From 4b60371e64601dba46387f8b7260b3deb770e097 Mon Sep 17 00:00:00 2001
From: riperiperi <rhy3756547@hotmail.com>
Date: Mon, 19 Jul 2021 23:10:54 +0100
Subject: Return mapped buffer pointer directly for flush, WriteableRegion for
 textures (#2494)

* Return mapped buffer pointer directly for flush, WriteableRegion for textures

A few changes here to generally improve performance, even for platforms not using the persistent buffer flush.

- Texture and buffer flush now return a ReadOnlySpan<byte>. It's guaranteed that this span is pinned in memory, but it will be overwritten on the next flush from that thread, so it is expected that the data is used before calling again.
- As a result, persistent mappings no longer copy to a new array - rather the persistent map is returned directly as a Span<>. A similar host array is used for the glGet flushes instead of allocating new arrays each time.
- Texture flushes now do their layout conversion into a WriteableRegion when the texture is not MultiRange, which allows the flush to happen directly into guest memory rather than into a temporary span, then copied over. This avoids another copy when doing layout conversion.

Overall, this saves 1 data copy for buffer flush, 1 copy for linear textures with matching source/target stride, and 2 copies for block textures or linear textures with mismatching strides.

* Fix tests

* Fix array pointer for Mesa/Intel path

* Address some feedback

* Update method for getting array pointer.
---
 Ryujinx.Graphics.Texture/LayoutConverter.cs | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

(limited to 'Ryujinx.Graphics.Texture/LayoutConverter.cs')

diff --git a/Ryujinx.Graphics.Texture/LayoutConverter.cs b/Ryujinx.Graphics.Texture/LayoutConverter.cs
index 1b7dad2a..970d08cb 100644
--- a/Ryujinx.Graphics.Texture/LayoutConverter.cs
+++ b/Ryujinx.Graphics.Texture/LayoutConverter.cs
@@ -359,6 +359,7 @@ namespace Ryujinx.Graphics.Texture
         }
 
         public static ReadOnlySpan<byte> ConvertLinearToBlockLinear(
+            Span<byte> output,
             int width,
             int height,
             int depth,
@@ -373,7 +374,10 @@ namespace Ryujinx.Graphics.Texture
             SizeInfo sizeInfo,
             ReadOnlySpan<byte> data)
         {
-            Span<byte> output = new byte[sizeInfo.TotalSize];
+            if (output.Length == 0)
+            {
+                output = new byte[sizeInfo.TotalSize];
+            }
 
             int inOffs = 0;
 
@@ -500,6 +504,7 @@ namespace Ryujinx.Graphics.Texture
         }
 
         public static ReadOnlySpan<byte> ConvertLinearToLinearStrided(
+            Span<byte> output,
             int width,
             int height,
             int blockWidth,
@@ -516,10 +521,21 @@ namespace Ryujinx.Graphics.Texture
 
             if (inStride == stride)
             {
-                return data;
+                if (output.Length != 0)
+                {
+                    data.CopyTo(output);
+                    return output;
+                }
+                else
+                {
+                    return data;
+                }
             }
 
-            Span<byte> output = new byte[h * stride];
+            if (output.Length == 0)
+            {
+                output = new byte[h * stride];
+            }
 
             int inOffs = 0;
             int outOffs = 0;
-- 
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