14 files changed, 223 insertions, 41 deletions

diff --git a/platform/javascript/api/api.cpp b/platform/javascript/api/api.cpp
index b377ca4e52..c7a6d53561 100644
--- a/platform/javascript/api/api.cpp
+++ b/platform/javascript/api/api.cpp
@@ -29,7 +29,7 @@
 /*************************************************************************/
 
 #include "api.h"
-#include "engine.h"
+#include "core/engine.h"
 #include "javascript_eval.h"
 
 static JavaScript *javascript_eval;
diff --git a/platform/javascript/api/javascript_eval.h b/platform/javascript/api/javascript_eval.h
index 05f7c9f38a..49d5309737 100644
--- a/platform/javascript/api/javascript_eval.h
+++ b/platform/javascript/api/javascript_eval.h
@@ -31,7 +31,7 @@
 #ifndef JAVASCRIPT_EVAL_H
 #define JAVASCRIPT_EVAL_H
 
-#include "object.h"
+#include "core/object.h"
 
 class JavaScript : public Object {
 private:
diff --git a/platform/javascript/audio_driver_javascript.cpp b/platform/javascript/audio_driver_javascript.cpp
index 7a6613bb32..a5b627b8dc 100644
--- a/platform/javascript/audio_driver_javascript.cpp
+++ b/platform/javascript/audio_driver_javascript.cpp
@@ -44,6 +44,11 @@ extern "C" EMSCRIPTEN_KEEPALIVE void audio_driver_js_mix() {
 	AudioDriverJavaScript::singleton->mix_to_js();
 }
 
+extern "C" EMSCRIPTEN_KEEPALIVE void audio_driver_process_capture(float sample) {
+
+	AudioDriverJavaScript::singleton->process_capture(sample);
+}
+
 void AudioDriverJavaScript::mix_to_js() {
 
 	int channel_count = get_total_channels_by_speaker_mode(get_speaker_mode());
@@ -51,31 +56,39 @@ void AudioDriverJavaScript::mix_to_js() {
 	int32_t *stream_buffer = reinterpret_cast<int32_t *>(internal_buffer);
 	audio_server_process(sample_count, stream_buffer);
 	for (int i = 0; i < sample_count * channel_count; i++) {
-		internal_buffer[i] = float(stream_buffer[i] >> 16) / 32768.0;
+		internal_buffer[i] = float(stream_buffer[i] >> 16) / 32768.f;
 	}
 }
 
+void AudioDriverJavaScript::process_capture(float sample) {
+
+	int32_t sample32 = int32_t(sample * 32768.f) * (1U << 16);
+	input_buffer_write(sample32);
+}
+
 Error AudioDriverJavaScript::init() {
 
 	/* clang-format off */
 	EM_ASM({
 		_audioDriver_audioContext = new (window.AudioContext || window.webkitAudioContext);
+		_audioDriver_audioInput = null;
+		_audioDriver_inputStream = null;
 		_audioDriver_scriptNode = null;
 	});
 	/* clang-format on */
 
 	int channel_count = get_total_channels_by_speaker_mode(get_speaker_mode());
 	/* clang-format off */
-	int buffer_length = EM_ASM_INT({
+	buffer_length = EM_ASM_INT({
 		var CHANNEL_COUNT = $0;
 
 		var channelCount = _audioDriver_audioContext.destination.channelCount;
 		try {
 			// Try letting the browser recommend a buffer length.
-			_audioDriver_scriptNode = _audioDriver_audioContext.createScriptProcessor(0, 0, channelCount);
+			_audioDriver_scriptNode = _audioDriver_audioContext.createScriptProcessor(0, 2, channelCount);
 		} catch (e) {
 			// ...otherwise, default to 4096.
-			_audioDriver_scriptNode = _audioDriver_audioContext.createScriptProcessor(4096, 0, channelCount);
+			_audioDriver_scriptNode = _audioDriver_audioContext.createScriptProcessor(4096, 2, channelCount);
 		}
 		_audioDriver_scriptNode.connect(_audioDriver_audioContext.destination);
 
@@ -91,6 +104,7 @@ Error AudioDriverJavaScript::init() {
 			memdelete_arr(internal_buffer);
 		internal_buffer = memnew_arr(float, buffer_length *channel_count);
 	}
+
 	return internal_buffer ? OK : ERR_OUT_OF_MEMORY;
 }
 
