OpenGL: software renderer for old Mac GPUs

We raised the minimum to GL 2.1 in Blender 2.77, and dropped support for older GPUs (pre-2012 Intel mostly). On Windows you get a popup message, but on Mac we simply crashed. Every Mac has a builtin software renderer for GL 2.1 so let's use that when the GPU is not capable!

Run blender --debug-gpu to see version detection & software fallback.

5 files changed, 74 insertions, 28 deletions

diff --git a/intern/ghost/intern/GHOST_ContextCGL.h b/intern/ghost/intern/GHOST_ContextCGL.h
index 953235669a8..dd49b81b561 100644
--- a/intern/ghost/intern/GHOST_ContextCGL.h
+++ b/intern/ghost/intern/GHOST_ContextCGL.h
@@ -136,6 +136,8 @@ private:
 
 	//static CGLEWContext *s_cglewContext;
 
+	const bool m_debug;
+
 	/** The first created OpenGL context (for sharing display lists) */
 	static NSOpenGLContext *s_sharedOpenGLContext;
 	static int              s_sharedCount;
diff --git a/intern/ghost/intern/GHOST_ContextCGL.mm b/intern/ghost/intern/GHOST_ContextCGL.mm
index e09de4be143..03c45f9945b 100644
--- a/intern/ghost/intern/GHOST_ContextCGL.mm
+++ b/intern/ghost/intern/GHOST_ContextCGL.mm
@@ -59,7 +59,8 @@ GHOST_ContextCGL::GHOST_ContextCGL(
         int contextResetNotificationStrategy)
     : GHOST_Context(stereoVisual, numOfAASamples),
       m_openGLView(openGLView),
-      m_openGLContext(nil)
+      m_openGLContext(nil),
+      m_debug(contextFlags)
 {
 	assert(openGLView != nil);
 }
@@ -172,20 +173,21 @@ static void makeAttribList(
         bool stereoVisual,
         int numOfAASamples,
         bool needAlpha,
-        bool needStencil)
+        bool needStencil,
+        bool softwareGL)
 {
+	attribs.clear();
+
 	// Pixel Format Attributes for the windowed NSOpenGLContext
 	attribs.push_back(NSOpenGLPFADoubleBuffer);
 
-	// Force software OpenGL, for debugging
-	/* XXX jwilkins: fixed this to work on Intel macs? useful feature for Windows and Linux too?
-	 * Maybe a command line flag is better... */
-	if (getenv("BLENDER_SOFTWAREGL")) {
+	if (softwareGL) {
 		attribs.push_back(NSOpenGLPFARendererID);
 		attribs.push_back(kCGLRendererGenericFloatID);
 	}
 	else {
 		attribs.push_back(NSOpenGLPFAAccelerated);
+		attribs.push_back(NSOpenGLPFANoRecovery);
 	}
 
 	/* Removed to allow 10.4 builds, and 2 GPUs rendering is not used anyway */
@@ -219,13 +221,21 @@ static void makeAttribList(
 
 		attribs.push_back(NSOpenGLPFASamples);
 		attribs.push_back((NSOpenGLPixelFormatAttribute) numOfAASamples);
-
-		attribs.push_back(NSOpenGLPFANoRecovery);
 	}
 
 	attribs.push_back((NSOpenGLPixelFormatAttribute) 0);
 }
 
+// TODO(merwin): make this available to all platforms
+static void getVersion(int *major, int *minor)
+{
+#if 1 // legacy GL
+	sscanf((const char*)glGetString(GL_VERSION), "%d.%d", major, minor);
+#else // 3.0+
+	glGetIntegerv(GL_MAJOR_VERSION, major);
+	glGetIntegerv(GL_MINOR_VERSION, minor);
+#endif
+}
 
 GHOST_TSuccess GHOST_ContextCGL::initializeDrawingContext()
 {
@@ -248,9 +258,12 @@ GHOST_TSuccess GHOST_ContextCGL::initializeDrawingContext()
 	static const bool needStencil = false;
 #endif
 
