From ea5b6b4026f9255c6c704dbaa64571e63972dc8b Mon Sep 17 00:00:00 2001
From: Tudor Brindus <me@tbrindus.ca>
Date: Sun, 5 Nov 2023 21:44:45 -0500
Subject: [PATCH] [host] DXGI: implement damage-aware RGB24 copy

---
 .../platform/Windows/capture/DXGI/src/d3d11.c |  9 +++++++--
 host/platform/Windows/capture/DXGI/src/dxgi.c | 19 ++++++++++++++++++-
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/host/platform/Windows/capture/DXGI/src/d3d11.c b/host/platform/Windows/capture/DXGI/src/d3d11.c
index d931c1b9..90836c95 100644
--- a/host/platform/Windows/capture/DXGI/src/d3d11.c
+++ b/host/platform/Windows/capture/DXGI/src/d3d11.c
@@ -140,6 +140,11 @@ static void d3d11_free(void)
   this = NULL;
 }
 
+static int scaleForBGR(int x)
+{
+  return x * 3 / 4;
+}
+
 static void copyFrameFull(Texture * tex, ID3D11Texture2D * src)
 {
   struct D3D11TexImpl * teximpl = TEXIMPL(*tex);
@@ -155,11 +160,11 @@ static void copyFrameFull(Texture * tex, ID3D11Texture2D * src)
       FrameDamageRect * rect = tex->texDamageRects + i;
       D3D11_BOX box =
       {
-        .left   = rect->x,
+        .left   = scaleForBGR(rect->x),
         .top    = rect->y,
         .front  = 0,
         .back   = 1,
-        .right  = rect->x + rect->width ,
+        .right  = scaleForBGR(rect->x + rect->width),
         .bottom = rect->y + rect->height,
       };
       ID3D11DeviceContext_CopySubresourceRegion(*dxgi->deviceContext,
diff --git a/host/platform/Windows/capture/DXGI/src/dxgi.c b/host/platform/Windows/capture/DXGI/src/dxgi.c
index a7f89507..817b331f 100644
--- a/host/platform/Windows/capture/DXGI/src/dxgi.c
+++ b/host/platform/Windows/capture/DXGI/src/dxgi.c
@@ -1365,6 +1365,11 @@ static CaptureResult dxgi_waitFrame(CaptureFrame * frame, const size_t maxFrameS
   return CAPTURE_RESULT_OK;
 }
 
+static int scaleForBGR(int x)
+{
+  return x * 3 / 4;
+}
+
 static CaptureResult dxgi_getFrame(FrameBuffer * frame, int frameIndex)
 {
   DEBUG_ASSERT(this);
@@ -1383,7 +1388,19 @@ static CaptureResult dxgi_getFrame(FrameBuffer * frame, int frameIndex)
     memcpy(damage->rects + damage->count, tex->damageRects,
       tex->damageRectsCount * sizeof(*tex->damageRects));
     damage->count += tex->damageRectsCount;
-    rectsBufferToFramebuffer(damage->rects, damage->count, this->bpp, frame,
+
+    FrameDamageRect scaledDamageRects[damage->count];
+    for (int i = 0; i < ARRAYSIZE(scaledDamageRects); i++) {
+      FrameDamageRect rect = damage->rects[i];
+      int originalX = rect.x;
+      int scaledX = scaleForBGR(originalX);
+      rect.x = scaledX;
+      rect.width = scaleForBGR(originalX + rect.width) - scaledX;
+
+      scaledDamageRects[i] = rect;
+    }
+
+    rectsBufferToFramebuffer(scaledDamageRects, damage->count, this->bpp, frame,
       this->pitch, this->dataHeight, tex->map, this->pitch);
   }