A surprise break from engine progress

Wanted to discuss about some other things that came up yesterday that caused what could possibly be considered a disruption from engine progress.

I use Archlinux btw.

And I did an few updates yesterday and all this past week, then rebooted my machine yesterday, and the install broke. Wouldn't even boot, on either my 5.15 kernel or my 4.16 kernel I keep as a backup. Got stuck on a waiting for save/load /dev/rfkill watchdog type message and had no login prompt or anything. I was able to later boot with the 4.xx kernel (and the 5.15 kernel too) with the nomodeset kernel option specified in grub. That's all fine and good, but nomodeset disables the Kernel Modesetting, which is basically saying when the GPU driver would set up the screen display size, etc. Well, most drivers, the amdgpu driver I use definitely includeed, do not support the type of modesetting that would be done if you specify this option. So that means my system boots, but I cannot get the GPU driver to work properly.

What this meant for my 5.15 kernel is different from my 4.xx kernel. 5.15 I compiled myself because that's the only way to get a kernel to boot on my setup (see below) and it also was configured to use only the amdgpu driver for graphics, on boot, it does not show the boot logs you typically see at start when you have those enabled on linux. instead you just see some pixels at the top of the screen flickering and changing, since the display is showing memory used for something else. With nomodeset it could "boot" and I would get put onto the login prompt, I know this only because I could see a pixel pattern that it settled to with some blinking pixels after about a regular boot time.
I could then even log in, and watch that pixel pattern change!

So instead I booted to the 4.xx kernel, which did show the boot logs, and would spit me out to a login prompt I could see. logging in worked fine, but then if I wanted to run startx, it initially didn't work with my config because the amdgpu driver was specified in the config. So I remove the config and ran startxfce4 (I used the XFCE4 environment) and that did actually spit me out onto a GUI desktop once the config was removed. A 800x600 GUI. Because of the nomodeset, that was the best I could do.

So this is a bit of a pain, and I decided its unworkable, so I did some testing yesterday to try to figure out what the issue could be, from checking some systemd and other configurations in /etc as well as checking the logs of what was updated.

I then decided its not worth trying to fix it, because of why I need to compile custom kernels anyways, that actually limits my ability to do any kind of distro hopping or anything like that.

Why I could't run a non-custom Linux kernel

I got my desktop workstation as a refurb workstation from pcserverandparts. It came with two 2TB HDDs set up in the BIOS in a RAID 0 configuration. Once I got it I did not change that configuration, I put Windows 10 onto a USB stick and installed it, and then promptly installed games.

Then when trying to install dualboot linux onto it, I discovered something awful. I couldn't for the life of me get Linux to boot from it for me, for the longest time.

The issue turned out to be that you need to have a very specific kernel setup, that I only once was able to completely build from scratch, using Gentoo's genkernel tools. This consisted of a special initramfs as well as a build of the kernel. This special build needed to have the kernel build to include mdadm not as a module, but compiled right on in. it also needed some configuration i don't remember anymore in the initramfs and could never successfully build again on archlinux (it started Gentoo, but I got tired of compiling everything on HDDs so I live swapped it to Arch by pacstrapping myself an arch install in a folder, and then copying files from that into the root of the OS while I was running that same OS. That feels both exhilarating and scary af at the same time, but super bad-ass when you pull it off and it works) So I was stuck with using an old initramfs from the 4.xx kernel, with the newer 5.15 kernel.

This whole mess meant that basically I relied on the setup I had in that install and could not or did not want to change any of it. Until it conveniently broke and I said forget it all.

my solution

So I went and solved it. I backed up my stuff from both the windows partition and the linux partition, then I went into the BIOS, undid the RAID configuration. Then wiped it, and now I have installed debian onto it (I had it laying on a USB stick already from installing it onto a laptop) and I'm running the KDE plasma desktop environment.

I also set it up, so I have one of the 2TB drives is my /home, and the other is partitioned into a 30% sized partition for my root partition, and then a EFI and a swap space of course. This way I can create new partitions and then do some distro hopping, while still having access to my /home and files.

Conclusion

I'm a bit sad that my arch install of 3 years broke and I wasn't able to or didn't try to fix it properly, but I'm quite glad that it helped me get rid of that hindrance of the drives being in RAID, and it's about time I got back to my distro hopping roots. I say even though I'm likely to not even switch away, I love Debian as a rock solid distro, and this is my first time running KDE on a machine that can handle it.

Who knows, maybe I'll get going on some Linux From Scratch stuff and do that instead of Gentoo or Arch or any of that.

Now I just need to re=clone my game engine project and get back to it!
And maybe see if the VR works better or if steam and maybe lutris work better and I can run Epic games?

Engine progress

Save/Load

Mesh Save/load

Well I had quite the run around with Mesh save/load involving valgrind and all sorts of wild debugging. For one, somehow I wound up with circular header includes or something, so I wound up having to forward declare some types just to get it to compile. Somehow that happened when trying to switch Mesh import/export to the SerDes system.

After that I found myself in another predicament where everything compiled but it segfaulted, and gave a really really wild stacktrace in gdb. That was caused by a function not having a return when it should have returned int. Returning int fixed that issue, and all was well. Need to figure out how to make that be a compile error with g++/gcc so that I don't have that issue. I've know for a while that there are some functions that didnt' have a return statement, but none of them thus far have caused an actual issue that I'm aware of, so possibly going and running cppcheck or making that a compile error would be helpful to fix all of those possible bugs.

To some extent the lua API is written so that it works fine if you don't make mistakes when using it, if you do, expect wild segfaulting and nonsense.

in any case, Mesh loading works! was able to save a cube, and then load the same cube back and apply a material to it. Next up is material save/load

Material Save/load

Then after mesh save/loading, I need/want to be able to save/load the materials that were assigned to the meshes. So now I'm trying to do the same convert from my silly uint8arr_to_glmvec3 type stuff to the new SerDes stuff for my import/export material methods I made eons ago. Finding similar compilation errors as before, but now that I figured out the solutions for the Mesh, then it should be similar for material to fix them.

