> However, I get a different (unrelated) error now which is that the browser crashes because it runs out of memory...
This sounds like a memory leak, AFAIK memory growth is now enabled by default in WASM, so ALLOW_MEMORY_GROWTH is redundant. Emscripten has various features to aid with memory debugging, this is probably a good starting point: https://web.dev/webassembly-memory-debugging/ On Tuesday, 2 November 2021 at 12:00:26 UTC+1 Floh wrote: > Ah dang, yeah totally makes sense. I guess that's one of those pitfalls in > C that are so obvious that one gets blind about. > > > Of course I have no idea WHY any of this needs to be done. > > The line: > > EmscriptenWebGLContextAttributes attrs; > > ...means that 'attrs' has random memory content (because it's a C struct, > not a C++ class with constructor), and the > emscripten_webgl_init_context_attributes() call initializes the memory to > something sane (probably just clearing the memory to zero). This > initialization pattern is fairly common in C APIs, but not in C++ APIs. > > Cheers! > > On Tuesday, 2 November 2021 at 08:09:08 UTC+1 [email protected] wrote: > >> It looks like I have found a solution thanks to someone in the Discord >> server. Here is what I changed: >> >> EmscriptenWebGLContextAttributes attrs; >> attrs.antialias = true; >> attrs.majorVersion = 3; >> attrs.minorVersion = 2; >> attrs.alpha = true; >> attrs.powerPreference = EM_WEBGL_POWER_PREFERENCE_DEFAULT; >> >> // The following lines must be done in exact order, or it will break! >> emscripten_webgl_init_context_attributes(&attrs); // you MUST init >> the attributes before creating the context >> attrs.majorVersion = 3; // you MUST set the version AFTER the above >> line >> EMSCRIPTEN_WEBGL_CONTEXT_HANDLE webgl_context = >> emscripten_webgl_create_context("#canvas", &attrs); >> emscripten_webgl_make_context_current(webgl_context); >> mainContext = SDL_GL_CreateContext(window); >> >> When you modify my main.cpp with this code then it actually shows the >> game on the screen and all of the above errors I mentioned disappear. So >> the solution is to call emscripten_webgl_init_context_attributes between >> creating the attributes and before creating the context. However, if you do >> that then it sets up the webgl context using OpenGL ES 2.0 (WebGL 1.0) >> which is not what I want (because I would need to change all my shader >> code). So that's why you need to set the attributes AGAIN after calling it >> (to set majorVersion=3) which results in OpenGL ES 3.0 / WebGL 2.0. >> >> Of course I have no idea WHY any of this needs to be done. I hope this >> can either be fixed or documented somewhere with an explanation. >> >> I managed to copy and paste this code into my larger game project and it >> worked like a charm. However, I get a different (unrelated) error now which >> is that the browser crashes because it runs out of memory... but at least I >> can see the game now. The preloaded data file is ~80 MB which isn't huge by >> video game standards, but it might be too big for the browser to download. >> I did set ALLOW_MEMORY_GROWTH=1 but that didn't seem to prevent the issue. >> If anyone can help me out with that too please let me know. Thanks. >> >> On Monday, November 1, 2021 at 9:20:16 AM UTC-5 Floh wrote: >> >>> PS: if you just want to get something on screen in a cross-platform >>> application, but don't care if it's SDL2 or GL, check out my sokol headers: >>> >>> https://floooh.github.io/sokol-html5/ >>> >>> No guarantee that this will protect you from any C++ shenanigans though, >>> the headers can be used from C++, but since I prefer plain old C these >>> days, most of the sample code is written in C (and the few C++ samples - >>> mainly the Dear ImGui stuff - doesn't use the STL). >>> On Monday, 1 November 2021 at 15:16:29 UTC+1 Floh wrote: >>> >>>> I'm also able to reproduce the problem on macOS with Chrome and Safari, >>>> but no idea either what's going wrong there. >>>> >>>> However, I suspect it's not the use of std::string, but that iostream >>>> is the culprit, because if I replace std::cout with printf but keep >>>> std::string, it works (replacing cout with printf is a good idea anyway, >>>> because cout adds an incredible amount of bloat last I checked). >>>> >>>> On