diff --git a/src/library_glemu.js b/src/library_glemu.js
index 51cf48fa57c46..3e439ec7aa497 100644
--- a/src/library_glemu.js
+++ b/src/library_glemu.js
@@ -6,7 +6,15 @@
 
 var LibraryGLEmulation = {
   // GL emulation: provides misc. functionality not present in OpenGL ES 2.0 or WebGL
-  $GLEmulation__deps: ['$GLImmediateSetup', 'glEnable', 'glDisable', 'glIsEnabled', 'glGetBooleanv', 'glGetIntegerv', 'glGetString', 'glCreateShader', 'glShaderSource', 'glCompileShader', 'glAttachShader', 'glDetachShader', 'glUseProgram', 'glDeleteProgram', 'glBindAttribLocation', 'glLinkProgram', 'glBindBuffer', 'glGetFloatv', 'glHint', 'glEnableVertexAttribArray', 'glDisableVertexAttribArray', 'glVertexAttribPointer', 'glActiveTexture', '$stringToNewUTF8', '$ptrToString'],
+  $GLEmulation__deps: ['$GLImmediateSetup', 'glEnable', 'glDisable',
+    'glIsEnabled', 'glGetBooleanv', 'glGetIntegerv', 'glGetString',
+    'glCreateShader', 'glShaderSource', 'glCompileShader', 'glAttachShader',
+    'glDetachShader', 'glUseProgram', 'glDeleteProgram', 'glBindAttribLocation',
+    'glLinkProgram', 'glBindBuffer', 'glGetFloatv', 'glHint',
+    'glEnableVertexAttribArray', 'glDisableVertexAttribArray',
+    'glVertexAttribPointer', 'glActiveTexture', '$stringToNewUTF8',
+    '$ptrToString', '$getEmscriptenSupportedExtensions',
+  ],
   $GLEmulation__postset:
 #if MAYBE_CLOSURE_COMPILER
     // Forward declare GL functions that are overridden by GLEmulation here to appease Closure compiler.
@@ -394,7 +402,7 @@ var LibraryGLEmulation = {
         if (GL.stringCache[name_]) return GL.stringCache[name_];
         switch (name_) {
           case 0x1F03 /* GL_EXTENSIONS */: // Add various extensions that we can support
-            var ret = stringToNewUTF8((GLctx.getSupportedExtensions() || []).join(' ') +
+            var ret = stringToNewUTF8(getEmscriptenSupportedExtensions(GLctx).join(' ') +
                    ' GL_EXT_texture_env_combine GL_ARB_texture_env_crossbar GL_ATI_texture_env_combine3 GL_NV_texture_env_combine4 GL_EXT_texture_env_dot3 GL_ARB_multitexture GL_ARB_vertex_buffer_object GL_EXT_framebuffer_object GL_ARB_vertex_program GL_ARB_fragment_program GL_ARB_shading_language_100 GL_ARB_shader_objects GL_ARB_vertex_shader GL_ARB_fragment_shader GL_ARB_texture_cube_map GL_EXT_draw_range_elements' +
                    (GL.currentContext.compressionExt ? ' GL_ARB_texture_compression GL_EXT_texture_compression_s3tc' : '') +
                    (GL.currentContext.anisotropicExt ? ' GL_EXT_texture_filter_anisotropic' : '')
diff --git a/src/library_glew.js b/src/library_glew.js
index 0c03085c3d8a3..e1058b90f3dff 100644
--- a/src/library_glew.js
+++ b/src/library_glew.js
@@ -20,7 +20,7 @@
  */
 
 var LibraryGLEW = {
-  $GLEW__deps: ['glGetString', '$stringToNewUTF8', '$UTF8ToString'],
+  $GLEW__deps: ['glGetString', '$stringToNewUTF8', '$UTF8ToString', '$glGetExtensions'],
   $GLEW: {
     isLinaroFork: 1,
     extensions: null,
@@ -99,7 +99,7 @@ var LibraryGLEW = {
     },
 
     extensionIsSupported(name) {
-      GLEW.extensions ||= GL.getExtensions();
+      GLEW.extensions ||= glGetExtensions();
 
       if (GLEW.extensions.includes(name))
         return 1;
diff --git a/src/library_glfw.js b/src/library_glfw.js
index 7f306a7e83240..ede30302e38f0 100644
--- a/src/library_glfw.js
+++ b/src/library_glfw.js
@@ -1483,9 +1483,9 @@ var LibraryGLFW = {
     GLFW.initialTime = GLFW.getTime() - time;
   },
 