@@ -101,11 +115,13 @@ void AudioDriverJavaScript::start() {
 		var INTERNAL_BUFFER_PTR = $0;
 
 		var audioDriverMixFunction = cwrap('audio_driver_js_mix');
+		var audioDriverProcessCapture = cwrap('audio_driver_process_capture', null, ['number']);
 		_audioDriver_scriptNode.onaudioprocess = function(audioProcessingEvent) {
 			audioDriverMixFunction();
-			// The output buffer contains the samples that will be modified and played.
+
+			var input = audioProcessingEvent.inputBuffer;
 			var output = audioProcessingEvent.outputBuffer;
-			var input = HEAPF32.subarray(
+			var internalBuffer = HEAPF32.subarray(
 					INTERNAL_BUFFER_PTR / HEAPF32.BYTES_PER_ELEMENT,
 					INTERNAL_BUFFER_PTR / HEAPF32.BYTES_PER_ELEMENT + output.length * output.numberOfChannels);
 
@@ -113,8 +129,16 @@ void AudioDriverJavaScript::start() {
 				var outputData = output.getChannelData(channel);
 				// Loop through samples.
 				for (var sample = 0; sample < outputData.length; sample++) {
-					// Set output equal to input.
-					outputData[sample] = input[sample * output.numberOfChannels + channel];
+					outputData[sample] = internalBuffer[sample * output.numberOfChannels + channel];
+				}
+			}
+
+			if (_audioDriver_audioInput) {
+				var inputDataL = input.getChannelData(0);
+				var inputDataR = input.getChannelData(1);
+				for (var i = 0; i < inputDataL.length; i++) {
+					audioDriverProcessCapture(inputDataL[i]);
+					audioDriverProcessCapture(inputDataR[i]);
 				}
 			}
 		};
@@ -152,14 +176,74 @@ void AudioDriverJavaScript::finish() {
 	/* clang-format off */
 	EM_ASM({
 		_audioDriver_audioContext = null;
+		_audioDriver_audioInput = null;
 		_audioDriver_scriptNode = null;
 	});
 	/* clang-format on */
-	memdelete_arr(internal_buffer);
-	internal_buffer = NULL;
+
+	if (internal_buffer) {
+		memdelete_arr(internal_buffer);
+		internal_buffer = NULL;
+	}
+}
+
+Error AudioDriverJavaScript::capture_start() {
+
+	input_buffer_init(buffer_length);
+
+	/* clang-format off */
+	EM_ASM({
+		function gotMediaInput(stream) {
+			_audioDriver_inputStream = stream;
+			_audioDriver_audioInput = _audioDriver_audioContext.createMediaStreamSource(stream);
+			_audioDriver_audioInput.connect(_audioDriver_scriptNode);
+		}
+
+		function gotMediaInputError(e) {
+			console.log(e);
+		}
+
+		if (navigator.mediaDevices.getUserMedia) {
+			navigator.mediaDevices.getUserMedia({"audio": true}).then(gotMediaInput, gotMediaInputError);
+		} else {
+			if (!navigator.getUserMedia)
+				navigator.getUserMedia = navigator.webkitGetUserMedia || navigator.mozGetUserMedia;
+			navigator.getUserMedia({"audio": true}, gotMediaInput, gotMediaInputError);
+		}
+	});
+	/* clang-format on */
+
+	return OK;
+}
+
+Error AudioDriverJavaScript::capture_stop() {
+
+	/* clang-format off */
+	EM_ASM({
+		if (_audioDriver_inputStream) {
+			const tracks = _audioDriver_inputStream.getTracks();
+			for (var i = 0; i < tracks.length; i++) {
+				tracks[i].stop();
+			}
+			_audioDriver_inputStream = null;
+		}
+
+		if (_audioDriver_audioInput) {
+			_audioDriver_audioInput.disconnect();
+			_audioDriver_audioInput = null;
+		}
+
+	});
+	/* clang-format on */
+
+	input_buffer.clear();
+
+	return OK;
 }
 
