Fixed bug 2696 - Mac: fix display mode refresh rate calculation

Alex Szpakowski

SDL's Cocoa backend uses the CGDisplayMode API to get refresh rate information about a display mode, but CGDisplayModeGetRefreshRate will return 0 on most non-CRT monitors.

The only way I know of to get correct refresh rate information in OS X is via the CoreVideo DisplayLink API.
I have attached a patch which tries to use the CVDisplayLinkGetNominalOutputVideoRefreshPeriod function if CGDisplayModeGetRefreshRate fails, which fixes display mode refresh rate information on the monitors I tested.

The CVDisplayLink API requires linking with the CoreVideo framework, and the patch updates the various build files to do so.

CMakeLists.txt

@@ -970,6 +970,7 @@ elseif(APPLE)
     set_source_files_properties(${EXTRA_SOURCES} PROPERTIES LANGUAGE C)
     set(HAVE_SDL_FILE TRUE)
     set(SDL_FRAMEWORK_COCOA 1)
+    set(SDL_FRAMEWORK_COREVIDEO 1)
   else()
     message_error("SDL_FILE must be enabled to build on MacOS X")
   endif()
@@ -1029,6 +1030,10 @@ elseif(APPLE)
   endif()
 
   # Actually load the frameworks at the end so we don't duplicate include.
+  if(SDL_FRAMEWORK_COREVIDEO)
+    find_library(COREVIDEO CoreVideo)
+    list(APPEND EXTRA_LIBS ${COREVIDEO})
+  endif()
   if(SDL_FRAMEWORK_COCOA)
     find_library(COCOA_LIBRARY Cocoa)
     list(APPEND EXTRA_LIBS ${COCOA_LIBRARY})

Xcode/SDL/SDL.xcodeproj/project.pbxproj

@@ -810,6 +810,9 @@
 		DB31407217554B71006C0E22 /* Carbon.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 007317C10858E15000B2BC32 /* Carbon.framework */; };
 		DB31408B17554D37006C0E22 /* ForceFeedback.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 00CFA89C106B4BA100758660 /* ForceFeedback.framework */; };
 		DB31408D17554D3C006C0E22 /* ForceFeedback.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 00CFA89C106B4BA100758660 /* ForceFeedback.framework */; };
+		FA73671D19A540EF004122E4 /* CoreVideo.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = FA73671C19A540EF004122E4 /* CoreVideo.framework */; };
+		FA73671E19A54140004122E4 /* CoreVideo.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = FA73671C19A540EF004122E4 /* CoreVideo.framework */; };
+		FA73671F19A54144004122E4 /* CoreVideo.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = FA73671C19A540EF004122E4 /* CoreVideo.framework */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -1109,13 +1112,15 @@
 		F5A2EF3900C6A39A01000001 /* BUGS.txt */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = text; name = BUGS.txt; path = ../../BUGS.txt; sourceTree = SOURCE_ROOT; };
 		F5A2EF3A00C6A3C201000001 /* README-macosx.txt */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = text; name = "README-macosx.txt"; path = "../../README-macosx.txt"; sourceTree = SOURCE_ROOT; };
 		F5F81AD400D706B101000001 /* Readme SDL Developer.txt */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = text; name = "Readme SDL Developer.txt"; path = "pkg-support/Readme SDL Developer.txt"; sourceTree = SOURCE_ROOT; };
+		FA73671C19A540EF004122E4 /* CoreVideo.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = CoreVideo.framework; path = /System/Library/Frameworks/CoreVideo.framework; sourceTree = "<absolute>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
 		BECDF6680761BA81005FE872 /* Frameworks */ = {
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				FA73671D19A540EF004122E4 /* CoreVideo.framework in Frameworks */,
 				007317A20858DECD00B2BC32 /* AudioToolbox.framework in Frameworks */,
 				007317A30858DECD00B2BC32 /* AudioUnit.framework in Frameworks */,
 				007317A40858DECD00B2BC32 /* Cocoa.framework in Frameworks */,
@@ -1131,6 +1136,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				FA73671E19A54140004122E4 /* CoreVideo.framework in Frameworks */,
 				007317A90858DECD00B2BC32 /* AudioToolbox.framework in Frameworks */,
 				007317AA0858DECD00B2BC32 /* AudioUnit.framework in Frameworks */,
 				007317AB0858DECD00B2BC32 /* Cocoa.framework in Frameworks */,
@@ -1145,6 +1151,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				FA73671F19A54144004122E4 /* CoreVideo.framework in Frameworks */,
 				DB31406C17554B71006C0E22 /* AudioToolbox.framework in Frameworks */,
 				DB31406D17554B71006C0E22 /* AudioUnit.framework in Frameworks */,
 				DB31406E17554B71006C0E22 /* Cocoa.framework in Frameworks */,
@@ -1738,6 +1745,7 @@
 		BEC562FE0761C0E800A33029 /* Linked Frameworks */ = {
 			isa = PBXGroup;
 			children = (
+				FA73671C19A540EF004122E4 /* CoreVideo.framework */,
 				00D0D08310675DD9004B05EF /* CoreFoundation.framework */,
 				007317C10858E15000B2BC32 /* Carbon.framework */,
 				0073179B0858DECD00B2BC32 /* AudioToolbox.framework */,

