Detach wgl and win32

3 files changed, 566 insertions, 0 deletions

diff --git a/src/api/wgl/gl.rs b/src/api/wgl/gl.rs
new file mode 100644
index 0000000..1354d95
--- /dev/null
+++ b/src/api/wgl/gl.rs
@@ -0,0 +1,12 @@
+/// WGL bindings
+pub mod wgl {
+    include!(concat!(env!("OUT_DIR"), "/wgl_bindings.rs"));
+}
+
+/// Functions that are not necessarly always available
+pub mod wgl_extra {
+    include!(concat!(env!("OUT_DIR"), "/wgl_extra_bindings.rs"));
+}
+
+#[link(name = "opengl32")]
+extern {}
diff --git a/src/api/wgl/make_current_guard.rs b/src/api/wgl/make_current_guard.rs
new file mode 100644
index 0000000..b890c82
--- /dev/null
+++ b/src/api/wgl/make_current_guard.rs
@@ -0,0 +1,47 @@
+use std::marker::PhantomData;
+use std::io;
+
+use libc;
+use winapi;
+use CreationError;
+
+use super::gl;
+/// 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(hdc: winapi::HDC, context: winapi::HGLRC)
+                               -> 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(hdc as *const _, context as *const _);
+        if result == 0 {
+            return Err(CreationError::OsError(format!("wglMakeCurrent function failed: {}",
+                                                      format!("{}", io::Error::last_os_error()))));
+        }
+
+        Ok(CurrentContextGuard {
+            previous_hdc: previous_hdc,
+            previous_hglrc: previous_hglrc,
+            marker1: PhantomData,
+            marker2: PhantomData,
+        })
+    }
+}
+
+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/api/wgl/mod.rs b/src/api/wgl/mod.rs
new file mode 100644
index 0000000..1da20aa
--- /dev/null
+++ b/src/api/wgl/mod.rs
@@ -0,0 +1,507 @@
+#![cfg(any(target_os = "windows"))]
+
+use BuilderAttribs;
+use CreationError;
+use GlContext;
+use GlRequest;
+use GlProfile;
+use PixelFormat;
+use Api;
+
+use self::make_current_guard::CurrentContextGuard;
+
+use libc;
+use std::ffi::{CStr, CString, OsStr};
+use std::os::windows::ffi::OsStrExt;
+use std::{mem, ptr};
+use std::io;
+
+use winapi;
+use kernel32;
+use user32;
+use gdi32;
+
+mod make_current_guard;
+mod gl;
+
+pub struct Context {
+    context: ContextWrapper,
+
+    hdc: winapi::HDC,
+
+    /// Binded to `opengl32.dll`.
+    ///
+    /// `wglGetProcAddress` returns null for GL 1.1 functions because they are
+    ///  already defined by the system. This module contains them.
+    gl_library: winapi::HMODULE,
+
+    /// The pixel format that has been used to create this context.
+    pixel_format: PixelFormat,
+}
+
+/// A simple wrapper that destroys the window when it is destroyed.
+struct WindowWrapper(winapi::HWND, winapi::HDC);
+
+impl Drop for WindowWrapper {
+    fn drop(&mut self) {
+        unsafe {
+            user32::DestroyWindow(self.0);
+        }
+    }
+}
+
+struct ContextWrapper(winapi::HGLRC);
+
+impl Drop for ContextWrapper {
+    fn drop(&mut self) {
+        unsafe {
+            gl::wgl::DeleteContext(self.0 as *const _);
+        }
+    }
+}
+
+impl Context {
+    /// Attempt to build a new WGL context on a window.
+    ///
+    /// The window must **not** have had `SetPixelFormat` called on it.
