Basic implementation of emscripten

src/api/emscripten/ffi.rs

@@ -0,0 +1,82 @@
+#![allow(dead_code)]
+#![allow(non_snake_case)]
+#![allow(non_camel_case_types)]
+
+use libc;
+
+pub type EM_BOOL = libc::c_int;
+pub type EM_UTF8 = libc::c_char;
+pub type EMSCRIPTEN_WEBGL_CONTEXT_HANDLE = libc::c_int;
+pub type EMSCRIPTEN_RESULT = libc::c_int;
+
+pub type em_webgl_context_callback = extern fn(libc::c_int, *const libc::c_void, *mut libc::c_void)
+    -> EM_BOOL;
+
+#[repr(C)]
+pub struct EmscriptenWebGLContextAttributes {
+    pub alpha: EM_BOOL,
+    pub depth: EM_BOOL,
+    pub stencil: EM_BOOL,
+    pub antialias: EM_BOOL,
+    pub premultipliedAlpha: EM_BOOL,
+    pub preserveDrawingBuffer: EM_BOOL,
+    pub preferLowPowerToHighPerformance: EM_BOOL,
+    pub failIfMajorPerformanceCaveat: EM_BOOL,
+    pub majorVersion: libc::c_int,
+    pub minorVersion: libc::c_int,
+    pub enableExtensionsByDefault: EM_BOOL,
+}
+
+// values for EMSCRIPTEN_RESULT
+pub const EMSCRIPTEN_RESULT_SUCCESS: libc::c_int = 0;
+pub const EMSCRIPTEN_RESULT_DEFERRED: libc::c_int = 1;
+pub const EMSCRIPTEN_RESULT_NOT_SUPPORTED: libc::c_int = -1;
+pub const EMSCRIPTEN_RESULT_FAILED_NOT_DEFERRED: libc::c_int = -2;
+pub const EMSCRIPTEN_RESULT_INVALID_TARGET: libc::c_int = -3;
+pub const EMSCRIPTEN_RESULT_UNKNOWN_TARGET: libc::c_int = -4;
+pub const EMSCRIPTEN_RESULT_INVALID_PARAM: libc::c_int = -5;
+pub const EMSCRIPTEN_RESULT_FAILED: libc::c_int = -6;
+pub const EMSCRIPTEN_RESULT_NO_DATA: libc::c_int = -7;
+
+extern {
+    pub fn emscripten_webgl_init_context_attributes(attributes: *mut EmscriptenWebGLContextAttributes);
+    pub fn emscripten_webgl_create_context(target: *const libc::c_char,
+        attributes: *const EmscriptenWebGLContextAttributes) -> EMSCRIPTEN_WEBGL_CONTEXT_HANDLE;
+
+    pub fn emscripten_webgl_make_context_current(context: EMSCRIPTEN_WEBGL_CONTEXT_HANDLE)
+    -> EMSCRIPTEN_RESULT;
+
+    pub fn emscripten_webgl_get_current_context() -> EMSCRIPTEN_WEBGL_CONTEXT_HANDLE;
+
+    pub fn emscripten_webgl_destroy_context(context: EMSCRIPTEN_WEBGL_CONTEXT_HANDLE)
+        -> EMSCRIPTEN_RESULT;
+
+    pub fn emscripten_webgl_enable_extension(context: EMSCRIPTEN_WEBGL_CONTEXT_HANDLE,
+        extension: *const libc::c_char) -> EM_BOOL;
+
+    pub fn emscripten_set_webglcontextlost_callback(target: *const libc::c_char,
+        userData: *mut libc::c_void, useCapture: EM_BOOL, callback: em_webgl_context_callback)
+        -> EMSCRIPTEN_RESULT;
+    pub fn emscripten_set_webglcontextrestored_callback(target: *const libc::c_char,
+        userData: *mut libc::c_void, useCapture: EM_BOOL, callback: em_webgl_context_callback)
+        -> EMSCRIPTEN_RESULT;
+
+    pub fn emscripten_is_webgl_context_lost(target: *const libc::c_char) -> EM_BOOL;
+
+    // note: this function is not documented but is used by the ports of glfw, SDL and EGL
+    pub fn emscripten_GetProcAddress(name: *const libc::c_char) -> *const libc::c_void;
+
+
+    pub fn emscripten_request_fullscreen(target: *const libc::c_char,
+        deferUntilInEventHandler: EM_BOOL) -> EMSCRIPTEN_RESULT;
+
+    pub fn emscripten_exit_fullscreen() -> EMSCRIPTEN_RESULT;
+
+    pub fn emscripten_set_element_css_size(target: *const libc::c_char, width: libc::c_double,
+        height: libc::c_double) -> EMSCRIPTEN_RESULT;
+
+    pub fn emscripten_get_element_css_size(target: *const libc::c_char, width: *mut libc::c_double,
+        height: *mut libc::c_double) -> EMSCRIPTEN_RESULT;
+
+    pub fn emscripten_sleep(delay: libc::c_uint);
+}