configure

         # The Mac OS X platform requires special setup.
         EXTRA_CFLAGS="$EXTRA_CFLAGS -fpascal-strings"
         EXTRA_LDFLAGS="$EXTRA_LDFLAGS -lobjc"
+        EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,-framework,CoreVideo"
         EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,-framework,Cocoa"
         EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,-framework,Carbon"
         EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,-framework,IOKit"

configure.in

@@ -3215,6 +3215,7 @@ AC_HELP_STRING([--enable-render-d3d], [enable the Direct3D render driver [[defau
         # The Mac OS X platform requires special setup.
         EXTRA_CFLAGS="$EXTRA_CFLAGS -fpascal-strings"
         EXTRA_LDFLAGS="$EXTRA_LDFLAGS -lobjc"
+        EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,-framework,CoreVideo"
         EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,-framework,Cocoa"
         EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,-framework,Carbon"
         EXTRA_LDFLAGS="$EXTRA_LDFLAGS -Wl,-framework,IOKit"

premake/README-macosx.txt

@@ -17,6 +17,7 @@ tests on that platform.
 
 The Mac OS X projects currently have reliance on the following dependencies:
 
+  -CoreVideo.framework
   -AudioToolbox.framework
   -AudioUnit.framework
   -Cocoa.framework

premake/projects/SDL2.lua

@@ -213,6 +213,7 @@ SDL_project "SDL2"
 		}
 		SDL_links
 		{
+			"CoreVideo.framework",
 			"AudioToolbox.framework",
 			"AudioUnit.framework",
 			"Cocoa.framework",

src/video/cocoa/SDL_cocoamodes.m

@@ -27,6 +27,10 @@
 /* We need this for IODisplayCreateInfoDictionary and kIODisplayOnlyPreferredName */
 #include <IOKit/graphics/IOGraphicsLib.h>
 
+/* We need this for CVDisplayLinkGetNominalOutputVideoRefreshPeriod */
+#include <CoreVideo/CVBase.h>
+#include <CoreVideo/CVDisplayLink.h>
+
 /* we need this for ShowMenuBar() and HideMenuBar(). */
 #include <Carbon/Carbon.h>
 
@@ -114,7 +118,7 @@
 }
 
 static SDL_bool
-GetDisplayMode(_THIS, const void *moderef, SDL_DisplayMode *mode)
+GetDisplayMode(_THIS, const void *moderef, CVDisplayLinkRef link, SDL_DisplayMode *mode)
 {
     SDL_DisplayModeData *data;
     long width = 0;
@@ -133,14 +137,17 @@
         CFStringRef fmt = CGDisplayModeCopyPixelEncoding(vidmode);
         width = (long) CGDisplayModeGetWidth(vidmode);
         height = (long) CGDisplayModeGetHeight(vidmode);
-        refreshRate = (long) CGDisplayModeGetRefreshRate(vidmode);
+        refreshRate = (long) (CGDisplayModeGetRefreshRate(vidmode) + 0.5);
 
