pull in skeleton SDL code

Rakefile.rb

@@ -3,10 +3,12 @@ require "rscons"
 task :default do
   Rscons::Environment.new do |env|
     env.build_root = "build"
+    env.parse_flags!("!sdl2-config --cflags --libs")
     env["CXXFLAGS"] += %w[-isystem oglplus/include]
     env["CPPDEFINES"] += %w[
       OGLPLUS_NO_SITE_CONFIG
     ]
+    env["LIBS"] << %w[GL]
     sources = Dir["*.cc"]
     env.Program("app", sources)
   end

main.cc

@@ -1,6 +1,63 @@
+#include <SDL.h>
 #include "oglplus/gl.hpp"
 
+#define WIDTH 800
+#define HEIGHT 600
+
+static void init();
+static void display(SDL_Window * 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("OGLplus example",
+                                           SDL_WINDOWPOS_UNDEFINED,
+                                           SDL_WINDOWPOS_UNDEFINED,
+                                           WIDTH,
+                                           HEIGHT,
+                                           SDL_WINDOW_OPENGL);
+    if (!window)
+    {
+        printf("Failed to create window!\n");
+        SDL_Quit();
+        return 1;
+    }
+
+    SDL_GLContext gl_context = SDL_GL_CreateContext(window);
+
+    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;
 }
+
+static void init()
+{
+}
+
+static void display(SDL_Window * window)
+{
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+    SDL_GL_SwapWindow(window);
+}