Added method allowing external OpenGL rendering on-top of raylib

src/core.c

@@ -1263,7 +1263,7 @@ void BeginDrawing(void)
 }
 
 // End canvas drawing and swap buffers (double buffering)
-void EndDrawing(void)
+void EndDrawingEx(void(*fn)())
 {
 #if defined(PLATFORM_RPI) && defined(SUPPORT_MOUSE_CURSOR_RPI)
     // On RPI native mode we have no system mouse cursor, so,
@@ -1273,6 +1273,9 @@ void EndDrawing(void)
 
     rlglDraw();                     // Draw Buffers (Only OpenGL 3+ and ES2)
 
+    if (fn != NULL)
+        fn();
+
 #if defined(SUPPORT_GIF_RECORDING)
     #define GIF_RECORD_FRAMERATE    10
 
@@ -1324,6 +1327,12 @@ void EndDrawing(void)
     }
 }
 
+// End canvas drawing and swap buffers (double buffering)
+void EndDrawing()
+{
+    return EndDrawingEx(NULL);
+}
+
 // Initialize 2D mode with custom camera (2D)
 void BeginMode2D(Camera2D camera)
 {

src/raylib.h

@@ -909,7 +909,8 @@ RLAPI void DisableCursor(void);                                   // Disables cu
 // Drawing-related functions
 RLAPI void ClearBackground(Color color);                          // Set background color (framebuffer clear color)
 RLAPI void BeginDrawing(void);                                    // Setup canvas (framebuffer) to start drawing
-RLAPI void EndDrawing(void);                                      // End canvas drawing and swap buffers (double buffering)
+RLAPI void EndDrawingEx(void(*fn)());                               // End canvas drawing and swap buffers (double buffering). This method adds a spot for additional rendering on-top of Raylib render.
+RLAPI void EndDrawing();                                          // End canvas drawing and swap buffers (double buffering)
 RLAPI void BeginMode2D(Camera2D camera);                          // Initialize 2D mode with custom camera (2D)
 RLAPI void EndMode2D(void);                                       // Ends 2D mode with custom camera
 RLAPI void BeginMode3D(Camera3D camera);                          // Initializes 3D mode with custom camera (3D)