Compilation error (OGL, emscripten)

[BinBashBanana]

Hello, I am trying to build desmume for emscripten, and I want to use desmume gl. After modifiying wifi.cpp to support emscripten, I edited the emscripten section of Makefile.libretro to look like this:

# Emscripten
else ifeq ($(platform), emscripten)
   TARGET := $(TARGET_NAME)_libretro_$(platform).bc
   LIBS := -lpthread -lpcap -lGL
   CXXFLAGS += -DHAVE_OPENGL
   DESMUME_OPENGL = 1
   STATIC_LINKING = 1

I also edited OGLRender.h to include my system glx.h because for some reason the current one wasn't working.

The inital build works fine, but when I try to link it in the RetroArch repository, it fails with messages like this one:

LD desmume_libretro.js
wasm-ld: error: symbol type mismatch: glDeleteBuffers
>>> defined as WASM_SYMBOL_TYPE_FUNCTION in obj-emscripten/gfx/drivers/gl.o
>>> defined as WASM_SYMBOL_TYPE_DATA in libretro_emscripten.bc(OGLRender.o)

Is this easily fixable, or is this not supported yet?

[BinBashBanana]

I tried adding these to makefile.emscripten, which changed the error, but it still doesn't work.

HAVE_OPENGLES = 0
HAVE_GL_CONTEXT = 1
HAVE_GL_MODERN = 1
HAVE_OPENGL = 1

New error:

LD desmume_libretro.js
warning: undefined symbol: _Z21OGLCreateRenderer_3_2PP14OpenGLRenderer (referenced by top-level compiled C/C++ code)
warning: undefined symbol: _Z22OGLLoadEntryPoints_3_2v (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glActiveTextureARB (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glAlphaFunc (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glColorPointer (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glDisableClientState (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glDrawBuffer (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glEnableClientState (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glReadBuffer (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glScalef (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glTexCoordPointer (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glTexEnvi (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glTexImage1D (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glTexSubImage1D (referenced by top-level compiled C/C++ code)
warning: undefined symbol: glXGetProcAddress (referenced by top-level compiled C/C++ code)
warning: undefined symbol: pthread_attr_setschedpolicy (referenced by top-level compiled C/C++ code)

[bearoso]

emscripten can't work with OpenGL like that. You'd have to create a port to WebGL or WebGPU. Also, wifi won't work either, and compiling with pthread is bad, too.

Basically, you're trying to do something that requires much, much bigger changes.

[BinBashBanana]

I got it down to only these 2 errors:

LD desmume_libretro.js
error: undefined symbol: _Z21OGLCreateRenderer_3_2PP14OpenGLRenderer (referenced by top-level compiled C/C++ code)
error: undefined symbol: _Z22OGLLoadEntryPoints_3_2v (referenced by top-level compiled C/C++ code)

Do you know how to fix them? Or were you saying that even if they were fixed, it wouldn't work?

[bearoso]

It won't work if you're trying to use the GLX path. Desmume does context creation manually for only a few platform contexts. emscripten most likely won't wrap that code automatically.

[BinBashBanana]

I'm using EGL, where is the code for context creation so I can add it?

[BinBashBanana]

Oh... it might be a better idea to use GLES, is there a way to do that?

[kurai021]

@BinBashBanana have you had any luck with this? it's a pity there is no working port for Emscripten.

[BinBashBanana]

No... though I now better understand how some of the GL stuff works... a little. Sorry.

[kurai021]

don't worry hopefully one day it will work

[arleypadua]

It seems that ever since, the build for emscripten has been fixed, but I still can't get it working.

@BinBashBanana , I did successfully build it, even using your suggestions from your webretro repository, but unfortunately it still doesn't work.

I can get stdio logs of desmume running, but the canvas would not show anything, it just stays black.

Did you have any luck with it so far?