Introduce nwindowGetDefault

nx/include/switch/display/native_window.h

@@ -43,6 +43,17 @@ typedef struct NWindow {
 /// Checks whether a pointer refers to a valid \ref NWindow object.
 bool nwindowIsValid(NWindow* nw);
 
+/**
+ * @brief Retrieves the default \ref NWindow object.
+ * @return Pointer to the default \ref NWindow object.
+ * @note When this function is used/referenced, libnx will initialize VI services
+ *       and create a \ref NWindow object from a \ref ViLayer created on the default \ref ViDisplay;
+ *       all of this happening automatically during application startup (i.e. before main is called).
+ *       If creating the default \ref NWindow fails, libnx will throw a LibnxError_BadGfxInit fatal error.
+ *       Likewise, after main returns (or exit is called) libnx will clean up all resources used by it.
+ */
+NWindow* nwindowGetDefault(void);
+
 /**
  * @brief Creates a \ref NWindow.
  * @param[out] nw Output \ref NWindow structure.

nx/source/display/default_window.c

@@ -0,0 +1,51 @@
+#include <string.h>
+#include "types.h"
+#include "result.h"
+#include "services/vi.h"
+#include "services/fatal.h"
+#include "display/binder.h"
+#include "display/buffer_producer.h"
+#include "display/native_window.h"
+#include "nvidia/graphic_buffer.h"
+
+static ViDisplay g_viDisplay;
+static ViLayer g_viLayer;
+static NWindow g_defaultWin;
+
+NWindow* nwindowGetDefault(void)
+{
+    return &g_defaultWin;
+}
+
+void __nx_win_init(void)
+{
+    Result rc;
+    rc = viInitialize(ViServiceType_Default);
+    if (R_SUCCEEDED(rc)) {
+        rc = viOpenDefaultDisplay(&g_viDisplay);
+        if (R_SUCCEEDED(rc)) {
+            rc = viCreateLayer(&g_viDisplay, &g_viLayer);
+            if (R_SUCCEEDED(rc)) {
+                rc = viSetLayerScalingMode(&g_viLayer, ViScalingMode_FitToLayer);
+                if (R_SUCCEEDED(rc))
+                    rc = nwindowCreateFromLayer(&g_defaultWin, &g_viLayer);
+                if (R_FAILED(rc))
+                    viCloseLayer(&g_viLayer);
+            }
+            if (R_FAILED(rc))
+                viCloseDisplay(&g_viDisplay);
+        }
+        if (R_FAILED(rc))
+            viExit();
+    }
+    if (R_FAILED(rc))
+        fatalSimple(MAKERESULT(Module_Libnx, LibnxError_BadGfxInit));
+}
+
+void __nx_win_exit(void)
+{
+    nwindowClose(&g_defaultWin);
+    viCloseLayer(&g_viLayer);
+    viCloseDisplay(&g_viDisplay);
+    viExit();
+}

nx/source/runtime/init.c

@@ -95,6 +95,7 @@ void __attribute__((weak)) __libnx_initheap(void)
     fake_heap_end   = (char*)addr + size;
 }
 
+void __attribute__((weak)) __nx_win_init(void);
 void __attribute__((weak)) userAppInit(void);
 
 void __attribute__((weak)) __appInit(void)
@@ -128,14 +129,18 @@ void __attribute__((weak)) __appInit(void)
 
     fsdevMountSdmc();
 
+    if (&__nx_win_init) __nx_win_init();
     if (&userAppInit) userAppInit();
 }
 
 void __attribute__((weak)) userAppExit(void);
+void __attribute__((weak)) __nx_win_exit(void);
 
 void __attribute__((weak)) __appExit(void)
 {
     if (&userAppExit) userAppExit();
+    if (&__nx_win_exit) __nx_win_exit();
+
     // Cleanup default services.
     fsdevUnmountAll();
     fsExit();