BlendTotal is now an actual total rather than a max

Engine/source/terrain/hlsl/terrFeatureHLSL.cpp

@@ -446,7 +446,7 @@ void TerrainDetailMapFeatHLSL::processPix(   Vector<ShaderComponent*> &component
    }
 
    // Add to the blend total.
-   meta->addStatement( new GenOp( "   @ = max( @, @ );\r\n", blendTotal, blendTotal, detailBlend ) );
+   meta->addStatement( new GenOp( "   @ += @;\r\n", blendTotal, detailBlend ) );
 
    // If we had a parallax feature... then factor in the parallax
    // amount so that it fades out with the layer blending.