-	makeAttribList(attribs, m_stereoVisual, m_numOfAASamples, needAlpha, needStencil);
-
+	static bool softwareGL = getenv("BLENDER_SOFTWAREGL"); // command-line argument would be better
+	GLint major = 0, minor = 0;
 	NSOpenGLPixelFormat *pixelFormat;
+	// TODO: keep pixel format for subsequent windows/contexts instead of recreating each time
+
+	makeAttribList(attribs, m_stereoVisual, m_numOfAASamples, needAlpha, needStencil, softwareGL);
 
 	pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:&attribs[0]];
 
@@ -261,7 +274,7 @@ GHOST_TSuccess GHOST_ContextCGL::initializeDrawingContext()
 		// (Now that I think about it, does WGL really require the code that it has for finding a lesser match?)
 
 		attribs.clear();
-		makeAttribList(attribs, m_stereoVisual, 0, needAlpha, needStencil);
+		makeAttribList(attribs, m_stereoVisual, 0, needAlpha, needStencil, softwareGL);
 		pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:&attribs[0]];
 	}
 
@@ -282,25 +295,47 @@ GHOST_TSuccess GHOST_ContextCGL::initializeDrawingContext()
 		}
 	}
 
-	[m_openGLView setPixelFormat:pixelFormat];
+	m_openGLContext = [[NSOpenGLContext alloc] initWithFormat:pixelFormat shareContext:s_sharedOpenGLContext];
+	[pixelFormat release];
 
-	m_openGLContext = [[NSOpenGLContext alloc] initWithFormat:pixelFormat shareContext:s_sharedOpenGLContext]; // +1 refCount to pixelFormat
+	[m_openGLContext makeCurrentContext];
 
-	if (m_openGLContext == nil)
-		goto error;
+	getVersion(&major, &minor);
+	if (m_debug) {
+		fprintf(stderr, "OpenGL version %d.%d%s\n", major, minor, softwareGL ? " (software)" : "");
+		fprintf(stderr, "Renderer: %s\n", glGetString(GL_RENDERER));
+	}
 
-	if (s_sharedCount == 0)
-		s_sharedOpenGLContext = m_openGLContext;
-	
-	[pixelFormat release]; // -1 refCount to pixelFormat
-	
-	s_sharedCount++;
+	if (major < 2 || (major == 2 && minor < 1)) {
+		// fall back to software renderer if GL < 2.1
+		fprintf(stderr, "OpenGL 2.1 is not supported on your hardware, falling back to software");
+		softwareGL = true;
+
+		// discard hardware GL context
+		[NSOpenGLContext clearCurrentContext];
+		[m_openGLContext release];
+
+		// create software GL context
+		makeAttribList(attribs, m_stereoVisual, m_numOfAASamples, needAlpha, needStencil, softwareGL);
+		pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:&attribs[0]];
+		m_openGLContext = [[NSOpenGLContext alloc] initWithFormat:pixelFormat shareContext:s_sharedOpenGLContext];
+		[pixelFormat release];
+
+		[m_openGLContext makeCurrentContext];
+
+		getVersion(&major, &minor);
+		if (m_debug) {
+			fprintf(stderr, "OpenGL version %d.%d%s\n", major, minor, softwareGL ? " (software)" : "");
+			fprintf(stderr, "Renderer: %s\n", glGetString(GL_RENDERER));
+		}
+	}
 
 #ifdef GHOST_MULTITHREADED_OPENGL
 	//Switch openGL to multhreaded mode
 	CGLContextObj cglCtx = (CGLContextObj)[tmpOpenGLContext CGLContextObj];
 	if (CGLEnable(cglCtx, kCGLCEMPEngine) == kCGLNoError)
-		printf("\nSwitched openGL to multithreaded mode\n");
+		if (m_debug)
+			fprintf(stderr, "\nSwitched OpenGL to multithreaded mode\n");
 #endif
 
 #ifdef GHOST_WAIT_FOR_VSYNC
@@ -311,10 +346,16 @@ GHOST_TSuccess GHOST_ContextCGL::initializeDrawingContext()
 	}
 #endif
 
