Add GLFW_COCOA_RETINA_FRAMEBUFFER

Look, a can of worms!  I wonder what's inside.

This adds the first platform specific window hint, transforming
a compile-time option to a run-time per-window one.

src/cocoa_init.m

@@ -381,9 +381,6 @@ const char* _glfwPlatformGetVersionString(void)
 #if defined(_GLFW_USE_MENUBAR)
         " menubar"
 #endif
-#if defined(_GLFW_USE_RETINA)
-        " retina"
-#endif
 #if defined(_GLFW_BUILD_DLL)
         " dynamic"
 #endif

src/cocoa_window.m

@@ -1038,9 +1038,8 @@ static GLFWbool createNativeWindow(_GLFWwindow* window,
 
     window->ns.view = [[GLFWContentView alloc] initWithGlfwWindow:window];
 
-#if defined(_GLFW_USE_RETINA)
-    [window->ns.view setWantsBestResolutionOpenGLSurface:YES];
-#endif /*_GLFW_USE_RETINA*/
+    if (wndconfig->ns.retina)
+        [window->ns.view setWantsBestResolutionOpenGLSurface:YES];
 
     [window->ns.object setContentView:window->ns.view];
     [window->ns.object makeFirstResponder:window->ns.view];

src/glfw_config.h.in

@@ -62,6 +62,4 @@
 #cmakedefine _GLFW_USE_CHDIR
 // Define this to 1 if glfwCreateWindow should populate the menu bar
 #cmakedefine _GLFW_USE_MENUBAR
-// Define this to 1 if windows should use full resolution on Retina displays
-#cmakedefine _GLFW_USE_RETINA
 

src/internal.h

@@ -264,6 +264,9 @@ struct _GLFWwndconfig
     GLFWbool      autoIconify;
     GLFWbool      floating;
     GLFWbool      maximized;
+    struct {
+        GLFWbool  retina;
+    } ns;
 };
 
 /*! @brief Context configuration.

src/window.c

@@ -266,6 +266,9 @@ void glfwDefaultWindowHints(void)
 
     // The default is to select the highest available refresh rate
     _glfw.hints.refreshRate = GLFW_DONT_CARE;
+
+    // The default is to use full Retina resolution framebuffers
+    _glfw.hints.window.ns.retina = GLFW_TRUE;
 }
 
 GLFWAPI void glfwWindowHint(int hint, int value)
@@ -340,6 +343,9 @@ GLFWAPI void glfwWindowHint(int hint, int value)
         case GLFW_VISIBLE:
             _glfw.hints.window.visible = value ? GLFW_TRUE : GLFW_FALSE;
             break;
+        case GLFW_COCOA_RETINA_FRAMEBUFFER:
+            _glfw.hints.window.ns.retina = value ? GLFW_TRUE : GLFW_FALSE;
+            break;
         case GLFW_CLIENT_API:
             _glfw.hints.context.client = value;
             break;