 AudioDriverJavaScript::AudioDriverJavaScript() {
 
+	internal_buffer = NULL;
+
 	singleton = this;
 }
diff --git a/platform/javascript/audio_driver_javascript.h b/platform/javascript/audio_driver_javascript.h
index a65a8ec29f..c8aeb0b446 100644
--- a/platform/javascript/audio_driver_javascript.h
+++ b/platform/javascript/audio_driver_javascript.h
@@ -37,8 +37,12 @@ class AudioDriverJavaScript : public AudioDriver {
 
 	float *internal_buffer;
 
+	int buffer_length;
+
 public:
 	void mix_to_js();
+	void process_capture(float sample);
+
 	static AudioDriverJavaScript *singleton;
 
 	virtual const char *get_name() const;
@@ -51,6 +55,9 @@ public:
 	virtual void unlock();
 	virtual void finish();
 
+	virtual Error capture_start();
+	virtual Error capture_stop();
+
 	AudioDriverJavaScript();
 };
 
diff --git a/platform/javascript/detect.py b/platform/javascript/detect.py
index 17b31f8d73..22b5f1f87a 100644
--- a/platform/javascript/detect.py
+++ b/platform/javascript/detect.py
@@ -122,12 +122,17 @@ def configure(env):
     ## Link flags
 
     env.Append(LINKFLAGS=['-s', 'BINARYEN=1'])
+    env.Append(LINKFLAGS=['-s', 'BINARYEN_TRAP_MODE=\'clamp\''])
 
     # Allow increasing memory buffer size during runtime. This is efficient
     # when using WebAssembly (in comparison to asm.js) and works well for
     # us since we don't know requirements at compile-time.
     env.Append(LINKFLAGS=['-s', 'ALLOW_MEMORY_GROWTH=1'])
 
+    # Since we use both memory growth and MEMFS preloading,
+    # this avoids unecessary copying on start-up.
+    env.Append(LINKFLAGS=['--no-heap-copy'])
+
     # This setting just makes WebGL 2 APIs available, it does NOT disable WebGL 1.
     env.Append(LINKFLAGS=['-s', 'USE_WEBGL2=1'])
 
diff --git a/platform/javascript/dom_keys.inc b/platform/javascript/dom_keys.inc
index dc8d67d52b..a30818decc 100644
--- a/platform/javascript/dom_keys.inc
+++ b/platform/javascript/dom_keys.inc
@@ -28,7 +28,7 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-#include "os/keyboard.h"
+#include "core/os/keyboard.h"
 
 // https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/keyCode#Constants_for_keyCode_value
 #define DOM_VK_CANCEL 0x03
diff --git a/platform/javascript/engine.js b/platform/javascript/engine.js
index c3ef5bbbb5..91458eb4c3 100644
--- a/platform/javascript/engine.js
+++ b/platform/javascript/engine.js
@@ -1,3 +1,6 @@
+		// The following is concatenated with generated code, and acts as the end
+		// of a wrapper for said code. See pre.js for the other part of the
+		// wrapper.
 		exposedLibs['PATH'] = PATH;
 		exposedLibs['FS'] = FS;
 		return Module;
diff --git a/platform/javascript/export/export.cpp b/platform/javascript/export/export.cpp
index a7f0084562..7a325e81dd 100644
--- a/platform/javascript/export/export.cpp
+++ b/platform/javascript/export/export.cpp
@@ -28,9 +28,9 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
+#include "core/io/zip_io.h"
 #include "editor/editor_node.h"
 #include "editor_export.h"
-#include "io/zip_io.h"
 #include "main/splash.gen.h"
 #include "platform/javascript/logo.gen.h"
 #include "platform/javascript/run_icon.gen.h"
@@ -58,7 +58,7 @@ public:
 	virtual Ref<Texture> get_logo() const;
 
 	virtual bool can_export(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates) const;
-	virtual String get_binary_extension(const Ref<EditorExportPreset> &p_preset) const;
+	virtual List<String> get_binary_extensions(const Ref<EditorExportPreset> &p_preset) const;
 	virtual Error export_project(const Ref<EditorExportPreset> &p_preset, bool p_debug, const String &p_path, int p_flags = 0);
 
 	virtual bool poll_devices();
@@ -174,9 +174,11 @@ bool EditorExportPlatformJavaScript::can_export(const Ref<EditorExportPreset> &p
 	return valid;
 }
 
