Added glfwCopyGLState.

include/GL/glfw3.h

@@ -583,6 +583,7 @@ GLFWAPI void  glfwSwapInterval(int interval);
 GLFWAPI int   glfwExtensionSupported(const char* extension);
 GLFWAPI void* glfwGetProcAddress(const char* procname);
 GLFWAPI void  glfwGetGLVersion(int* major, int* minor, int* rev);
+GLFWAPI void  glfwCopyGLState(GLFWwindow src, GLFWwindow dst, unsigned long mask);
 
 /* Enable/disable functions */
 GLFWAPI void glfwEnable(GLFWwindow window, int token);

readme.html

@@ -273,6 +273,7 @@ version of GLFW.</p>
   <li>Added <code>glfwSetWindowIconifyCallback</code> function and <code>GLFWwindowiconifyfun</code> type for receiving window iconification events</li>
   <li>Added <code>glfwGetCurrentWindow</code> function for retrieving the window whose OpenGL context is current</li>
   <li>Added <code>glfwInitWithModels</code> function and <code>GLFWallocator</code> and <code>GLFWthreadmodel</code> types for pluggable memory allocation and threading models</li>
+  <li>Added <code>glfwCopyGLState</code> function for copying OpenGL state categories between contexts</li>
   <li>Added <code>GLFW_OPENGL_ES2_PROFILE</code> profile for creating OpenGL ES 2.0 contexts using the <code>GLX_EXT_create_context_es2_profile</code> and <code>WGL_EXT_create_context_es2_profile</code> extensions</li>
   <li>Added <code>GLFW_OPENGL_ROBUSTNESS</code> window hint and associated strategy tokens for <code>GL_ARB_robustness</code> support</li>
   <li>Added <code>windows</code> simple multi-window test program</li>

src/cocoa/cocoa_opengl.m

@@ -86,3 +86,12 @@ void* _glfwPlatformGetProcAddress(const char* procname)
     return symbol;
 }
 
+//========================================================================
+// Copies the specified OpenGL state categories from src to dst
+//========================================================================
+
+void _glfwPlatformCopyGLState(_GLFWwindow* src, _GLFWwindow* dst, unsigned long mask)
+{
+    [dst->NSGL.context copyAttributesFromContext:src->NSGL.context withMask:mask];
+}
+

src/internal.h

@@ -310,6 +310,7 @@ void _glfwPlatformSwapInterval(int interval);
 void _glfwPlatformRefreshWindowParams(void);
 int  _glfwPlatformExtensionSupported(const char* extension);
 void* _glfwPlatformGetProcAddress(const char* procname);
+void _glfwPlatformCopyGLState(_GLFWwindow* src, _GLFWwindow* dst, unsigned long mask);
 
 
 //========================================================================

src/opengl.c

@@ -587,3 +587,25 @@ GLFWAPI void glfwGetGLVersion(int* major, int* minor, int* rev)
         *rev = window->glRevision;
 }
 
+
+//========================================================================
+// Copies the specified OpenGL state categories from src to dst
+//========================================================================
+
+GLFWAPI void glfwCopyGLState(GLFWwindow hsrc, GLFWwindow hdst, unsigned long mask)
+{
+    _GLFWwindow* src;
+    _GLFWwindow* dst;
+
+    if (!_glfwInitialized)
+    {
+        _glfwSetError(GLFW_NOT_INITIALIZED, NULL);
+        return;
+    }
+
+    src = (_GLFWwindow*) hsrc;
+    dst = (_GLFWwindow*) hdst;
+
+    _glfwPlatformCopyGLState(src, dst, mask);
+}
+

src/win32/win32_opengl.c

@@ -103,3 +103,14 @@ void* _glfwPlatformGetProcAddress(const char* procname)
     return (void*) wglGetProcAddress(procname);
 }
 
+
+//========================================================================
+// Copies the specified OpenGL state categories from src to dst
+//========================================================================
+
+void _glfwPlatformCopyGLState(_GLFWwindow* src, _GLFWwindow* dst, unsigned long mask)
+{
+    if (!wglCopyContext(src->WGL.context, dst->WGL.context, mask))
+        _glfwSetError(GLFW_PLATFORM_ERROR, "Win32/WGL: Failed to copy OpenGL context attributes");
+}
+

src/x11/x11_opengl.c

@@ -116,3 +116,16 @@ void* _glfwPlatformGetProcAddress(const char* procname)
     return (void*) _glfw_glXGetProcAddress((const GLubyte*) procname);
 }
 
+
+//========================================================================
+// Copies the specified OpenGL state categories from src to dst
+//========================================================================
+
+void _glfwPlatformCopyGLState(_GLFWwindow* src, _GLFWwindow* dst, unsigned long mask)
+{
+    glXCopyContext(_glfwLibrary.X11.display,
+                   src->GLX.context,
+                   dst->GLX.context,
+                   mask);
+}
+