-  glfwExtensionSupported__deps: ['glGetString'],
+  glfwExtensionSupported__deps: ['glGetString', 'glGetExtensions'],
   glfwExtensionSupported: (extension) => {
-    GLFW.extensions ||= GL.getExtensions();
+    GLFW.extensions ||= glGetExtensions();
 
     if (GLFW.extensions.includes(extension)) return 1;
 
diff --git a/src/library_html5_webgl.js b/src/library_html5_webgl.js
index c0e984bc4dd62..468fe487c6423 100644
--- a/src/library_html5_webgl.js
+++ b/src/library_html5_webgl.js
@@ -440,6 +440,9 @@ var LibraryHtml5WebGL = {
 
   emscripten_webgl_get_supported_extensions__proxy: 'sync_on_current_webgl_context_thread',
   emscripten_webgl_get_supported_extensions__deps: ['$stringToNewUTF8'],
+  // Here we report the full list of extensions supported by WebGL rather than
+  // using getEmscriptenSupportedExtensions which filters the list based on
+  // what is has explicit support in.
   emscripten_webgl_get_supported_extensions: () =>
     stringToNewUTF8(GLctx.getSupportedExtensions().join(' ')),
 
diff --git a/src/library_webgl.js b/src/library_webgl.js
index 2096d85d59543..ebc59456f4ef0 100644
--- a/src/library_webgl.js
+++ b/src/library_webgl.js
@@ -135,6 +135,56 @@ for (/**@suppress{duplicate}*/var i = 0; i < {{{ GL_POOL_TEMP_BUFFERS_SIZE }}};
   emscripten_webgl_enable_WEBGL_multi_draw__deps: ['$webgl_enable_WEBGL_multi_draw'],
   emscripten_webgl_enable_WEBGL_multi_draw: (ctx) => webgl_enable_WEBGL_multi_draw(GL.contexts[ctx].GLctx),
 
