sub-edge-iterator.hpp

#pragma once
 
// Ripped straight from https://github.com/ValveSoftware/source-sdk-2013/blob/master/sp/src/public/disp_common.h#L48
 
#include "./triangulated-displacement.hpp"
 
namespace BspParser::Internal {
  struct VertexCoordinate {
    enum class Axis : uint8_t { X, Y };
 
    int32_t x = 0;
    int32_t y = 0;
 
    int32_t& operator[](const Axis axis) {
      return axis == Axis::X ? x : y;
    }
 
    const int32_t& operator[](const Axis axis) const {
      return axis == Axis::X ? x : y;
    }
  };
 
  class SubEdgeIterator {
  public:
    SubEdgeIterator(
      const TriangulatedDisplacement& displacement,
      const Structs::DispSubNeighbour& subNeighbour,
      const TriangulatedDisplacement& neighbour,
      int32_t edgeIndex,
      int32_t subNeighbourIndex,
      bool shouldTouchCorners = false
    );
 
    bool next();
 
    [[nodiscard]] const VertexCoordinate& getVertexCoordinate() const;
    [[nodiscard]] int32_t getVertexIndex() const;
    [[nodiscard]] int32_t getNeighbourVertexIndex() const;
 
    [[nodiscard]] bool isLastVertex() const;
 
    [[nodiscard]] VertexCoordinate::Axis getFreeAxis() const;
 
  private:
    const TriangulatedDisplacement* displacement = nullptr;
    const TriangulatedDisplacement* neighbour = nullptr;
 
    uint8_t neighbourOrientation = 0;
 
    uint8_t span = 0;
    uint8_t neighbourSpan = 0;
 
    VertexCoordinate coordinate{};
    VertexCoordinate increment{};
 
    VertexCoordinate neighbourCoordinate{};
    VertexCoordinate neighbourIncrement{};
 
    int32_t end = 0;
    VertexCoordinate::Axis freeAxis = VertexCoordinate::Axis::X;
    VertexCoordinate::Axis neighbourFreeAxis = VertexCoordinate::Axis::X;
 
    void setupEdgeIncrements(int32_t edgeIndex, int32_t subNeighbourIndex);
    [[nodiscard]] VertexCoordinate transformIntoSubNeighbour(int32_t edgeIndex, const VertexCoordinate& toTransform);
  };
}