Monday, 1 November 2021 at 12:38:16 UTC+1 [email protected] >>>> wrote: >>>> >>>>> I'm glad someone was able to reproduce it, but that didn't answer any >>>>> of my questions. >>>>> >>>>> I've tried a few more things and maybe the issue is related to strings >>>>> in some way. If I add a class that takes a string as a parameter in the >>>>> constructor, and then ONLY if I instantiate it, like so: >>>>> >>>>> class Test >>>>> { >>>>> public: >>>>> Test(std::string test) {} ; >>>>> }; >>>>> >>>>> int main() >>>>> { >>>>> Test test("test"); >>>>> InitOpenGL(1280, 720, window, mainContext); >>>>> BeforeMainLoop(); >>>>> >>>>> return 1; >>>>> } >>>>> >>>>> Then that also results in a black screen. Instantiating a vector of >>>>> strings also results in a black screen, like so: >>>>> std::vector<std::string> languages = { "english", "japanese" }; >>>>> >>>>> And my original problem with the Log function also happens to involve >>>>> strings on some level. If I change the constructor from a string to a >>>>> const >>>>> char* then it works. But changing all instances of strings to const char* >>>>> is not ideal (my program needs strings), and I actually tried that with >>>>> the >>>>> Log function and that did not help, so I'm still looking for a solution. >>>>> So >>>>> hopefully this information is helpful for someone to figure out what is >>>>> wrong and how to fix it. >>>>> >>>>> >>>>> On Sunday, October 31, 2021 at 12:23:53 AM UTC-5 Shlomi Fish wrote: >>>>> >>>>>> Hi all! >>>>>> >>>>>> On Sat, 30 Oct 2021 18:46:19 -0700 (PDT) >>>>>> Anton Strickland <[email protected]> wrote: >>>>>> >>>>>> > I have been stuck on a very simple issue for multiple days and need >>>>>> someone >>>>>> > who knows what they are doing. I'm trying to use SDL2 and WebGL2 >>>>>> (OpenGL ES >>>>>> > 3) and sometimes it works, but sometimes it doesn't, depending on >>>>>> seemingly >>>>>> > arbitrary code. Please help. See here for the full details and >>>>>> source code: >>>>>> > >>>>>> > >>>>>> https://gist.github.com/AntonStrickland/433c911151ca73826ee679b120fe8d9e >>>>>> > >>>>>> >>>>>> Note that I was able to reproduce the issue on fedora v34 x86-64 with >>>>>> firefox: >>>>>> >>>>>> ``` >>>>>> System: >>>>>> Host: telaviv1.shlomifish.org Kernel: 5.14.14-200.fc34.x86_64 x86_64 >>>>>> bits: 64 Desktop: Xfce 4.16.0 Distro: Fedora release 34 (Thirty Four) >>>>>> CPU: >>>>>> Info: Dual Core model: Intel Core i3-2100 bits: 64 type: MT MCP >>>>>> cache: >>>>>> L2: 3 MiB >>>>>> Speed: 2750 MHz min/max: 1600/3100 MHz Core speeds (MHz): 1: 2750 >>>>>> 2: 2698 3: 2709 4: 2694 >>>>>> Graphics: >>>>>> Device-1: Intel 2nd Generation Core Processor Family Integrated >>>>>> Graphics >>>>>> driver: i915 v: kernel Display: x11 server: X.Org 1.20.11 driver: >>>>>> loaded: >>>>>> modesetting unloaded: fbdev,vesa resolution: 1920x1080~60Hz >>>>>> OpenGL: renderer: Mesa DRI Intel HD Graphics 2000 (SNB GT1) >>>>>> v: 3.3 Mesa 21.1.8 >>>>>> ``` >>>>>> >>>>>> As a side note: main.cpp has some trailing whitespace: >>>>>> https://perl-begin.org/tutorials/bad-elements/#trailing-whitespace >>>>>> >>>>>> > Basically, I have a simple program (just over 100 lines of code) >>>>>> that >>>>>> > changes the background color of the screen by calling glClear(). >>>>>> Probably >>>>>> > the most basic OpenGL program one can write. When the color is >>>>>> pink, that >>>>>> > means it's working, and when it's black, it's not working. In the >>>>>> above >>>>>> > link there is main.cpp which works correctly. I have been doing >>>>>> trial and >>>>>> > error for this past week commenting out random lines of code to >>>>>> isolate the >>>>>> > problem, but it seems like changing arbitrary lines of code stops >>>>>> it from >>>>>> > working. I've noticed that it happens when calling some SDL >>>>>> functions, but >>>>>> > even just commenting out printing to the console is enough to break >>>>>> it. See >>>>>> > main.cpp for details. >>>>>> > >>>>>> > I don't know if this is just an issue with me not understanding how >>>>>> this >>>>>> > works or if this is an actual bug in emscripten or the SDL port. >>>>>> it's >>>>>> > frustrating because when it works, it works all the way (I can use >>>>>> shaders >>>>>> > and textures to have a working app), but if