use newer emsdk and use single CMakeLists.txt for both wasm and native

CMakeLists.txt

@@ -1,20 +1,36 @@
 cmake_minimum_required(VERSION 3.0)
+
+# If the EMSDK environment variable is set, configure the toolchain file. this has to be done before the project(demo) line below
+if(DEFINED ENV{EMSDK})
+    set(CMAKE_TOOLCHAIN_FILE "$ENV{EMSDK}/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake" CACHE STRING "Emscripten toolchain file")
+    message(STATUS "WebAssembly build enabled")
+    message(STATUS "CMAKE_TOOLCHAIN_FILE='${CMAKE_TOOLCHAIN_FILE}'")
+else()
+    message(STATUS "WebAssembly build NOT enabled. EMSDK environment variable is not set. Falling back to native build. If you want to compile for WebAssembly, first `source emsdk_env.sh` in the emsdk directory")
+endif()
+
 project(demo)
 
 add_definitions(-std=c++14)
 set(CMAKE_CXX_STANDARD 14)
+
+if(NOT DEFINED ENV{EMSDK})
+    set(GLFW_BUILD_EXAMPLES OFF CACHE BOOL "Build GLFW examples" FORCE)
+    find_package(glfw3 REQUIRED) # Locate the system-installed GLFW3
+    find_package(OpenGL REQUIRED) # OpenGL is needed for GLFW
+endif()
+
+# Source files
 set(DEMO_SOURCE src/demo.cpp)
 
-message(STATUS "WebAssembly build enabled")
-message(STATUS "CMAKE_TOOLCHAIN_FILE='${CMAKE_TOOLCHAIN_FILE}'")
-if(DEFINED ENV{EMSCRIPTEN})
-    message(STATUS "emscripten environment is loaded")
+# Build target
+add_executable(demoapp ${DEMO_SOURCE})
+
+if(DEFINED ENV{EMSDK})
+    set_target_properties(demoapp
+        PROPERTIES SUFFIX ".html"
+        LINK_FLAGS "-Os -s USE_WEBGL2=1 -s FULL_ES3=1 -s USE_GLFW=3 -s WASM=1")
 else()
-    message(FATAL_ERROR "emscripten environment is NOT loaded")
+    # Link against GLFW and OpenGL for native builds
+    target_link_libraries(demoapp glfw OpenGL::GL)
 endif()
-
-add_executable(wasm ${DEMO_SOURCE})
-set_target_properties(wasm 
-    PROPERTIES SUFFIX ".html"
-    LINK_FLAGS "-Os -s USE_WEBGL2=1 -s FULL_ES3=1 -s USE_GLFW=3 -s WASM=1")
-em_link_js_library(wasm ${libraryJsFiles})

README.md

@@ -2,56 +2,45 @@
 
 A starting point for a new web and native cross-platform 3D project.
 
-Builds with CMake. Supports [GLFW](http://www.glfw.org/).
+Builds with CMake. Uses [GLFW](http://www.glfw.org/).
 
 ## Details
 
-* Requires `Make` and `CMake` installed.
-* `CMake` configures `Make` to build for both environments.
-* The `Makefile` in the root is only a task runner.
-* [Libraries available in emscripten][emsdklib].
-* Displays an empty off-white window. Nothing else.
-
-[emsdklib]:https://github.com/kripken/emscripten/tree/incoming/system/include
+* Requires `CMake` and `GLFW` installed.
+* Displays an empty green window. Nothing else.
 
 ## Building
 
 ### WebAssembly
 
 * [Download or Compile the WASM Toolchain][wasm-toolchain].
 * Setup the WASM toolchain
+  * `git clone https://github.com/emscripten-core/emsdk.git`
   * `cd emsdk`
   * `./emsdk install latest`
   * `./emsdk activate latest`
   * `source ./emsdk_env.sh`
 * Build/Run the example
   * `cd starter-wasm-webgl-opengl`
-  * `make wasm`
-  * Available at: http://localhost:8080/wasm.html
+  * `mkdir buildwasm && cd buildwasm`
+  * `cmake ..`
+  * `cmake --build .`
+  * `python -m SimpleHTTPServer 8080 #or other webserver`
+  * Available at: http://localhost:8080/demoapp.html
 
 [wasm-toolchain]:http://webassembly.org/getting-started/developers-guide/
 
 ### Native Linux
 
-Tested on Ubuntu 16.04.
+Tested on Debian 11.
 
-* Install development tools X11 and OpenGL: `sudo apt install xorg-dev libgl1-mesa-dev`
-* Install GLFW: http://www.glfw.org/download.html
-  * `wget https://github.com/glfw/glfw/releases/download/3.2.1/glfw-3.2.1.zip`
-  * `unzip glfw-3.2.1.zip`
-  * `cd glfw-3.2.1`
-  * `cmake .`
-  * `sudo make install`
+* Install development tools X11 and OpenGL: `sudo apt install xorg-dev libgl1-mesa-dev libglfw3-dev`
 * Build/Run the example
   * `cd starter-wasm-webgl-opengl`
-  * `make native`
-
-[glfw-dl]:http://www.glfw.org/download.html
-
-## Notes
-
-I was hoping to build both in the same CMake tree, but the `CMAKE_TOOLCHAIN_FILE` change
-for emscripten breaks the native build.
+  * `mkdir buildnative && cd buildnative`
+  * `cmake ..`
+  * `cmake --build .`
+  * `./demoapp`
 
 Thanks to:
 

src/demo.cpp

@@ -66,7 +66,7 @@ int main() {
   glfwMakeContextCurrent(window);
 
   // Near white background
-  glClearColor(0.9f, 0.9f, 0.9f, 0.0f);
+  glClearColor(0.0f, 1.0f, 0.0f, 0.0f);
 
   // Run the loop correctly for the target environment
 #ifdef __EMSCRIPTEN__