Putting a Vec3-like vector into a json object

[PopThis]

I have a struct like this

struct Vertexes
{
public:
	// Construction
	float x_;
	float y_;
	float z_;

	Vertexes(float x, float y, float z) : x_(x), y_(y), z_(z) {}

	// Getters
	float getX() const { return x_; }
	float getY() const { return y_; }
	float getZ() const { return z_; }

	// Setters
	void setX(float val) { x_ = val; }
	void setY(float val) { y_ = val; }
	void setZ(float val) { z_ = val; }

	std::string getString() {
		return std::to_string(x_) + ", " + std::to_string(z_) + ", " + std::to_string(y_);
	}

	Vertexes flip() const { return Vertexes{ x_ , z_ , y_ }; }
	Vertexes smaller() const { return Vertexes{ x_ / 100, y_ / 100, z_ / 100 }; }
	Vertexes smallerflip() const { return Vertexes{ x_ / 100, z_ / 100, y_ / 100 }; }

};

Sure, I could even flatten this down to just a

struct Vec3
{
   float x, y, z;
}

But

std::vector<Vertexes> SavedPoints = { {10, 1, 5}, {7,2,2} };
json v(SavedPoints);
std::ofstream o("file.json");
o << std::setw(4) << v << std::endl;

Would not work with to_json template (line 312 at to_json.hpp)

Is there a way to store this vector of vertexes as a json output? such as
v["list"] = SavedPoints and results in

{"0":[
     [10, 1, 5]
     ],
 "1":[[7,2 ,2]
     ]
 }

Thank you very much!

[PopThis]

I might've messed up the last json example. But you get the gist. Thank you again.

[nlohmann]

Did you have a look at https://github.com/nlohmann/json/blob/develop/README.md#arbitrary-types-conversions ? This section describes how you can convert arbitrary types to/from JSON.

[PopThis]

The Solution I am looking into can work if it is a Vec3, but having a std::vector of Vec3 is causing the issue since you would need to create a loop to read/write indexes individually. Such as key 0, 1, 2, 3 all having their own xyz. Thank you.

[PopThis]

namespace ns {
	void to_json(json& j, std::vector<Vertexes>& p) {

		for (std::vector<Vertexes>::iterator it = p.begin(); it != p.end(); ++it) {
			j = json{ {*it, { "x", it->x_ },{ "z", it->z_ },{ "y", it->y_ } } };
		}
	}
}

And then using it by

std::vector<Vertexes> SavedPoints = { { 10, 1, 5 },{ 7,2,2 } };
json jx;
ns::to_json(jx, SavedPoints);

or

std::vector<Vertexes> SavedPoints = { { 10, 1, 5 },{ 7,2,2 } };
json jx = SavedPoints;

still giving me issue at could not find to_json() method in T's Namespace

[nlohmann]

You need to put the to_json function exactly into the namespace of Vertexes. ns is just a namespace from the example.

[PopThis]

I've gotten it to work and it looks good. Thank you. The only issue left is I am sure I am doing this the wrong way.

		for (std::vector<Vertexes>::iterator it = p.begin(); it != p.end(); ++it) {
			j = json{ { unsigned int(it - p.begin()),{ "x", it->x_ },{ "z", it->z_ },{ "y", it->y_ } } };
		}

resulted in only the last index when it is printed out.

instead of the expected

[[0,["x",1.0],["z",2.0],["y",3.0],
[1,["x",7.0],["z",2.0],["y",2.0]]

it only prints out

[[1,["x",7.0],["z",2.0],["y",2.0]]]

I know this is a whole different issue on my part and I appreciate your time.

[PopThis]

I've solved the issue. I forgot that I am setting j = the new json instead of push_back on it. Thank you.

namespace ns {
	void to_json(json& j, std::vector<Vertexes>& p) {

		for (std::vector<Vertexes>::iterator it = p.begin(); it != p.end(); ++it) {
			j.push_back(json{ { unsigned int(it - p.begin()),{ "x", it->x_ },{ "z", it->z_ },{ "y", it->y_ } } });
		}
	}

for example

[PopThis]

One last note. Due to the push_back already taking care of the keys for us, we don't need to manually create our own key with the loop. This result in so much better solution. Thank you. Closed now.

namespace ns {
	void to_json(json& j, std::vector<Vertexes>& p) {

		for (std::vector<Vertexes>::iterator it = p.begin(); it != p.end(); ++it) {
			j.push_back(json{ { "x", it->x_ },{ "z", it->z_ },{ "y", it->y_ } } );
		}
	}
} 

[PopThis]

Actually, LAST one. The other one kept increasing the size if you keep calling the function so we set it like this instead and it is all good.

	void to_json(json& j, std::vector<Vertexes>& p) {
		for (std::vector<Vertexes>::iterator it = p.begin(); it != p.end(); ++it) {
			j[it-p.begin()] = (json{ { "x", it->x_ },{ "z", it->z_ },{ "y", it->y_ } } );
		}
	}

[gregmarr]

You should do void to_json(json& j, Vertexes const &v) instead, then std::vector is handled automatically.

[nlohmann]

@PopThis Can I close this issue?