OK, it appears that dramatic hacks are not necessary to make Cocoa work...

TODO

 Eli Gottlieb's checklist for the GSOC shaped windows project.  Dated July 9, 2010.
 1. Enable proper linking of the X11 implementation and test it.
---> Find the place in the build system for platform-specific linking flags.  STATUS: BLOODY IMPOSSIBLE.
---> Add a linker flag to bring in libXext.a. STATUS: WILL BE SIMPLE ONCE PREVIOUS STEP IS ACCOMPLISHED (kshemashiach yagia).
+--> Find the place in the build system for platform-specific linking flags.  STATUS: DONE
+--> Add a linker flag to bring in libXext.a. STATUS: DONE.
 2. Build the Win32 implementation of shaped-windows functionality.
 --> Add driver functions to the SDL_ShapeDriver in the Win32 driver's SDL_DisplayDevice at the proper point in the code.  STATUS: CHECK.
 --> Add a hook in the Windows resize-window code to call Win32_ResizeWindowShape().  STATUS: CHECK.
+--> Get the Windows code to build and run properly.  STATUS: IN PROGRESS.
 3. Enable building the testeyes program.
 --> Reprogram it to use the latest shaped-windows API.  STATUS: CHECK.
---> Get it, along with the rest of the test suite in my branch, building successfully.  STATUS: REQUIRES X11 IMPLEMENTATION TO LINK PROPERLY AND/OR A BUILD-BUDDY BUILDING AND RUNNING THE TEST FOR ME.
---> Debug testeyes and the platform-specific shaped-window implementations in tandem.  STATUS: TO BEGIN, CURRENT SPRINT.
-4. Implement the SDL shaped-windows API for Mac OS X using Cocoa.  STATUS: NEXT SPRINT.
---> Locate (once more) the API documentation for shaped windows under Cocoa.
---> Design and encode a version of SDL_ShapeData for Cocoa.
---> Write Cocoa_CreateShaper().
---> Write Cocoa_ResizeWindowShape().
---> Write Cocoa_SetWindowShape().
+--> Get it, along with the rest of the test suite in my branch, building successfully.  STATUS: DONE.
+--> Debug testeyes and the platform-specific shaped-window implementations in tandem.  STATUS: IN PROGRESS.
+4. Implement the SDL shaped-windows API for Mac OS X using Cocoa.  STATUS: IN PROGRESS
+--> Locate (once more) the API documentation for shaped windows under Cocoa.  STATUS: NEARLY FINISHED.
+--> Design and encode a version of SDL_ShapeData for Cocoa.  STATUS: IN PROGRESS.
+--> Write Cocoa_CreateShaper().  STATUS: IN PROGRESS.
+--> Write Cocoa_ResizeWindowShape().  STATUS: IN PROGRESS.
+--> Write Cocoa_SetWindowShape().  STATUS: IN PROGRESS.
 --> If necessary, implement functionality adjunct to SDL_CalculateShapeBitmap() for Cocoa usage.
 5. Use testeyes to debug all implementations. STATUS: SPRINT + 2.
 --> Debug Cocoa implementation.

src/video/SDL_shape.c

@@ -28,11 +28,8 @@
 #include "SDL_surface.h"
 #include "SDL_shape.h"
 
-extern SDL_VideoDisplay* SDL_ThisDisplay();
-
 SDL_Window* SDL_CreateShapedWindow(const char *title,unsigned int x,unsigned int y,unsigned int w,unsigned int h,Uint32 flags) {
-	SDL_VideoDisplay* display = SDL_ThisDisplay();
-	SDL_Window *result = display->device->shape_driver.CreateShapedWindow(title,x,y,w,h,SDL_WINDOW_BORDERLESS | flags & !SDL_WINDOW_FULLSCREEN & !SDL_WINDOW_SHOWN);
+	SDL_Window *result = SDL_CreateWindow(title,x,y,w,h,SDL_WINDOW_BORDERLESS | flags & !SDL_WINDOW_FULLSCREEN & !SDL_WINDOW_SHOWN);
 	if(result != NULL) {
 		result->shaper = result->display->device->shape_driver.CreateShaper(result);
 		if(result->shaper != NULL) {

