void UPaperSprite::Triangulate(const FSpritePolygonCollection& Source, TArray<FVector2D>& Target)
{
Target.Empty();
for (int32 PolygonIndex = 0; PolygonIndex < Source.Polygons.Num(); ++PolygonIndex)
{
const FSpritePolygon& SourcePoly = Source.Polygons[PolygonIndex];
if (SourcePoly.Vertices.Num() >= 3)
{
// Convert our format into one the triangulation library supports
FClipSMPolygon ClipPolygon(0);
for (int32 VertexIndex = 0; VertexIndex < SourcePoly.Vertices.Num() ; ++VertexIndex)
{
FClipSMVertex* ClipVertex = new (ClipPolygon.Vertices) FClipSMVertex;
FMemory::Memzero(ClipVertex, sizeof(FClipSMVertex));
const FVector2D& SourceVertex = SourcePoly.Vertices[VertexIndex];
ClipVertex->Pos.X = SourceVertex.X;
ClipVertex->Pos.Z = SourceVertex.Y;
}
ClipPolygon.FaceNormal = FVector(0.0f, -1.0f, 0.0f);
// Attempt to triangulate this polygon
TArray<FClipSMTriangle> GeneratedTriangles;
if (TriangulatePoly(/*out*/ GeneratedTriangles, ClipPolygon))
{
// Convert the triangles back to our 2D data structure
for (int32 TriangleIndex = 0; TriangleIndex < GeneratedTriangles.Num(); ++TriangleIndex)
{
const FClipSMTriangle& Triangle = GeneratedTriangles[TriangleIndex];
new (Target) FVector2D(Triangle.Vertices[0].Pos.X, Triangle.Vertices[0].Pos.Z);
new (Target) FVector2D(Triangle.Vertices[1].Pos.X, Triangle.Vertices[1].Pos.Z);
new (Target) FVector2D(Triangle.Vertices[2].Pos.X, Triangle.Vertices[2].Pos.Z);
}
}
}
}
}
int32 FPoly::Triangulate( ABrush* InOwnerBrush, TArray<FPoly>& OutTriangles )
{
#if WITH_EDITOR
if( Vertices.Num() < 3 )
{
return 0;
}
FClipSMPolygon Polygon(0);
for( int32 v = 0 ; v < Vertices.Num() ; ++v )
{
FClipSMVertex vtx;
vtx.Pos = Vertices[v];
// Init other data so that VertsAreEqual won't compare garbage
vtx.TangentX = FVector::ZeroVector;
vtx.TangentY = FVector::ZeroVector;
vtx.TangentZ = FVector::ZeroVector;
vtx.Color = FColor(0, 0, 0);
for( int32 uvIndex=0; uvIndex<ARRAY_COUNT(vtx.UVs); ++uvIndex )
{
vtx.UVs[uvIndex] = FVector2D(0.f, 0.f);
}
Polygon.Vertices.Add( vtx );
}
Polygon.FaceNormal = Normal;
// Attempt to triangulate this polygon
TArray<FClipSMTriangle> Triangles;
if( TriangulatePoly( Triangles, Polygon ) )
{
// Create a set of FPolys from the triangles
OutTriangles.Empty();
FPoly TrianglePoly;
for( int32 p = 0 ; p < Triangles.Num() ; ++p )
{
FClipSMTriangle* tri = &(Triangles[p]);
TrianglePoly.Init();
TrianglePoly.Base = tri->Vertices[0].Pos;
TrianglePoly.Vertices.Add( tri->Vertices[0].Pos );
TrianglePoly.Vertices.Add( tri->Vertices[1].Pos );
TrianglePoly.Vertices.Add( tri->Vertices[2].Pos );
if( TrianglePoly.Finalize( InOwnerBrush, 0 ) == 0 )
{
OutTriangles.Add( TrianglePoly );
}
}
}
#endif
return OutTriangles.Num();
}