The once Material save/load works, it should be possible for meshes to save their own materials out and then load them back. Then Next after that is Model save/load

Model Save/load

Okay model save/load has been having me flip flop on how I want to do it, because it's hard to figure out how I want to do it if separately at all from the Mesh save/load.

This is partly because of 2 reasons:

1. Models can consist of multiple meshes, Do I represent that as each individual mesh in each their own entity or do I combine it all into one entity or what?
2. What if the material loading doesn't work for the model, or I want to set individual materials for each mesh in the model, how do I save that, along with letting me load back the model again if the source model file changes?
3. what if the material loaded from the model is fine for a few instances, but what if I want to go change the material on one or all of the meshes in a later entity using the same model? I can't change the model because I would likely want the model to be able to be shared across multiple entities/meshes.

So what is the solution? I think the solution would likely be to just take models, and load them into a bunch of meshes, each with their own assigned material. and then just save/load the meshes as part of the scene, ignoring that they came from a model at all. This means that I would simply not care about the models at all in scene save/load, but instead I would just write some sort of logic in the Lua scripts that implement the editor to track tying the models to the meshes to allow reloading meshes when the source models have changed.

This may sound a bit like just putting off the whole issue until later, but I actually see it as having a few benefits. I mean in the shipping game would I really care/need to ship the model source files themselves? why wouldn't I just save them out to my own format to load them from, so I can load faster/with fewer steps? In the final game you're likely never going to need to reload the mesh from a source mesh file.

Additionally, if I do need the ability to do that, I just take whatever logic I implemented in the editor for doing that, and I can copy /paste it into the game logic lua scripts. So really no feature issues here, just make the lua scripts care about it.

Additionally, loading things through assimp requires stepping it through intermediary aiMesh, aiMaterial, and ton of other types that I don't use in my engine to render crap out, so really this will skip that whole middle step, granted this does mean that right now all models/meshes are saved/loaded with Json of all things, which is likely a larger file size than even a obj, but it loads directly into the formats I need, with all of the data that I need. That means that it's likely the best for me right now, and will have less overhead of loading things from file, then looping through all the vertices to convert it to my own data structures, instead now it will just load from file, no extra steps. Later on I can implement Binary save/load and it'll likely be smaller file sizes, and maybe faster loading because of that, but its still better imo than having overhead of converting between data structures after loading from file.

UI

Back onto the topic of Nuklear and UI stuffs. Still haven't gotten to implementation yet, trying to sort out the save/load first since UI isn't technically in the 0.0.1 release, I just want to get going on it sooner so that I can have a UI for my editor stuff, which will make editing/creating things much faster than the current console commands, which means I could get that much closer to making a game in this engine.

I think I've sort of figured out how I want to do UI, basically the UI needs to be rendering by calling nuklear methods for each item/element of the UI, which means that somehow I need Lua to be able to do that. I think to make it makes the most sense to create some kind of UI manager which will take some sort of data structure or structures populated by the Lua, and then will basically iterate through them to call the Nuklear commands, and then the UI would be drawn via Nuklear's drawing methods, which means that all Lua would have to do is basically set up the structure, say what Lua method to call when there is some input on the UI widgets, and then it goes into a entity or something somewhere which gets pulled into the RenderState and then rendered from there.

I will say this process of implementing Nuklear compared to if I used my own UI system does seem a bit more convoluted, because basically the steps are:

1. generate data structure for the UI/menu in lua and stick it into a component or some shit to be saved/loaded as well as pulled in to be rendered
2. in the Update Thread pull the UI data into the RenderState to be passed to the render thread
3. in render thread, convert the data structure into nuklear calls. Along the way add callbacks for UI input to the stack of tasks to happen in the update thread
4. then render the nuklear crap also in the rendering thread.

This means that basically the render thread now has to not just render all the rendering crap, but also call the methods to populate the nuklear UI, as well as to render the Nuklear UI. Not sure if that's more overhead than if I used my own system or not, since I would basically be going from data -> rendered right away. However Nuklear seems still like the best option for now, because of the sheer quantity of already implemented UI widgets and input boxes, along with it all being skinnable already. It just makes sense to use Nuklear for now and eat the overhead costs if any. Maybe if I get to profiling everything later and find out that it's taking too long on just the nuklear calls and rendering in the render thread, maybe then I'll change it.

But it also may be worth, instead of just doing the nuklear calls in the render thread, I could likely just save a nuklear context in the RenderState, and call all the Nuklear UI widget calls in the Update thread instead, and just pass the context to the render thread to do the actual rendering, so the UI population would happen on a different thread than the rendering. Hard to say, right now without many models, Rendering goes as fast as it wants, Update thread is tick limited, although I've noticed differences between Linux and Windows in what speed it claims to be going, on Windows it was going half the tick speed I told it to, so then I changed it to be 60 ticks a second on windows, and now it's basically double that on Linux. Not sure that matters so much, I don't think it should matter anyways.

Also I'll likely want a way to configure the UI look from Lua. there are ways you can do different skinning, and apparently you can get a modified version of Nuklear to look like this:

If that's not like, a regular ass game menu then I don't know what is. So if I can make something that looks like that or works like that with Nuklear, then I think we're golden. might need to do some hacky stuff to make it work with controller but obviously its been done before.

A Rendering Conundrum

So some time after I had the mesh save/load working, I noticed that I was no longer having the lighting work on the mesh I was testing with (the usual brick textured cube you see if you scroll wayyy back.) I'm pretty sure right when I tested the mesh save/load it was working, but now it isn't.

