MainTex (Texture, diffuse color in the RGB channels, transparency in the A channel)
• _Color (Color, diffuse color tint. This is multiplied by _MainTex)
• _SpecMap (Texture, specular map)
• _SpecColor (Color, specular color tint)
• _Shininess (Value or Slider, controls glossiness)
• _BumpMap (Texture, normal map)
• _TransparencyLM (Texture, rgb channels define colored transparency)
• _Illum (Texture, for emissive materials. This will be a mask of _MainTex * _Color)

Standard

• Albedo  (diffuse color)
• Normal (tangent space normal, if written)
• Emission
• Specular (specular power in 0..1 range)
• Gloss (specular intensity)
• Alpha (alpha for transparencies)

Physical (metallic)

• Albedo (base - diffuse or specular - color)
• Normal (tangent space normal, if written)
• Emission
• Metallic (0=non-metal, 1=metal)
• Smoothness (0=rough, 1=smooth)
• Occlusion (occlusion - default 1)
• Alpha (alpha for transparencies)

Physical (specular)

• Albedo (diffuse color)
• Specular (specular color)
• Normal (tangent space normal, if written)
• Emission
• Smoothness (0=rough, 1=smooth)
• Occlusion (occlusion  - default 1)
• Alpha (alpha for transparencies)

Unity3D Shader LOD Stuff

Unity3D Documentation:

• Shader LOD Values
  VertexLit kind of shaders = 100
  Decal, Reflective VertexLit = 150
  Diffuse = 200
  Diffuse Detail, Reflective Bumped Unlit, Reflective Bumped VertexLit = 250
  Bumped, Specular = 300
  Bumped Specular = 400
  Parallax = 500
  Parallax Specular = 600
  
• Global Shader LOD Setting

Shader Forge:

• Shader Forge Subshader Workaround
  "There's no way to make subshaders in SF at the moment, but you can define a fallback shader and specify the LOD level"