From 061256a3b3ac5e389c84264d105f1658b2d9f919 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <icculus@icculus.org>
Date: Wed, 7 Oct 2020 14:45:24 -0400
Subject: [PATCH] metal: Clear the framebuffer if presenting without any other
 operations.

---
 src/render/metal/SDL_render_metal.m | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/render/metal/SDL_render_metal.m b/src/render/metal/SDL_render_metal.m
index 04616e374..cb3f9cc6a 100644
--- a/src/render/metal/SDL_render_metal.m
+++ b/src/render/metal/SDL_render_metal.m
@@ -1518,17 +1518,21 @@ METAL_RenderPresent(SDL_Renderer * renderer)
 { @autoreleasepool {
     METAL_RenderData *data = (__bridge METAL_RenderData *) renderer->driverdata;
 
-    METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionLoad, NULL, nil);
+    // If we don't have a command buffer, we can't present, so activate to get one.
+    if (data.mtlcmdencoder == nil) {
+        // We haven't even gotten a backbuffer yet? Clear it to black. Otherwise, load the existing data.
+        if (data.mtlbackbuffer == nil) {
+            MTLClearColor color = MTLClearColorMake(0.0f, 0.0f, 0.0f, 1.0f);
+            METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionClear, &color, nil);
+        } else {
+            METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionLoad, NULL, nil);
+        }
+    }
+
+    [data.mtlcmdencoder endEncoding];
+    [data.mtlcmdbuffer presentDrawable:data.mtlbackbuffer];
+    [data.mtlcmdbuffer commit];
 
-    if (data.mtlcmdencoder != nil) {
-        [data.mtlcmdencoder endEncoding];
-    }
-    if (data.mtlbackbuffer != nil) {
-        [data.mtlcmdbuffer presentDrawable:data.mtlbackbuffer];
-    }
-    if (data.mtlcmdbuffer != nil) {
-        [data.mtlcmdbuffer commit];
-    }
     data.mtlcmdencoder = nil;
     data.mtlcmdbuffer = nil;
     data.mtlbackbuffer = nil;