Add support for sRGB attribute and fix creation on windows

build.rs

@@ -31,6 +31,7 @@ fn main() {
                                             "WGL_ARB_pixel_format".to_string(),
                                             "WGL_EXT_create_context_es2_profile".to_string(),
                                             "WGL_EXT_extensions_string".to_string(),
+                                            "WGL_EXT_framebuffer_sRGB".to_string(),
                                             "WGL_EXT_swap_control".to_string(),
                                         ],
                                         "1.0", "core", &mut file).unwrap();

src/lib.rs

@@ -253,6 +253,7 @@ pub struct BuilderAttribs<'a> {
     color_bits: Option<u8>,
     alpha_bits: Option<u8>,
     stereoscopy: bool,
+    srgb: Option<bool>,
 }
 
 impl BuilderAttribs<'static> {
@@ -274,6 +275,7 @@ impl BuilderAttribs<'static> {
             color_bits: None,
             alpha_bits: None,
             stereoscopy: false,
+            srgb: None,
         }
     }
 }
@@ -299,6 +301,7 @@ impl<'a> BuilderAttribs<'a> {
             color_bits: self.color_bits,
             alpha_bits: self.alpha_bits,
             stereoscopy: self.stereoscopy,
+            srgb: self.srgb,
         };
 
         (new_attribs, sharing)
@@ -332,6 +335,16 @@ impl<'a> BuilderAttribs<'a> {
                 continue;
             }
 
+            if self.multisampling.is_some() && format.multisampling.is_none() {
+                continue;
+            }
+
+            if let Some(srgb) = self.srgb {
+                if srgb != format.srgb {
+                    continue;
+                }
+            }
+
             current_software_result = Some((id.clone(), format.clone()));
             if format.hardware_accelerated {
                 current_result = Some((id, format));

src/win32/init.rs

@@ -140,7 +140,7 @@ unsafe fn init(title: Vec<u16>, builder: BuilderAttribs<'static>,
         // getting the pixel format that we will use and setting it
         {
             let formats = enumerate_native_pixel_formats(&dummy_window);
-            let (id, _) = try!(builder.choose_pixel_format(formats.into_iter().map(|(a, b)| (b, a))));
+            let id = try!(choose_dummy_pixel_format(formats.into_iter()));
             try!(set_pixel_format(&dummy_window, id));
         }
 
@@ -502,6 +502,8 @@ unsafe fn enumerate_arb_pixel_formats(extra: &gl::wgl_extra::Wgl, hdc: &WindowWr
             },
             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
             },
@@ -562,3 +564,21 @@ unsafe fn is_extension_supported(extra: &gl::wgl_extra::Wgl, hdc: &WindowWrapper
 
     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)
+}

src/window.rs

@@ -129,6 +129,12 @@ impl<'a> WindowBuilder<'a> {
         self
     }
 
+    /// Sets whether sRGB should be enabled on the window. `None` means "I don't care".
+    pub fn with_srgb(mut self, srgb_enabled: Option<bool>) -> WindowBuilder<'a> {
+        self.attribs.srgb = srgb_enabled;
+        self
+    }
+
     /// Builds the window.
     ///
     /// Error should be very rare and only occur in case of permission denied, incompatible system,