+  $getEmscriptenSupportedExtensions__internal: true,
+  $getEmscriptenSupportedExtensions: function(ctx) {
+    // Restrict the list of advertised extensions to those that we actually
+    // support.
+    var supportedExtensions = [
+#if MIN_WEBGL_VERSION == 1
+      // WebGL 1 extensions
+      'ANGLE_instanced_arrays',
+      'EXT_blend_minmax',
+      'EXT_disjoint_timer_query',
+      'EXT_frag_depth',
+      'EXT_shader_texture_lod',
+      'EXT_sRGB',
+      'OES_element_index_uint',
+      'OES_fbo_render_mipmap',
+      'OES_standard_derivatives',
+      'OES_texture_float',
+      'OES_texture_half_float',
+      'OES_texture_half_float_linear',
+      'OES_vertex_array_object',
+      'WEBGL_color_buffer_float',
+      'WEBGL_depth_texture',
+      'WEBGL_draw_buffers',
+#endif
+#if MAX_WEBGL_VERSION >= 2
+      // WebGL 2 extensions
+      'EXT_color_buffer_float',
+      'EXT_disjoint_timer_query_webgl2',
+      'EXT_texture_norm16',
+      'WEBGL_clip_cull_distance',
+#endif
+      // WebGL 1 and WebGL 2 extensions
+      'EXT_color_buffer_half_float',
+      'EXT_float_blend',
+      'EXT_texture_compression_bptc',
+      'EXT_texture_compression_rgtc',
+      'EXT_texture_filter_anisotropic',
+      'KHR_parallel_shader_compile',
+      'OES_texture_float_linear',
+      'WEBGL_compressed_texture_s3tc',
+      'WEBGL_compressed_texture_s3tc_srgb',
+      'WEBGL_debug_renderer_info',
+      'WEBGL_debug_shaders',
+      'WEBGL_lose_context',
+      'WEBGL_multi_draw',
+    ];
+    // .getSupportedExtensions() can return null if context is lost, so coerce to empty array.
+    return (ctx.getSupportedExtensions() || []).filter(ext => supportedExtensions.includes(ext));
+  },
+
   $GL__postset: 'var GLctx;',
 #if GL_SUPPORT_AUTOMATIC_ENABLE_EXTENSIONS
   // If GL_SUPPORT_AUTOMATIC_ENABLE_EXTENSIONS is enabled, GL.initExtensions() will call to initialize these.
@@ -153,8 +203,9 @@ for (/**@suppress{duplicate}*/var i = 0; i < {{{ GL_POOL_TEMP_BUFFERS_SIZE }}};
     '$webgl_enable_WEBGL_multi_draw_instanced_base_vertex_base_instance',
 #endif
     '$webgl_enable_WEBGL_multi_draw',
+    '$getEmscriptenSupportedExtensions',
   ],
-#endif
+#endif // GL_SUPPORT_AUTOMATIC_ENABLE_EXTENSIONS
   $GL: {
 #if GL_DEBUG
     debug: true,
@@ -738,60 +789,6 @@ for (/**@suppress{duplicate}*/var i = 0; i < {{{ GL_POOL_TEMP_BUFFERS_SIZE }}};
       }
       disableHalfFloatExtensionIfBroken(ctx);
 #endif
-
-      // If end user enables *glGetProcAddress() functionality or
-      // GL_SUPPORT_AUTOMATIC_ENABLE_EXTENSIONS, then we must filter out
-      // all future WebGL extensions from being passed to the user, and only restrict to advertising
-      // extensions that the *glGetProcAddress() function knows to handle.
-#if GL_ENABLE_GET_PROC_ADDRESS || GL_SUPPORT_AUTOMATIC_ENABLE_EXTENSIONS
-      var _allSupportedExtensions = ctx.getSupportedExtensions;
-      var supportedExtensionsForGetProcAddress = [
-#if MIN_WEBGL_VERSION == 1
-        // WebGL 1 extensions
-        'ANGLE_instanced_arrays',
-        'EXT_blend_minmax',
-        'EXT_disjoint_timer_query',
-        'EXT_frag_depth',
-        'EXT_shader_texture_lod',
-        'EXT_sRGB',
-        'OES_element_index_uint',
-        'OES_fbo_render_mipmap',
-        'OES_standard_derivatives',
-        'OES_texture_float',
-        'OES_texture_half_float',
-        'OES_texture_half_float_linear',
-        'OES_vertex_array_object',
-        'WEBGL_color_buffer_float',
-        'WEBGL_depth_texture',
-        'WEBGL_draw_buffers',
-#endif
-#if MAX_WEBGL_VERSION >= 2
-        // WebGL 2 extensions
-        'EXT_color_buffer_float',
-        'EXT_disjoint_timer_query_webgl2',
-        'EXT_texture_norm16',
-        'WEBGL_clip_cull_distance',
-#endif
-        // WebGL 1 and WebGL 2 extensions
-        'EXT_color_buffer_half_float',
-        'EXT_float_blend',
-        'EXT_texture_compression_bptc',
-        'EXT_texture_compression_rgtc',
-        'EXT_texture_filter_anisotropic',
-        'KHR_parallel_shader_compile',
-        'OES_texture_float_linear',
-        'WEBGL_compressed_texture_s3tc',
-        'WEBGL_compressed_texture_s3tc_srgb',
-        'WEBGL_debug_renderer_info',
-        'WEBGL_debug_shaders',
-        'WEBGL_lose_context',
-        'WEBGL_multi_draw',
-      ];
-      ctx.getSupportedExtensions = function() {
-        return (_allSupportedExtensions.apply(this) || []).filter(ext => supportedExtensionsForGetProcAddress.includes(ext));
-      }
-#endif
-
       return handle;
     },
 
@@ -1206,10 +1203,7 @@ for (/**@suppress{duplicate}*/var i = 0; i < {{{ GL_POOL_TEMP_BUFFERS_SIZE }}};
 
       webgl_enable_WEBGL_multi_draw(GLctx);
 
-      // .getSupportedExtensions() can return null if context is lost, so coerce
-      // to empty array.
-      var exts = GLctx.getSupportedExtensions() || [];
-      exts.forEach((ext) => {
+      getEmscriptenSupportedExtensions(GLctx).forEach((ext) => {
         // WEBGL_lose_context, WEBGL_debug_renderer_info and WEBGL_debug_shaders
         // are not enabled by default.
         if (!ext.includes('lose_context') && !ext.includes('debug')) {
@@ -1220,14 +1214,16 @@ for (/**@suppress{duplicate}*/var i = 0; i < {{{ GL_POOL_TEMP_BUFFERS_SIZE }}};
     },
 #endif
 