+    pub fn new(builder: &BuilderAttribs<'static>, window: winapi::HWND,
+               builder_sharelists: Option<winapi::HGLRC>)
+               -> Result<Context, CreationError>
+    {
+        unsafe {
+            let hdc = user32::GetDC(window);
+            if hdc.is_null() {
+                let err = Err(CreationError::OsError(format!("GetDC function failed: {}",
+                                                          format!("{}", io::Error::last_os_error()))));
+                return err;
+            }
+
+            // the first step is to create a dummy window and a dummy context which we will use
+            // to load the pointers to some functions in the OpenGL driver in `extra_functions`
+            let extra_functions = {
+                let (ex_style, style) = (winapi::WS_EX_APPWINDOW, winapi::WS_POPUP |
+                                         winapi::WS_CLIPSIBLINGS | winapi::WS_CLIPCHILDREN);
+
+                // creating a dummy invisible window
+                let dummy_window = {
+                    let rect = {
+                        let mut placement: winapi::WINDOWPLACEMENT = unsafe { mem::zeroed() };
+                        placement.length = mem::size_of::<winapi::WINDOWPLACEMENT>() as winapi::UINT;
+                        if unsafe { user32::GetWindowPlacement(window, &mut placement) } == 0 {
+                            panic!();
+                        }
+                        placement.rcNormalPosition
+                    };
+
+                    let mut class_name = [0u16; 128];
+                    if user32::GetClassNameW(window, class_name.as_mut_ptr(), 128) == 0 {
+                        return Err(CreationError::OsError(format!("GetClassNameW function failed: {}",
+                                                          format!("{}", io::Error::last_os_error()))));
+                    }
+
+                    let handle = user32::CreateWindowExW(ex_style, class_name.as_ptr(),
+                                                         b"dummy window\0".as_ptr() as *const _, style,
+                                                         winapi::CW_USEDEFAULT, winapi::CW_USEDEFAULT,
+                                                         rect.right - rect.left, rect.bottom - rect.top,
+                                                         ptr::null_mut(), ptr::null_mut(),
+                                                         kernel32::GetModuleHandleW(ptr::null()),
+                                                         ptr::null_mut());
+
+                    if handle.is_null() {
+                        return Err(CreationError::OsError(format!("CreateWindowEx function failed: {}",
+                                                          format!("{}", io::Error::last_os_error()))));
+                    }
+
+                    let hdc = user32::GetDC(handle);
+                    if hdc.is_null() {
+                        let err = Err(CreationError::OsError(format!("GetDC function failed: {}",
+                                                           format!("{}", io::Error::last_os_error()))));
+                        return err;
+                    }
+
+                    WindowWrapper(handle, hdc)
+                };
+
+                // getting the pixel format that we will use and setting it
+                {
+                    let formats = enumerate_native_pixel_formats(dummy_window.1);
+                    let id = try!(choose_dummy_pixel_format(formats.into_iter()));
+                    try!(set_pixel_format(dummy_window.1, id));
+                }
+
+                // creating the dummy OpenGL context and making it current
+                let dummy_context = try!(create_context(None, dummy_window.0, dummy_window.1, None));
+                let _current_context = try!(CurrentContextGuard::make_current(dummy_window.1,
+                                                                              dummy_context.0));
+
+                // loading the extra WGL functions
+                gl::wgl_extra::Wgl::load_with(|addr| {
+                    let addr = CString::new(addr.as_bytes()).unwrap();
+                    let addr = addr.as_ptr();
+                    gl::wgl::GetProcAddress(addr) as *const libc::c_void
+                })
+            };
+
+            // calling SetPixelFormat
+            let pixel_format = {
+                let formats = if extra_functions.GetPixelFormatAttribivARB.is_loaded() {
+                    let f = enumerate_arb_pixel_formats(&extra_functions, hdc);
+                    if f.is_empty() {
+                        enumerate_native_pixel_formats(hdc)
+                    } else {
+                        f
+                    }
+                } else {
+                    enumerate_native_pixel_formats(hdc)
+                };
+
+                let (id, f) = try!(builder.choose_pixel_format(formats.into_iter().map(|(a, b)| (b, a))));
+                try!(set_pixel_format(hdc, id));
+                f
+            };
+
+            // creating the OpenGL context
+            let context = try!(create_context(Some((&extra_functions, builder)), window, hdc,
+                                              builder_sharelists));
+
+            // loading the opengl32 module
+            let gl_library = try!(load_opengl32_dll());
+
+            // handling vsync
+            if builder.vsync {
+                if extra_functions.SwapIntervalEXT.is_loaded() {
+                    let _guard = try!(CurrentContextGuard::make_current(hdc, context.0));
+
+                    if extra_functions.SwapIntervalEXT(1) == 0 {
+                        return Err(CreationError::OsError(format!("wglSwapIntervalEXT failed")));
+                    }
+                }
+            }
+
+            Ok(Context {
+                context: context,
+                hdc: hdc,
+                gl_library: gl_library,
+                pixel_format: pixel_format,
+            })
+        }
+    }
+
+    /// Returns the raw HGLRC.
