Add support for specific OpenGL version for Win32

3 files changed, 34 insertions, 4 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 88ef43c..356dbd5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -29,6 +29,7 @@ pub struct WindowBuilder {
     dimensions: (uint, uint),
     title: String,
     monitor: Option<winimpl::MonitorID>,
+    gl_version: Option<(uint, uint)>,
 }
 
 impl WindowBuilder {
@@ -38,6 +39,7 @@ impl WindowBuilder {
             dimensions: (1024, 768),
             title: String::new(),
             monitor: None,
+            gl_version: None,
         }
     }
 
@@ -57,6 +59,15 @@ impl WindowBuilder {
         self
     }
 
+    /// Requests to use a specific OpenGL version.
+    ///
+    /// Version is a (major, minor) pair. For example to request OpenGL 3.3
+    ///  you would pass `(3, 3)`.
+    pub fn with_gl_version(mut self, version: (uint, uint)) -> WindowBuilder {
+        self.gl_version = Some(version);
+        self
+    }
+
     /// Builds the window.
     /// 
     /// Error should be very rare and only occur in case of permission denied, incompatible system,
diff --git a/src/win32/ffi.rs b/src/win32/ffi.rs
index a217e20..73ade51 100644
--- a/src/win32/ffi.rs
+++ b/src/win32/ffi.rs
@@ -365,6 +365,17 @@ pub static VK_NONAME: WPARAM = 0xFC;
 pub static VK_PA1: WPARAM = 0xFD;
 pub static VK_OEM_CLEAR: WPARAM = 0xFE;
 
+// ?
+pub static WGL_CONTEXT_DEBUG_BIT_ARB: libc::c_int = 0x00000001;
+pub static WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB: libc::c_int = 0x00000002;
+pub static WGL_CONTEXT_MAJOR_VERSION_ARB: libc::c_int = 0x2091;
+pub static WGL_CONTEXT_MINOR_VERSION_ARB: libc::c_int = 0x2092;
+pub static WGL_CONTEXT_LAYER_PLANE_ARB: libc::c_int = 0x2093;
+pub static WGL_CONTEXT_FLAGS_ARB: libc::c_int = 0x2094;
+pub static WGL_CONTEXT_PROFILE_MASK_ARB: libc::c_int = 0x9126;
+pub static WGL_CONTEXT_CORE_PROFILE_BIT_ARB: libc::c_int = 0x00000001;
+pub static WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB: libc::c_int = 0x00000002;
+
 // messages
 pub static WM_LBUTTONDOWN: UINT = 0x0201;
 pub static WM_LBUTTONUP: UINT = 0x0202;
diff --git a/src/win32/init.rs b/src/win32/init.rs
index c4d31da..09df5b0 100644
--- a/src/win32/init.rs
+++ b/src/win32/init.rs
@@ -250,14 +250,22 @@ pub fn new_window(builder: WindowBuilder) -> Result<Window, String> {
         let context = {
             use libc;
 
-            let attributes: [libc::c_int, ..1] = [
-                0
-            ];
+            let mut attributes = Vec::new();
+
+            if builder.gl_version.is_some() {
+                let version = builder.gl_version.as_ref().unwrap();
+                attributes.push(ffi::WGL_CONTEXT_MAJOR_VERSION_ARB);
+                attributes.push(version.val0() as libc::c_int);
+                attributes.push(ffi::WGL_CONTEXT_MINOR_VERSION_ARB);
+                attributes.push(version.val1() as libc::c_int);
+            }
+
+            attributes.push(0);
 
             let ctxt = unsafe {
                 match create_context_attribs {
                     None => ffi::wglCreateContext(hdc),
-                    Some(ptr) => ptr(hdc, ptr::mut_null(), attributes.as_ptr())
+                    Some(ptr) => ptr(hdc, ptr::mut_null(), attributes.as_slice().as_ptr())
                 }
             };