So I set up renderdoc and took a capture of it to try to see what is wrong, and I found this when I looked at the normal texture used to compute lighting:

For those of you unfamiliar with what normals should look like when rendered to a texture, this is not it, there are somehow is no normal data for the mesh.

And of course, a little analysis later, and I found this in my git log:

-    Mesh.setMaterial(mesh,material);
-    Mesh.GenerateNormals(mesh);
+    --Mesh.setMaterial(mesh,material);
+    --Mesh.GenerateNormals(mesh);
+    --Mesh.Save(mesh, "MESH_01.bin");

So I commented out the line that generates the normals of the mesh, not sure if I saved it or not, so I'm uncommenting it, and going to save out the data, and see if the lighting works then. could be the saved mesh just got saved without normals.

EDIT: I did some more investigation, the save/load was working fine, but I hadn't yet actually added any normals to a mesh before with the add normals command, I had only had the mesh generate them procedurally. the issue proved to be within my add normals and I found one in the add colors methods on my mesh.

Basically I had used the .data() of a std::vector<glm::vec3> but I used it on the argument passed to the method, when I should have used the .data() call on the vector that was saved as a member of the mesh class. Problem solved!

Next Steps

Next steps: wrap up testing the material save/load, then I think I'll call it quits on model save/load for now until I get the editor commands/UI more figured out. maybe I'll implement Lua bindings to be able to load meshes/materials from models, that will help me verify my whole Assimp loading stuff is working in this version. I tested that in a previous engine iteration years ago, so likely a good idea to test it with some actual models.

Then also, get going on the nuklear stuff, and also check up on my Quire issue tracking, and wrap up the 0.0.1 release, tag it, and bump the version. once material/mesh save/load is all tested, as far as I'm concerned that's a wrap on 0.0.1!!!

Engine progress

Save/Load

Alright, been a bit of a slowdown here on the engine progress in terms of save/load. basically I was confused on how to do the whole mesh/model saving/loading stuff, which was all fine and dandy, so I decided to just save out the meshes to binary and then load them back. I already had a importMesh and an exportMesh built out at some point in the now distant past.

So I went, made a quick MeshLoader to do the save/load on the meshes, then decided I'd write some lua bindings to let me test it before I try to chunk it into the rest of the scene save/load stuff. And it segfaults massively and with unhelpful stacktraces, and valgrind gives some serious output crap.

So let's take a look at this code I wrote eons past and then see why I'm going to just dump it and use my SerDes type stuff for this instead.

Here are the functions called to do the binary serialization of types that I have defined in a handily named Util.h:

 88 inline std::vector<uint8_t> glmquat_to_uint8vec(glm::quat quaternion){
 89     std::vector<uint8_t> array;
 90     uint8_t* flx=reinterpret_cast<uint8_t*>(&quaternion.x);
 91     uint8_t* fly=reinterpret_cast<uint8_t*>(&quaternion.y);
 92     uint8_t* flz=reinterpret_cast<uint8_t*>(&quaternion.z);
 93     uint8_t* flw=reinterpret_cast<uint8_t*>(&quaternion.w);
 94 
 95     for(int i=0;i<sizeof(float);i++){
 96         array.push_back(flx[i]);
 97     }
 98     for(int i=0;i<sizeof(float);i++){
 99         array.push_back(fly[i]);
100     }
101     for(int i=0;i<sizeof(float);i++){
102         array.push_back(flz[i]);
103     }
104     for(int i=0;i<sizeof(float);i++){
105         array.push_back(flw[i]);
106     }
107     return array;
108 }
109 
110 inline uint32_t uint8arr_to_uint32(uint8_t** arr){
111     //AABBCCDD where AA is uppermost byte, DD is lowermost, in order read
112     uint8_t upperupper=(*arr)[0];
113     (*arr)++;
114     uint8_t lowerupper=(*arr)[0];
115     (*arr)++;
116     uint8_t upperlower=(*arr)[0];
117     (*arr)++;
118     uint8_t lowerlower=(*arr)[0];
119     (*arr)++;
120     uint32_t value=(upperupper<<24)+(lowerupper<<16)+(upperlower<<8)+(lowerlower);
121     return value;
122 }
123 
124 inline uint16_t uint8arr_to_uint16(uint8_t** arr){
125     //AABBCCDD where AA is uppermost byte, DD is lowermost, in order read
126     uint8_t upperlower=(*arr)[0];
127     (*arr)++;
128     uint8_t lowerlower=(*arr)[0];
129     (*arr)++;
130     uint16_t value=(upperlower<<8)+(lowerlower);
131     return value;
132 }

Boy that looks fun, and I still wish it worked, I mean saving out works just loading it in finished the whole loading part, and then malloc gives an error when I try to free the data. Some googling says its related to reading past the allotted memory, and yeah I suspect that might be the case, but I sure as heck can't find where that issue would be, but I'm not familiar with some of the . Anyway I'll save trying to get that working in binary for when I implement a binary SerDes if ever, for now I'm going to just swap it all out for my JsonSerDes stuff and be good to go. Plus who cares about endianness when it's a json text file?

Arts

Okay, been a bit slower on Blender the past week as well. Was trying to make some modular pieces for making buildings and such, but realized that I don't really know how I want to go about doing that, not sure if I should like, make the pieces separate and then try to force them to fit into something I'm making, or if I should try to make something first and then cut it up into pieces somehow?

Never having made a modular building kit before of art, I guess I'm a little confused on how to start or go about making one. Also I found myself getting distracted with wanting to make procedural materials for the building pieces instead of making more pieces or just using textures from somewhere.

Definitely seeking input/advice on how you would make a modular kit to use to build various art assets, doesn't have to be 3d or buildings specifically, but if you prefer to make it all as one art piece and then slice/dice it later, or if you prefer to make pieces and put them together later, and have some sort of reasoning behind it, that sounds great, would love to hear some input on how you do it and maybe there's a new way or method I could try.

