Add draft for the EGL API

3 files changed, 227 insertions, 0 deletions

diff --git a/src/api/egl/ffi.rs b/src/api/egl/ffi.rs
new file mode 100644
index 0000000..e3cf32e
--- /dev/null
+++ b/src/api/egl/ffi.rs
@@ -0,0 +1,41 @@
+use libc;
+
+#[cfg(target_os = "windows")]
+extern crate winapi;
+#[cfg(target_os = "linux")]
+use api::x11::ffi;
+#[cfg(target_os = "android")]
+use api::android::ffi;
+
+pub mod egl {
+    pub type khronos_utime_nanoseconds_t = super::khronos_utime_nanoseconds_t;
+    pub type khronos_uint64_t = super::khronos_uint64_t;
+    pub type khronos_ssize_t = super::khronos_ssize_t;
+    pub type EGLNativeDisplayType = super::EGLNativeDisplayType;
+    pub type EGLNativePixmapType = super::EGLNativePixmapType;
+    pub type EGLNativeWindowType = super::EGLNativeWindowType;
+    pub type EGLint = super::EGLint;
+    pub type NativeDisplayType = super::EGLNativeDisplayType;
+    pub type NativePixmapType = super::EGLNativePixmapType;
+    pub type NativeWindowType = super::EGLNativeWindowType;
+
+    include!(concat!(env!("OUT_DIR"), "/egl_bindings.rs"));
+}
+
+pub type khronos_utime_nanoseconds_t = khronos_uint64_t;
+pub type khronos_uint64_t = libc::uint64_t;
+pub type khronos_ssize_t = libc::c_long;
+pub type EGLint = libc::int32_t;
+pub type EGLNativeDisplayType = *const libc::c_void;
+pub type EGLNativePixmapType = *const libc::c_void;     // FIXME: egl_native_pixmap_t instead
+
+#[cfg(target_os = "windows")]
+pub type EGLNativeWindowType = winapi::HWND;
+#[cfg(target_os = "linux")]
+pub type EGLNativeWindowType = ffi::Window;
+#[cfg(target_os = "android")]
+pub type EGLNativeWindowType = *const ffi::ANativeWindow;
+
+#[cfg(not(target_os = "windows"))]
+#[link(name = "EGL")]
+extern {}
diff --git a/src/api/egl/mod.rs b/src/api/egl/mod.rs
new file mode 100644
index 0000000..d9ac313
--- /dev/null
+++ b/src/api/egl/mod.rs
@@ -0,0 +1,185 @@
+#![cfg(all(target_os = "windows", target_os = "linux"))]        // always false of the moment
+
+use BuilderAttribs;
+use CreationError;
+use GlRequest;
+use Api;
+
+use libc;
+use std::ffi::CString;
+use std::{mem, ptr};
+
+pub mod ffi;
+
+pub struct Context {
+    egl: ffi::egl::Egl,
+    display: ffi::egl::types::EGLDisplay,
+    context: ffi::egl::types::EGLContext,
+    surface: ffi::egl::types::EGLSurface,
+}
+
+impl Context {
+    pub fn new(egl: ffi::egl::Egl, builder: BuilderAttribs,
+               native_display: Option<ffi::EGLNativeDisplayType>,
+               native_window: ffi::EGLNativeWindowType) -> Result<Context, CreationError>
+    {
+        if builder.sharing.is_some() {
+            unimplemented!()
+        }
+
+        let display = unsafe {
+            let display = egl.GetDisplay(native_display.unwrap_or(mem::transmute(ffi::egl::DEFAULT_DISPLAY)));
+            if display.is_null() {
+                return Err(CreationError::OsError("No EGL display connection available".to_string()));
+            }
+            display
+        };
+
+        let (_major, _minor) = unsafe {
+            let mut major: ffi::egl::types::EGLint = mem::uninitialized();
+            let mut minor: ffi::egl::types::EGLint = mem::uninitialized();
+
+            if egl.Initialize(display, &mut major, &mut minor) == 0 {
+                return Err(CreationError::OsError(format!("eglInitialize failed")))
+            }
+
+            (major, minor)
+        };
+
+        let use_gles2 = match builder.gl_version {
+            GlRequest::Specific(Api::OpenGlEs, (2, _)) => true,
+            GlRequest::Specific(Api::OpenGlEs, _) => false,
+            GlRequest::Specific(_, _) => return Err(CreationError::NotSupported),
+            GlRequest::GlThenGles { opengles_version: (2, _), .. } => true,
+            _ => false,
+        };
+
+        let mut attribute_list = vec!();
+        attribute_list.push(ffi::egl::RENDERABLE_TYPE as i32);
+        attribute_list.push(ffi::egl::OPENGL_ES2_BIT as i32);
+
+        attribute_list.push(ffi::egl::CONFORMANT as i32);
+        attribute_list.push(ffi::egl::OPENGL_ES2_BIT as i32);
+
+        attribute_list.push(ffi::egl::SURFACE_TYPE as i32);
