git.y1.nz

commit a9c01d35fc0bb567a70040c3d5a2debd13891f4d
parent 686a506e174dfdc761a45b5733438c163b6ba01a
Author: Lior Halphon <LIJI32@gmail.com>
Date:   Sat, 13 Jan 2024 15:49:37 +0200

Fix a bug where the Metal renderer would sometimes flicker in the Cocoa/iOS frontends

Diffstat:
M
AppleCommon/GBViewBase.m
4
+++-
M
AppleCommon/GBViewMetal.m
44
+++++++++++++++++++++++++++++++++-----------
M
Cocoa/Document.xib
2
+-

3 files changed, 37 insertions(+), 13 deletions(-)
diff --git a/AppleCommon/GBViewBase.m b/AppleCommon/GBViewBase.m
@@ -5,6 +5,7 @@
     uint32_t *_imageBuffers[3];
     unsigned _currentBuffer;
     GB_frame_blending_mode_t _frameBlendingMode;
+    bool _oddFrame;
 }
 
 - (void)screenSizeChanged
@@ -23,6 +24,7 @@
 - (void)flip
 {
     _currentBuffer = (_currentBuffer + 1) % self.numberOfBuffers;
+    _oddFrame = GB_is_odd_frame(_gb);
 }
 
 - (unsigned) numberOfBuffers
@@ -62,7 +64,7 @@
         if (!_gb || GB_is_sgb(_gb)) {
             return GB_FRAME_BLENDING_MODE_SIMPLE;
         }
-        return GB_is_odd_frame(_gb)? GB_FRAME_BLENDING_MODE_ACCURATE_ODD : GB_FRAME_BLENDING_MODE_ACCURATE_EVEN;
+        return _oddFrame ? GB_FRAME_BLENDING_MODE_ACCURATE_ODD : GB_FRAME_BLENDING_MODE_ACCURATE_EVEN;
     }
     return _frameBlendingMode;
 }
diff --git a/AppleCommon/GBViewMetal.m b/AppleCommon/GBViewMetal.m
@@ -85,7 +85,7 @@ static const vector_float2 rect[] =
 #endif
 }
 
-- (void) loadShader
+- (void)loadShader
 {
     NSError *error = nil;
     NSString *shader_source = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"MasterShader"
@@ -160,22 +160,44 @@ static const vector_float2 rect[] =
         {texture.width, texture.height, 1} // MTLSize
     };
 
-    [texture replaceRegion:region
-               mipmapLevel:0
-                 withBytes:[self currentBuffer]
-               bytesPerRow:texture.width * 4];
-    if ([self frameBlendingMode]) {
-        [previous_texture replaceRegion:region
-                            mipmapLevel:0
-                              withBytes:[self previousBuffer]
-                            bytesPerRow:texture.width * 4];
+    GB_frame_blending_mode_t mode = [self frameBlendingMode];
+    
+    switch (mode) {
+        case GB_FRAME_BLENDING_MODE_SIMPLE:
+        case GB_FRAME_BLENDING_MODE_ACCURATE_EVEN:
+            [previous_texture replaceRegion:region
+                                mipmapLevel:0
+                                  withBytes:[self previousBuffer]
+                                bytesPerRow:texture.width * 4];
+        case GB_FRAME_BLENDING_MODE_DISABLED:
+            [texture replaceRegion:region
+                       mipmapLevel:0
+                         withBytes:[self currentBuffer]
+                       bytesPerRow:texture.width * 4];
+            break;
+        case GB_FRAME_BLENDING_MODE_ACCURATE_ODD:
+            /*
+             I don't understand GPUs. When rapidly changing `mode`, the shader might sometimes incorrectly
+             use the old value. I couldn't figure out how to fix it, so I just work around the issue by
+             avoiding rapid changes in `mode`.
+             */
+            mode = GB_FRAME_BLENDING_MODE_ACCURATE_EVEN;
+            [previous_texture replaceRegion:region
+                                mipmapLevel:0
+                                  withBytes:[self currentBuffer]
+                                bytesPerRow:texture.width * 4];
+            [texture replaceRegion:region
+                       mipmapLevel:0
+                         withBytes:[self previousBuffer]
+                       bytesPerRow:texture.width * 4];
+            break;
     }
     
     MTLRenderPassDescriptor *render_pass_descriptor = view.currentRenderPassDescriptor;
     id<MTLCommandBuffer> command_buffer = [command_queue commandBuffer];
 
     if (render_pass_descriptor) {
-        *(GB_frame_blending_mode_t *)[frame_blending_mode_buffer contents] = [self frameBlendingMode];
+        *(GB_frame_blending_mode_t *)[frame_blending_mode_buffer contents] = mode;
         *(vector_float2 *)[output_resolution_buffer contents] = output_resolution;
 
         id<MTLRenderCommandEncoder> render_encoder =
diff --git a/Cocoa/Document.xib b/Cocoa/Document.xib
@@ -703,7 +703,7 @@
                     </toolbarItem>
                     <toolbarItem implicitItemIdentifier="NSToolbarSpaceItem" id="AoG-LH-J4b"/>
                     <toolbarItem implicitItemIdentifier="NSToolbarFlexibleSpaceItem" id="Q0x-n5-Q2Y"/>
-                    <toolbarItem implicitItemIdentifier="E8F74F8F-6DE2-4774-A690-F71D92CD932E" label="" paletteLabel="" tag="-1" title="wtf" sizingBehavior="auto" id="CJX-Ff-7iQ">
+                    <toolbarItem implicitItemIdentifier="E8F74F8F-6DE2-4774-A690-F71D92CD932E" label="" paletteLabel="" tag="-1" sizingBehavior="auto" id="CJX-Ff-7iQ">
                         <nil key="toolTip"/>
                         <progressIndicator key="view" wantsLayer="YES" maxValue="100" displayedWhenStopped="NO" indeterminate="YES" controlSize="small" style="spinning" id="rrz-Uh-Nae">
                             <rect key="frame" x="0.0" y="14" width="16" height="16"/>

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