src/video/SDL_sysvideo.h

@@ -156,7 +156,6 @@ struct SDL_WindowShaper
 /* Define the SDL shape driver structure */
 struct SDL_ShapeDriver
 {
-    SDL_Window *(*CreateShapedWindow)(const char *title,unsigned int x,unsigned int y,unsigned int w,unsigned int h,Uint32 flags);
     SDL_WindowShaper *(*CreateShaper)(SDL_Window * window);
     int (*SetWindowShape)(SDL_WindowShaper *shaper,SDL_Surface *shape,SDL_WindowShapeMode *shapeMode);
     int (*ResizeWindowShape)(SDL_Window *window);

src/video/SDL_video.c

@@ -105,10 +105,6 @@ static VideoBootStrap *bootstrap[] = {
 
 static SDL_VideoDevice *_this = NULL;
 
-SDL_VideoDisplay* SDL_ThisDisplay() {
-    return SDL_CurrentDisplay;
-}
-
 #define CHECK_WINDOW_MAGIC(window, retval) \
     if (!_this) { \
         SDL_UninitializedVideo(); \

src/video/cocoa/SDL_cocoashape.m

@@ -21,5 +21,22 @@
 */
 
 #include "SDL_shape.h"
+#include "SDL_cocoashape.h"
 
-/* Functions implementing shaped windows for Cocoa will be implemented when the API is decided on. */
+SDL_WindowShaper* Cocoa_CreateShaper(SDL_Window* window) {
+	SDL_WindowData* data = (SDL_WindowData*)window->driverdata;
+	[data->nswindow setAlpha:1.0];
+	[data->nswindow setOpaque:YES];
+	SDL_Shaper* result = result = malloc(sizeof(SDL_WindowShaper));
+	result->window = window;
+	result->mode.mode = ShapeModeDefault;
+	result->mode.parameters.binarizationCutoff = 1;
+	result->usershownflag = 0;
+	window->shaper = result;
+	int resized_properly = Cocoa_ResizeWindowShape(window);
+	assert(resized_properly == 0);
+	return result;
+}
+
+extern int Cocoa_SetWindowShape(SDL_WindowShaper *shaper,SDL_Surface *shape,SDL_WindowShapeMode *shapeMode);
+extern int Cocoa_ResizeWindowShape(SDL_Window *window);

src/video/cocoa/SDL_cocoavideo.m

@@ -92,6 +92,11 @@ Cocoa_CreateDevice(int devindex)
     device->SetWindowGrab = Cocoa_SetWindowGrab;
     device->DestroyWindow = Cocoa_DestroyWindow;
     device->GetWindowWMInfo = Cocoa_GetWindowWMInfo;
+    
+    device->shape_driver.CreateShaper = Cocoa_CreateShaper;
+    device->shape_driver.SetWindowShape = Cocoa_SetWindowShape;
+    device->shape_driver.ResizeWindowShape = Cocoa_ResizeWindowShape;
+    
 #ifdef SDL_VIDEO_OPENGL_CGL
     device->GL_LoadLibrary = Cocoa_GL_LoadLibrary;
     device->GL_GetProcAddress = Cocoa_GL_GetProcAddress;

src/video/win32/SDL_win32video.c

@@ -185,7 +185,6 @@ WIN_CreateDevice(int devindex)
     device->DestroyWindow = WIN_DestroyWindow;
     device->GetWindowWMInfo = WIN_GetWindowWMInfo;
     
-    device->shape_driver.CreateShapedWindow = Win32_CreateShapedWindow;
     device->shape_driver.CreateShaper = Win32_CreateShaper;
     device->shape_driver.SetWindowShape = Win32_SetWindowShape;
     device->shape_driver.ResizeWindowShape = Win32_ResizeWindowShape;

src/video/x11/SDL_x11video.c

@@ -203,7 +203,6 @@ X11_CreateDevice(int devindex)
     device->SetWindowGrab = X11_SetWindowGrab;
     device->DestroyWindow = X11_DestroyWindow;
     device->GetWindowWMInfo = X11_GetWindowWMInfo;
-    device->shape_driver.CreateShapedWindow = X11_CreateShapedWindow;
     device->shape_driver.CreateShaper = X11_CreateShaper;
     device->shape_driver.SetWindowShape = X11_SetWindowShape;
     device->shape_driver.ResizeWindowShape = X11_ResizeWindowShape;