Add GLFW_OCCLUDED window attribute

docs/window.dox

@@ -1150,6 +1150,12 @@ void window_occlusion_callback(GLFWwindow* window, int occluded)
 }
 @endcode
 
+You can also get the current occlusion state with @ref glfwGetWindowAttrib.
+
+@code
+int occluded = glfwGetWindowAttrib(window, GLFW_OCCLUDED);
+@endcode
+
 @note This is currently implemented on macOS only.
 
 
@@ -1289,6 +1295,10 @@ for details.
 __GLFW_VISIBLE__ indicates whether the specified window is visible.  See @ref
 window_hide for details.
 
+@anchor GLFW_OCCLUDED_attrib
+__GLFW_OCCLUDED__ indicates whether the specified window is occluded.
+See @ref window_occlusion for details.
+
 @anchor GLFW_RESIZABLE_attrib
 __GLFW_RESIZABLE__ indicates whether the specified window is resizable _by the
 user_.  This can be set before creation with the

include/GLFW/glfw3.h

@@ -825,6 +825,11 @@ extern "C" {
  *  [window attribute](@ref GLFW_FOCUS_ON_SHOW_attrib).
  */
 #define GLFW_FOCUS_ON_SHOW          0x0002000C
+/*! @brief Occlusion window attribute
+ *
+ *  Occlusion [window attribute](@ref GLFW_OCCLUDED_attrib).
+ */
+#define GLFW_OCCLUDED               0x0002000D
 
 /*! @brief Framebuffer bit depth hint.
  *

src/cocoa_window.m

@@ -1515,6 +1515,11 @@ int _glfwPlatformWindowFocused(_GLFWwindow* window)
     return [window->ns.object isKeyWindow];
 }
 
+int _glfwPlatformWindowOccluded(_GLFWwindow* window)
+{
+    return !([window->ns.object occlusionState] & NSWindowOcclusionStateVisible);
+}
+
 int _glfwPlatformWindowIconified(_GLFWwindow* window)
 {
     return [window->ns.object isMiniaturized];

src/internal.h

@@ -657,6 +657,7 @@ void _glfwPlatformSetWindowMonitor(_GLFWwindow* window, _GLFWmonitor* monitor,
                                    int xpos, int ypos, int width, int height,
                                    int refreshRate);
 int _glfwPlatformWindowFocused(_GLFWwindow* window);
+int _glfwPlatformWindowOccluded(_GLFWwindow* window);
 int _glfwPlatformWindowIconified(_GLFWwindow* window);
 int _glfwPlatformWindowVisible(_GLFWwindow* window);
 int _glfwPlatformWindowMaximized(_GLFWwindow* window);

src/null_window.c

@@ -222,6 +222,11 @@ int _glfwPlatformWindowFocused(_GLFWwindow* window)
     return GLFW_FALSE;
 }
 
+int _glfwPlatformWindowOccluded(_GLFWwindow* window)
+{
+    return GLFW_FALSE;
+}
+
 int _glfwPlatformWindowIconified(_GLFWwindow* window)
 {
     return GLFW_FALSE;

src/win32_window.c

@@ -1760,6 +1760,11 @@ int _glfwPlatformWindowFocused(_GLFWwindow* window)
     return window->win32.handle == GetActiveWindow();
 }
 
+int _glfwPlatformWindowOccluded(_GLFWwindow* window)
+{
+    return GLFW_FALSE;
+}
+
 int _glfwPlatformWindowIconified(_GLFWwindow* window)
 {
     return IsIconic(window->win32.handle);

src/window.c

@@ -832,6 +832,8 @@ GLFWAPI int glfwGetWindowAttrib(GLFWwindow* handle, int attrib)
             return window->focusOnShow;
         case GLFW_TRANSPARENT_FRAMEBUFFER:
             return _glfwPlatformFramebufferTransparent(window);
+        case GLFW_OCCLUDED:
+            return _glfwPlatformWindowOccluded(window);
         case GLFW_RESIZABLE:
             return window->resizable;
         case GLFW_DECORATED:

src/wl_window.c

@@ -1243,6 +1243,11 @@ int _glfwPlatformWindowFocused(_GLFWwindow* window)
     return _glfw.wl.keyboardFocus == window;
 }
 
+int _glfwPlatformWindowOccluded(_GLFWwindow* window)
+{
+    return GLFW_FALSE;
+}
+
 int _glfwPlatformWindowIconified(_GLFWwindow* window)
 {
     // wl_shell doesn't have any iconified concept, and xdg-shell doesn’t give

src/x11_window.c

@@ -2433,6 +2433,11 @@ int _glfwPlatformWindowFocused(_GLFWwindow* window)
     return window->x11.handle == focused;
 }
 
+int _glfwPlatformWindowOccluded(_GLFWwindow* window)
+{
+    return GLFW_FALSE;
+}
+
 int _glfwPlatformWindowIconified(_GLFWwindow* window)
 {
     return getWindowState(window) == IconicState;