+    pub fn get_hglrc(&self) -> winapi::HGLRC {
+        self.context.0
+    }
+}
+
+impl GlContext for Context {
+    unsafe fn make_current(&self) {
+        // TODO: check return value
+        gl::wgl::MakeCurrent(self.hdc as *const _, self.context.0 as *const _);
+    }
+
+    fn is_current(&self) -> bool {
+        unsafe { gl::wgl::GetCurrentContext() == self.context.0 as *const libc::c_void }
+    }
+
+    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 {
+            let p = gl::wgl::GetProcAddress(addr) as *const _;
+            if !p.is_null() { return p; }
+            kernel32::GetProcAddress(self.gl_library, addr) as *const _
+        }
+    }
+
+    fn swap_buffers(&self) {
+        unsafe {
+            gdi32::SwapBuffers(self.hdc);
+        }
+    }
+
+    fn get_api(&self) -> Api {
+        // FIXME: can be opengl es
+        Api::OpenGl
+    }
+
+    fn get_pixel_format(&self) -> PixelFormat {
+        self.pixel_format.clone()
+    }
+}
+
+unsafe impl Send for Context {}
+unsafe impl Sync for Context {}
+
+unsafe fn create_context(extra: Option<(&gl::wgl_extra::Wgl, &BuilderAttribs<'static>)>,
+                         _: winapi::HWND, hdc: winapi::HDC, share: Option<winapi::HGLRC>)
+                         -> Result<ContextWrapper, CreationError>
+{
+    let share = share.unwrap_or(ptr::null_mut());
+
+    let ctxt = if let Some((extra_functions, builder)) = extra {
+        if extra_functions.CreateContextAttribsARB.is_loaded() {
+            let mut attributes = Vec::new();
+
+            match builder.gl_version {
+                GlRequest::Latest => {},
+                GlRequest::Specific(Api::OpenGl, (major, minor)) => {
+                    attributes.push(gl::wgl_extra::CONTEXT_MAJOR_VERSION_ARB as libc::c_int);
+                    attributes.push(major as libc::c_int);
+                    attributes.push(gl::wgl_extra::CONTEXT_MINOR_VERSION_ARB as libc::c_int);
+                    attributes.push(minor as libc::c_int);
+                },
+                GlRequest::Specific(Api::OpenGlEs, (major, minor)) => {
+                    if is_extension_supported(extra_functions, hdc,
+                                              "WGL_EXT_create_context_es2_profile")
+                    {
+                        attributes.push(gl::wgl_extra::CONTEXT_PROFILE_MASK_ARB as libc::c_int);
+                        attributes.push(gl::wgl_extra::CONTEXT_ES2_PROFILE_BIT_EXT as libc::c_int);
+                    } else {
+                        return Err(CreationError::NotSupported);
+                    }
+
+                    attributes.push(gl::wgl_extra::CONTEXT_MAJOR_VERSION_ARB as libc::c_int);
+                    attributes.push(major as libc::c_int);
+                    attributes.push(gl::wgl_extra::CONTEXT_MINOR_VERSION_ARB as libc::c_int);
+                    attributes.push(minor as libc::c_int);
+                },
+                GlRequest::Specific(_, _) => return Err(CreationError::NotSupported),
+                GlRequest::GlThenGles { opengl_version: (major, minor), .. } => {
+                    attributes.push(gl::wgl_extra::CONTEXT_MAJOR_VERSION_ARB as libc::c_int);
+                    attributes.push(major as libc::c_int);
+                    attributes.push(gl::wgl_extra::CONTEXT_MINOR_VERSION_ARB as libc::c_int);
+                    attributes.push(minor as libc::c_int);
+                },
+            }
+
+            if let Some(profile) = builder.gl_profile {
+                if is_extension_supported(extra_functions, hdc,
+                                          "WGL_ARB_create_context_profile")
+                {
+                    let flag = match profile {
+                        GlProfile::Compatibility =>
+                            gl::wgl_extra::CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB,
+                        GlProfile::Core =>
+                            gl::wgl_extra::CONTEXT_CORE_PROFILE_BIT_ARB,
+                    };
+                    attributes.push(gl::wgl_extra::CONTEXT_PROFILE_MASK_ARB as libc::c_int);
