Emscripten build

CMakeLists.txt

@@ -89,13 +89,16 @@ endif()
 # Link and create SDL2 Definition if we're using it
 if (SDL2_ENABLED)
 	add_compile_definitions(BLAH_USE_SDL2)
-
+	if (${CMAKE_SYSTEM_NAME} MATCHES "Emscripten")
+  		set_target_properties(blah PROPERTIES COMPILE_FLAGS "-s USE_SDL=2")
+	else()
 		if (NOT DEFINED SDL2_INCLUDE_DIRS OR NOT DEFINED SDL2_LIBRARIES)
 			find_package(SDL2 REQUIRED)
 		endif()
 		
 		target_include_directories(blah PUBLIC "$<BUILD_INTERFACE:${SDL2_INCLUDE_DIRS}>")
 		set(LIBS ${LIBS} ${SDL2_LIBRARIES})
+	endif()
 endif()
 
 target_link_libraries(blah PUBLIC ${LIBS})

src/core/app.cpp

@@ -7,13 +7,20 @@
 #include "../internal/graphics_backend.h"
 #include "../internal/input_backend.h"
 
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#include <emscripten/html5.h>
+#endif
+
 using namespace Blah;
 
 namespace
 {
-	Config app_config;
+	static Config app_config;
-	bool app_is_running = false;
+	static bool app_is_running = false;
-	bool app_is_exiting = false;
+	static bool app_is_exiting = false;
+	static uint64_t time_last;
+	static uint64_t time_accumulator = 0;
 }
 
 Config::Config()
@@ -34,48 +41,9 @@ Config::Config()
 	on_error = nullptr;
 }
 
-bool App::run(const Config* c)
+namespace {
-{
-	BLAH_ASSERT(!app_is_running, "The Application is already running");
-	BLAH_ASSERT(c != nullptr, "The Application requires a valid Config");
-	BLAH_ASSERT(c->name != nullptr, "The Application Name cannot be null");
-	BLAH_ASSERT(c->width > 0 && c->height > 0, "The Width and Height must be larget than 0");
-	BLAH_ASSERT(c->max_updates > 0, "Max Updates must be >= 1");
-	BLAH_ASSERT(c->target_framerate > 0, "Target Framerate must be >= 1");
 
-	app_config = *c;
+void loop_iteration() {
-	app_is_running = true;
-	app_is_exiting = false;
-
-	// initialize the system
-	if (!PlatformBackend::init(&app_config))
-	{
-		Log::error("Failed to initialize Platform module");
-		return false;
-	}
-
-	// initialize graphics
-	if (!GraphicsBackend::init())
-	{
-		Log::error("Failed to initialize Graphics module");
-		return false;
-	}
-
-	// input
-	InputBackend::init();
-
-	// startup
-	if (app_config.on_startup != nullptr)
-		app_config.on_startup();
-
-	uint64_t time_last = PlatformBackend::time();
-	uint64_t time_accumulator = 0;
-
-	// display window
-	PlatformBackend::ready();
-
-	while (!app_is_exiting)
-	{
 	// poll system events
 	PlatformBackend::frame();
 
@@ -143,9 +111,58 @@ bool App::run(const Config* c)
 		GraphicsBackend::after_render();
 		PlatformBackend::present();
 	}
+}
+} // namespace
 
+bool App::run(const Config* c)
+{
+	BLAH_ASSERT(!app_is_running, "The Application is already running");
+	BLAH_ASSERT(c != nullptr, "The Application requires a valid Config");
+	BLAH_ASSERT(c->name != nullptr, "The Application Name cannot be null");
+	BLAH_ASSERT(c->width > 0 && c->height > 0, "The Width and Height must be larget than 0");
+	BLAH_ASSERT(c->max_updates > 0, "Max Updates must be >= 1");
+	BLAH_ASSERT(c->target_framerate > 0, "Target Framerate must be >= 1");
+
+	app_config = *c;
+	app_is_running = true;
+	app_is_exiting = false;
+
+	// initialize the system
+	if (!PlatformBackend::init(&app_config))
+	{
+		Log::error("Failed to initialize Platform module");
+		return false;
 	}
 
+	// initialize graphics
+	if (!GraphicsBackend::init())
+	{
+		Log::error("Failed to initialize Graphics module");
+		return false;
+	}
+
+	// input
+	InputBackend::init();
+
+	// startup
+	if (app_config.on_startup != nullptr)
+		app_config.on_startup();
+
+	time_last = PlatformBackend::time();
+	time_accumulator = 0;
+
+	// display window
+	PlatformBackend::ready();
+
+#ifdef __EMSCRIPTEN__
+	emscripten_set_main_loop(loop_iteration, 0, 1);
+#else
+	while (!app_is_exiting)
+	{
+		loop_iteration();
+	}
+#endif
+
 	// shutdown
 	if (app_config.on_shutdown != nullptr)
 		app_config.on_shutdown();

src/drawing/batch.cpp

@@ -19,7 +19,11 @@ namespace
 
 	const ShaderData shader_data = {
 		// vertex shader
+#ifdef __EMSCRIPTEN__
+		"#version 300 es\n"
+#else
 		"#version 330\n"
+#endif
 		"uniform mat4 u_matrix;\n"
 		"layout(location=0) in vec2 a_position;\n"
 		"layout(location=1) in vec2 a_tex;\n"
@@ -37,7 +41,12 @@ namespace
 		"}",
 
 		// fragment shader
+#ifdef __EMSCRIPTEN__
+		"#version 300 es\n"
+		"precision mediump float;\n"
+#else
 		"#version 330\n"
+#endif
 		"uniform sampler2D u_texture;\n"
 		"in vec2 v_tex;\n"
 		"in vec4 v_col;\n"

src/internal/platform_backend_sdl2.cpp

@@ -81,6 +81,10 @@ bool PlatformBackend::init(const Config* config)
 	{
 		flags |= SDL_WINDOW_OPENGL;
 
+#ifdef __EMSCRIPTEN__
+		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
+		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
+#else
 		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
 		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
 		SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
@@ -93,6 +97,7 @@ bool PlatformBackend::init(const Config* config)
 		SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
 		SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
 		SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 4);
+#endif
 	}
 	// enable DirectX
 	else if (App::renderer() == Renderer::D3D11)
@@ -140,9 +145,11 @@ bool PlatformBackend::init(const Config* config)
 
 void PlatformBackend::ready()
 {
+#ifndef __EMSCRIPTEN__
 	// enable V-Sync
 	if (App::renderer() == Renderer::OpenGL)
 		SDL_GL_SetSwapInterval(1);
+#endif
 }
 
 void PlatformBackend::shutdown()