Feature Request: Ability to render Polyscope viewer in multiple ImGui windows

Start with the main.cpp ImGui, GLFW, and OpenGL3 example in the issue, then inspect how Polyscope currently owns its window and event loop. Determine the architectural entry points needed for rendering separate visualizations in multiple ImGui windows; done means the requested multi-window rendering API works within one GUI.

Hello Polyscope maintainers and community,

I'm using Polyscope to visualize point cloud data within a GUI application.

Currently, Polyscope encapsulates its own window and event loop and doesn't provide an API to render into multiple ImGui windows. In my case, I would like to show the 3D data in one window alongside 2 other windows to show the two 2D cameras windows. Specifically, I'm looking to render different Polyscope visualizations in separate ImGui windows within the same GUI.

I understand that this feature might involve significant changes to Polyscope's architecture, but I believe the added flexibility would benefit many users and use cases. I look forward to hearing your thoughts on this suggestion.

Thank you for your time and the excellent work on Polyscope!

This is the implementation of two different windows in the same GUI using ImGUI, GLFW and OpenGL3:

// main.cpp
#include "imgui.h"
#include "imgui_impl_glfw.h"
#include "imgui_impl_opengl3.h"
#include <GLFW/glfw3.h>

int main() {
    // Set up window
    glfwInit();
    GLFWwindow* window = glfwCreateWindow(1280, 720, "Hello", NULL, NULL);
    glfwMakeContextCurrent(window);
    glfwSwapInterval(1); // Enable vsync

    // Set up Dear ImGui context
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO();

    // Set up Platform/Renderer bindings
    ImGui_ImplGlfw_InitForOpenGL(window, true);
    ImGui_ImplOpenGL3_Init("#version 130");

    while (!glfwWindowShouldClose(window)) {
        glfwPollEvents();

        // Start ImGui frame
        ImGui_ImplOpenGL3_NewFrame();
        ImGui_ImplGlfw_NewFrame();
        ImGui::NewFrame();

        // Here we construct our GUI
        ImGui::SetNextWindowPos(ImVec2(0, 0));
        ImGui::SetNextWindowSize(ImVec2(640, 720));
        ImGui::Begin("Window 1");
        ImGui::Text("This is window 1");
        ImGui::End();

        ImGui::SetNextWindowPos(ImVec2(640, 0));
        ImGui::SetNextWindowSize(ImVec2(640, 720));
        ImGui::Begin("Window 2");
        ImGui::Text("This is window 2");
        ImGui::End();

        // Render ImGui frame
        ImGui::Render();
        int display_w, display_h;
        glfwGetFramebufferSize(window, &display_w, &display_h);
        glViewport(0, 0, display_w, display_h);
        glClearColor(0.45f, 0.55f, 0.60f, 1.00f);
        glClear(GL_COLOR_BUFFER_BIT);
        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());

        glfwSwapBuffers(window);
    }

    // Cleanup
    ImGui_ImplOpenGL3_Shutdown();
    ImGui_ImplGlfw_Shutdown();
    ImGui::DestroyContext();

    glfwDestroyWindow(window);
    glfwTerminate();

    return 0;
}