RuntimeMeshCore.cpp

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// Copyright 2016-2018 Chris Conway (Koderz). All Rights Reserved.

#include "RuntimeMeshCore.h"
#include "RuntimeMeshComponentPlugin.h"


//      FRuntimeMeshVertexStreamStructureElement

bool FRuntimeMeshVertexStreamStructureElement::operator==(const FRuntimeMeshVertexStreamStructureElement& Other) const
{
        return Offset == Other.Offset && Stride == Other.Stride && Type == Other.Type;
}

bool FRuntimeMeshVertexStreamStructureElement::operator!=(const FRuntimeMeshVertexStreamStructureElement& Other) const
{
        return !(*this == Other);
}


//      FRuntimeMeshVertexStreamStructure

bool FRuntimeMeshVertexStreamStructure::operator==(const FRuntimeMeshVertexStreamStructure& Other) const
{
        // First check the UVs
        if (UVs.Num() != Other.UVs.Num())
        {
                return false;
        }

        for (int32 Index = 0; Index < UVs.Num(); Index++)
        {
                if (UVs[Index] != Other.UVs[Index])
                {
                        return false;
                }
        }

        // Then check the other components
        return Position == Other.Position &&
                Normal == Other.Normal &&
                Tangent == Other.Tangent &&
                Color == Other.Color;
}

bool FRuntimeMeshVertexStreamStructure::operator!=(const FRuntimeMeshVertexStreamStructure& Other) const
{
        return !(*this == Other);
}

bool FRuntimeMeshVertexStreamStructure::HasAnyElements() const
{
        static const auto IsElementValid = [](const FRuntimeMeshVertexStreamStructureElement& Element) -> bool
        {
                return Element.Type != EVertexElementType::VET_None;
        };

        for (const auto& Elem : UVs)
        {
                if (IsElementValid(Elem))
                {
                        return true;
                }
        }

        return IsElementValid(Position) || IsElementValid(Normal) || IsElementValid(Tangent) || IsElementValid(Color);
}

bool FRuntimeMeshVertexStreamStructure::HasUVs() const
{
        return UVs.Num() > 0;
}

uint8 FRuntimeMeshVertexStreamStructure::CalculateStride() const
{
        uint8 MaxStride = 0;
        const auto AddElement = [&MaxStride](const FRuntimeMeshVertexStreamStructureElement& Element)
        {
                if (Element.Type != EVertexElementType::VET_None)
                {
                        check(MaxStride == 0 || Element.Stride == MaxStride || Element.Stride == 0);
                        MaxStride = FMath::Max(MaxStride, Element.Stride);
                }
        };

        AddElement(Position);
        AddElement(Normal);
        AddElement(Tangent);
        for (const auto& Elem : UVs)
        {
                AddElement(Elem);
        }
        AddElement(Color);


        return MaxStride;
}

bool FRuntimeMeshVertexStreamStructure::IsValid() const
{
        static const auto IsElementValid = [](const FRuntimeMeshVertexStreamStructureElement& Element) -> bool
        {
                return Element.Type == EVertexElementType::VET_None || Element.Stride > 0;
        };

        for (const auto& Elem : UVs)
        {
                if (!IsElementValid(Elem))
                {
                        return false;
                }
        }

        return IsElementValid(Position) && IsElementValid(Normal) && IsElementValid(Tangent) && IsElementValid(Color);
}

bool FRuntimeMeshVertexStreamStructure::HasNoOverlap(const FRuntimeMeshVertexStreamStructure& Other) const
{
        static const auto HasNoOverlap = [](const FRuntimeMeshVertexStreamStructureElement& Left, const FRuntimeMeshVertexStreamStructureElement& Right) -> bool
        {
                return Left.Type == EVertexElementType::VET_None || Right.Type == EVertexElementType::VET_None;
        };

        // two streams can't have UVs
        if (UVs.Num() > 0 && Other.UVs.Num() > 0)
        {
                return false;
        }

        // Now check overlap of the other components
        return HasNoOverlap(Position, Other.Position) && HasNoOverlap(Normal, Other.Normal) && HasNoOverlap(Tangent, Other.Tangent) && HasNoOverlap(Color, Other.Color);
}

bool FRuntimeMeshVertexStreamStructure::ValidTripleStream(const FRuntimeMeshVertexStreamStructure& Stream1, const FRuntimeMeshVertexStreamStructure& Stream2, const FRuntimeMeshVertexStreamStructure& Stream3)
{
        return Stream1.IsValid() && Stream2.IsValid() && Stream3.IsValid() &&
                Stream1.HasNoOverlap(Stream2) && Stream1.HasNoOverlap(Stream3) && Stream2.HasNoOverlap(Stream3) &&
                Stream1.HasAnyElements() && Stream1.Position.IsValid() &&
                (!Stream3.HasAnyElements() || Stream2.HasAnyElements());
}