Right now I think I'm sort of stuck because for props its easy to pull out one specific small piece and then find reference for that item, for buildings or other complex structures its hard to get inspiration for what the modular pieces would be/look like, and I have some concerns about the pieces possibly not fitting together well if I try to cut it all up from a combined model first.

Next steps

I think next step is to rewrite my import/export Mesh with the SerDes and then maybe I'll get to the Nuklear stuff I've been ranting about the past post or two.

Also been looking at houses, those darn things sell so fast here, all the things I looked at like 4 days ago are all already under contract and have all their offers, and they were all released onto the market like, that day or the day before.

Been trying to maintain momentum on my engine since I find that if I'm enjoying it, it's easier to get more stuff done, so I'm also going to try to maintain momentum by continuing to write these things on a weekly or more often schedule when I'm excited to write stuff, because it helps me maintain that momentum and excitement for what I'm working on.

Engine progress

Save/load

Engine progress! Basically save/loading is working and tested with basic entities and components, aside from the whole saving/loading meshes and materials. I tested by saving out an entity, removing that entity, and then loading it back, and then saving it again. if the two save files matches, i considered it a pass. They matched!

This leads to kind of the next little difficulty though, saving/loading models. So right now my rendering renders Meshes, in MeshComponents that are attached to each entity that has a mesh. This is great an all, and a Mesh will have a material set for it by calling mesh.setMaterial(material) on it. The issue comes though, in that when you load a model, the model can have multiple meshes. So then there is the question of how does one handle that?

My previous plan was to load a model, save it in a ModelComponent and then use the meshes from that to populate child entities with MeshComponents filled out for each of the meshes in the model. I thought this would be good because then rendering just cares about the mesh components and that's that. The problem here comes in with a few things:

1. I don't have anything to handle having children transformations be based on the parent transformation, that means if a model needs to be moved, with all of its pieces, then each mesh piece needs to be moved individually.
2. If a model doesn't load a material properly to each mesh every time, there is no good way to save the material modifications needed to work
3. If I want to change a mesh material after the model is loaded, I cannot do that and then save it. This is especially problematic because I see myself wanting to be able to change the model on the fly or change the materials used with the model on the fly.

So how I plan to deal with this, I think my best bet is to add ModelComponent to the list of things the renderer basically cares about, so I would pull the meshes from there, and then figure out how to save the model with changes to the materials, etc, and/or figure out how to save just the mesh data out, and then not worry about "models" other than for importing things, then each mesh would be saved out with its own material, or maybe it would be saved out sans material and I would just use a MaterialComponent for each entity that has a MeshComponent so that I can change materials on a per entity basis.

Obviously I'm still working out the hiccups, but that's my thought process so far.

GUI

The other item is that the amount of commands I would have to type out to load up a material and model are getting quite long, so I figure its time I get looking into the GUI stuff at least to have a GUI for editing.

My latest decision was to use Nuklear for UI things. Nuklear is basically a single header file GUI library, the main hurdles for using it seem to be implementing whatever rendering stuff it needs, and then also figuring out how to deal with an immediate mode UI rendering, but making all the UI stuff be configurable from Lua code.

I think in my mind it makes most sense for the Lua code to configure/lay out the UI stuff in some data format, and then just have C++ go parse the data structure or layout or whatever it is, and then call the nuklear methods based on that.

So right now I'm browsing the 1k lines of code example for Nuklear, and then going to try to figure out how to implement the necessary rendering stuff for it to render, then i'll probably try to figure out how to store/communicate what the UI is that is needed by Lua into the C++ engine.

Arts

Artwork is still happening, I have a few more models since the last post but I don't have a big image made including the new ones, so no new render today I think, I've been posting renders from Blender in the discord, and will hopefully get the model stuff in and then be able to post in engine screenshots instead of blender renders.

I've also been browsing street view in various countries as well to try to get a feel for what different cities in different places feel like and look like, may try my hand at making some city shops or buildings at some point, but I would like to make them as modular as possible so that I can go in later and reuse the pieces for different things.

Next steps

Finish off the model loading/saving/materials nonsense and then UI. then audio. and making sure my issue tracker is up to date.

After that, likely making sure the physics engine data goes into the save/load stuff (it is not saveable or loadable yet) and then testing that out. Already have a design doc somewhat started on a racing game, may share that at some point in the future, but as usual my game ideas snowball like crazy with scope creep so will probably need to pare it down at some point to a demo-able piece compared to the MVP and the full wishlist.

Saving/loading progress

Saving and loading is going great, now that I'm not using Cereal, but I'm also doing it in a sane fashion.

Basically I have an abstract class like this:

 13 class SerDes {
 14     public:
 15     virtual void save(int)=0;
 16     virtual void save(float)=0;
 17     virtual void save(double)=0;
 18     //virtual void save(uint8_t);
 19     //virtual void save(uint16_t);
 20     virtual void save(std::string)=0;

Which basically has save and load functions for each type I need to save or load. Then I extend it with a class for a specific file/save type to save/load, so right now I'm working on a JsonSerDes class which implements all of those functions.

This does mean that if I want to add saving for a type, I will need to add it in the abstract class, and then add it in every single sub class to avoid compilation errors, however this seems to be the best way to do it from a usability perspective for now. better than piling all the picojson crap all into my scene loading/saving for every single thing.

Additionally, now when I need to save a complex type that is a struct or class full of other types, I can just add a save/load pair for it, but then call the save/load functions for each of the types that it needs saved, which means it is now relatively non-painful.

So far I have all the things except for MaterialComponent saving working but untested, I had some pre-existing tech debt around saving/loading materials that I need to re-wrap my head around how I used to want it to work, and to see if I want to change it to work differently now.

