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
> .
>
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