AxisFlipMesh.hpp

Go to the documentation of this file.

//
//  CeresEngine - A game development framework
//
//  Created by Rogiel Sulzbach.
//  Copyright (c) 2018-2022 Rogiel Sulzbach. All rights reserved.
//
 
#pragma once
 
#include "TransformMesh.hpp"
#include "Triangle.hpp"
 
namespace CeresEngine::MeshGenerator {
 
    template<typename Mesh> class AxisFlipMesh {
    private:
        using Impl = TransformMesh<Mesh>;
        Impl mTransformMesh;
 
    public:
        class Triangles {
        public:
            [[nodiscard]] Triangle generate() const {
                Triangle triangle = mTriangles.generate();
                if(mMesh->mFlip)
                    std::swap(triangle.vertices[0], triangle.vertices[2]);
                return triangle;
            }
 
            [[nodiscard]] bool done() const noexcept { return mTriangles.done(); }
            void next() { mTriangles.next(); }
 
        private:
            const AxisFlipMesh* mMesh;
 
            typename TriangleGeneratorType<TransformMesh<Mesh>>::Type mTriangles;
 
            Triangles(const AxisFlipMesh& mesh) : mMesh{&mesh}, mTriangles{mesh.mTransformMesh.triangles()} {}
 
            friend class AxisFlipMesh;
        };
 
        AxisFlipMesh(Mesh mesh, bool x, bool y, bool z)
                : mTransformMesh{std::move(mesh),
                      [x, y, z](MeshVertex& vertex) {
                          if(x) {
                              vertex.position[0] *= -1.0;
                              vertex.normal[0] *= -1.0;
                          }
 
                          if(y) {
                              vertex.position[1] *= -1.0;
                              vertex.normal[1] *= -1.0;
                          }
 
                          if(z) {
                              vertex.position[2] *= -1.0;
                              vertex.normal[2] *= -1.0;
                          }
                      }},
                  mFlip{false} {
            if(x) {
                mFlip = !mFlip;
            }
 
            if(y) {
                mFlip = !mFlip;
            }
 
            if(z) {
                mFlip = !mFlip;
            }
        }
 
        [[nodiscard]] Triangles triangles() const noexcept { return {*this}; }
 
        using Vertices = typename Impl::Vertices;
        [[nodiscard]] Vertices vertices() const noexcept { return mTransformMesh.vertices(); }
 
    private:
        bool mFlip;
    };
 
    template<typename Mesh> AxisFlipMesh<Mesh> axisFlipMesh(Mesh mesh, bool x, bool y, bool z) { return AxisFlipMesh<Mesh>{std::move(mesh), x, y, z}; }
 
} // namespace CeresEngine::MeshGenerator