+	initContextGLEW();
+
 	[m_openGLView setOpenGLContext:m_openGLContext];
 	[m_openGLContext setView:m_openGLView];
 
-	initContextGLEW();
+	if (s_sharedCount == 0)
+		s_sharedOpenGLContext = m_openGLContext;
+	
+	s_sharedCount++;
+
 
 	initClearGL();
 	[m_openGLContext flushBuffer];
diff --git a/intern/ghost/intern/GHOST_SystemCocoa.mm b/intern/ghost/intern/GHOST_SystemCocoa.mm
index b0d5ab31ce3..f31cba498e5 100644
--- a/intern/ghost/intern/GHOST_SystemCocoa.mm
+++ b/intern/ghost/intern/GHOST_SystemCocoa.mm
@@ -562,7 +562,7 @@ GHOST_IWindow* GHOST_SystemCocoa::createWindow(
 	// Add contentRect.origin.y to respect docksize
 	bottom = bottom > contentRect.origin.y ? bottom + contentRect.origin.y : contentRect.origin.y;
 
-	window = new GHOST_WindowCocoa (this, title, left, bottom, width, height, state, type, ((glSettings.flags & GHOST_glStereoVisual) != 0), glSettings.numOfAASamples);
+	window = new GHOST_WindowCocoa(this, title, left, bottom, width, height, state, type, glSettings.flags & GHOST_glStereoVisual, glSettings.numOfAASamples, glSettings.flags & GHOST_glDebugContext);
 
 	if (window->getValid()) {
 		// Store the pointer to the window
diff --git a/intern/ghost/intern/GHOST_WindowCocoa.h b/intern/ghost/intern/GHOST_WindowCocoa.h
index 3ed88086184..b234291396b 100644
--- a/intern/ghost/intern/GHOST_WindowCocoa.h
+++ b/intern/ghost/intern/GHOST_WindowCocoa.h
@@ -74,7 +74,8 @@ public:
 	    GHOST_TWindowState state,
 	    GHOST_TDrawingContextType type = GHOST_kDrawingContextTypeNone,
 	    const bool stereoVisual = false,
-	    const GHOST_TUns16 numOfAASamples = 0
+	    const GHOST_TUns16 numOfAASamples = 0,
+	    bool is_debug = false
 	    );
 
 	/**
@@ -305,6 +306,7 @@ protected:
 	bool m_lionStyleFullScreen;
 
 	bool m_immediateDraw;
+	bool m_debug_context; // for debug messages during context setup
 };
 
 #endif // __GHOST_WINDOWCOCOA_H__
diff --git a/intern/ghost/intern/GHOST_WindowCocoa.mm b/intern/ghost/intern/GHOST_WindowCocoa.mm
index e23cf9ccd37..97615dcea96 100644
--- a/intern/ghost/intern/GHOST_WindowCocoa.mm
+++ b/intern/ghost/intern/GHOST_WindowCocoa.mm
@@ -528,10 +528,11 @@ GHOST_WindowCocoa::GHOST_WindowCocoa(
 	GHOST_TUns32 height,
 	GHOST_TWindowState state,
 	GHOST_TDrawingContextType type,
-	const bool stereoVisual, const GHOST_TUns16 numOfAASamples
+	const bool stereoVisual, const GHOST_TUns16 numOfAASamples, bool is_debug
 ) :
 	GHOST_Window(width, height, state, stereoVisual, false, numOfAASamples),
-	m_customCursor(0)
+	m_customCursor(0),
+	m_debug_context(is_debug)
 {
 	m_systemCocoa = systemCocoa;
 	m_fullScreen = false;
@@ -1115,7 +1116,7 @@ GHOST_Context *GHOST_WindowCocoa::newDrawingContext(GHOST_TDrawingContextType ty
 			m_openGLView,
 			0, // profile bit
 			0, 0,
-			GHOST_OPENGL_CGL_CONTEXT_FLAGS,
+			m_debug_context,
 			GHOST_OPENGL_CGL_RESET_NOTIFICATION_STRATEGY);
 #else
 #  error