match3D - a 3D viewer bootstrapping library

The match3D app prototyping library combines three ingredients: windowing library (GLFW), UI library (Dear ImGui), and build system infrastructure (CMake) to all but eliminate the boilerplate involved in making simple 3D applications with a UI.

Requirements

• CMake
• C++11 compiler
• GLFW

match3D is developed and tested on Linux, but has nothing inherently platform specific in it. If you try it on macOS or Windows and find a problem, let me know!

Building with match3D

The match3D library is consumed as a source library. This is easiest to do using CMake via the provided package config. The provided example (found in examples/simple) is built like an external consumer of the library.

The library is found by pointing your project's build to a local copy of the match3D source with either match3D_DIR variable or appending it to CMAKE_PREFIX_PATH. Then the consuming CMake is very straightforward and will look something like:

find_package(match3D REQUIRED)
add_executable(myApplication)
target_link_libraries(myApplication PRIVATE match3D::match3D)

Linking with the match3D::match3D target is all that is needed to bring in the necessary includes and linked libraries to build your application, including GLFW and Dear Imgui. Note that find_package(match3D) will require GLFW to be found in your environment in order to succeed in finding match3D itself.

Downstream targets which link against match3D::match3D have everything directly built into it.

Using additional components

match3D can optionally bring in additional header-only libraries: currently stb_image and glm. These are optionally added to the build by passing them to find_package as components. For example, the following will also fetch glm when constructing the match3D targets:

find_package(match3D REQUIRED COMPONENTS glm)

Which then lets you include glm normally in your app:

#include <glm/glm.hpp>

Using the library to create an application

The match3D library revoles around a single C++ base class: Application. This class has applications override methods to inject functionality for creating the UI and drawing objects (with OpenGL) each frame. Specifically, applications must override:

• Application::setup() -- this is invoked before the main UI loop is started
• Application::buildUI() -- where all ImGui calls are made to create the UI
• Application::drawBackground() -- where any drawing underneath the UI happens
• Application::teardown() -- cleanup to occur before the destructor

Each of the above methods are pure-virtual (=0) so that each customization point is always visible in an implementation. The provided example shows a minimal demonstration of an application.

NOTE: all mouse and keyboard I/O is to be done through Dear ImGui -- see example app to see it in action.

Window resize events are queried on each call to buildUI() via the protected method bool Application::getWindowSize(int &width, int &height). The method always writes the width/height as out parameters and returns true if the window has been resized since the last frame.

Finally, applications must create a simple main() function to instantiate and run the application. This may look something like:

int main()
{
  MyMatch3DApp app;
  app.run(1280, 800, "Example match3D application");
}

The arguments provided to Application::run() are the initial window size and title bar text.

TODO

• mulitple windowing library options (SDL2, GLUT, etc.)