src/api/emscripten/mod.rs

@@ -0,0 +1,251 @@
+#![cfg(target_os = "emscripten")]
+
+use std::ffi::CString;
+use libc;
+use {Event, BuilderAttribs, CreationError, MouseCursor};
+use Api;
+use PixelFormat;
+use GlContext;
+
+use std::collections::VecDeque;
+
+mod ffi;
+
+pub struct Window {
+    context: ffi::EMSCRIPTEN_WEBGL_CONTEXT_HANDLE,
+}
+
+pub struct PollEventsIterator<'a> {
+    window: &'a Window,
+}
+
+impl<'a> Iterator for PollEventsIterator<'a> {
+    type Item = Event;
+
+    fn next(&mut self) -> Option<Event> {
+        None
+    }
+}
+
+pub struct WaitEventsIterator<'a> {
+    window: &'a Window,
+}
+
+impl<'a> Iterator for WaitEventsIterator<'a> {
+    type Item = Event;
+
+    fn next(&mut self) -> Option<Event> {
+        None
+    }
+}
+
+#[derive(Clone)]
+pub struct WindowProxy;
+
+impl WindowProxy {
+    pub fn wakeup_event_loop(&self) {
+        unimplemented!()
+    }
+}
+
+pub struct MonitorID;
+
+pub fn get_available_monitors() -> VecDeque<MonitorID> {
+    let mut list = VecDeque::new();
+    list.push_back(MonitorID);
+    list
+}
+
+pub fn get_primary_monitor() -> MonitorID {
+    MonitorID
+}
+
+impl MonitorID {
+    pub fn get_name(&self) -> Option<String> {
+        Some("Canvas".to_string())
+    }
+
+    pub fn get_dimensions(&self) -> (u32, u32) {
+        unimplemented!()
+    }
+}
+
+impl Window {
+    pub fn new(builder: BuilderAttribs) -> Result<Window, CreationError> {
+        // getting the default values of attributes
+        let mut attributes = unsafe {
+            use std::mem;
+            let mut attributes: ffi::EmscriptenWebGLContextAttributes = mem::uninitialized();
+            ffi::emscripten_webgl_init_context_attributes(&mut attributes);
+            attributes
+        };
+
+        // setting the attributes
+        // FIXME: 
+        /*match builder.gl_version {
+            Some((major, minor)) => {
+                attributes.majorVersion = major as libc::c_int;
+                attributes.minorVersion = minor as libc::c_int;
+            },
+            None => ()
+        };*/
+
+        // creating the context
+        let context = unsafe {
+            use std::{mem, ptr};
+            let context = ffi::emscripten_webgl_create_context(ptr::null(), &attributes);
+            if context <= 0 {
+                return Err(CreationError::OsError(format!("Error while calling emscripten_webgl_create_context: {}",
+                    error_to_str(mem::transmute(context)))));
+            }
+            context
+        };
+
+        // TODO: emscripten_set_webglcontextrestored_callback
+
+        Ok(Window {
+            context: context
+        })
+    }
+
+    pub fn is_closed(&self) -> bool {
+        use std::ptr;
+        unsafe { ffi::emscripten_is_webgl_context_lost(ptr::null()) != 0 }
+    }
+
+    pub fn set_title(&self, _title: &str) {
+    }
+
+    pub fn get_position(&self) -> Option<(i32, i32)> {
+        Some((0, 0))
+    }
+
+    pub fn set_position(&self, _: i32, _: i32) {
+    }
+
+    pub fn get_inner_size(&self) -> Option<(u32, u32)> {
+        unsafe {
+            use std::{mem, ptr};
+            let mut width = mem::uninitialized();
+            let mut height = mem::uninitialized();
+
+            if ffi::emscripten_get_element_css_size(ptr::null(), &mut width, &mut height)
+                != ffi::EMSCRIPTEN_RESULT_SUCCESS
+            {
+                None
+            } else {
+                Some((width as u32, height as u32))
+            }
+        }
+    }
+
+    pub fn get_outer_size(&self) -> Option<(u32, u32)> {
+        self.get_inner_size()
+    }
+
+    pub fn set_inner_size(&self, width: u32, height: u32) {
+        unsafe {
+            use std::ptr;
+            ffi::emscripten_set_element_css_size(ptr::null(), width as libc::c_double, height
+                as libc::c_double);
+        }
+    }
+
+    pub fn poll_events(&self) -> PollEventsIterator {
+        PollEventsIterator {
+            window: self,
+        }
+    }
+
+    pub fn wait_events(&self) -> WaitEventsIterator {
+        WaitEventsIterator {
+            window: self,
+        }
+    }
+
+    pub fn create_window_proxy(&self) -> WindowProxy {
+        WindowProxy
+    }
+
+    pub fn show(&self) {}
+    pub fn hide(&self) {}
+
+    pub fn platform_display(&self) -> *mut libc::c_void {
+        unimplemented!()
+    }
+
+    pub fn platform_window(&self) -> *mut libc::c_void {
+        unimplemented!()
+    }
+
+    pub fn set_window_resize_callback(&mut self, _: Option<fn(u32, u32)>) {
+    }
+
+    pub fn set_cursor(&self, _cursor: MouseCursor) {
+        unimplemented!()
+    }
+
+    pub fn hidpi_factor(&self) -> f32 {
+        1.0
+    }
+}
+
+impl GlContext for Window {
+    unsafe fn make_current(&self) {
+        // TOOD: check if == EMSCRIPTEN_RESULT
+        ffi::emscripten_webgl_make_context_current(self.context);
+    }
+
+    fn is_current(&self) -> bool {
+        true        // FIXME: 
+    }
+
+    fn get_proc_address(&self, addr: &str) -> *const libc::c_void {
+        let addr = CString::new(addr.as_bytes()).unwrap();
+        let addr = addr.as_ptr();
+
+        unsafe {
+            ffi::emscripten_GetProcAddress(addr) as *const _
+        }
+    }
+
+    fn swap_buffers(&self) {
+        unsafe {
+            ffi::emscripten_sleep(1);   // FIXME: 
+        }
+    }
+
+    fn get_api(&self) -> Api {
+        Api::WebGl
+    }
+
+    fn get_pixel_format(&self) -> PixelFormat {
+        unimplemented!();
+    }
+}
+
+impl Drop for Window {
+    fn drop(&mut self) {
+        unsafe {
+            ffi::emscripten_exit_fullscreen();
+            ffi::emscripten_webgl_destroy_context(self.context);
+        }
+    }
+}
+
+fn error_to_str(code: ffi::EMSCRIPTEN_RESULT) -> &'static str {
+    match code {
+        ffi::EMSCRIPTEN_RESULT_SUCCESS | ffi::EMSCRIPTEN_RESULT_DEFERRED
+            => "Internal error in the library (success detected as failure)",
+
+        ffi::EMSCRIPTEN_RESULT_NOT_SUPPORTED => "Not supported",
+        ffi::EMSCRIPTEN_RESULT_FAILED_NOT_DEFERRED => "Failed not deferred",
+        ffi::EMSCRIPTEN_RESULT_INVALID_TARGET => "Invalid target",
+        ffi::EMSCRIPTEN_RESULT_UNKNOWN_TARGET => "Unknown target",
+        ffi::EMSCRIPTEN_RESULT_INVALID_PARAM => "Invalid parameter",
+        ffi::EMSCRIPTEN_RESULT_FAILED => "Failed",
+        ffi::EMSCRIPTEN_RESULT_NO_DATA => "No data",
+
+        _ => "Undocumented error"
+    }
+}

