|
|
- Native Client
- ================================================================================
-
- Requirements:
-
- * Native Client SDK (https://developer.chrome.com/native-client),
- (tested with Pepper version 33 or higher).
-
- The SDL backend for Chrome's Native Client has been tested only with the PNaCl
- toolchain, which generates binaries designed to run on ARM and x86_32/64
- platforms. This does not mean it won't work with the other toolchains!
-
- ================================================================================
- Building SDL for NaCl
- ================================================================================
-
- Set up the right environment variables (see naclbuild.sh), then configure SDL with:
-
- configure --host=pnacl --prefix some/install/destination
-
- Then "make".
-
- As an example of how to create a deployable app a Makefile project is provided
- in test/nacl/Makefile, which includes some monkey patching of the common.mk file
- provided by NaCl, without which linking properly to SDL won't work (the search
- path can't be modified externally, so the linker won't find SDL's binaries unless
- you dump them into the SDK path, which is inconvenient).
- Also provided in test/nacl is the required support file, such as index.html,
- manifest.json, etc.
- SDL apps for NaCl run on a worker thread using the ppapi_simple infrastructure.
- This allows for blocking calls on all the relevant systems (OpenGL ES, filesystem),
- hiding the asynchronous nature of the browser behind the scenes...which is not the
- same as making it disappear!
-
-
- ================================================================================
- Running tests
- ================================================================================
-
- Due to the nature of NaCl programs, building and running SDL tests is not as
- straightforward as one would hope. The script naclbuild.sh in build-scripts
- automates the process and should serve as a guide for users of SDL trying to build
- their own applications.
-
- Basic usage:
-
- ./naclbuild.sh path/to/pepper/toolchain (i.e. ~/naclsdk/pepper_35)
-
- This will build testgles2.c by default.
-
- If you want to build a different test, for example testrendercopyex.c:
-
- SOURCES=~/sdl/SDL/test/testrendercopyex.c ./naclbuild.sh ~/naclsdk/pepper_35
-
- Once the build finishes, you have to serve the contents with a web server (the
- script will give you instructions on how to do that with Python).
-
- ================================================================================
- RWops and nacl_io
- ================================================================================
-
- SDL_RWops work transparently with nacl_io. Two functions control the mount points:
-
- int mount(const char* source, const char* target,
- const char* filesystemtype,
- unsigned long mountflags, const void *data);
- int umount(const char *target);
-
- For convenience, SDL will by default mount an httpfs tree at / before calling
- the app's main function. Such setting can be overridden by calling:
-
- umount("/");
-
- And then mounting a different filesystem at /
-
- It's important to consider that the asynchronous nature of file operations on a
- browser is hidden from the application, effectively providing the developer with
- a set of blocking file operations just like you get in a regular desktop
- environment, which eases the job of porting to Native Client, but also introduces
- a set of challenges of its own, in particular when big file sizes and slow
- connections are involved.
-
- For more information on how nacl_io and mount points work, see:
-
- https://developer.chrome.com/native-client/devguide/coding/nacl_io
- https://src.chromium.org/chrome/trunk/src/native_client_sdk/src/libraries/nacl_io/nacl_io.h
-
- To be able to save into the directory "/save/" (like backup of game) :
-
- mount("", "/save", "html5fs", 0, "type=PERSISTENT");
-
- And add to manifest.json :
-
- "permissions": [
- "unlimitedStorage"
- ]
-
- ================================================================================
- TODO - Known Issues
- ================================================================================
- * Testing of all systems with a real application (something other than SDL's tests)
- * Key events don't seem to work properly
-
|