-String EditorExportPlatformJavaScript::get_binary_extension(const Ref<EditorExportPreset> &p_preset) const {
+List<String> EditorExportPlatformJavaScript::get_binary_extensions(const Ref<EditorExportPreset> &p_preset) const {
 
-	return "html";
+	List<String> list;
+	list.push_back("html");
+	return list;
 }
 
 Error EditorExportPlatformJavaScript::export_project(const Ref<EditorExportPreset> &p_preset, bool p_debug, const String &p_path, int p_flags) {
diff --git a/platform/javascript/http_client_javascript.cpp b/platform/javascript/http_client_javascript.cpp
index 8d90e01ae1..ccf4f8a11b 100644
--- a/platform/javascript/http_client_javascript.cpp
+++ b/platform/javascript/http_client_javascript.cpp
@@ -28,8 +28,8 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
+#include "core/io/http_client.h"
 #include "http_request.h"
-#include "io/http_client.h"
 
 Error HTTPClient::connect_to_host(const String &p_host, int p_port, bool p_ssl, bool p_verify_host) {
 
@@ -237,7 +237,7 @@ Error HTTPClient::poll() {
 		case STATUS_CONNECTION_ERROR:
 			return ERR_CONNECTION_ERROR;
 
-		case STATUS_REQUESTING:
+		case STATUS_REQUESTING: {
 
 #ifdef DEBUG_ENABLED
 			if (!has_polled) {
@@ -281,6 +281,10 @@ Error HTTPClient::poll() {
 			godot_xhr_get_response(xhr_id, write.ptr(), polled_response.size());
 			write = PoolByteArray::Write();
 			break;
+		}
+
+		default:
+			ERR_FAIL_V(ERR_BUG);
 	}
 	return OK;
 }
diff --git a/platform/javascript/javascript_eval.cpp b/platform/javascript/javascript_eval.cpp
index 07b4c192e6..9b8174cc71 100644
--- a/platform/javascript/javascript_eval.cpp
+++ b/platform/javascript/javascript_eval.cpp
@@ -140,8 +140,9 @@ Variant JavaScript::eval(const String &p_code, bool p_use_global_exec_context) {
 		case Variant::POOL_BYTE_ARRAY:
 			arr_write = PoolByteArray::Write();
 			return arr;
+		default:
+			return Variant();
 	}
-	return Variant();
 }
 
 #endif // JAVASCRIPT_EVAL_ENABLED
diff --git a/platform/javascript/javascript_main.cpp b/platform/javascript/javascript_main.cpp
index 3829e8d406..ec60571402 100644
--- a/platform/javascript/javascript_main.cpp
+++ b/platform/javascript/javascript_main.cpp
@@ -28,7 +28,7 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-#include "io/resource_loader.h"
+#include "core/io/resource_loader.h"
 #include "main/main.h"
 #include "os_javascript.h"
 
diff --git a/platform/javascript/os_javascript.cpp b/platform/javascript/os_javascript.cpp
index a7a26411b7..9250ca4903 100644
--- a/platform/javascript/os_javascript.cpp
+++ b/platform/javascript/os_javascript.cpp
@@ -30,15 +30,16 @@
 
 #include "os_javascript.h"
 
-#include "gles2/rasterizer_gles2.h"
-#include "gles3/rasterizer_gles3.h"
-#include "io/file_access_buffered_fa.h"
+#include "core/io/file_access_buffered_fa.h"
+#include "drivers/gles2/rasterizer_gles2.h"
+#include "drivers/gles3/rasterizer_gles3.h"
+#include "drivers/unix/dir_access_unix.h"
+#include "drivers/unix/file_access_unix.h"
 #include "main/main.h"
 #include "servers/visual/visual_server_raster.h"
-#include "unix/dir_access_unix.h"
-#include "unix/file_access_unix.h"
 
 #include <emscripten.h>
+#include <png.h>
 #include <stdlib.h>
 
 #include "dom_keys.inc"
@@ -120,14 +121,14 @@ void OS_JavaScript::set_window_size(const Size2 p_size) {
 			emscripten_exit_soft_fullscreen();
 			window_maximized = false;
 		}
-		emscripten_set_canvas_size(p_size.x, p_size.y);
+		emscripten_set_canvas_element_size(NULL, p_size.x, p_size.y);
 	}
 }
 
