Added method OpenGLContext::deactivateCurrentContext().

modules/juce_opengl/native/juce_OpenGL_android.h

@@ -68,6 +68,7 @@ public:
 
     bool makeActive() const noexcept            { return isInsideGLCallback; }
     bool isActive() const noexcept              { return isInsideGLCallback; }
+    static void deactivateCurrentContext()      {}
 
     void swapBuffers() const noexcept           {}
     bool setSwapInterval (const int)            { return false; }

modules/juce_opengl/native/juce_OpenGL_ios.h

@@ -81,7 +81,7 @@ public:
         // so causes myserious timing-related failures.
         [EAGLContext setCurrentContext: context];
         createGLBuffers();
-        [EAGLContext setCurrentContext: nil];
+        deactivateCurrentContext();
     }
 
     ~NativeContext()
@@ -119,6 +119,11 @@ public:
         return [EAGLContext currentContext] == context;
     }
 
+    static void deactivateCurrentContext()
+    {
+        [EAGLContext setCurrentContext: nil];
+    }
+
     void swapBuffers()
     {
         glBindRenderbuffer (GL_RENDERBUFFER, colorBufferHandle);

modules/juce_opengl/native/juce_OpenGL_linux.h

@@ -114,7 +114,7 @@ public:
 
     void shutdownOnRenderThread()
     {
-        glXMakeCurrent (display, None, 0);
+        deactivateCurrentContext();
         glXDestroyContext (display, renderContext);
         renderContext = nullptr;
     }
@@ -130,6 +130,11 @@ public:
         return glXGetCurrentContext() == renderContext && renderContext != 0;
     }
 
+    static void deactivateCurrentContext()
+    {
+        glXMakeCurrent (display, None, 0);
+    }
+
     void swapBuffers()
     {
         glXSwapBuffers (display, embeddedWindow);

modules/juce_opengl/native/juce_OpenGL_osx.h

@@ -185,6 +185,11 @@ public:
         return [NSOpenGLContext currentContext] == renderContext;
     }
 
+    static void deactivateCurrentContext()
+    {
+        [NSOpenGLContext clearCurrentContext];
+    }
+
     struct Locker
     {
         Locker (NativeContext& nc) : cglContext ((CGLContextObj) [nc.renderContext CGLContextObj])

modules/juce_opengl/native/juce_OpenGL_win32.h

@@ -50,7 +50,7 @@ public:
             initialiseGLExtensions();
 
             const int wglFormat = wglChoosePixelFormatExtension (pixelFormat);
-            wglMakeCurrent (0, 0);
+            deactivateCurrentContext();
 
             if (wglFormat != pixFormat && wglFormat != 0)
             {
@@ -84,6 +84,7 @@ public:
     void initialiseOnRenderThread() {}
     void shutdownOnRenderThread() {}
 
+    static void deactivateCurrentContext()  { wglMakeCurrent (0, 0); }
     bool makeActive() const noexcept        { return wglMakeCurrent (dc, renderContext) != FALSE; }
     bool isActive() const noexcept          { return wglGetCurrentContext() == renderContext; }
     void swapBuffers() const noexcept       { SwapBuffers (dc); }

modules/juce_opengl/opengl/juce_OpenGLContext.cpp

@@ -545,6 +545,7 @@ OpenGLContext* OpenGLContext::getCurrentContext()
 
 bool OpenGLContext::makeActive() const noexcept     { return nativeContext != nullptr && nativeContext->makeActive(); }
 bool OpenGLContext::isActive() const noexcept       { return nativeContext != nullptr && nativeContext->isActive(); }
+void OpenGLContext::deactivateCurrentContext()      { NativeContext::deactivateCurrentContext(); }
 
 void OpenGLContext::triggerRepaint()
 {

modules/juce_opengl/opengl/juce_OpenGLContext.h

@@ -176,6 +176,11 @@ public:
     /** Returns true if this context is currently active for the calling thread. */
     bool isActive() const noexcept;
 
+    /** If any context is active on the current thread, this deactivates it.
+        Note that on some platforms, like Android, this isn't possible.
+    */
+    static void deactivateCurrentContext();
+
     //==============================================================================
     /** Swaps the buffers (if the context can do this).
         There's normally no need to call this directly - the buffers will be swapped