New features

For those with GPUs (or GPU drivers) which do not support OpenGL 4.1: check out the OpenGL_3.3 branch.
In any of the assignments, you can use F11 to toggle between windowed and fullscreen mode.
In the first assignment for EDAF80, textures for all planets (plus the Sun and the Moon) are loaded by default, and constants for their orbit and spin configurations are provided.
In the second assignment for EDAF80, a set of control points is now provided; there are represented as small spheres in the 3-D view (once parametric_shapes::createSphere() has been implemented).
When using the node::render() function and GL_KHR_debug is available, all OpenGL calls will be placed within a glPushDebugGroup() and glPopDebugGroup() pair using the node’s name, to improve debugging.

Improvements

All assignments have received several improvements and tweaks, for example EDAF80’s third assignment will create and render two spheres by default (one for the skybox, and one on which Phong shading and normal mapping will be performed).
The API of all parametric_shapes methods has been modified to be more consistent and clearer.
displayTexture() no longer takes a camera as input to retrieve the near and far parameters used to linearise values read from depth textures, but now take those directly as argument instead.
The shader for celestial bodies’ rings no longer uses an opacity texture but instead uses the alpha channel of the diffuse texture.
Removed unused code and replaced other with standard types.
The vertical inversion of textures is now performed by STB.
Re-use functionalities from GLAD
The set_uniforms parameter of several methods of Node, has been made optional.
Switch Travis to use Ubuntu Focal and add macOS to the tested environment.
A lot of improvements on the CMake configuration files to modernise them, make them clearer, remove unnecessary operations, display additional information when dependencies fail to download or build, etc.
Reorganise CHANGES.rst and add release date for v2019.1

Bump CMake requirements to version 3.13
CMake: Fix the version of stb and tinyfiledialogs
Update the downloaded version of GLFW to 3.3.2
Update GLM to 0.9.9.5 and require exact version
Update Dear ImGui to 1.78 and ship with the code
Re-generate the GLAD files and up to OpenGL 4.6
Update assimp requirement to 5.0, update the downloaded version to 5.0.1 and apply additional fixes
Update the resources archive