src/api/mod.rs

@@ -3,6 +3,7 @@ pub mod caca;
 pub mod cocoa;
 pub mod dlopen;
 pub mod egl;
+pub mod emscripten;
 pub mod glx;
 pub mod osmesa;
 pub mod win32;

src/platform/emscripten/mod.rs

@@ -0,0 +1,49 @@
+#![cfg(target_os = "emscripten")]
+
+use GlContext;
+
+pub use api::emscripten::{Window, WindowProxy, MonitorID, get_available_monitors};
+pub use api::emscripten::{get_primary_monitor, WaitEventsIterator, PollEventsIterator};
+
+#[cfg(feature = "headless")]
+pub struct HeadlessContext(Window);
+
+#[cfg(feature = "headless")]
+impl HeadlessContext {
+    /// See the docs in the crate root file.
+    pub fn new(builder: BuilderAttribs) -> Result<HeadlessContext, CreationError> {
+        Window::new(builder).map(|w| HeadlessContext(w))
+    }
+}
+
+#[cfg(feature = "headless")]
+impl GlContext for HeadlessContext {
+    unsafe fn make_current(&self) {
+        self.0.make_current()
+    }
+
+    fn is_current(&self) -> bool {
+        self.0.is_current()
+    }
+
+    fn get_proc_address(&self, addr: &str) -> *const libc::c_void {
+        self.0.get_proc_address(addr)
+    }
+
+    fn swap_buffers(&self) {
+        self.0.swap_buffers()
+    }
+
+    fn get_api(&self) -> Api {
+        self.0.get_api()
+    }
+
+    fn get_pixel_format(&self) -> PixelFormat {
+        self.0.get_pixel_format()
+    }
+}
+
+#[cfg(feature = "headless")]
+unsafe impl Send for HeadlessContext {}
+#[cfg(feature = "headless")]
+unsafe impl Sync for HeadlessContext {}