One I get all the saving done/polished from this big master SerDes class, then I should be able to go into the sceneloader and basically make the SerDes class, and then just go through the entity, and save the components with a SerDes.save(Comp) type deal. making sure to save the hierarchies properly of course.

Currently when I use the scene saving command it outputs this:

{"0":"NameComponent","1":"MeshEntity","10":1,"11":"EntityEnd","2":"TransformComponent","3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0}

So we're almost there, need to test it out more, add saving for more components, and then test the loading and we'll see where we get.

Art break

I also took a break from coding for a few days this week and did some art things in Blender. Basically I went through Google maps street view looking for things to model, and made a spreadsheet of all the city street/residential street things to model.

I also modeled a few of those items, and then made this render in blender with them, along with some quick/sloppy buildings and pavement, an image pulled from google images in the background, and a car pulled from blendkit:

All of the concrete barriers, traffic light, and construction cones, barrels, and bike racks are modeled for my street props stuff.

I don't know that me starting with modeling street/city props means I will be making a game set in a city or street any time soon, but browsing maps street view seemed like a good way to see what different areas look like and figure out what props belong there or are needed. So rather than try to browse pinterest or google images for reference, it was easier to just "travel" to the location via street view instead to see what different things look like.

I was also reminded that Google maps actually lets you view inside some buildings with the street view type features, so I could potentially use that as a resource for how to layout some buildings, restaurants, or other attractions. Since it's not like I would leave the house to go do any of that IRL. Okay I do and have still gone outside and like, gone to restaurants I'm not entirely a hermit, but I'm not about to go take in a 360 camera to take panoramas everywhere I go. Pretty sure that would draw some serious looks.

Summary/Next steps

I think that after the save/load works, I need to spend some time testing/verifying things. I've gone and done a bunch of changes, but haven't fully tested all of it out yet. So I'll be testing the save/load of course, but also need to test/verify the model saving/loading, since that is something I haven't yet, I think I tested 3d rendering with just a mesh generated via Lua, I'd like to be able to test out that model loading of different file types works as expected/desired, and if not need to finish that up, then I think I'll be in business for doing some brief game prototyping.

Additionally, I'll need to go test out and implement the physics stuff as well, and the save/load for the physics data. Maybe some sort of physics sandbox game is in the future? or perhaps some sort of street racing/street crashing game. that could be fun.

Also the miniaudio sound stuff is planned in the near future, so perhaps some music making stuff should be done too, I haven't brushed up on playing piano or percussion in like 7-8 years, I've been thinking of getting a MIDI keyboard of some kind to practice up again, but I might just satisfy myself with using musescore or LMMS for now, just with the keyboard or with clicking on the piano roll. issue is getting inspiration to make music that way is much harder because you can't really just jam out on a piano roll.

Well I've been trying to do Cereal, but here's kind of the issue, I follow the tutorials but it doesn't work for me, I can't get it to compile because it's for whatever reason not able to find the serialization functions I've written, unless I specialize each of the functions as I mentioned before, where I re-write the same thing for every combination of input and output that I want to do.

To me that means I'd rather just write the serialization stuff myself to do Json, XMl, Binary, whatever I want to do rather than try to get Cereal to work the way its supposed to.

Additionally, I found this issue which basically says that Cereal doesn't work right in a recent version of clang, but they were able to work around it by uncommenting some asserts. I use g++ with cmake, but I figured what the heck, I'll go uncomment the asserts that are causing failures too. That let's it compile! but then I just get this for the json output:

  1 {
  2     "value0": "NameComponent",
  3     "value1": {},
  4     "value2": "TransformComponent",
  5     "value3": {},
  6     "value4": "EntityEnd"
~                               

And what I didn't even notice until now, I don't even have the closing } in there. So in my mind, Cereal is out of the competition now, if you can get it to work with your compiler, great, but for me, I don't think having XMl, Json, and Binary support if I want to write the same thing 6 times is enough for me to use it.

So I'm planning to go back to the picojson, however this time i'm going to try to not do it the dumb dumb way, and I'll write serialization methods for types, that way I can have less struggle of writing everything out the long way. This does mean I'm still re-writing my serialization stuff I had before, even though I kept what I had before, but I think my hope is that this means that I can more easily use the serialization again elsewhere if needed, so I could serialize things like settings, configuration, input mappings, etc hopefully more easily in the future.

So right now the plan is to basically make a SerDes abstract class, which I would then use as a base for having a JsonSerDes and other such serialization classes, so I could potentially serialize to multiple formats that way, and then each such class would have a .save(type) function implemented for each type that needs to be serialized. This does mean writing all the serialization for each type manually, but hopefully that should be minimal effort, and then hopefully I can find a way to have Json, Binary, etc saving/loading happen by just changing which class is used, and then calling the same set of methods on it.

This does add some complications in that Json is key/value based, and binary and other formats are not, so there may be some confusion/confusing stuff going on there to where it might not be as clear to read the Json as it would be if I did it the way I did before, but I think this will be least effort in terms of being able to write the SceneLoader to be able to save/load to each format without any extra effort, and as long as saving it out happens in the same way as loading it in does, maybe that does not matter. I could also likely allow using std::map<std::string, value> type deals to allow saving things that already have key/value pairs, perhaps there is a way I can denote the key/string in a binary format as well without much issues. Something yet to be determined I suppose, or maybe I could use BSON or protobuf for binary save/load instead of a custom format.

On top of that, I will probably also need to get bindings together to use it from Lua, either the serialization data directly, or just have a way for Lua to save chunks of memory somehow, that way scripts can save things if they need. Perhaps I could even find a pre-canned Json library for Lua that I could include, that would allow for generating lua saves from Lua, and then just use some API to save it to disk.

Next steps

I'm going to keep including these next steps sections even if I keep rehashing the same crap every time. it helps me keep my duckies in a row in terms of what is next, and it's nice to be able to see how close I am to having something usable when I'm slogging through saving/loading nonsense.

