From 2a18a0c1355392bb8b4974a38a61f3e565069012 Mon Sep 17 00:00:00 2001
From: Elias Naur <mail@eliasnaur.com>
Date: Tue, 19 Dec 2023 17:24:56 -0600
Subject: [PATCH] app: [macOS] synchronize rendering with Core Animation for
 smooth resizes

Magic incantations lifted from

https://thume.ca/2019/06/19/glitchless-metal-window-resizing/

Signed-off-by: Elias Naur <mail@eliasnaur.com>
---
 app/metal_darwin.go | 3 ++-
 app/metal_ios.go    | 5 ++++-
 app/metal_macos.go  | 6 +++++-
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/app/metal_darwin.go b/app/metal_darwin.go
index e93b0251..0043ffb3 100644
--- a/app/metal_darwin.go
+++ b/app/metal_darwin.go
@@ -60,8 +60,9 @@ static void presentDrawable(CFTypeRef queueRef, CFTypeRef drawableRef) {
 		id<MTLDrawable> drawable = (__bridge id<MTLDrawable>)drawableRef;
 		id<MTLCommandQueue> queue = (__bridge id<MTLCommandQueue>)queueRef;
 		id<MTLCommandBuffer> cmdBuffer = [queue commandBuffer];
-		[cmdBuffer presentDrawable:drawable];
 		[cmdBuffer commit];
+		[cmdBuffer waitUntilScheduled];
+		[drawable present];
 	}
 }
 
diff --git a/app/metal_ios.go b/app/metal_ios.go
index 860ba1aa..d5b5dc41 100644
--- a/app/metal_ios.go
+++ b/app/metal_ios.go
@@ -21,7 +21,10 @@ Class gio_layerClass(void) {
 static CFTypeRef getMetalLayer(CFTypeRef viewRef) {
 	@autoreleasepool {
 		UIView *view = (__bridge UIView *)viewRef;
-		return CFBridgingRetain(view.layer);
+		CAMetalLayer *l = (CAMetalLayer *)view.layer;
+		l.needsDisplayOnBoundsChange = YES;
+		l.presentsWithTransaction = YES;
+		return CFBridgingRetain(l);
 	}
 }
 
diff --git a/app/metal_macos.go b/app/metal_macos.go
index 8b602ee3..4fe7586c 100644
--- a/app/metal_macos.go
+++ b/app/metal_macos.go
@@ -14,7 +14,11 @@ package app
 
 CALayer *gio_layerFactory(void) {
 	@autoreleasepool {
-		return [CAMetalLayer layer];
+		CAMetalLayer *l = [CAMetalLayer layer];
+		l.autoresizingMask = kCALayerHeightSizable|kCALayerWidthSizable;
+		l.needsDisplayOnBoundsChange = YES;
+		l.presentsWithTransaction = YES;
+		return l;
 	}
 }