emscripten: fixes to get bgfx working (#13255)

* Emscripten: Fixes to get BGFX working

* Move emscripten specific setup into an #elif statement

* Fix indentation

* emscripten: remove no longer link option DEMANGLE_SUPPORT

Author: algestam

docs/source/initialsetup/compilingmame.rst

@@ -353,7 +353,7 @@ above in All Platforms.
 Emscripten Javascript and HTML
 ------------------------------
 
-First, download and install Emscripten 2.0.25 or later by following the
+First, download and install Emscripten 3.1.35 or later by following the
 instructions at the `official site <https://emscripten.org/docs/getting_started/downloads.html>`_.
 
 Once Emscripten has been installed, it should be possible to compile MAME

scripts/genie.lua

@@ -1170,26 +1170,24 @@ configuration { "asmjs" }
 		"-O" .. _OPTIONS["OPTIMIZE"],
 		"-s USE_SDL=2",
 		"-s USE_SDL_TTF=2",
-		"--memory-init-file 0",
 		"-s DEFAULT_LIBRARY_FUNCS_TO_INCLUDE=\"['\\$$ERRNO_CODES']\"",
 		"-s EXPORTED_FUNCTIONS=\"['_main', '_malloc', '__ZN15running_machine30emscripten_get_running_machineEv', '__ZN15running_machine17emscripten_get_uiEv', '__ZN15running_machine20emscripten_get_soundEv', '__ZN15mame_ui_manager12set_show_fpsEb', '__ZNK15mame_ui_manager8show_fpsEv', '__ZN13sound_manager4muteEbh', '_SDL_PauseAudio', '_SDL_SendKeyboardKey', '__ZN15running_machine15emscripten_saveEPKc', '__ZN15running_machine15emscripten_loadEPKc', '__ZN15running_machine21emscripten_hard_resetEv', '__ZN15running_machine21emscripten_soft_resetEv', '__ZN15running_machine15emscripten_exitEv']\"",
 		"-s EXPORTED_RUNTIME_METHODS=\"['cwrap']\"",
 		"-s ERROR_ON_UNDEFINED_SYMBOLS=0",
-		"-s USE_WEBGL2=1",
-		"-s LEGACY_GL_EMULATION=1",
-		"-s GL_UNSAFE_OPTS=0",
+		"-s STACK_SIZE=5MB",
+		"-s MAX_WEBGL_VERSION=2",
 		"--pre-js " .. _MAKE.esc(MAME_DIR) .. "src/osd/modules/sound/js_sound.js",
 		"--post-js " .. _MAKE.esc(MAME_DIR) .. "scripts/resources/emscripten/emscripten_post.js",
 		"--embed-file " .. _MAKE.esc(MAME_DIR) .. "bgfx/chains@bgfx/chains",
 		"--embed-file " .. _MAKE.esc(MAME_DIR) .. "bgfx/effects@bgfx/effects",
 		"--embed-file " .. _MAKE.esc(MAME_DIR) .. "bgfx/shaders/essl@bgfx/shaders/essl",
 		"--embed-file " .. _MAKE.esc(MAME_DIR) .. "artwork/bgfx@artwork/bgfx",
+		"--embed-file " .. _MAKE.esc(MAME_DIR) .. "artwork/lut-default.png@artwork/lut-default.png",
 		"--embed-file " .. _MAKE.esc(MAME_DIR) .. "artwork/slot-mask.png@artwork/slot-mask.png",
 	}
 	if _OPTIONS["SYMBOLS"]~=nil and _OPTIONS["SYMBOLS"]~="0" then
 		linkoptions {
 			"-g" .. _OPTIONS["SYMLEVEL"],
-			"-s DEMANGLE_SUPPORT=1",
 		}
 	end
 	if _OPTIONS["WEBASSEMBLY"] then
@@ -1205,11 +1203,12 @@ configuration { "asmjs" }
 		-- define a fixed memory size because allowing memory growth disables asm.js optimizations
 		linkoptions {
 			"-s ALLOW_MEMORY_GROWTH=0",
-			"-s TOTAL_MEMORY=268435456",
+			"-s INITIAL_MEMORY=256MB",
 		}
 	else
 		linkoptions {
 			"-s ALLOW_MEMORY_GROWTH=1",
+			"-s INITIAL_MEMORY=24MB"
 		}
 	end
 	archivesplit_size "20"

src/osd/modules/font/font_sdl.cpp

@@ -15,11 +15,8 @@
 #include "unicode.h"
 #include "osdcore.h"
 
-#ifdef SDLMAME_EMSCRIPTEN
-#include <SDL_ttf.h>
-#else
 #include <SDL2/SDL_ttf.h>
-#endif
+
 #if !defined(SDLMAME_HAIKU) && !defined(SDLMAME_EMSCRIPTEN)
 #include <fontconfig/fontconfig.h>
 #endif

src/osd/modules/render/bgfx/shadermanager.cpp

@@ -83,6 +83,15 @@ std::string shader_manager::make_path_string(const osd_options &options, const s
 {
 	std::string shader_path(options.bgfx_path());
 	shader_path += PATH_SEPARATOR "shaders" PATH_SEPARATOR;
+
+#if defined(SDLMAME_EMSCRIPTEN)
+	// Hard-code renderer type to OpenGL ES for emscripten builds since the
+	// bgfx::getRendererType() is called here before BGFX has been
+	// initialized and therefore gives the wrong renderer type (Noop).
+	shader_path += "essl" PATH_SEPARATOR;
+	return shader_path;
+#endif
+
 	switch (bgfx::getRendererType())
 	{
 		case bgfx::RendererType::Noop:

src/osd/modules/render/drawbgfx.cpp

@@ -394,6 +394,9 @@ bool video_bgfx::set_platform_data(bgfx::PlatformData &platform_data, osd_window
 #elif defined(OSD_MAC)
 	platform_data.ndt = nullptr;
 	platform_data.nwh = GetOSWindow(dynamic_cast<mac_window_info const &>(window).platform_window());
+#elif defined(SDLMAME_EMSCRIPTEN)
+	platform_data.ndt = nullptr;
+	platform_data.nwh = (void *)"#canvas"; // HTML5 target selector
 #else // defined(OSD_*)
 	SDL_SysWMinfo wmi;
 	SDL_VERSION(&wmi.version);