+        attribute_list.push(ffi::egl::WINDOW_BIT as i32);
+
+        {
+            let (red, green, blue) = match builder.color_bits.unwrap_or(24) {
+                24 => (8, 8, 8),
+                16 => (6, 5, 6),
+                _ => panic!("Bad color_bits"),
+            };
+
+            attribute_list.push(ffi::egl::RED_SIZE as i32);
+            attribute_list.push(red);
+            attribute_list.push(ffi::egl::GREEN_SIZE as i32);
+            attribute_list.push(green);
+            attribute_list.push(ffi::egl::BLUE_SIZE as i32);
+            attribute_list.push(blue);
+        }
+
+        attribute_list.push(ffi::egl::DEPTH_SIZE as i32);
+        attribute_list.push(builder.depth_bits.unwrap_or(8) as i32);
+
+        attribute_list.push(ffi::egl::NONE as i32);
+
+        let config = unsafe {
+            let mut num_config: ffi::egl::types::EGLint = mem::uninitialized();
+            let mut config: ffi::egl::types::EGLConfig = mem::uninitialized();
+            if egl.ChooseConfig(display, attribute_list.as_ptr(), &mut config, 1,
+                                &mut num_config) == 0
+            {
+                return Err(CreationError::OsError(format!("eglChooseConfig failed")))
+            }
+
+            if num_config <= 0 {
+                return Err(CreationError::OsError(format!("eglChooseConfig returned no available config")))
+            }
+
+            config
+        };
+
+        let surface = unsafe {
+            let surface = egl.CreateWindowSurface(display, config, native_window, ptr::null());
+            if surface.is_null() {
+                return Err(CreationError::OsError(format!("eglCreateWindowSurface failed")))
+            }
+            surface
+        };
+
+        let context = unsafe {
+            let mut context_attributes = vec!();
+            context_attributes.push(ffi::egl::CONTEXT_CLIENT_VERSION as i32);
+            context_attributes.push(2);
+            context_attributes.push(ffi::egl::NONE as i32);
+
+            let context = egl.CreateContext(display, config, ptr::null(),
+                                            context_attributes.as_ptr());
+            if context.is_null() {
+                return Err(CreationError::OsError(format!("eglCreateContext failed")))
+            }
+            context
+        };
+
+        Ok(Context {
+            egl: egl,
+            display: display,
+            context: context,
+            surface: surface,
+        })
+    }
+
+    pub fn make_current(&self) {
+        let ret = unsafe {
+            self.egl.MakeCurrent(self.display, self.surface, self.surface, self.context)
+        };
+
+        if ret == 0 {
+            panic!("eglMakeCurrent failed");
+        }
+    }
+
+    pub fn is_current(&self) -> bool {
+        unsafe { self.egl.GetCurrentContext() == self.context }
+    }
+
+    pub fn get_proc_address(&self, addr: &str) -> *const () {
+        let addr = CString::new(addr.as_bytes()).unwrap();
+        let addr = addr.as_ptr();
+        unsafe {
+            self.egl.GetProcAddress(addr) as *const ()
+        }
+    }
+
+    pub fn swap_buffers(&self) {
+        let ret = unsafe {
+            self.egl.SwapBuffers(self.display, self.surface)
+        };
+
+        if ret == 0 {
+            panic!("eglSwapBuffers failed");
+        }
+    }
+
+    pub fn get_api(&self) -> ::Api {
+        ::Api::OpenGlEs
+    }
+}
+
+unsafe impl Send for Context {}
+unsafe impl Sync for Context {}
+
+impl Drop for Context {
+    fn drop(&mut self) {
+        use std::ptr;
+
+        unsafe {
+            // we don't call MakeCurrent(0, 0) because we are not sure that the context
+            // is still the current one
+            self.egl.DestroyContext(self.display, self.context);
+            self.egl.DestroySurface(self.display, self.surface);
+            self.egl.Terminate(self.display);
+        }
+    }
+}
diff --git a/src/api/mod.rs b/src/api/mod.rs
index 472c716..b791880 100644
--- a/src/api/mod.rs
+++ b/src/api/mod.rs
@@ -1,4 +1,5 @@
 pub mod android;
 pub mod cocoa;
+pub mod egl;
 pub mod win32;
 pub mod x11;