Split library_gl.js into library_webgl.js and library_webgl2.js. (#8059)

* Split library_gl.js into library_webgl.js and library_webgl2.js.

* Build GL library once for WebGL 1 and once for WebGL 2 because of missing symbols otherwise.

* Update GL emulation function pointer fetching to drop nonexisting GL functions

cmake/Modules/FindOpenGL.cmake

@@ -21,7 +21,7 @@ SET(OPENGL_XMESA_FOUND FALSE)
 # This is the path where <GL/gl.h> is found
 SET(OPENGL_INCLUDE_DIR "${EMSCRIPTEN_ROOT_PATH}/system/include")
 
-# No library to link against for OpenGL, since Emscripten picks it up automatically from library_gl.js,
+# No library to link against for OpenGL, since Emscripten picks it up automatically from library_webgl.js,
 # but need to report something, or CMake thinks we failed in the search.
 SET(OPENGL_LIBRARIES "nul")
 SET(OPENGL_gl_LIBRARY "nul")

embuilder.py

@@ -53,6 +53,12 @@
         libc++abi
         gl
         gl-mt
+        gl-emu
+        gl-mt-emu
+        gl-webgl2
+        gl-mt-webgl2
+        gl-emu-webgl2
+        gl-mt-emu-webgl2
         native_optimizer
         binaryen
         bullet
@@ -110,7 +116,8 @@
       '''
 
 SYSTEM_TASKS = [
-    'al', 'compiler-rt', 'gl', 'gl-mt', 'libc', 'libc-mt', 'libc-extras',
+    'al', 'compiler-rt', 'gl', 'gl-mt', 'gl-emu', 'gl-mt-emu', 'gl-webgl2',
+    'gl-mt-webgl2', 'gl-emu-webgl2', 'gl-mt-emu-webgl2', 'libc', 'libc-mt', 'libc-extras',
     'emmalloc', 'emmalloc_debug', 'dlmalloc', 'dlmalloc_threadsafe', 'pthreads',
     'pthreads_stub', 'dlmalloc_debug', 'dlmalloc_threadsafe_debug', 'libc++',
     'libc++_noexcept', 'dlmalloc_debug_noerrno', 'dlmalloc_threadsafe_debug_noerrno',
@@ -239,20 +246,20 @@ def main():
           return y->y;
         }
       ''', [static_library_name('libc++abi')])
-    elif what == 'gl':
+    elif what == 'gl' or what.startswith('gl-'):
+      opts = []
+      if '-mt' in what:
+        opts += ['-s', 'USE_PTHREADS=1']
+      if '-emu' in what:
+        opts += ['-s', 'LEGACY_GL_EMULATION=1']
+      if '-webgl2' in what:
+        opts += ['-s', 'USE_WEBGL2=1']
       build('''
         extern "C" { extern void* emscripten_GetProcAddress(const char *x); }
         int main() {
           return int(emscripten_GetProcAddress("waka waka"));
         }
-      ''', [static_library_name('libgl')])
-    elif what == 'gl-mt':
-      build('''
-        extern "C" { extern void* emscripten_GetProcAddress(const char *x); }
-        int main() {
-          return int(emscripten_GetProcAddress("waka waka"));
-        }
-      ''', [static_library_name('libgl-mt')], ['-s', 'USE_PTHREADS=1'])
+      ''', [static_library_name('lib%s' % what)], opts)
     elif what == 'native_optimizer':
       build(C_BARE, ['optimizer.2.exe'], ['-O2', '-s', 'WASM=0'])
     elif what == 'compiler_rt_wasm':

site/source/docs/porting/connecting_cpp_and_javascript/Interacting-with-code.rst

@@ -580,7 +580,7 @@ See the `library_*.js`_ files for other examples.
      ``autoAddDeps(myLibrary, name)`` where myLibrary is the object with
      all your methods, and ``name`` is the thing they all depend upon.
      This is useful when all the implemented methods use a JavaScript
-     singleton containing helper methods. See ``library_gl.js`` for
+     singleton containing helper methods. See ``library_webgl.js`` for
      an example.
    - If a JavaScript library depends on a compiled C library (like most
      of *libc*), you must edit `src/deps_info.json`_. Search for

src/library_glemu.js

@@ -2879,7 +2879,9 @@ var LibraryGLEmulation = {
 #endif
     }
   },
+
   glColor4d: 'glColor4f',
+
   glColor4ub__deps: ['glColor4f'],
   glColor4ub: function(r, g, b, a) {
     _glColor4f((r&255)/255, (g&255)/255, (b&255)/255, (a&255)/255);