From 61601587295f6d0ef1c4084530fe0318e0c72b16 Mon Sep 17 00:00:00 2001
From: Chris Schultz <christopher.schultz@auth0.com>
Date: Fri, 5 Apr 2019 14:08:20 -0500
Subject: devdraw: prefer low-power GPU for macOS metal rendering (#231)

---
 src/cmd/devdraw/cocoa-screen-metal.m | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/cmd/devdraw/cocoa-screen-metal.m b/src/cmd/devdraw/cocoa-screen-metal.m
index 78110302..21c041a5 100644
--- a/src/cmd/devdraw/cocoa-screen-metal.m
+++ b/src/cmd/devdraw/cocoa-screen-metal.m
@@ -153,6 +153,7 @@ threadmain(int argc, char **argv)
 	id<MTLLibrary> library;
 	MTLRenderPipelineDescriptor *pipelineDesc;
 	NSError *error;
+	NSArray *allDevices;
 
 	const NSWindowStyleMask Winstyle = NSWindowStyleMaskTitled
 		| NSWindowStyleMaskClosable
@@ -197,8 +198,18 @@ threadmain(int argc, char **argv)
 	[win setContentView:myContent];
 	[myContent setWantsLayer:YES];
 	[myContent setLayerContentsRedrawPolicy:NSViewLayerContentsRedrawOnSetNeedsDisplay];
-
-	device = MTLCreateSystemDefaultDevice();
+	
+	device = nil;
+	allDevices = MTLCopyAllDevices();
+	for(id mtlDevice in allDevices) {
+		if ([mtlDevice isLowPower] && ![mtlDevice isRemovable]) {
+			device = mtlDevice;
+			break;
+		}
+	}
+	if(!device)
+		device = MTLCreateSystemDefaultDevice();
+	
 	commandQueue = [device newCommandQueue];
 
 	layer = (DrawLayer *)[myContent layer];
-- 
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