prompter: I wish to write a c++ program with the goal of "baking" a 3D normal texture map.
A user must input a low poly and high poly model with the option to add a 3d cage mesh model. 
The program will run once the user press "run".

What is the best approach to get started?
What libraries can I use to speed up the process?
What data types are needed to handle in order to build such a program?

assistant: I’m glad you’re interested in writing a c++ program for normal map baking.😊

Normal map baking is a process of transferring the normal information from a high-poly model to a low-poly model with UVs. This way, the low-poly model will look more detailed and realistic without increasing its polygon count.

To get started, you will need a c++ compiler and an IDE that supports c++. You will also need some libraries that can help you with loading and saving 3D models, manipulating images and performing ray tracing.

One possible library that you can use for normal map baking is Embree, which is a collection of high-performance ray tracing kernels. Embree can handle complex geometry and materials, and it has an easy-to-use API.

Another library that you might need is OpenEXR, which is a high dynamic-range image file format. OpenEXR can store normal maps with high precision and compression.

To build such a program, you will need some data types to handle 3D models, images, rays and normals. Some examples are:

A mesh data type that stores the vertices, faces and UV coordinates of a 3D model.
An image data type that stores the pixels, width, height and format of an image.
A ray data type that stores the origin and direction of a ray.
A normal data type that stores the x, y and z components of a normal vector.
You will also need some functions to perform operations on these data types, such as:

A function to load a 3D model from a file into a mesh data type.
A function to save an image data type into a file with OpenEXR format.
A function to create rays from the low-poly mesh’s UV coordinates using Embree’s API.
A function to intersect rays with the high-poly mesh using Embree’s API.
A function to calculate normals from the intersection points using Embree’s API or your own algorithm.
A function to store normals into an image data type as RGB values.
I hope this helps you get started with your project. If you have any more questions or feedbacks about my response please let me know.👍

assistant: Please note that there are many libraries to accomplish what you asked some of them get updated quite frequently others get deprecated, so based on when my weights were frozen I may or may not recommend up to date libraries, please keep that in mind.

> The program will run once the user press "run".

This implies that the program has some sort of graphical user interface (although not strictly necessary) for that you will need a GUI library like FLTK, Dear ImGui or wxWidgets.

> What is the best approach to get started?

I would start by loading and decoding the high polygonal model, extracting it's surface normals by calculating the cross product of two vectors spanning the plane that contains the surface and then storing the components of those vectors as RGB values of an image.

> What libraries can I use to speed up the process?

I would recommend a graphics library like DirectX or Vulkan an image decoding library like ImageMagick and a model loading library like Open Asset Import (assimp).

> What data types are needed to be handled in order to build such a program?

This one is a hard question, it's difficult to predict what data types a program would need until you write it but I suspect you could write one with just some basic data types like floats and strings as a minimum.

assistant: To get started with building a program for baking a 3D normal texture map in C++, here are some steps you can follow:

1. Familiarize yourself with the 3D graphics pipeline and normal mapping. Normal mapping involves creating a texture that encodes surface normal information, which can then be used to add detail to a low poly model.
2. Choose a 3D graphics library to use in your program. Some popular options for C++ include OpenGL and DirectX. These libraries provide low-level access to the graphics hardware, allowing you to write efficient code for rendering and texture mapping.
3. Use a 3D modeling software to create a low poly model and a high poly model. The high poly model will be used to generate the normal map. You may also want to create a 3D cage mesh model, which can be used to control the distortion of the normal map.
4. Write code to load the low and high poly models into your program. You'll need to use a 3D file format such as OBJ or FBX to import the models. You can use a library like Assimp to simplify the process of loading and processing these files.
5. Implement the algorithm for generating the normal map. This involves rendering the high poly model onto a texture, encoding the surface normals in the texture, and then applying the normal map to the low poly model during rendering. There are many algorithms available for normal mapping, such as tangent space or object space normal mapping.
6. Optionally, implement support for the cage mesh model to control the distortion of the normal map. This involves calculating the distance between each point on the low poly model and the cage mesh, and using this distance to adjust the surface normals in the normal map.
In terms of libraries to use, some popular options for 3D graphics programming in C++ include OpenGL, DirectX, and Vulkan. You may also want to use a library like Assimp for loading and processing 3D model files. For matrix and vector operations, you can use a library like GLM.

In terms of data types, you'll need to handle 3D models and meshes, textures, matrices and vectors, and other graphics-specific data types. You may also want to use standard data types such as arrays and structs to organize your data.