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-rw-r--r--src/win32/init.rs23
-rw-r--r--src/win32/make_current_guard.rs53
-rw-r--r--src/win32/mod.rs1
3 files changed, 61 insertions, 16 deletions
diff --git a/src/win32/init.rs b/src/win32/init.rs
index f842028..09d5878 100644
--- a/src/win32/init.rs
+++ b/src/win32/init.rs
@@ -9,6 +9,7 @@ use super::Window;
use super::MonitorID;
use super::ContextWrapper;
use super::WindowWrapper;
+use super::make_current_guard::CurrentContextGuard;
use Api;
use BuilderAttribs;
@@ -143,24 +144,18 @@ unsafe fn init(title: Vec<u16>, builder: BuilderAttribs<'static>,
let dummy_context = try!(create_context(None, &dummy_window, None));
// making context current
- gl::wgl::MakeCurrent(dummy_window.1 as *const libc::c_void,
- dummy_context.0 as *const libc::c_void);
+ let current_context = try!(CurrentContextGuard::make_current(&dummy_window,
+ &dummy_context));
// loading the extra WGL functions
- let extra_functions = gl::wgl_extra::Wgl::load_with(|addr| {
+ gl::wgl_extra::Wgl::load_with(|addr| {
use libc;
let addr = CString::new(addr.as_bytes()).unwrap();
let addr = addr.as_ptr();
gl::wgl::GetProcAddress(addr) as *const libc::c_void
- });
-
- // removing current context
- gl::wgl::MakeCurrent(ptr::null(), ptr::null());
-
- // returning the address
- extra_functions
+ })
};
// creating the real window this time
@@ -237,15 +232,11 @@ unsafe fn init(title: Vec<u16>, builder: BuilderAttribs<'static>,
// handling vsync
if builder.vsync {
if extra_functions.SwapIntervalEXT.is_loaded() {
- gl::wgl::MakeCurrent(real_window.1 as *const libc::c_void,
- context.0 as *const libc::c_void);
+ let guard = try!(CurrentContextGuard::make_current(&real_window, &context));
+
if extra_functions.SwapIntervalEXT(1) == 0 {
return Err(OsError(format!("wglSwapIntervalEXT failed")));
}
-
- // it is important to remove the current context, otherwise you get very weird
- // errors
- gl::wgl::MakeCurrent(ptr::null(), ptr::null());
}
}
diff --git a/src/win32/make_current_guard.rs b/src/win32/make_current_guard.rs
new file mode 100644
index 0000000..d6bcc8e
--- /dev/null
+++ b/src/win32/make_current_guard.rs
@@ -0,0 +1,53 @@
+use std::marker::PhantomData;
+use std::os;
+
+use libc;
+use winapi;
+use CreationError;
+
+use super::gl;
+use super::ContextWrapper;
+use super::WindowWrapper;
+
+/// A guard for when you want to make the context current. Destroying the guard restores the
+/// previously-current context.
+pub struct CurrentContextGuard<'a, 'b> {
+ previous_hdc: winapi::HDC,
+ previous_hglrc: winapi::HGLRC,
+ marker1: PhantomData<&'a ()>,
+ marker2: PhantomData<&'b ()>,
+}
+
+impl<'a, 'b> CurrentContextGuard<'a, 'b> {
+ pub unsafe fn make_current(window: &'a WindowWrapper, context: &'b ContextWrapper)
+ -> Result<CurrentContextGuard<'a, 'b>, CreationError>
+ {
+ let previous_hdc = gl::wgl::GetCurrentDC() as winapi::HDC;
+ let previous_hglrc = gl::wgl::GetCurrentContext() as winapi::HGLRC;
+
+ let result = gl::wgl::MakeCurrent(window.1 as *const libc::c_void,
+ context.0 as *const libc::c_void);
+
+ if result == 0 {
+ return Err(CreationError::OsError(format!("wglMakeCurrent function failed: {}",
+ os::error_string(os::errno()))));
+ }
+
+ Ok(CurrentContextGuard {
+ previous_hdc: previous_hdc,
+ previous_hglrc: previous_hglrc,
+ marker1: PhantomData,
+ marker2: PhantomData,
+ })
+ }
+}
+
+#[unsafe_destructor]
+impl<'a, 'b> Drop for CurrentContextGuard<'a, 'b> {
+ fn drop(&mut self) {
+ unsafe {
+ gl::wgl::MakeCurrent(self.previous_hdc as *const libc::c_void,
+ self.previous_hglrc as *const libc::c_void);
+ }
+ }
+}
diff --git a/src/win32/mod.rs b/src/win32/mod.rs
index 4e6a803..327b71d 100644
--- a/src/win32/mod.rs
+++ b/src/win32/mod.rs
@@ -21,6 +21,7 @@ mod event;
mod gl;
mod headless;
mod init;
+mod make_current_guard;
mod monitor;
/// The Win32 implementation of the main `Window` object.