Im still 'thinking' about a way to remove the if's and replace with consecutive lerps. Something LIKE this...
Code:
float4  Color = tex2D(SandSampler, InTex); 
        Color = lerp(Color, tex2D(GrassSampler,InTex), [insert evil formula here]);
        Color = lerp(Color, tex2D(RockSampler,InTex),  [insert evil formula here]);
        Color = lerp(Color, tex2D(SnowSampler, InTex), [insert evil formula here]);

But while Im thinking about that "evil formula", Im also looking to
my own future needs with this THREAD HERE . Which, if possible,
would make this optimisation (for ME) unnecessary...

"There is no fate but what WE make." - CEO Cyberdyne Systems Corp.
A8.30.5 Commercial