overgrowth VS 3DWorld

No but they released the source code, so many one day? Lol https://github.com/WolfireGames/overgrowth

Overgrowth does this as well

Looks like Lugaru is fully open sourced (All Wolfire assets are now licensed under CC-BY-SA 3.0). You can get it here: https://github.com/osslugaru/lugaru/releases If you want something newer, then there is engine for Overgrowth: https://github.com/WolfireGames/overgrowth But game data Overgrowth is still proprietary.

Here's the FOSS source code, the buy page, the Steam page, and the blog announcement.

Overgrowth is the only one that I know of that uses OpenGL exclusively. Just checked it again and they actually released source code just two weeks ago!

Wolfire Games is a tiny studio. Wikipedia says 4 employees. Development of Overgrowth is mostly one person, who documented the whole process in fascinating weekly videos:

https://m.youtube.com/c/WolfireGames/videos

The title says "game engine" because the artwork remains proprietary (similar to old id games, buy the game to get it).

However, just to clarify, all the game code (including gameplay logic, which is sometimes not considered part of the "game engine") is Apache 2.0.

GitHub page: https://github.com/WolfireGames/overgrowth

The (not linked?) GitHub repository WolfireGames/overgrowth

If you're referring to riggedobject.cpp, that apparently includes most of their procedural/physics based animation code. 5k lines sounds reasonable for that.

You mean you want to draw the individual stars themselves? It's likely just a texture, probably white so that it can be colored differently for each star. This is how I've done it. Try a Google image search for "flare texture". You can find some of the ones I used here (flare*.jpg): https://github.com/fegennari/3DWorld/tree/master/textures

I remember it being called "wave surfing", where you start at the current pixel and draw a line to the light source, checking the elevation vs. the altitude value of the line (Y or Z) at every step. I have the code in my mesh_shadow_gen class here: https://github.com/fegennari/3DWorld/blob/master/src/visibility.cpp

This all sounds complex, but the system can be made to work well. I've written something similar myself, except with VBOs rather than SSBOs. My code can be found in these two files: https://github.com/fegennari/3DWorld/blob/master/src/buildings.h

C++ code for drawing spiders can be found in my GitHub project, in the spider_draw_t class: https://github.com/fegennari/3DWorld/blob/master/src/building_animal_draw.cpp

Filling the cracks properly generally gives better performance and fewer drawing artifacts compared to skirts. If you use indexed triangles and set them up in neat rows and columns, it's pretty easy to get right. No lookup tables or big switch cases, and it works with any number of LODs. See the crack_ibuf_t code starting around like 1800 here: https://github.com/fegennari/3DWorld/blob/master/src/tiled_mesh.cpp

I wrote a planet name generator that combines multi-character combinations. It may not do as good as a proper Markov Chain, but may produce names that sound better than your simple approach. If you're interested, the code can be found here: https://github.com/fegennari/3DWorld/blob/master/src/Universe_name.cpp

The code for this is in my voxel_manager::add_triangles_for_voxel() on line 497 here: https://github.com/fegennari/3DWorld/blob/master/src/voxels.cpp

Thanks. Yes, I was looking at this. The problem is that the texture atlases are in a different format than the ones I currently use. The MSDF versions don't have all of the ASCII characters and some characters have a different number of pixels. So it's not a drop in replacement for my system, which is using texture atlases like this: https://github.com/fegennari/3DWorld/blob/master/textures/atlas/text_atlas.png

I have some code for this here, but it's part of a large project and not easy to read/understand: https://github.com/fegennari/3DWorld/blob/master/src/free_obj.cpp