Next steps are to finish up the save/load junk, and then I'll basically be done with the first 0.0.1 milestone. Next up is miniaudio audio playback, likely using low level API so I can implement my own stuff on top. not that I need to spend the time implementing my own stuff on top...

other than that, multithreaded loading of things I think is high desire, currently my whole update thread stops to load things, which means large time spend lagging out. Render thread keeps going but no processing happens there, so it basically looks frozen and is frozen. Probably going to need to look into the future/promise types that are C++11/whatever for threading. Then basically just not render/use those assets until they are loaded in. Yes this means that assets that are not loaded at the time they are needed will be invisible and pop in, I might need to implement some kind of preloading system to allow loading crap on a loading screen or with a loading bar, or background pre-loading stuff for nearby areas to load them before they are visible or needed.

Test games/testing the engine

After the audio stuff is done, I think it'll be a good idea to implement a simple toy game to prove out that the lua bindings work, and everything works. I think my plan for that is likely to be a breakout clone, just because I've done those before, the logic is minimal, and the physics can be fairly simple.

I also technically have bullet physics already "integrated" but I haven't actually tested that, or implemented the lua bindings to create rigidbody components for entities, so that as well as save/load for the rigidbody component will be needed. Then a different test game will be needed, likely i'll go for some sort of sandbox-y type thing or something where you walk a player character around and can throw things and bump into things. Just to make sure that the physics of things all works as expected.

Once those basic tests are complete, I think it can be time to actually try to go implement a game. the engine would be mostly in a usable state hopefully by that point, maybe with some UI work to be done, I'm still not decided on if I want to finish implementing my own UI elements as originally planned, or to proceed with using the nuklear library, although I'm not sure nuklear is set up to be used with an entity/component system like I have.

I've gotten a few ideas/plans together for what I would want my first game or games to be in engine, but of course I keep switching around what I would want to do, between a basic FPS type campaign game, to a horror game, to something else entirely. I think for starting out I would want minimal effort dialog and/or just no dialog options/responses, and no quest systems, that would let me prove out and thoroughly test the basic features before moving on to implementing further elements that would not be able to be thoroughly tested until later. Likely i would add an achievement system before a branching dialog and quest systems, so the achievement system could be tacked on to an existing campaign style FPS game I think.

Or alternatively, I could just jump around between prototypes, slowly building up a library of 3d assets and scripts that could be re-used in other projects. hard to say.

Well Cereal has been a bit more of a pain than I expected, the examples make it all look easy, you just do something like the following:

template<class Archive>
void serialize(Archive & ar, NameComponent & ncomp){
    ar(ncomp.string);
}

And then now that component can be saved and loaded, with some extra setup crap of course, but that's how its supposed to work.

Well, I do that, but there's little info on if you put it in the header or in your cpp file, or what, so I've tried a few combinations and keep getting some errors that look like this:

Error: static assertion failed: cereal could not find any output serialization functions for the provided type and archive combination. 

 Types must either have a serialize function, load/save pair, or load_minimal/save_minimal pair (you may not mix these). 
 Serialize functions generally have the following signature: 

 template<class Archive> 
   void serialize(Archive & ar) 
   { 
     ar( member1, member2, member3 ); 
   } 

And in fact it's longer than that, and this is repeated multiple times too. So now I've tried doing some combination of crap like this:

269 template<class Archive>
270 void serialize(Archive & ar, TransformComponent &tcomp){
271     ar(tcomp.position.x, tcomp.position.y, tcomp.position.z);
272     ar(tcomp.rotation.x, tcomp.rotation.y, tcomp.rotation.z, tcomp.rotation.w);
273     ar(tcomp.scale);
274 }
275 template<>
276 void serialize<cereal::JSONOutputArchive>(cereal::JSONOutputArchive & ar, TransformComponent &tcomp){
277     ar(tcomp.position.x, tcomp.position.y, tcomp.position.z);
278     ar(tcomp.rotation.x, tcomp.rotation.y, tcomp.rotation.z, tcomp.rotation.w);
279     ar(tcomp.scale);
280 }
281 template<>
282 void serialize<cereal::JSONInputArchive>(cereal::JSONInputArchive & ar, TransformComponent &tcomp){
283     ar(tcomp.position.x, tcomp.position.y, tcomp.position.z);
284     ar(tcomp.rotation.x, tcomp.rotation.y, tcomp.rotation.z, tcomp.rotation.w);
285     ar(tcomp.scale);
286 }

And I think that kind of fixes some of it? but that's not what the docs say you can do, that's not how the EnTT serialization example does it, and it's specific to outputting to JSON, so if I want to switch what format I output to, since Cereal bakes in JSON, XML, and Binary outputting, then I'd have to rewrite the same function 2x for each additional format. Not an ideal situation.

I suspect the answer is that either its a quirk of templates that I always forget about, to where you have to have the template stuff be either only in the cpp or only in the header, (And it doesn't help I'm doing this all in a single header, where I use defines to compile the "cpp" part of it, stb header style, so that means it's easy to confuse myself in which section I'm putting it into) or it's to do with the Cereal supporting C++ 11 but I'm compiling against C++ 17 and something changed.

In other news, I'm doing Cereal a little bit non-mainstream. Basically the library writes to streams, so you would usually do an ifstream to input a file directly, or an ofstream to output to a file directly. That doesn't fit in with how I planned things, to where I want everything File/FS related to be handled by my FSManager so that I could possibly be loading stuff from a zipped archive or something else entirely instead of just files straight on the disk. So I needed to figure out how to get it to write to/read from memory so that the underlying file/whatever doesn't actually matter. stringstream is okay for that, if you need to write strings, but what if you want to write binary streams to memory instead of to a file?

