TravisCI and Makefile integration for the emscripten build!

For testing the emscripten build in TravisCI, it looks like some
arcane combination of node + Browserify + the wasmify plugin + maybe
some other stuff *might* work, but I have no real idea yet.

For grabbing the build artifacts from Travis, you can temporarily
insert lines into the .travis.yml such as

    curl --upload-file ./hyper.html https://transfer.sh/hyper.html
    curl --upload-file ./hyper.js https://transfer.sh/hyper.js
    curl --upload-file ./hyper.wasm https://transfer.sh/hyper.wasm

However, "hyper.wasm" is about 2.8 megabytes in size, so this hack
definitely should never become part of the *master* `.travis.yml`.

.travis.yml

@@ -1,4 +1,6 @@
 language: cpp
+services:
+  - docker
 matrix:
   include:
   - os: linux
@@ -62,6 +64,11 @@ matrix:
       HYPERROGUE_USE_GLEW=0
       HYPERROGUE_USE_PNG=0
       HYPERROGUE_USE_ROGUEVIZ=0
+  - os: linux
+    env: >-
+      TRAVIS_OS_NAME=linux
+      TRAVIS_COMPILER_NAME=emscripten
+      TRAVIS_BUILD_SYSTEM=emscripten
 
 before_install:
 - |-
@@ -120,12 +127,18 @@ script:
     make
   elif [[ "$TRAVIS_BUILD_SYSTEM" == "Makefile" ]]; then
     make -f Makefile.simple
+  elif [[ "$TRAVIS_BUILD_SYSTEM" == "emscripten" ]]; then
+    docker run --rm -v $(pwd):/src trzeci/emscripten make -f Makefile.simple emscripten
   else
     exit 'Unsupported build system'
   fi
 - |-
   # Test hyperrogue.
-  ./hyperrogue --help
+  if [[ "$TRAVIS_BUILD_SYSTEM" == "emscripten" ]]; then
+    ls -lAF hyper.html hyper.js hyper.wasm
+  else
+    ./hyperrogue --help
+  fi
 - |-
   # Test "make dist". ("make distcheck" is expected to fail.)
   if [[ "$TRAVIS_BUILD_SYSTEM" == "autotools" ]]; then make dist; fi

Makefile.simple

@@ -136,7 +136,7 @@ hyperrogue$(EXE_EXTENSION): $(hyper_OBJS) $(hyper_RES)
 	$(CXX) $(CXXFLAGS) $(hyper_OBJS) $(hyper_RES) $(LDFLAGS) $(hyper_LDFLAGS) -o $@
 
 hyper$(OBJ_EXTENSION): *.cpp language-data.cpp
-	$(CXX) -O2 $(CXXFLAGS) $(hyper_CXXFLAGS) -c hyper.cpp
+	$(CXX) -O2 $(CXXFLAGS) $(hyper_CXXFLAGS) -c hyper.cpp -o $@
 
 hyper.res: hyper.rc hr-icon.ico
 	windres hyper.rc -O coff -o hyper.res
@@ -148,9 +148,17 @@ language-data.cpp: langen$(EXE_EXTENSION)
 	./langen > language-data.cpp
 
 savepng$(OBJ_EXTENSION): savepng.cpp
-	$(CXX) $(CXXFLAGS) -O2 -c savepng.cpp -o $@
+	$(CXX) -O2 $(CXXFLAGS) -c savepng.cpp -o $@
+
+emscripten: hyper.html
+
+%.html %.js %.wasm: %.emscripten-sources
+	emcc -std=c++11 -O3 -s LEGACY_GL_EMULATION=1 -s TOTAL_MEMORY=128*1024*1024 hyperweb.cpp -o hyper.html
+
+hyper.emscripten-sources: *.cpp
 
 .PHONY: clean
 
 clean:
 	rm -f hyperrogue$(EXE_EXTENSION) hyper$(OBJ_EXTENSION) $(hyper_RES) langen$(EXE_EXTENSION) language-data.cpp savepng$(OBJ_EXTENSION)
+	rm -f hyper.html hyper.js hyper.wasm

README.md

@@ -3,6 +3,7 @@
 <a href="https://travis-ci.org/zenorogue/hyperrogue/builds">
 <img align="right" src="https://badges.herokuapp.com/travis/zenorogue/hyperrogue?branch=master&env=TRAVIS_BUILD_SYSTEM=autotools&label=autotools" alt="TravisCI badge">
 <img align="right" src="https://badges.herokuapp.com/travis/zenorogue/hyperrogue?branch=master&env=TRAVIS_BUILD_SYSTEM=Makefile&label=make" alt="TravisCI badge">
+<img align="right" src="https://badges.herokuapp.com/travis/zenorogue/hyperrogue?branch=master&env=TRAVIS_BUILD_SYSTEM=emscripten&label=web" alt="TravisCI badge">
 </a>
 </p>
 <p align="left">