Large landscape performance problem

Development World Creation
,
10 



//inputs
ALandscape* l = ...
FVector lightDir = ...
#if WITH_EDITOR
for (ULandscapeComponent* c : l->LandscapeComponents)
{
    bool canCastShadow = false;
 
    // Checks if any triangle of component can cast shadow from that light direction.
    FLandscapeComponentDataInterface CDI(c);           
    for (int32 y = 0; y < c->ComponentSizeQuads; y++)
    {
        for (int32 x = 0; x < c->ComponentSizeQuads; x++)
        {
            FVector center = CDI.GetWorldVertex(x, y);
            FVector up = CDI.GetWorldVertex(x, y + 1);
            FVector left = CDI.GetWorldVertex(x + 1, y);
            FVector upLeft = CDI.GetWorldVertex(x + 1, y + 1);
 
            FVector n0 = FVector::CrossProduct(up - center, center - upLeft);
            FVector n1 = FVector::CrossProduct(upLeft - center, center - left);
            canCastShadow |= FVector::DotProduct(lightDir, n0) < 0.f;
            canCastShadow |= FVector::DotProduct(lightDir, n1) < 0.f;
        }
    }
    c->bCastDynamicShadow = canCastShadow;
}
#endif

This little code snippet checks if landscape components are casting shadows for absolute no reason. In our map 90% of landscape components never contributed to dynamic cascaded shadows but costed hefty amount of performance.
I am now calling this using blueprint but with source code access you can make landscape edit tools to call these kind of optimization functions every time you have finished edits.