From 4f98ea3128e406e351038646398aed93982bf4c4 Mon Sep 17 00:00:00 2001 From: Pierre Krieger Date: Sun, 1 Mar 2015 13:57:09 +0100 Subject: Add a guard for the calls to MakeCurrent during initialization --- src/win32/make_current_guard.rs | 53 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 src/win32/make_current_guard.rs (limited to 'src/win32/make_current_guard.rs') 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, 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); + } + } +} -- cgit v1.2.3