+                    attributes.push(flag as libc::c_int);
+                } else {
+                    return Err(CreationError::NotSupported);
+                }
+            }
+
+            if builder.gl_debug {
+                attributes.push(gl::wgl_extra::CONTEXT_FLAGS_ARB as libc::c_int);
+                attributes.push(gl::wgl_extra::CONTEXT_DEBUG_BIT_ARB as libc::c_int);
+            }
+
+            attributes.push(0);
+
+            Some(extra_functions.CreateContextAttribsARB(hdc as *const libc::c_void,
+                                                         share as *const libc::c_void,
+                                                         attributes.as_ptr()))
+
+        } else {
+            None
+        }
+    } else {
+        None
+    };
+
+    let ctxt = match ctxt {
+        Some(ctxt) => ctxt,
+        None => {
+            let ctxt = gl::wgl::CreateContext(hdc as *const libc::c_void);
+            if !ctxt.is_null() && !share.is_null() {
+                gl::wgl::ShareLists(share as *const libc::c_void, ctxt);
+            };
+            ctxt
+        }
+    };
+
+    if ctxt.is_null() {
+        return Err(CreationError::OsError(format!("OpenGL context creation failed: {}",
+                                                  format!("{}", io::Error::last_os_error()))));
+    }
+
+    Ok(ContextWrapper(ctxt as winapi::HGLRC))
+}
+
+unsafe fn enumerate_native_pixel_formats(hdc: winapi::HDC) -> Vec<(PixelFormat, libc::c_int)> {
+    let size_of_pxfmtdescr = mem::size_of::<winapi::PIXELFORMATDESCRIPTOR>() as u32;
+    let num = gdi32::DescribePixelFormat(hdc, 1, size_of_pxfmtdescr, ptr::null_mut());
+
+    let mut result = Vec::new();
+
+    for index in (0 .. num) {
+        let mut output: winapi::PIXELFORMATDESCRIPTOR = mem::zeroed();
+        
+        if gdi32::DescribePixelFormat(hdc, index, size_of_pxfmtdescr, &mut output) == 0 {
+            continue;
+        }
+
+        if (output.dwFlags & winapi::PFD_DRAW_TO_WINDOW) == 0 {
+            continue;
+        }
+
+        if (output.dwFlags & winapi::PFD_SUPPORT_OPENGL) == 0 {
+            continue;
+        }
+
+        if output.iPixelType != winapi::PFD_TYPE_RGBA {
+            continue;
+        }
+
+        result.push((PixelFormat {
+            hardware_accelerated: (output.dwFlags & winapi::PFD_GENERIC_FORMAT) == 0,
+            color_bits: output.cRedBits + output.cGreenBits + output.cBlueBits,
+            alpha_bits: output.cAlphaBits,
+            depth_bits: output.cDepthBits,
+            stencil_bits: output.cStencilBits,
+            stereoscopy: (output.dwFlags & winapi::PFD_STEREO) != 0,
+            double_buffer: (output.dwFlags & winapi::PFD_DOUBLEBUFFER) != 0,
+            multisampling: None,
+            srgb: false,
+        }, index));
+    }
+
+    result
+}
+
+unsafe fn enumerate_arb_pixel_formats(extra: &gl::wgl_extra::Wgl, hdc: winapi::HDC)
+                                      -> Vec<(PixelFormat, libc::c_int)>
+{
+    let get_info = |index: u32, attrib: u32| {
+        let mut value = mem::uninitialized();
+        extra.GetPixelFormatAttribivARB(hdc as *const _, index as libc::c_int,
+                                        0, 1, [attrib as libc::c_int].as_ptr(),
+                                        &mut value);
+        value as u32
+    };
+
+    // getting the number of formats
+    // the `1` is ignored
+    let num = get_info(1, gl::wgl_extra::NUMBER_PIXEL_FORMATS_ARB);
+
+    let mut result = Vec::new();
+
+    for index in (0 .. num) {
+        if get_info(index, gl::wgl_extra::DRAW_TO_WINDOW_ARB) == 0 {
+            continue;
+        }
+        if get_info(index, gl::wgl_extra::SUPPORT_OPENGL_ARB) == 0 {
+            continue;
+        }
+
+        if get_info(index, gl::wgl_extra::ACCELERATION_ARB) == gl::wgl_extra::NO_ACCELERATION_ARB {
+            continue;
+        }
+
+        if get_info(index, gl::wgl_extra::PIXEL_TYPE_ARB) != gl::wgl_extra::TYPE_RGBA_ARB {
+            continue;
+        }