-    getExtensions() {
-      // .getSupportedExtensions() can return null if context is lost, so coerce to empty array.
-      var exts = GLctx.getSupportedExtensions() || [];
+  },
+
+  $glGetExtensions__internal: true,
+  $glGetExtensions__deps: ['$getEmscriptenSupportedExtensions'],
+  $glGetExtensions() {
+    var exts = getEmscriptenSupportedExtensions(GLctx);
 #if GL_EXTENSIONS_IN_PREFIXED_FORMAT
-      exts = exts.concat(exts.map((e) => "GL_" + e));
+    exts = exts.concat(exts.map((e) => "GL_" + e));
 #endif
-      return exts;
-    },
+    return exts;
   },
 
   glPixelStorei: (pname, param) => {
@@ -1237,13 +1233,13 @@ for (/**@suppress{duplicate}*/var i = 0; i < {{{ GL_POOL_TEMP_BUFFERS_SIZE }}};
     GLctx.pixelStorei(pname, param);
   },
 
-  glGetString__deps: ['$stringToNewUTF8'],
+  glGetString__deps: ['$stringToNewUTF8', '$glGetExtensions'],
   glGetString: (name_) => {
     var ret = GL.stringCache[name_];
     if (!ret) {
       switch (name_) {
         case 0x1F03 /* GL_EXTENSIONS */:
-          ret = stringToNewUTF8(GL.getExtensions().join(' '));
+          ret = stringToNewUTF8(glGetExtensions().join(' '));
           break;
         case 0x1F00 /* GL_VENDOR */:
         case 0x1F01 /* GL_RENDERER */:
@@ -1305,7 +1301,11 @@ for (/**@suppress{duplicate}*/var i = 0; i < {{{ GL_POOL_TEMP_BUFFERS_SIZE }}};
     return ret;
   },
 
-  $emscriptenWebGLGet__deps: ['$writeI53ToI64'],
+  $emscriptenWebGLGet__deps: ['$writeI53ToI64',
+#if MAX_WEBGL_VERSION >= 2
+    '$glGetExtensions', // For GL_NUM_EXTENSIONS
+#endif
+  ],
   $emscriptenWebGLGet: (name_, p, type) => {
     // Guard against user passing a null pointer.
     // Note that GLES2 spec does not say anything about how passing a null
@@ -1368,15 +1368,7 @@ for (/**@suppress{duplicate}*/var i = 0; i < {{{ GL_POOL_TEMP_BUFFERS_SIZE }}};
           return;
         }
 #endif
-        // .getSupportedExtensions() can return null if context is lost, so coerce to empty array.
-        var exts = GLctx.getSupportedExtensions() || [];
-#if GL_EXTENSIONS_IN_PREFIXED_FORMAT
-        // each extension is duplicated, first in unprefixed WebGL form, and
-        // then a second time with "GL_" prefix.
-        ret = 2 * exts.length;
-#else
-        ret = exts.length;
-#endif
+        ret = glGetExtensions(GLctx).length;
         break;
       case 0x821B: // GL_MAJOR_VERSION
       case 0x821C: // GL_MINOR_VERSION
diff --git a/src/library_webgl2.js b/src/library_webgl2.js
index c972f726c3a1e..aecfc05077483 100644
--- a/src/library_webgl2.js
+++ b/src/library_webgl2.js
@@ -5,7 +5,7 @@
  */
 
 var LibraryWebGL2 = {
-  glGetStringi__deps: ['$stringToNewUTF8'],
+  glGetStringi__deps: ['$glGetExtensions', '$stringToNewUTF8'],
   glGetStringi: (name, index) => {
     if (GL.currentContext.version < 2) {
       GL.recordError(0x502 /* GL_INVALID_OPERATION */); // Calling GLES3/WebGL2 function with a GLES2/WebGL1 context
@@ -24,7 +24,7 @@ var LibraryWebGL2 = {
     }
     switch (name) {
       case 0x1F03 /* GL_EXTENSIONS */:
-        var exts = GL.getExtensions().map((e) => stringToNewUTF8(e));
+        var exts = glGetExtensions().map((e) => stringToNewUTF8(e));
         stringiCache = GL.stringiCache[name] = exts;
         if (index < 0 || index >= stringiCache.length) {
           GL.recordError(0x501/*GL_INVALID_VALUE*/);