Support for building with Emscripten

Makefile.linux

@@ -1,9 +1,17 @@
-
 CFLAGS=-Wall -Wpedantic -std=c99
 
 LDLIBS=-lSDL2
 
-EXE =   jc_reborn
+BASE_EXE = jc_reborn
+
+ifdef EMSCRIPTEN
+EXE =   $(BASE_EXE).js
+ASSET_DIR=./assets@/
+CFLAGS+=-sUSE_SDL=2 -Os
+LDFLAGS+=--embed-file $(ASSET_DIR) -sASYNCIFY -sALLOW_MEMORY_GROWTH -sSTANDALONE_WASM=0 -sEXIT_RUNTIME
+else
+EXE =   $(BASE_EXE)
+endif
 
 OBJ =   jc_reborn.o \
         utils.o \
@@ -22,11 +30,13 @@ OBJ =   jc_reborn.o \
         events.o \
         config.o
 
-
 all: $(EXE)
 
 $(EXE): $(OBJ)
+ifdef EMSCRIPTEN
+	emcc $(OBJ) -o $(EXE) $(LDLIBS) $(LDFLAGS)
+endif
 
 clean:
-	rm -v $(OBJ) $(EXE) 2> /dev/null ; true
+	rm -v $(OBJ) $(BASE_EXE) $(BASE_EXE).js $(BASE_EXE).wasm 2> /dev/null ; true
 

README.md

@@ -2,7 +2,7 @@
 
 Johnny Reborn is an open source engine for the classic Johnny Castaway screen saver, developed by Dynamix for Windows 3.x and published by Sierra, back in 1992.
 
-It is written in C using the SDL2 library, and was successfully compiled and tested on Linux as well as Windows (MinGW), both 32 and 64 bits.
+It is written in C using the SDL2 library, and was successfully compiled and tested on Linux, on MacOSX, on Chrome and FireFox via Emscripten, as well as Windows (MinGW), both 32 and 64 bits.
 
 
 ## How to install

events.c

@@ -25,6 +25,9 @@
 #include <stdio.h>
 
 #include <SDL2/SDL.h>
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#endif
 #include "mytypes.h"
 #include "graphics.h"
 #include "events.h"
@@ -72,15 +75,23 @@ static void eventsProcessEvents()
 
                         case SDLK_ESCAPE:
                             graphicsEnd();
+#ifdef __EMSCRIPTEN__
+                            emscripten_force_exit(255);
+#else
                             exit(255);
+#endif
                             break;
                     }
                 }
                 else {
                     // Normal behaviour : no hot keys, the screen saver
                     // terminates if any key is pressed
                     graphicsEnd();
+#ifdef __EMSCRIPTEN__
+                    emscripten_force_exit(255);
+#else
                     exit(255);
+#endif
                 }
                 break;
 
@@ -90,7 +101,11 @@ static void eventsProcessEvents()
 
             case SDL_QUIT:
                 graphicsEnd();
+#ifdef __EMSCRIPTEN__
+                emscripten_force_exit(255);
+#else
                 exit(255);
+#endif
                 break;
         }
     }
@@ -112,7 +127,11 @@ void eventsWaitTick(uint16 delay)
 
     while ((paused && !oneFrame)
             || (!maxSpeed && (SDL_GetTicks() - lastTicks < delay))) {
+#ifdef __EMSCRIPTEN__
+        emscripten_sleep(5);
+#else
         SDL_Delay(5);
+#endif
         eventsProcessEvents();
     }
 

graphics.c

@@ -25,6 +25,9 @@
 #include <string.h>
 #include <time.h>
 #include <SDL2/SDL.h>
+#ifdef __EMSCRIPTEN__
+#include <emscripten/html5.h>
+#endif
 
 #include "mytypes.h"
 #include "utils.h"
@@ -122,6 +125,9 @@ void graphicsInit()
         SCREEN_HEIGHT,
         (grWindowed ? 0 : SDL_WINDOW_FULLSCREEN)
     );
+#ifdef __EMSCRIPTEN__
+    emscripten_set_canvas_element_size("#canvas", 640, 480);
+#endif
 
     if (sdl_window == NULL)
         fatalError("Could not create window: %s", SDL_GetError());

sound.c

@@ -22,6 +22,10 @@
  */
 
 #include <SDL2/SDL.h>
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+EM_JS_DEPS(sdlaudio, "$autoResumeAudioContext,$dynCall")
+#endif
 #include <string.h>
 
 #include "mytypes.h"

story.c

@@ -276,4 +276,3 @@ void storyPlay()
             adsReleaseIsland();
     }
 }
-