Sphere Mask ArgInvHardness missing multiplication

Hi Epic,

In MaterialExpressions.cpp UMaterialExpressionSphereMask::Compile(), hardness is not calculated the same way in both <if> conditions. One is missing a multiplication by 0.01f.

Specifically:

int32 Softness = Compiler->Sub(Compiler->Constant(1.0f), Hardness.Compile(Compiler));

should be:

int32 Softness = Compiler->Sub(Compiler->Constant(1.0f), Compiler->Mul(Hardness.Compile(Compiler), Compiler->Constant(0.01f)));

<pre class="ql-syntax" spellcheck="false">In addition, FMath::Max(x, 0.00001f); doesn't work well with half precision shaders because 1 / 0.00001f = 100000. Which is a number higher than the highest half precision value supported. For that reason consider using 0.0001f instead (for radius and other cases too).

</pre>

1. Add a SphereMaskNode
2. Examine the HLSL output of the node when an input is provided to the node vs without.