From c26f6ed94f2e6dcbb9c849cc95ed56ba155aa43d Mon Sep 17 00:00:00 2001
From: Alex Szpakowski <slime73@gmail.com>
Date: Sat, 22 Jan 2022 23:12:42 -0400
Subject: [PATCH] metal: improve performance of auto depth/stencil in
 setCanvas.

---
 src/modules/graphics/Graphics.cpp      |  5 +++++
 src/modules/graphics/metal/Graphics.mm | 10 ++++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/modules/graphics/Graphics.cpp b/src/modules/graphics/Graphics.cpp
index ee43b8275..dbfda2983 100644
--- a/src/modules/graphics/Graphics.cpp
+++ b/src/modules/graphics/Graphics.cpp
@@ -907,6 +907,11 @@ void Graphics::setRenderTargets(const RenderTargets &rts)
 	renderTargetSwitchCount++;
 
 	resetProjection();
+
+	// Invalidate temporary depth/stencil. This could be a clear, but if the
+	// user also clears a double-clear may be slow...
+	if (rts.depthStencil.texture == nullptr && rts.temporaryRTFlags != 0)
+		discard({}, true);
 }
 
 void Graphics::setRenderTarget()
diff --git a/src/modules/graphics/metal/Graphics.mm b/src/modules/graphics/metal/Graphics.mm
index 232ef1ebd..12e65b80c 100644
--- a/src/modules/graphics/metal/Graphics.mm
+++ b/src/modules/graphics/metal/Graphics.mm
@@ -1370,10 +1370,12 @@ void Graphics::endPass()
 
 	// Discard the depth/stencil buffer if we're using an internal cached one,
 	// or if this is the backbuffer.
-	if (depthstencil == nullptr && (rts.temporaryRTFlags & (TEMPORARY_RT_DEPTH | TEMPORARY_RT_STENCIL)) != 0)
-		discard({}, true);
-	else if (!rts.getFirstTarget().texture.get())
-		discard({}, true); // Backbuffer
+	if ((depthstencil == nullptr && (rts.temporaryRTFlags & (TEMPORARY_RT_DEPTH | TEMPORARY_RT_STENCIL)) != 0)
+		|| !rts.getFirstTarget().texture.get())
+	{
+		attachmentStoreActions.depth = MTLStoreActionDontCare;
+		attachmentStoreActions.stencil = MTLStoreActionDontCare;
+	}
 
 	submitRenderEncoder(SUBMIT_DONE);