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]. To view this discussion on the web visit https://groups.google.com/d/msgid/emscripten-discuss/af15c29e-cc47-474c-bbb4-110c7fe2dc31n%40googlegroups.com.