Well I found spanstream! A feature that is part of the C++ 23 standard... which isn't released/supported yet... So now I know how to implement binary save/load to memory later, for now I guess I'm just using stringstream but there are a few issues with that I think, specifically that I'm not sure how Cereal would deal with endianess, etc etc. Suppose that's a battle for another day...

Plus I'm sure I won't really have much of anything actually implemented using this engine until like 2023 or 2024 anyways, so it's likely that the C++23 standard would be out by the time I'm ready to release anything

ECS switch progress

The good news though on progress with converting to EnTT is that I sort of have the hierarchy stuff figured out, the only iffy part is really in deleting the children of children when you remove an entity, I haven't written it to traverse down the tree that far, and I'm not doing recursion on that part because of simplicity, and laziness.

Maybe I'll do the traversal farther down the tree at a later time, but I'm not really expecting to have many cases of children of children, but I suppose I should allow it to delete them eventually. Most likely I'll want it all to be flat/in loops instead of recursive though, recursion just seems like a bad idea if you're trying to be portable to a bunch of different platforms because it's hard to say if there will be enough space for all the stack frames needed, and you can potentially loop infinitely but good luck recursing infinitely.

Also another issue though is that this deletion all happens in the Update Thread, so it will basically hold up updating anything until it finishes, so I think not letting it get caught in a loop is likely a good idea, and for now I can just be careful about not having things nested more than one layer that will need to be deleted.

Summary/Next Steps

So I'm basically at the same place I was at with Flecs already, just struggling through saving/loading again/still. Just with a different type of struggle, but I think this struggle is worth it, because being able to save/load from 3 types at once is far better than the previous single type i had of just json.

After I finish off the serialization crap I basically just need to test it, which I've been keeping the lua bindings updates for all this so it should be EZ PZ to just get in game, send some commands and such in the console to add some stuff, then save it out, then remove the entities I added, and load them back and make sure they're still there.

Then after that I'll be pretty much done with my 0.0.1 milestone. Next would be my 0.0.2 milestone, I'll probably need to update the Quire a bit but it basically consists of implementing saving/loading assets/scene data from archives, creating those archives (Since I'm planning to implement all editing in engine, this also has the added benefit of basically being able to bundle world editing/map making/modding tools in game, it's not laziness of not wanting to make a separate editor, its a feature!)

Then beyond that for the 0.0.2 milestone is basic audio features implemented with miniaudio which I think now has a high level API which does 3d spatial audio if I read the docs correctly, not sure if I'll do that or just use the low level API as planned previously.

So switching over to EnTT actually wasn't as painful as I was expecting. I'm not quite fully at the same features as it was on flecs, and the saving/loading is entirely nuked, but so far the rendering and all that crap is mostly working on EnTT, really only took a couple sessions of sitting down and replacing all the flecs includes with entt and then seeing what broke.

I did have an issue with EnTT asserting when removing and entity, but I suspect I just need to check that my threads aren't screwing themselves up and make sure all is deleted in a "single" thread.

Also a few differences I've noticed between EnTT and Flecs:

1. There are no built in Entity names in EnTT, meaning there's no built in name lookup.
   • Easily fixed by keeping a map of strings to entities myself, only issue is the difficulty of going from entity to name, so might need a component too? not too difficult since that's how it was done on Flecs, there was a EcsName component that held the name.
2. There is no built in hierarchy mechanism in EnTT.
   • This means that I'll need to roll my own, but that's not honestly too painful, I've done data structures stuff before and there are some examples of structures/how to store it.

Also funny thing, there is an example of serializing the tree, and it uses a library I hadn't heard of before called Cereal, which by the looks of it, makes serializing stuff to various formats fairly trivial. So I'm likely going to be redoing all the saving/loading stuff with that, which is great because the save/load isn't working too well anyways.

Next steps are:

• Figure out the remaining issues with getting Entity names and how to store that (likely adding a component for it, which I already was going to do with Flecs but then found they had their own, so now I just need to add mine back and use it.
• Figure out how to do a hierarchy, or if I don't need to do that at all
  • Likely want to still do it, makes adding/deleting large chunks of scene much easier. For Example if I want to load in a room, and then delete that room, I can just load in the root and automatically load the children, and then just delete the root (From Lua, I have to traverse the trees in C++) and the rest can be deleted too.
• Add in the saving/loading stuff with Cereal, there is actually a bunch of examples on how to save snapshots of the entity component system with Cereal, but I'm not sure if I'll want to do that, or if I'll go with my previous layout. My previous plan was basically to make it so you would call save on the root node in Lua, and then the C++ binding for that would also save all the children of that entity, so your workflow would consist of basically having a root node for each major thing you want to break the scene into logically, and then that would let you save/remove/load that whole chunk at once.

I'm not concerned about the extra effort of handling the tree traversal myself, I can do that in C++ and I expect all logic to be done in Lua, so from the standpoint of using my engine, it will be just as usable as if it was handled by the ECS library, just in this case I have the power to define the hierarchy tree myself, which could have advantages as well.

I also found that the getting/modifying components for an entity is a bit different than I expected/how it was on Flecs. I expected to be able to basically get a reference to the component and then modify that, however I found that the way I was doing that at least did not modify the values on the entity, so I had to use a separate method to "patch" the component.

Guess I'm not good at doing these posts weekly anymore so I'll jump in here again even though I'm not where I wish I was.

I have entity saving working for saving out the children of entities now! fixed some bugs with getting the list of children from the Lua code!

Working on getting the loading done now, and it's as boring/painful a slog as saving was but worse somehow. (I didn't write any helpers, I'm writing crap out longform like picojson::value and std::map<std::string,picojson::value> and then value.get<std::map<std::string,picojson::value>>() kind of things.
For each time I need to get an object out. and then more crap for getting values from the object.

