feat(build): initial support for WASM via Emscripten

CMakeLists.txt

@@ -14,7 +14,7 @@ option(PXC_ENABLE_ASAN "phoenix-shared: Enable sanitizers in debug builds." ON)
 
 add_subdirectory(vendor/phoenix)
 
-set(PXC_SOURCES
+list(APPEND PXC_SOURCES
         src/Animation.cc
         src/BspTree.cc
         src/Buffer.cc
@@ -37,7 +37,15 @@ set(PXC_SOURCES
 
 bs_select_cflags(${PXC_ENABLE_ASAN} PXC_COMPILE_FLAGS PXC_LINK_FLAGS)
 
-add_library(phoenix-shared SHARED)
+if (EMSCRIPTEN)
+    list(APPEND PXC_SOURCES src/Main.cc)
+    list(APPEND PXC_COMPILE_FLAGS -fexceptions)
+    list(APPEND PXC_LINK_FLAGS -sWASM=1 -sMODULARIZE -sEXPORTED_FUNCTIONS=_malloc,_free -sEXPORTED_RUNTIME_METHODS=ccall,cwrap,addFunction,AsciiToString,setValue,getValue -sSINGLE_FILE=1 -sALLOW_MEMORY_GROWTH=1 -sALLOW_TABLE_GROWTH=1 -fexceptions)
+    add_executable(phoenix-shared)
+else ()
+    add_library(phoenix-shared SHARED)
+endif ()
+
 set_target_properties(phoenix-shared PROPERTIES CXX_VISIBILITY_PRESET hidden VISIBILITY_INLINES_HIDDEN 1)
 
 target_sources(phoenix-shared PRIVATE ${PXC_SOURCES})

include/phoenix/cffi/Api.h

@@ -3,8 +3,15 @@
 #pragma once
 #include <stdint.h>
 
+#ifdef __EMSCRIPTEN__
+	#include <emscripten/emscripten.h>
+	#define PXC_PRELUDE EMSCRIPTEN_KEEPALIVE
+#else
+	#define PXC_PRELUDE
+#endif
+
 #ifdef __cplusplus
-	#define PXC_EXTERN extern "C"
+	#define PXC_EXTERN extern "C" PXC_PRELUDE
 #else
 	#define PXC_EXTERN
 #endif

src/Buffer.cc

@@ -66,7 +66,7 @@ uint64_t pxBufferSize(PxBuffer* buffer) {
 }
 
 uint8_t* pxBufferArray(PxBuffer* buffer) {
-	auto* data = new std::uint8_t[buffer->limit()];
+	auto* data = new std::uint8_t[(size_t) buffer->limit()];
 	buffer->get(data, buffer->limit());
 	return data;
 }

src/Main.cc

@@ -0,0 +1,7 @@
+// Copyright © 2023. GothicKit Contributors
+// SPDX-License-Identifier: MIT
+
+// Dummy main for Emscripten!
+int main(int, char**) {
+	return 0;
+}