add test application; move gl3w sources under GL3 directory

Rakefile

@@ -1,19 +1,30 @@
 require "rscons"
 
+base_env = Rscons::Environment.new do |env|
+  env["build_root"] = lambda {|args| args[:env].build_root}
+  env["CPPPATH"] << "include"
+  env["CPPPATH"] << "test/gl3w"
+  env["CPPDEFINES"] << %[GLCXX_GL_INCLUDE="GL3/gl3w.h"]
+  env["CCFLAGS"] += %w[-Wall]
+  env["CXXFLAGS"] += %w[-std=gnu++11]
+end
+
 task :lib do
-  Rscons::Environment.new do |env|
+  base_env.clone do |env|
-    env["build_root"] = "build/lib"
+    env.build_root = "build/lib"
-    env.build_root = env["build_root"]
     sources = Dir["src/**/*.cpp"]
-    env["CPPPATH"] << "include"
-    env["CPPPATH"] << "test/gl3w"
-    env["CPPDEFINES"] << %[GLCXX_GL_INCLUDE="gl3w.h"]
-    env["CXXFLAGS"] += %w[-Wall -std=gnu++11]
     env.Library("${build_root}/lib.a", sources)
   end
 end
 
 task :test do
+  base_env.clone do |env|
+    env.build_root = "build/test"
+    env.parse_flags!("!sdl2-config --cflags --libs")
+    sources = Dir["src/**/*.cpp", "test/**/*.{cpp,c}"]
+    env["LIBS"] += %w[dl GL]
+    env.Program("${build_root}/testapp", sources)
+  end
 end
 
 task :clean do

test/test.cpp

@@ -0,0 +1,75 @@
+#include <SDL.h>
+#include GLCXX_GL_INCLUDE
+#include <iostream>
+
+using namespace std;
+
+#define WIDTH   800
+#define HEIGHT  600
+
+void init(void)
+{
+    glClearColor (0.0, 0.0, 0.0, 0.0);
+}
+
+void display(SDL_Window * window)
+{
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+    SDL_GL_SwapWindow(window);
+}
+
+int main(int argc, char *argv[])
+{
+    if (SDL_Init(SDL_INIT_VIDEO))
+    {
+        printf("Failed to initialize SDL!\n");
+        return 1;
+    }
+
+    atexit(SDL_Quit);
+
+    SDL_Window * window = SDL_CreateWindow(argv[0],
+                                           SDL_WINDOWPOS_UNDEFINED,
+                                           SDL_WINDOWPOS_UNDEFINED,
+                                           WIDTH,
+                                           HEIGHT,
+                                           SDL_WINDOW_OPENGL);
+    if (!window)
+    {
+        printf("Failed to create window!\n");
+        SDL_Quit();
+        return 2;
+    }
+
+    SDL_GL_CreateContext(window);
+
+    if (gl3wInit())
+    {
+        cerr << "Failed to initialize gl3w!" << endl;
+        return 1;
+    }
+    if (!gl3wIsSupported(3, 0))
+    {
+        cerr << "OpenGL 3.0 is not supported!" << endl;
+        return 1;
+    }
+
+    init();
+    display(window);
+
+    SDL_Event event;
+    while (SDL_WaitEvent(&event))
+    {
+        if (event.type == SDL_QUIT)
+            break;
+        else if (event.type == SDL_KEYDOWN)
+        {
+            if (event.key.keysym.sym == SDLK_ESCAPE)
+                break;
+            if (event.key.keysym.sym == SDLK_RETURN)
+                display(window);
+        }
+    }
+
+    return 0;
+}