 Size2 OS_JavaScript::get_window_size() const {
 
-	int canvas[3];
-	emscripten_get_canvas_size(canvas, canvas + 1, canvas + 2);
+	int canvas[2];
+	emscripten_get_canvas_element_size(NULL, canvas, canvas + 1);
 	return Size2(canvas[0], canvas[1]);
 }
 
@@ -377,15 +378,13 @@ static void set_css_cursor(const char *p_cursor) {
 	/* clang-format on */
 }
 
-static const char *get_css_cursor() {
+static bool is_css_cursor_hidden() {
 
-	char cursor[16];
 	/* clang-format off */
-	EM_ASM_INT({
-		stringToUTF8(Module.canvas.style.cursor ? Module.canvas.style.cursor : 'auto', $0, 16);
-	}, cursor);
+	return EM_ASM_INT({
+		return Module.canvas.style.cursor === 'none';
+	});
 	/* clang-format on */
-	return cursor;
 }
 
 void OS_JavaScript::set_cursor_shape(CursorShape p_shape) {
@@ -429,7 +428,7 @@ void OS_JavaScript::set_mouse_mode(OS::MouseMode p_mode) {
 
 OS::MouseMode OS_JavaScript::get_mouse_mode() const {
 
-	if (String::utf8(get_css_cursor()) == "none")
+	if (is_css_cursor_hidden())
 		return MOUSE_MODE_HIDDEN;
 
 	EmscriptenPointerlockChangeEvent ev;
@@ -708,7 +707,7 @@ Error OS_JavaScript::initialize(const VideoMode &p_desired, int p_video_driver,
 	video_driver_index = p_video_driver;
 
 	video_mode = p_desired;
-	// Can't fulfil fullscreen request during start-up due to browser security.
+	// Can't fulfill fullscreen request during start-up due to browser security.
 	video_mode.fullscreen = false;
 	/* clang-format off */
 	if (EM_ASM_INT_V({ return Module.resizeCanvasOnStart })) {
@@ -834,13 +833,13 @@ bool OS_JavaScript::main_loop_iterate() {
 			strategy.canvasResizedCallback = NULL;
 			emscripten_enter_soft_fullscreen(NULL, &strategy);
 		} else {
-			emscripten_set_canvas_size(windowed_size.width, windowed_size.height);
+			emscripten_set_canvas_element_size(NULL, windowed_size.width, windowed_size.height);
 		}
 		just_exited_fullscreen = false;
 	}
 
-	int canvas[3];
-	emscripten_get_canvas_size(canvas, canvas + 1, canvas + 2);
+	int canvas[2];
+	emscripten_get_canvas_element_size(NULL, canvas, canvas + 1);
 	video_mode.width = canvas[0];
 	video_mode.height = canvas[1];
 	if (!window_maximized && !video_mode.fullscreen && !just_exited_fullscreen && !entering_fullscreen) {
@@ -863,6 +862,24 @@ void OS_JavaScript::finalize() {
 
 // Miscellaneous
 
+Error OS_JavaScript::execute(const String &p_path, const List<String> &p_arguments, bool p_blocking, ProcessID *r_child_id, String *r_pipe, int *r_exitcode, bool read_stderr) {
+
+	ERR_EXPLAIN("OS::execute() is not available on the HTML5 platform");
+	ERR_FAIL_V(ERR_UNAVAILABLE);
+}
+
+Error OS_JavaScript::kill(const ProcessID &p_pid) {
+
+	ERR_EXPLAIN("OS::kill() is not available on the HTML5 platform");
+	ERR_FAIL_V(ERR_UNAVAILABLE);
+}
+
+int OS_JavaScript::get_process_id() const {
+
+	ERR_EXPLAIN("OS::get_process_id() is not available on the HTML5 platform");
+	ERR_FAIL_V(0);
+}
+
 extern "C" EMSCRIPTEN_KEEPALIVE void send_notification(int p_notification) {
 
 	if (p_notification == MainLoop::NOTIFICATION_WM_MOUSE_ENTER || p_notification == MainLoop::NOTIFICATION_WM_MOUSE_EXIT) {
@@ -912,6 +929,57 @@ void OS_JavaScript::set_window_title(const String &p_title) {
 	/* clang-format on */
 }
 