Needless to say I'm not super highly confident/happy with it but hey it'll work once I slog it all out... Just adding saving/loading new components will be some major pain I think.

I was just going to go get some screen shots of some commands and such, and found a new bug. so that's exciting.

I added an entity Entity01 then added Entity02 as a child of Entity01 then added Entity03 as a child of Entity02 and then tried to get the children of Entity02 and got this:

12-20-2021 11:43:03 | I LUASCRIPT: ayyy we got a command: 'getChildrenOf Entity02'

(null):19: error: unresolved component identifier 'Entity02'
    CHILDOF | Entity02
                      ^
Aborted (core dumped)

So that's so wonderful. it's an error from the ECS library I use called flecs I think, but not sure if its a bug in how I did the query writing, or if it's a bug in the library, or what.

Starting to think I might need to either upgrade the flecs version, switch to a different ECS library, or write my own since I keep having issues with it that are somewhat outside of my control.

Starting to think that ECSes aren't that great if you' only really using the E and C parts of them and not the Systems part. having all my logic outside of the systems has been a bit of a struggle with the library asserting on me for various reasons.

It might also not help that I'm on like version 2.2.0 but there's since been a 2.3.0, and now the latest is like 2.4.8 or something, so there have been a lot of patch releases since I last updated. I'd already update but it's hard to find all the changelog/patch notes and there are basically breaking changes with nearly every update.

So I'm actually going to go completely off tangent here from how I started writing this post (because I'm too lazy to delete all that I already wrote and start over), i originally meant to show off some new loading/saving crap I did. Instead I'm going to bring up alternative ECS solutions, and then I think I'll just pick one and say I'm switching to it and go with that.

I'm currently using Flecs a ECS system that is for C and C++ and is supposedly fast and all that crap. I don't remember how I chose it, I know my requirements for chosing one were basically easy to integrate, fast enough, and works.

Flecs is basically a c file and a header file, so it checked the easy to integrate part. and the documentation was fairly solid in terms of having examples and stuff on how to use it. The problem is every time it updates it has breaking changes, and I keep running into threading issues, or issues where I add entities outside of it, and it doesn't seem super thread safe.

I went and looked back at a different ECS library I saw before but didn't go with, called EnTT which is supposedly the "fastest" and used by minecraft. I don't care about the fastest, but looking at it again, what caught my eye was in the integration section, it actually lets you just include only the Entity and Component part. Which seems to be literally the only part I need/use right now.

EnTT is also single header only, and all that, so now I'm of the mind of basically branching my engine, swapping the ECS library to EnTT, and then seeing how that works instead.

For obvious reasons of the fact that I'm lazy, I didn't bother wrapping the ECS library in any way shape or form, because it's so vital/tied in to everything in the engine I didn't plan on ever needing to change the library.

I may yet decide I need to wrap it this time, I'm not sure. if I wrap it that will help me to switch back and forth between ECS libraries and possibly help me to upgrade from one version to another, so that does seem like a good idea.

In order to pull off the switch to EnTT I will also need to modify basically the entirety of my engine. I need to change the lua binding code to use the new methods of adding/removing/modifying entities and components, I need to change the update thread where it pulls out the entities that get rendered to pass them to the render thread. I need to update the saving/loading stuff already and its not even done yet. And maybe more. Definitely will be quite a project so wrapping the ECS seems like a logical thing to do in case I need to do this again in the future, and I suspect it can be done without tanking performance as well, either via macros or via inlining things.

Well that's it for now, I guess I'll post again in a few months when I've got the new ECS library in

Well here we are, the end of November. I 1000% got distracted by other things instead of working on the roguelike for the crunchless challenge thing I was trying to do. But hey I didn't crunch on anything so i succeeded on the crunchless part of it! I just didn't do much of anything programming or game dev related.

My 3d printer came in and I got distracted and now have another new project: I'm making a redox split keyboard with Kailh box jade switches. Parts are all on order and arrive in January, printing the case and the keycaps myself, so far the two test keycaps I made feel okay to me, but I don't have any other box switches to test fit them with so I need to wait until january when they arrive to test fit them to make sure that they will work.

Back to the Game engine project

Yeah I went back to working on my game engine project again. Still trying to get scene saving/loading working, still using json for that, and currently bored of writing save/load logic so will likely keep saving json until either I run into it taking up too much memory/space, or it takes too long to load when needed. I think lazy route is best for getting anything actually finished/shipped.

So basically I'm stuck on writing out how to convert a bunch of different components that an entity might have to JSON, and then I eventually need to write the code to load all that back in too, which I don't think is even started yet.

But it has been a while since I provided screenshots, and I was super close to getting json output actually, so here have some screenshots of me showing me typing a console command to save an entity, and then let me show some json that was generated from the Entity that was saved.

Screenshot first:

And a screenshot showing the feedback you get from running the command, I know it's not much feedback but its something:

And now check out the json generated for the cube you see in the screenshot, in a file called "MeshEntity.json"

 {"EcsName":{"value":"MeshEntity"},"TransformComponent":{"position":{"x":0,"y    ":0,"z":0},"rotation":{"w":0,"x":0,"y":0,"z":0},"scale":1},"VisibleComponent    ":{"opaque":true,"visible":true}}

I haven't fully figured out how I want to save Mesh components yet, part of the issue is with this specific case, I don't have a RUID/path to just store to a model, that mesh is generated in Lua, which means that if I wanted to store it I would likely have to parse/store out the entire freaking mesh into the json, including vert data, face data, texcoord data, and maybe vert color data, and texture data somehow since the texture is handled by being a material set to the mesh.

So I'm so close yet so far. I'm hoping that if I set up model loading from files, that I can make it easier to save that out to json, and then either just won't save programmically generated meshes, or something. idk yet.

I also have a few other components not implemented yet, and loading hasn't been touched at all, neither is saving the children of the entity selected to save. But still this is good progress!