         if (CFStringCompare(fmt, CFSTR(IO32BitDirectPixels),
                             kCFCompareCaseInsensitive) == kCFCompareEqualTo) {
             bpp = 32;
         } else if (CFStringCompare(fmt, CFSTR(IO16BitDirectPixels),
                             kCFCompareCaseInsensitive) == kCFCompareEqualTo) {
             bpp = 16;
+        } else if (CFStringCompare(fmt, CFSTR(kIO30BitDirectPixels),
+                            kCFCompareCaseInsensitive) == kCFCompareEqualTo) {
+            bpp = 30;
         } else {
             bpp = 0;  /* ignore 8-bit and such for now. */
         }
@@ -151,6 +158,7 @@
     #if MAC_OS_X_VERSION_MIN_REQUIRED < 1060
     if (!IS_SNOW_LEOPARD_OR_LATER()) {
         CFNumberRef number;
+        double refresh;
         CFDictionaryRef vidmode = (CFDictionaryRef) moderef;
         number = CFDictionaryGetValue(vidmode, kCGDisplayWidth);
         CFNumberGetValue(number, kCFNumberLongType, &width);
@@ -159,15 +167,27 @@
         number = CFDictionaryGetValue(vidmode, kCGDisplayBitsPerPixel);
         CFNumberGetValue(number, kCFNumberLongType, &bpp);
         number = CFDictionaryGetValue(vidmode, kCGDisplayRefreshRate);
-        CFNumberGetValue(number, kCFNumberLongType, &refreshRate);
+        CFNumberGetValue(number, kCFNumberDoubleType, &refresh);
+        refreshRate = (long) (refresh + 0.5);
     }
     #endif
 
+    /* CGDisplayModeGetRefreshRate returns 0 for many non-CRT displays. */
+    if (refreshRate == 0 && link != NULL) {
+        CVTime time = CVDisplayLinkGetNominalOutputVideoRefreshPeriod(link);
+        if ((time.flags & kCVTimeIsIndefinite) == 0 && time.timeValue != 0) {
+            refreshRate = (long) ((time.timeScale / (double) time.timeValue) + 0.5);
+        }
+    }
+
     mode->format = SDL_PIXELFORMAT_UNKNOWN;
     switch (bpp) {
     case 16:
         mode->format = SDL_PIXELFORMAT_ARGB1555;
         break;
+    case 30:
+        mode->format = SDL_PIXELFORMAT_ARGB2101010;
+        break;
     case 32:
         mode->format = SDL_PIXELFORMAT_ARGB8888;
         break;
@@ -241,6 +261,7 @@
             SDL_DisplayData *displaydata;
             SDL_DisplayMode mode;
             const void *moderef = NULL;
+            CVDisplayLinkRef link = NULL;
 
             if (pass == 0) {
                 if (!CGDisplayIsMain(displays[i])) {
@@ -277,16 +298,21 @@
             }
             displaydata->display = displays[i];
 
+            CVDisplayLinkCreateWithCGDisplay(displays[i], &link);
+
             SDL_zero(display);
             /* this returns a stddup'ed string */
             display.name = (char *)Cocoa_GetDisplayName(displays[i]);
-            if (!GetDisplayMode (_this, moderef, &mode)) {
+            if (!GetDisplayMode(_this, moderef, link, &mode)) {
+                CVDisplayLinkRelease(link);
                 Cocoa_ReleaseDisplayMode(_this, moderef);
                 SDL_free(display.name);
                 SDL_free(displaydata);
                 continue;
             }
 
+            CVDisplayLinkRelease(link);
+
             display.desktop_mode = mode;
             display.current_mode = mode;
             display.driverdata = displaydata;
@@ -328,20 +354,24 @@
     #endif
 
     if (modes) {
+        CVDisplayLinkRef link = NULL;
         const CFIndex count = CFArrayGetCount(modes);
         CFIndex i;
 
+        CVDisplayLinkCreateWithCGDisplay(data->display, &link);
+
         for (i = 0; i < count; i++) {
             const void *moderef = CFArrayGetValueAtIndex(modes, i);
             SDL_DisplayMode mode;
-            if (GetDisplayMode(_this, moderef, &mode)) {
+            if (GetDisplayMode(_this, moderef, link, &mode)) {
                 if (IS_SNOW_LEOPARD_OR_LATER()) {
                     CGDisplayModeRetain((CGDisplayModeRef) moderef);
                 }
                 SDL_AddDisplayMode(display, &mode);
             }
         }
 
+        CVDisplayLinkRelease(link);
         Cocoa_ReleaseDisplayModeList(_this, modes);
     }
 }