Merge pull request #1 from ezillinger/wasm

Add emscripten build
ezillinger · May 6, 2024 · ce9149b · ce9149b
2 parents b3afe28 + 0840653
commit ce9149b
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Showing 17 changed files with 33,213 additions and 71 deletions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -3,9 +3,13 @@ cmake_minimum_required(VERSION 3.29)
 # set the project name
 project( ezgb )
 
-# specify the C++ standard
-set(CMAKE_CXX_STANDARD 20)
-set(CMAKE_CXX_STANDARD_REQUIRED True)
+# for some reason emscripten tries to link to the system libc++ if we use CMAKE_CXX_STANDARD
+if(NOT EMSCRIPTEN)
+    set(CMAKE_CXX_STANDARD 20)
+    set(CMAKE_CXX_STANDARD_REQUIRED True)
+else()
+    set(CMAKE_EXECUTABLE_SUFFIX ".html")
+endif()
 
 option(EZ_ADDRESS_SANITIZER "Enable Clang address sanitiizer" False)
 option(EZ_USE_FREETYPE "Use Freetype for font rendering" False)

diff --git a/data/index.html b/data/index.html
@@ -0,0 +1,26 @@
+<!DOCTYPE html>
+<html style="margin: 0; height: 100%; overflow: hidden">
+
+<head>
+    <meta charset="utf-8">
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+</head>
+
+<body style="margin: 0; height: 100%; overflow: hidden">
+
+    <!-- Create the canvas that the C++ code will draw into -->
+    <canvas style="width: 100vw; height: 100vh;" id="canvas" oncontextmenu="event.preventDefault()"></canvas>
+
+    <!-- Allow the C++ to access the canvas element --> 
+    <script type='text/javascript'>
+        var Module = {
+            canvas: (function() { return document.getElementById('canvas'); })()
+        };
+    </script>
+
+    <!-- Add the javascript glue code (index.js) as generated by Emscripten -->
+    <script src="index.js"></script>
+
+</body>
+
+</html>
diff --git a/readme.md b/readme.md
@@ -5,11 +5,15 @@
 
 This is a Gameboy emulator written from scratch in C++20. It's not super accurate but it is mostly feature complete 
 
+[Click here to try me in your browser!](https://zillinger.ca/ezgb_wasm)
+
 #### Features
 
 * Plays most simple commercial games - ROM Only and MBC1 cartridge types
+* Runs in the browser via WebAssembly
 * Audio
 * Debugger/Disassembler with breakpoints
+* PPU Vram Debug Display
 
 #### Things that can be improved
 
@@ -31,6 +35,7 @@ I tried to use as few 3rd party libraries as possible The only 3rd party librari
 ### Building
 
 * Requires CMake, a C++20 compiler, and SDL2
+* Tested on GCC, LLVM Clang, MSVC, and Emscripten
 * On Linux/MacOS install SDL2 with your package manager
 * You'll need to install GCC or LLVM Clang on MacOS - AppleClang doesn't have enough C++20 support
 * On Windows download an SDL2 release and set the path in the top level CmakeLists.txt

diff --git a/screenshot.png b/screenshot.png
diff --git a/src/Bootrom.h b/src/Bootrom.h
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
@@ -54,7 +54,23 @@ if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
 find_package(SDL2 REQUIRED)
 find_package(OpenGL REQUIRED)
 
-target_link_libraries(ezgb SDL2::SDL2 OpenGL::GL)
+if(NOT EMSCRIPTEN)
+  target_link_libraries(ezgb SDL2::SDL2 OpenGL::GL)
+else()
+  # for some reason setting set(CMAKE_CXX_STANDARD 20) chooses the wrong version
+  target_compile_options(ezgb PRIVATE 
+    "-std=c++20" 
+    "-sUSE_SDL=2"
+  )
+  target_link_options(ezgb PRIVATE 
+    "-sUSE_SDL=2" 
+    "-sWASM=1"
+    "-sALLOW_MEMORY_GROWTH=1"
+    "-sNO_EXIT_RUNTIME=0"
+    "-sASSERTIONS=1"
+    "--shell-file ./index.html" # todo, why doesn't this work?!
+  )
+endif()
 
 if(EZ_USE_FREETYPE)
   find_package(Freetype REQUIRED)

diff --git a/src/Emulator.cpp b/src/Emulator.cpp
@@ -1,19 +1,28 @@
 #include "Emulator.h"
 #include "MiscOps.h"
 #include "OpCodes.h"
+#include "Bootrom.h"
 
 namespace ez {
 
 Emulator::Emulator(Cart& cart, EmuSettings settings)
     : m_cart(cart)
     , m_settings(settings) {
-    const auto bootromPath = "./roms/bootix_dmg.bin";
-    //const auto bootromPath = "./roms/dmg_boot.bin";
-    log_info("Loading bootrom: {}", bootromPath);
-    auto fp = fopen(bootromPath, "rb");
-    ez_assert(fp);
-    ez_assert(BOOTROM_BYTES == fread(m_bootrom.data(), 1, BOOTROM_BYTES, fp));
-    fclose(fp);
+
+    static constexpr bool loadBootromFromFile = false;
+    if(loadBootromFromFile){
+        const auto bootromPath = "./roms/bootix_dmg.bin";
+        log_info("Loading bootrom: {}", bootromPath);
+        auto fp = fopen(bootromPath, "rb");
+        ez_assert(fp);
+        ez_assert(BOOTROM_BYTES == fread(m_bootrom.data(), 1, BOOTROM_BYTES, fp));
+        fclose(fp);
+    }
+    else {
+        memcpy(m_bootrom.data(), BOOTROM.data(), BOOTROM_BYTES);
+    }
+
+    log_info("Bootrom loaded successfully");
 
     if (m_settings.m_skipBootROM) {
         m_reg.a = 0x01;