From ec26b1a43bf194a36e1965b009203f87b6e83cca Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sun, 8 Aug 2021 15:13:44 +0900
Subject: [PATCH] internal/graphicsdriver/metal: Refactoring: Remove
 vsyncInited

---
 internal/graphicsdriver/metal/ca/ca.go | 11 +++++++++++
 internal/graphicsdriver/metal/ca/ca.h  |  2 ++
 internal/graphicsdriver/metal/ca/ca.m  | 14 ++++++--------
 internal/graphicsdriver/metal/view.go  | 20 ++++++++++++--------
 4 files changed, 31 insertions(+), 16 deletions(-)

diff --git a/internal/graphicsdriver/metal/ca/ca.go b/internal/graphicsdriver/metal/ca/ca.go
index c8582ede7..a8febd527 100644
--- a/internal/graphicsdriver/metal/ca/ca.go
+++ b/internal/graphicsdriver/metal/ca/ca.go
@@ -154,6 +154,17 @@ func (ml MetalLayer) PresentsWithTransaction() bool {
 	return C.MetalLayer_PresentsWithTransaction(ml.metalLayer) != 0
 }
 
+// SetPresentsWithTransaction sets a Boolean value that determines whether the layer presents its content using a Core Animation transaction.
+//
+// Reference: https://developer.apple.com/documentation/quartzcore/cametallayer/1478157-presentswithtransaction
+func (ml MetalLayer) SetPresentsWithTransaction(presentsWithTransaction bool) {
+	if presentsWithTransaction {
+		C.MetalLayer_SetPresentsWithTransaction(ml.metalLayer, 1)
+	} else {
+		C.MetalLayer_SetPresentsWithTransaction(ml.metalLayer, 0)
+	}
+}
+
 // SetFramebufferOnly sets a Boolean value that determines whether the layer’s textures are used only for rendering.
 //
 // https://developer.apple.com/documentation/quartzcore/cametallayer/1478168-framebufferonly
diff --git a/internal/graphicsdriver/metal/ca/ca.h b/internal/graphicsdriver/metal/ca/ca.h
index afa8f2add..2c0ed8ba8 100644
--- a/internal/graphicsdriver/metal/ca/ca.h
+++ b/internal/graphicsdriver/metal/ca/ca.h
@@ -29,6 +29,8 @@ const char *MetalLayer_SetMaximumDrawableCount(void *metalLayer,
 void MetalLayer_SetDisplaySyncEnabled(void *metalLayer,
                                       uint8_t displaySyncEnabled);
 void MetalLayer_SetDrawableSize(void *metalLayer, double width, double height);
+void MetalLayer_SetPresentsWithTransaction(void *metalLayer,
+                                           uint8_t presentsWithTransaction);
 void *MetalLayer_NextDrawable(void *metalLayer);
 void MetalLayer_SetFramebufferOnly(void *metalLayer, uint8_t framebufferOnly);
 uint8_t MetalLayer_PresentsWithTransaction(void *metalLayer);
diff --git a/internal/graphicsdriver/metal/ca/ca.m b/internal/graphicsdriver/metal/ca/ca.m
index 11d13921e..ff1ae6190 100644
--- a/internal/graphicsdriver/metal/ca/ca.m
+++ b/internal/graphicsdriver/metal/ca/ca.m
@@ -85,20 +85,18 @@ void MetalLayer_SetDisplaySyncEnabled(void *metalLayer,
     [((CAMetalLayer *)metalLayer) setDisplaySyncEnabled:displaySyncEnabled];
   }
 #endif
-
-  // setting presentsWithTransaction YES makes the FPS stable (#1196). We're not
-  // sure why...
-  if (displaySyncEnabled) {
-    [((CAMetalLayer *)metalLayer) setPresentsWithTransaction:YES];
-  } else {
-    [((CAMetalLayer *)metalLayer) setPresentsWithTransaction:NO];
-  }
 }
 
 void MetalLayer_SetDrawableSize(void *metalLayer, double width, double height) {
   ((CAMetalLayer *)metalLayer).drawableSize = (CGSize){width, height};
 }
 
+void MetalLayer_SetPresentsWithTransaction(void *metalLayer,
+                                           uint8_t presentsWithTransaction) {
+  [((CAMetalLayer *)metalLayer)
+      setPresentsWithTransaction:presentsWithTransaction];
+}
+
 void *MetalLayer_NextDrawable(void *metalLayer) {
   return [(CAMetalLayer *)metalLayer nextDrawable];
 }
diff --git a/internal/graphicsdriver/metal/view.go b/internal/graphicsdriver/metal/view.go
index 10a12a3c2..51df46dc0 100644
--- a/internal/graphicsdriver/metal/view.go
+++ b/internal/graphicsdriver/metal/view.go
@@ -29,8 +29,7 @@ type view struct {
 	uiview uintptr
 
 	windowChanged bool
-	vsync         bool
-	vsyncInited   bool
+	vsyncDisabled bool
 
 	device mtl.Device
 	ml     ca.MetalLayer
@@ -47,12 +46,19 @@ func (v *view) getMTLDevice() mtl.Device {
 }
 
 func (v *view) setDisplaySyncEnabled(enabled bool) {
-	if v.vsync == enabled && !v.vsyncInited {
+	if !v.vsyncDisabled == enabled {
 		return
 	}
+	v.forceSetDisplaySyncEnabled(enabled)
+}
+
+func (v *view) forceSetDisplaySyncEnabled(enabled bool) {
 	v.ml.SetDisplaySyncEnabled(enabled)
-	v.vsync = enabled
-	v.vsyncInited = true
+
+	// setting presentsWithTransaction true makes the FPS stable (#1196). We're not sure why...
+	v.ml.SetPresentsWithTransaction(enabled)
+
+	v.vsyncDisabled = !enabled
 }
 
 func (v *view) colorPixelFormat() mtl.PixelFormat {
@@ -80,9 +86,7 @@ func (v *view) reset() error {
 	v.ml.SetMaximumDrawableCount(2)
 
 	// The vsync state might be reset. Set the state again (#1364).
-	if v.vsyncInited {
-		v.ml.SetDisplaySyncEnabled(v.vsync)
-	}
+	v.forceSetDisplaySyncEnabled(!v.vsyncDisabled)
 	v.ml.SetFramebufferOnly(true)
 
 	return nil