- Implemented BGFX_CAPS_SWAP_CHAIN in OpenGl on Macos (#2400)

src/glcontext_nsgl.mm

@@ -21,22 +21,119 @@ namespace bgfx { namespace gl
 
 	struct SwapChainGL
 	{
-		SwapChainGL(void* _nwh)
+		SwapChainGL(void* _nwh,NSOpenGLContext *_context)
 		{
-			BX_UNUSED(_nwh);
+			NSObject* nwh=(NSObject*)_nwh;
+
+			NSWindow* nsWindow = nil;
+			NSView* contentView = nil;
+			if ([nwh isKindOfClass:[NSView class]])
+			{
+				contentView = (NSView*)nwh;
+			}
+			else if ([nwh isKindOfClass:[NSWindow class]])
+			{
+				nsWindow = (NSWindow*)nwh;
+				contentView = [nsWindow contentView];
+			}
+
+#if defined(MAC_OS_X_VERSION_MAX_ALLOWED) && (MAC_OS_X_VERSION_MAX_ALLOWED >= 1070)
+			NSOpenGLPixelFormatAttribute profile =
+#if BGFX_CONFIG_RENDERER_OPENGL >= 31
+				NSOpenGLProfileVersion3_2Core
+#else
+				NSOpenGLProfileVersionLegacy
+#endif // BGFX_CONFIG_RENDERER_OPENGL >= 31
+				;
+#endif // defined(MAC_OS_X_VERSION_MAX_ALLOWED) && (MAC_OS_X_VERSION_MAX_ALLOWED >= 1070)
+
+			NSOpenGLPixelFormatAttribute pixelFormatAttributes[] = {
+#if defined(MAC_OS_X_VERSION_MAX_ALLOWED) && (MAC_OS_X_VERSION_MAX_ALLOWED >= 1070)
+				NSOpenGLPFAOpenGLProfile, profile,
+#endif // defined(MAC_OS_X_VERSION_MAX_ALLOWED) && (MAC_OS_X_VERSION_MAX_ALLOWED >= 1070)
+				NSOpenGLPFAColorSize,     24,
+				NSOpenGLPFAAlphaSize,     8,
+				NSOpenGLPFADepthSize,     24,
+				NSOpenGLPFAStencilSize,   8,
+				NSOpenGLPFADoubleBuffer,  true,
+				NSOpenGLPFAAccelerated,   true,
+				NSOpenGLPFANoRecovery,    true,
+				0,                        0,
+			};
+
+			NSOpenGLPixelFormat* pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:pixelFormatAttributes];
+			BGFX_FATAL(NULL != pixelFormat, Fatal::UnableToInitialize, "Failed to initialize pixel format.");
+
+			NSRect glViewRect = [contentView bounds];
+			NSOpenGLView* glView = [[NSOpenGLView alloc] initWithFrame:glViewRect pixelFormat:pixelFormat];
+
+
+			// GLFW creates a helper contentView that handles things like keyboard and drag and
+			// drop events. We don't want to clobber that view if it exists. Instead we just
+			// add ourselves as a subview and make the view resize automatically.
+			if (nil != contentView)
+			{
+				[glView setAutoresizingMask:( NSViewHeightSizable |
+						NSViewWidthSizable |
+						NSViewMinXMargin |
+						NSViewMaxXMargin |
+						NSViewMinYMargin |
+						NSViewMaxYMargin )];
+				[contentView addSubview:glView];
+			}
+			else
+			{
+				if (nil != nsWindow)
+					[nsWindow setContentView:glView];
+			}
+
+			NSOpenGLContext* glContext = [[NSOpenGLContext alloc] initWithFormat:pixelFormat shareContext:_context];
+			BGFX_FATAL(NULL != glContext, Fatal::UnableToInitialize, "Failed to initialize GL context.");
+
+			void (^attachBlock)(void) = ^(void) {
+				[glView setOpenGLContext: glContext];
+				[glContext setView:glView];
+			};
+
+			if([NSThread isMainThread])
+			{
+				attachBlock();
+			}
+			else
+			{
+				dispatch_sync(dispatch_get_main_queue(),attachBlock);
+			}
+
+			[pixelFormat release];
+
+			[glContext makeCurrentContext];
+			GLint interval = 0;
+			[glContext setValues:&interval forParameter:NSOpenGLCPSwapInterval];
+
+
+			m_view    = glView;
+			m_context = glContext;
 		}
 
 		~SwapChainGL()
 		{
+			if(m_context!=nil) [m_context release];
+			if(m_view!=nil) [m_view release];
 		}
 
 		void makeCurrent()
 		{
+			[m_context makeCurrentContext];
 		}
 
 		void swapBuffers()
 		{
+			[m_context makeCurrentContext];
+			[m_context flushBuffer];
 		}
+
+		NSOpenGLView *m_view;
+		NSOpenGLContext *m_context;
 	};
 
 	class AutoreleasePoolHolder
@@ -202,12 +299,13 @@ namespace bgfx { namespace gl
 		if ([nwh respondsToSelector:@selector(backingScaleFactor)] && (1.0f < [(id)nwh backingScaleFactor]))
 			caps |= BGFX_CAPS_HIDPI;
 #endif // defined(MAC_OS_X_VERSION_MAX_ALLOWED) && (MAC_OS_X_VERSION_MAX_ALLOWED >= 1070)
+		caps |= BGFX_CAPS_SWAP_CHAIN;
 		return caps;
 	}
 
 	SwapChainGL* GlContext::createSwapChain(void* _nwh)
 	{
-		return BX_NEW(g_allocator, SwapChainGL)(_nwh);
+		return BX_NEW(g_allocator, SwapChainGL)(_nwh,(NSOpenGLContext*)m_context);
 	}
 
 	void GlContext::destroySwapChain(SwapChainGL* _swapChain)