+
+        result.push((PixelFormat {
+            hardware_accelerated: true,
+            color_bits: get_info(index, gl::wgl_extra::RED_BITS_ARB) as u8 + 
+                        get_info(index, gl::wgl_extra::GREEN_BITS_ARB) as u8 +
+                        get_info(index, gl::wgl_extra::BLUE_BITS_ARB) as u8,
+            alpha_bits: get_info(index, gl::wgl_extra::ALPHA_BITS_ARB) as u8,
+            depth_bits: get_info(index, gl::wgl_extra::DEPTH_BITS_ARB) as u8,
+            stencil_bits: get_info(index, gl::wgl_extra::STENCIL_BITS_ARB) as u8,
+            stereoscopy: get_info(index, gl::wgl_extra::STEREO_ARB) != 0,
+            double_buffer: get_info(index, gl::wgl_extra::DOUBLE_BUFFER_ARB) != 0,
+            multisampling: {
+                if is_extension_supported(extra, hdc, "WGL_ARB_multisample") {
+                    match get_info(index, gl::wgl_extra::SAMPLES_ARB) {
+                        0 => None,
+                        a => Some(a as u16),
+                    }
+                } else {
+                    None
+                }
+            },
+            srgb: if is_extension_supported(extra, hdc, "WGL_ARB_framebuffer_sRGB") {
+                get_info(index, gl::wgl_extra::FRAMEBUFFER_SRGB_CAPABLE_ARB) != 0
+            } else if is_extension_supported(extra, hdc, "WGL_EXT_framebuffer_sRGB") {
+                get_info(index, gl::wgl_extra::FRAMEBUFFER_SRGB_CAPABLE_EXT) != 0
+            } else {
+                false
+            },
+        }, index as libc::c_int));
+    }
+
+    result
+}
+
+unsafe fn set_pixel_format(hdc: winapi::HDC, id: libc::c_int) -> Result<(), CreationError> {
+    let mut output: winapi::PIXELFORMATDESCRIPTOR = mem::zeroed();
+
+    if gdi32::DescribePixelFormat(hdc, id, mem::size_of::<winapi::PIXELFORMATDESCRIPTOR>()
+                                  as winapi::UINT, &mut output) == 0
+    {
+        return Err(CreationError::OsError(format!("DescribePixelFormat function failed: {}",
+                                                  format!("{}", io::Error::last_os_error()))));
+    }
+
+    if gdi32::SetPixelFormat(hdc, id, &output) == 0 {
+        return Err(CreationError::OsError(format!("SetPixelFormat function failed: {}",
+                                                  format!("{}", io::Error::last_os_error()))));
+    }
+
+    Ok(())
+}
+
+unsafe fn load_opengl32_dll() -> Result<winapi::HMODULE, CreationError> {
+    let name = OsStr::new("opengl32.dll").encode_wide().chain(Some(0).into_iter())
+                                         .collect::<Vec<_>>();
+
+    let lib = kernel32::LoadLibraryW(name.as_ptr());
+
+    if lib.is_null() {
+        return Err(CreationError::OsError(format!("LoadLibrary function failed: {}",
+                                                  format!("{}", io::Error::last_os_error()))));
+    }
+
+    Ok(lib)
+}
+
+unsafe fn is_extension_supported(extra: &gl::wgl_extra::Wgl, hdc: winapi::HDC,
+                                 extension: &str) -> bool
+{
+    let extensions = if extra.GetExtensionsStringARB.is_loaded() {
+        let data = extra.GetExtensionsStringARB(hdc as *const _);
+        let data = CStr::from_ptr(data).to_bytes().to_vec();
+        String::from_utf8(data).unwrap()
+
+    } else if extra.GetExtensionsStringEXT.is_loaded() {
+        let data = extra.GetExtensionsStringEXT();
+        let data = CStr::from_ptr(data).to_bytes().to_vec();
+        String::from_utf8(data).unwrap()
+
+    } else {
+        return false;
+    };
+
+    extensions.split(" ").find(|&e| e == extension).is_some()
+}
+
+fn choose_dummy_pixel_format<I>(iter: I) -> Result<libc::c_int, CreationError>
+                                where I: Iterator<Item=(PixelFormat, libc::c_int)>
+{
+    let mut backup_id = None;
+
+    for (format, id) in iter {
+        if backup_id.is_none() {
+            backup_id = Some(id);
+        }
+
+        if format.hardware_accelerated {
+            return Ok(id);
+        }
+    }
+
+    backup_id.ok_or(CreationError::NotSupported)
+}