Examples: Emscripten: Add 'make serve' helper, move output to web/ folder. (#3705)

examples/example_emscripten_opengl3/.gitignore

@@ -0,0 +1,2 @@
+# Ignore Web Instance
+web/

examples/example_emscripten_opengl3/Makefile

@@ -15,7 +15,8 @@
 
 CC = emcc
 CXX = em++
-EXE = example_emscripten_opengl3.html
+WEB_DIR = web
+EXE = $(WEB_DIR)/example_emscripten_opengl3.html
 IMGUI_DIR = ../..
 SOURCES = main.cpp
 SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
@@ -78,8 +79,14 @@ LDFLAGS += --shell-file shell_minimal.html
 all: $(EXE)
 	@echo Build complete for $(EXE)
 
-$(EXE): $(OBJS)
-	$(CXX) -o $@ $^ $(LIBS) $(LDFLAGS)
+$(WEB_DIR):
+	mkdir $@
+
+serve: all
+	python3 -m http.server -d $(WEB_DIR)
+
+$(EXE): $(OBJS) $(WEB_DIR)
+	$(CXX) -o $@ $(OBJS) $(LIBS) $(LDFLAGS)
 
 clean:
-	rm -f $(EXE) $(OBJS) *.js *.wasm *.wasm.pre
+	rm -rf $(EXE) $(OBJS) *.js *.wasm *.wasm.pre $(WEB_DIR)

examples/example_emscripten_opengl3/README.md

@@ -11,8 +11,8 @@
 To run on a local machine:
 - Generally you may need a local webserver. Quoting [https://emscripten.org/docs/getting_started](https://emscripten.org/docs/getting_started/Tutorial.html#generating-html):<br>
 _"Unfortunately several browsers (including Chrome, Safari, and Internet Explorer) do not support file:// [XHR](https://emscripten.org/docs/site/glossary.html#term-xhr) requests, and can’t load extra files needed by the HTML (like a .wasm file, or packaged file data as mentioned lower down). For these browsers you’ll need to serve the files using a [local webserver](https://emscripten.org/docs/getting_started/FAQ.html#faq-local-webserver) and then open http://localhost:8000/hello.html."_
-- Emscripten SDK has a handy `emrun` command: `emrun example_emscripten_opengl3.html` which will spawn a temporary local webserver. See https://emscripten.org/docs/compiling/Running-html-files-with-emrun.html for details.
-- Otherwise you may use Python builtin webserver: `python -m http.server` in Python 3 or `python -m SimpleHTTPServer` in Python 2. After doing that, you can visit http://localhost:8000/.
+- Emscripten SDK has a handy `emrun` command: `emrun web/example_emscripten_opengl3.html --browser firefox` which will spawn a temporary local webserver (in Firefox). See https://emscripten.org/docs/compiling/Running-html-files-with-emrun.html for details.
+- Otherwise you may use Python builtin webserver: `python -m http.server -d web` in Python 3 (or run shortcut `make serve`) or `cd web && python -m SimpleHTTPServer` in Python 2. After doing that, you can visit http://localhost:8000/.
 
 ## Obsolete features: