From fd79bb1333ed196ac03da91c27ed8ce3a300f76d Mon Sep 17 00:00:00 2001
From: Geoffrey McRae <geoff@hostfission.com>
Date: Tue, 7 Nov 2023 21:14:01 +1100
Subject: [PATCH] [host] dxgi: add option to enable RGB24 packing support

---
 host/platform/Windows/capture/DXGI/src/dxgi.c     | 11 ++++++++++-
 host/platform/Windows/capture/DXGI/src/pp/rgb24.c |  4 ++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/host/platform/Windows/capture/DXGI/src/dxgi.c b/host/platform/Windows/capture/DXGI/src/dxgi.c
index 5d68ec5c..d5cbef76 100644
--- a/host/platform/Windows/capture/DXGI/src/dxgi.c
+++ b/host/platform/Windows/capture/DXGI/src/dxgi.c
@@ -119,6 +119,7 @@ struct DXGIInterface
   LG_Lock                    deviceContextLock;
   bool                       debug;
   bool                       useAcquireLock;
+  bool                       allowRGB24;
   bool                       dwmFlush;
   bool                       disableDamage;
   D3D_FEATURE_LEVEL          featureLevel;
@@ -260,6 +261,13 @@ static void dxgi_initOptions(void)
       .type           = OPTION_TYPE_BOOL,
       .value.x_bool   = false
     },
+    {
+      .module         = "dxgi",
+      .name           = "allowRGB24",
+      .description    = "Losslessly pack 32-bit RGBA8 into 24-bit RGB (saves bandwidth)",
+      .type           = OPTION_TYPE_BOOL,
+      .value.x_bool   = false
+    },
     {0}
   };
 
@@ -291,6 +299,7 @@ static bool dxgi_create(CaptureGetPointerBuffer getPointerBufferFn, CapturePostP
 
   this->debug               = option_get_bool("dxgi", "debug");
   this->useAcquireLock      = option_get_bool("dxgi", "useAcquireLock");
+  this->allowRGB24          = option_get_bool("dxgi", "allowRGB24");
   this->dwmFlush            = option_get_bool("dxgi", "dwmFlush");
   this->disableDamage       = option_get_bool("dxgi", "disableDamage");
   this->texture             = calloc(this->maxTextures, sizeof(*this->texture));
@@ -842,7 +851,7 @@ static bool dxgi_init(void)
   }
 
   //If not HDR, pack to RGB24
-  if (!this->hdr)
+  if (!this->hdr && this->allowRGB24)
   {
     if (!ppInit(&DXGIPP_RGB24, shareable))
       DEBUG_WARN("Failed to initialize the RGB24 post processor");
diff --git a/host/platform/Windows/capture/DXGI/src/pp/rgb24.c b/host/platform/Windows/capture/DXGI/src/pp/rgb24.c
index 2544585b..7ddf25ca 100644
--- a/host/platform/Windows/capture/DXGI/src/pp/rgb24.c
+++ b/host/platform/Windows/capture/DXGI/src/pp/rgb24.c
@@ -141,6 +141,10 @@ static bool rgb24_configure(void * opaque,
     }
 
     comRef_toGlobal(this.pshader, pshader);
+
+    DEBUG_INFO("RGBA to RGB packing enabled, %.2f MiB per frame saved",
+      (float)((*width * *height - this.width * this.height) * 4) / 1048576
+    );
   }
 
   // This texture is actually going to contain the packed BGR24 output