Algorithms.h

#pragma once
 
#include <glm/glm.hpp>
#include <memory>
 
#include "block/Face.h"
 
namespace engine {
    class Block;
    class World;
    class Chunk;
    class Face;
    class Geometry;
    using UnaryPredicate = std::function<bool(const Block*, const Face*)>;
 
    // TODO maybe add state?
    struct DDAResult {
        glm::vec3 position;
        glm::vec3 faceNormal;
        FaceTag faceTag;
        const Block* block;
        float distance;
        std::shared_ptr<Chunk> chunk;
    };
 
    struct Ray {
        glm::vec3 origin;
        glm::vec3 direction;
    };
    struct Triangle {
        glm::vec3 p1, p2, p3;
    };
 
    // https://gamedev.stackexchange.com/questions/47362/cast-ray-to-select-block-in-voxel-game/49423#49423
    DDAResult DDA(
        World& world, glm::vec3 start, glm::vec3 direction, float length, UnaryPredicate pred
    ) noexcept;
 
 
    const Face* getAimedFace(const Ray& ray, const Geometry* geometry) noexcept;
 
    float rayTriangleIntersection(const Ray& ray, Triangle& t, float& uOut, float& vOut) noexcept;
 
    glm::vec3 rotatePoint(
        const glm::vec3& point,
        const glm::vec3& axis,
        float angle,
        const glm::vec3& center = {0.5f, 0.5f, 0.5f}
    );
 
    std::vector<glm::vec3> rotatePoints(
        const std::vector<glm::vec3>& points,
        const glm::vec3& axis,
        float angle,
        const glm::vec3& center = {0.5f, 0.5f, 0.5f}
    );
}  // namespace engine