+void OS_JavaScript::set_icon(const Ref<Image> &p_icon) {
+
+	ERR_FAIL_COND(p_icon.is_null());
+	Ref<Image> icon = p_icon;
+	if (icon->is_compressed()) {
+		icon = icon->duplicate();
+		ERR_FAIL_COND(icon->decompress() != OK)
+	}
+	if (icon->get_format() != Image::FORMAT_RGBA8) {
+		if (icon == p_icon)
+			icon = icon->duplicate();
+		icon->convert(Image::FORMAT_RGBA8);
+	}
+
+	png_image png_meta;
+	memset(&png_meta, 0, sizeof png_meta);
+	png_meta.version = PNG_IMAGE_VERSION;
+	png_meta.width = icon->get_width();
+	png_meta.height = icon->get_height();
+	png_meta.format = PNG_FORMAT_RGBA;
+
+	PoolByteArray png;
+	size_t len;
+	PoolByteArray::Read r = icon->get_data().read();
+	ERR_FAIL_COND(!png_image_write_get_memory_size(png_meta, len, 0, r.ptr(), 0, NULL));
+
+	png.resize(len);
+	PoolByteArray::Write w = png.write();
+	ERR_FAIL_COND(!png_image_write_to_memory(&png_meta, w.ptr(), &len, 0, r.ptr(), 0, NULL));
+	w = PoolByteArray::Write();
+
+	r = png.read();
+	/* clang-format off */
+	EM_ASM_ARGS({
+		var PNG_PTR = $0;
+		var PNG_LEN = $1;
+
+		var png = new Blob([HEAPU8.slice(PNG_PTR, PNG_PTR + PNG_LEN)], { type: "image/png" });
+		var url = URL.createObjectURL(png);
+		var link = document.getElementById('-gd-engine-icon');
+		if (link === null) {
+			link = document.createElement('link');
+			link.rel = 'icon';
+			link.id = '-gd-engine-icon';
+			document.head.appendChild(link);
+		}
+		link.href = url;
+	}, r.ptr(), len);
+	/* clang-format on */
+}
+
 String OS_JavaScript::get_executable_path() const {
 
 	return OS::get_executable_path();
diff --git a/platform/javascript/os_javascript.h b/platform/javascript/os_javascript.h
index f40fb8fc7e..79dac5940f 100644
--- a/platform/javascript/os_javascript.h
+++ b/platform/javascript/os_javascript.h
@@ -32,10 +32,10 @@
 #define OS_JAVASCRIPT_H
 
 #include "audio_driver_javascript.h"
+#include "drivers/unix/os_unix.h"
 #include "main/input_default.h"
 #include "servers/audio_server.h"
 #include "servers/visual/rasterizer.h"
-#include "unix/os_unix.h"
 
 #include <emscripten/html5.h>
 
@@ -133,8 +133,13 @@ public:
 	void run_async();
 	bool main_loop_iterate();
 
+	virtual Error execute(const String &p_path, const List<String> &p_arguments, bool p_blocking, ProcessID *r_child_id = NULL, String *r_pipe = NULL, int *r_exitcode = NULL, bool read_stderr = false);
+	virtual Error kill(const ProcessID &p_pid);
+	virtual int get_process_id() const;
+
 	virtual void alert(const String &p_alert, const String &p_title = "ALERT!");
 	virtual void set_window_title(const String &p_title);
+	virtual void set_icon(const Ref<Image> &p_icon);
 	String get_executable_path() const;
 	virtual Error shell_open(String p_uri);
 	virtual String get_name();
diff --git a/platform/javascript/pre.js b/platform/javascript/pre.js
index 02194bc75e..a870e676ea 100644
--- a/platform/javascript/pre.js
+++ b/platform/javascript/pre.js
@@ -1,2 +1,5 @@
 var Engine = {
 	RuntimeEnvironment: function(Module, exposedLibs) {
+		// The above is concatenated with generated code, and acts as the start of
+		// a wrapper for said code. See engine.js for the other part of the
+		// wrapper.