I change just a tiny >>>>>> little >>>>>> > thing (even just commenting out an unrelated line of code), >>>>>> suddenly >>>>>> > nothing works at all. I have no idea where to even start debugging >>>>>> this. >>>>>> > >>>>>> > I would imagine that there has to be a way to do this since people >>>>>> are >>>>>> > obviously making WebGL games in C++, but since there are no >>>>>> tutorials >>>>>> > online for how to do that it becomes impossible to even set up a >>>>>> simple >>>>>> > "hello world" script. I purchased a book on how to make games in >>>>>> web >>>>>> > assembly but they use the SDL renderer and not OpenGL rendering. >>>>>> Other >>>>>> > OpenGL web assembly tutorials just use OpenGL without SDL. Surely >>>>>> there >>>>>> > must be a way to use them together as I have done for my desktop >>>>>> app? >>>>>> > >>>>>> > I have already reached out on the discord but to no avail so far. >>>>>> Someone >>>>>> > suggested adding -fsanitize=address when compiling but that >>>>>> actually causes >>>>>> > the above working code to stop working. I don't really have the >>>>>> time to >>>>>> > just wait for an answer so I'm hoping this post will get the >>>>>> attention of >>>>>> > more people. >>>>>> > >>>>>> > So I know this is getting long, but I'm very confused. Since >>>>>> technically by >>>>>> > code works, but it's one step away from breaking, and I have no >>>>>> idea what >>>>>> > that step is or why. My ultimate goal is to copy and paste this >>>>>> code into a >>>>>> > larger project, but every time I do so, it results in a black >>>>>> screen with >>>>>> > no indication of what I did wrong. >>>>>> > >>>>>> > I would like to understand a few things: >>>>>> > >>>>>> > - Is this a problem with my code, my makefile, SDL, or emscripten? >>>>>> > - If this is not a problem with my code, is someone going to fix >>>>>> the >>>>>> > issue? >>>>>> > - If my desktop code is Open GL 3.3, should I be using OpenGL ES 3 >>>>>> or is >>>>>> > that part of the problem? And what files do I need to include and >>>>>> where do >>>>>> > I get them (if what I have isn't correct?) >>>>>> > - What is the proper way to set up an emscripten webgl context? My >>>>>> > source code includes two different ways of setting it up and I am >>>>>> not sure >>>>>> > which is correct, even after trial and error. >>>>>> > - Can I get someone who is willing to at least compile the code >>>>>> > themselves and try out different solutions until they find >>>>>> something that >>>>>> > can provide an explanation? I don't want someone to suggest adding >>>>>> a >>>>>> > single argument to my makefile, and then hours later I get home to >>>>>> try it out >>>>>> > and realize that it actually causes the program to fail. My program >>>>>> is small >>>>>> > enough that someone can copy and paste it together, compile it, and >>>>>> run it >>>>>> > in less than 2 minutes. There is no reason to not do that yourself >>>>>> to >>>>>> > check that it works before suggesting a solution to me. I am just a >>>>>> little >>>>>> > frustrated at this point so please don't take it the wrong way, I >>>>>> just >>>>>> > want someone to take me seriously so I can move on to the next step >>>>>> of my >>>>>> > project. >>>>>> > - If this mailing list is not the best place to quickly get help >>>>>> like >>>>>> > that, who do I need to contact? I am willing to pay for work if >>>>>> that needs >>>>>> > to be done, but I don't think that should be necessary to get a >>>>>> "hello >>>>>> > world" program up and running, especially when I've already come >>>>>> this far >>>>>> > on my own. >>>>>> > >>>>>> > >>>>>> > >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> >>>>>> Shlomi Fish https://www.shlomifish.org/ >>>>>> Free (Creative Commons) Music Downloads, Reviews and more - >>>>>> https://jamendo.com/ >>>>>> >>>>>> <LeoNerd> “I hear eclipse is really nice, but I’m still waiting for >>>>>> it to >>>>>> load.” >>>>>> — Freenode’s #perl >>>>>> >>>>>> Please reply to list if it's a mailing list post - >>>>>> https://shlom.in/reply . >>>>>> >>>>> -- You received this message because you are subscribed to the Google Groups "emscripten-discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. 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