Improve build usage

- Local dependency paths are now grouped in a few vars on top of SConstruct
- Added an option to generate bindings as part of the build

include/SConstruct

@@ -1,5 +1,12 @@
 #!python
-import os
+import os, subprocess
+
+
+# Local dependency paths, adapt them to your setup
+godot_headers_path = "../../godot_headers/"
+godot_bin_path = "../../godot_fork/bin/"
+godot_lib_path = "../../godot_fork/bin/"
+
 
 env = Environment()
 
@@ -7,46 +14,59 @@ if ARGUMENTS.get("use_llvm", "no") == "yes":
     env["CXX"] = "clang++"
 
 target = ARGUMENTS.get("target", "core")
-
 platform = ARGUMENTS.get("p", "linux")
 
-if (target == "core"):
+
+godot_name = "godot." + platform + ".tools.64"
+
+
+def add_sources(sources, directory):
+    for file in os.listdir(directory):
+        if file.endswith('.cpp'):
+            sources.append(directory + '/' + file)
+
+
+if target == "core":
     if platform == "linux":
         env.Append(CCFLAGS = ['-g','-O3', '-std=c++14'])
     
-    env.Append(CPPPATH=['.', './godot'])
-	
+    env.Append(CPPPATH=['.', godot_headers_path])
+
     if platform == "windows":
-        env.Append(LIBS=['godot.windows.tools.64.lib'])
-	
+        env.Append(LIBS=[godot_name + '.lib'])
+        env.Append(LIBPATH=[godot_lib_path])
+
     env.Append(CPPFLAGS=['-D_GD_CPP_CORE_API_IMPL'])
 
-    sources = [
-        'godot_cpp/core/Array.cpp',
-        'godot_cpp/core/Basis.cpp',
-        'godot_cpp/core/Color.cpp',
-        'godot_cpp/core/Dictionary.cpp',
-        'godot_cpp/core/Image.cpp',
-        'godot_cpp/core/InputEvent.cpp',
-        'godot_cpp/core/NodePath.cpp',
-        'godot_cpp/core/Plane.cpp',
-        'godot_cpp/core/PoolArrays.cpp',
-        'godot_cpp/core/Quat.cpp',
-        'godot_cpp/core/Rect2.cpp',
-        'godot_cpp/core/Rect3.cpp',
-        'godot_cpp/core/RID.cpp',
-        'godot_cpp/core/String.cpp',
-        'godot_cpp/core/Transform.cpp',
-        'godot_cpp/core/Transform2D.cpp',
-        'godot_cpp/core/Variant.cpp',
-        'godot_cpp/core/Vector2.cpp',
-        'godot_cpp/core/Vector3.cpp'
-    ]
+    sources = []
+    add_sources(sources, "godot_cpp/core")
 
     library = env.SharedLibrary(target='godot_cpp_core', source=sources)
     Default(library)
 
+
 elif target == "bindings":
+
+    if ARGUMENTS.get("generate_bindings", "no") == "yes":
+        godot_executable = godot_bin_path + godot_name
+        if platform == "windows":
+            godot_executable += ".exe"
+        
+        # TODO Generating the API should be done only if the Godot build is more recent than the JSON file
+        json_api_file = 'godot_api.json'
+        subprocess.call([godot_executable, '--gdnative-generate-json-api', json_api_file])
+
+        binding_generator_executable = '../binding_generator/target/debug/binding_generator'
+        if platform == "windows":
+            binding_generator_executable += ".exe"
+
+        # TODO Should that be the job of the generator?
+        if not os.path.isdir('godot_cpp/impl'):
+            os.mkdir('godot_cpp/impl')
+
+        # Note: the binding generator should have been built before
+        subprocess.call([binding_generator_executable, json_api_file, 'godot_cpp/'])
+
     if platform == "linux":
         if env["CXX"] == "clang++":
             env.Append(CCFLAGS = ['-Wno-writable-strings'])
@@ -55,16 +75,19 @@ elif target == "bindings":
         
         env.Append(CCFLAGS = ['-g','-O3', '-std=c++14'])
         env.Append(LINKFLAGS = ['-Wl,-R,\'$$ORIGIN\''])
-    env.Append(CPPPATH=['.', './godot', './godot_cpp'])
+    env.Append(CPPPATH=['.', godot_headers_path, './godot_cpp'])
 
     if platform == "windows":
-        env.Append(LIBS=['godot.windows.tools.64'])
+        env.Append(LIBS=[godot_name])
+        env.Append(LIBPATH=[godot_lib_path])
+
     env.Append(LIBS=['godot_cpp_core'])
-    env.Append(LIBPATH=["."])
+    env.Append(LIBPATH=['.'])
 
     env.Append(CPPFLAGS=['-D_GD_CPP_BINDING_IMPL'])
 
-    sources = [os.path.join("godot_cpp/impl/", f) for f in os.listdir("godot_cpp/impl/") if f.endswith('.cpp')]
+    sources = []
+    add_sources(sources, "godot_cpp/impl/")
 
     library = env.SharedLibrary(target='godot_cpp_bindings', source=sources)
     Default(library)