Module emscripten

Select functions (with rust-native parameter and return value types) from the emscripten emscripten.h header file, and helper functions and types for them. Only most of the “Calling JavaScript From C/C++” and “Browser Execution Environment” functions are implemented.

Structs

MainLoopInvalidTiming

The main loop timing parameters can be set to other values than the ones with valid modes. If this is the case and we want to retrieve them, we use this error type.

ScreenSize

The result of the get_screen_size function.

Enums

MainLoopTiming

Parameters of the main loop’s scheduling mode.

Functions

cancel_main_loop

Cancels the main loop of the calling thread that was set using set_main_loop_with_arg or set_main_loop.

exit_with_live_runtime

Exits the program immediately while keeping the runtime alive, using emscripten_exit_with_live_runtime.

force_exit

Exits the program and kills the runtime, using emscripten_force_exit. Like libc’s exit, but works even if exit_with_live_runtime was run.

get_device_pixel_ratio

Returns the value of window.devicePixelRatio, using the emscripten-defined emscripten_get_device_pixel_ratio.

get_main_loop_timing

Returns the main loop timing parameters of the main loop.

get_now

Returns the representation of the current app running time with the highest precision using the emscripten-defined emscripten_get_now. It is most likely implemented using performance.now(), and is relevant only in comparison with other calls to this function.

get_screen_size

Returns the width and height of the screen in a nice ScreenSize structure.

get_window_title

Returns the window title, using the emscripten-defined emscripten_get_window_title.

hide_mouse

Hides the OS mouse cursor over the canvas, unlike SDL’s SDL_ShowCursor, which works with the SDL cursor.

is_main_loop_set

It returns true if the main loop function is set, and false if the main loop function isn’t set.

pause_main_loop

Pauses the main loop of the calling thread.

random

Returns a random number in range [0,1), with Math.random(), using the emscripten-defined emscripten_random.

resume_main_loop

Resumes the main loop of the calling thread.

run_script

Runs the given JavaScript script string with the eval() JS function, in the calling thread, using the emscripten-defined emscripten_run_script.

run_script_int

Runs the given JavaScript script string with the eval() JS function, in the calling thread, using the emscripten-defined emscripten_run_script_int. It returns the return result of the script, interpreted as a C int. Most probably the return result is passed to parseInt(), with NaN represented as 0.

run_script_main_thread

Runs the given JavaScript script string with the eval() JS function, in the main thread, using the emscripten-defined MAIN_THREAD_EM_ASM.

run_script_main_thread_double

Runs the given JavaScript script string with the eval() JS function, in the main thread, using the emscripten-defined MAIN_THREAD_EM_ASM_DOUBLE. It returns the return result of the script, interpreted as a C double.

run_script_main_thread_int

Runs the given JavaScript script string with the eval() JS function, in the main thread, using the emscripten-defined MAIN_THREAD_EM_ASM_INT. It returns the return result of the script, interpreted as a C int. Most probably the return result is passed to parseInt(), with NaN represented as 0.

run_script_string

Runs the given JavaScript script string with the eval() JS function, in the calling thread, using the emscripten-defined emscripten_run_script_string. It returns the return result of the script, interpreted as a string if possible. Otherwise, it returns None.

set_main_loop

Sets the given function as the main loop of the calling thread, using the emscripten-defined emscripten_set_main_loop. The given function has no parameters.

set_main_loop_timing

Applies the given main loop timing parameters to the main loop.

set_main_loop_with_arg

Sets the given function as the main loop of the calling thread, using the emscripten-defined emscripten_set_main_loop. The given function accepts a mutable reference (argument arg) to the variable that will contain the loop state and whatever else is needed for it to run.

set_window_title

Sets the window title, using the emscripten-defined emscripten_set_window_title.