OpenGL fallback

Cocoa/GBView.m

@@ -26,7 +26,10 @@
 + (instancetype)allocWithZone:(struct _NSZone *)zone
 {
     if (self == [GBView class]) {
-        return [GBViewMetal allocWithZone: zone];
+        if ([GBViewMetal isSupported]) {
+            return [GBViewMetal allocWithZone: zone];
+        }
+        return [GBViewGL allocWithZone: zone];
     }
     return [super allocWithZone:zone];
 }

Cocoa/GBViewMetal.h

@@ -3,5 +3,5 @@
 #import "GBView.h"
 
 @interface GBViewMetal : GBView<MTKViewDelegate>
-
++ (bool) isSupported;
 @end

Cocoa/GBViewMetal.m

@@ -29,6 +29,14 @@ static const vector_float2 rect[] =
     vector_float2 output_resolution;
 }
 
++ (bool)isSupported
+{
+    if (MTLCopyAllDevices) {
+        return [MTLCopyAllDevices() count];
+    }
+    return false;
+}
+
 - (void)createInternalView
 {
     MTKView *view = [[MTKView alloc] initWithFrame:self.frame device:(device = MTLCreateSystemDefaultDevice())];

Makefile

@@ -61,7 +61,7 @@ ifeq ($(PLATFORM),Darwin)
 SYSROOT := $(shell xcodebuild -sdk macosx -version Path 2> /dev/null)
 CFLAGS += -F/Library/Frameworks
 OCFLAGS += -x objective-c -fobjc-arc -Wno-deprecated-declarations -isysroot $(SYSROOT) -mmacosx-version-min=10.9
-LDFLAGS += -framework AppKit -framework PreferencePanes -framework Carbon -framework QuartzCore -framework Metal -framework MetalKit
+LDFLAGS += -framework AppKit -framework PreferencePanes -framework Carbon -framework QuartzCore -weak_framework Metal -weak_framework MetalKit
 SDL_LDFLAGS := -F/Library/Frameworks -framework SDL2 -framework OpenGL
 endif
 CFLAGS += -Wno-deprecated-declarations