From b529bba53a71007185ce6ad694486a0801fbe309 Mon Sep 17 00:00:00 2001
From: Joshua Ashton <joshua@froggi.es>
Date: Wed, 5 Apr 2023 19:28:07 +0100
Subject: [PATCH] steamcompmgr: Add GAMESCOPE_COLOR_APP_WANTS_HDR_FEEDBACK

Tell Steam whether this app is wanting HDR or not.

(Whether it's submitting  HDR buffers)
---
 src/drm.hpp          |  6 ++++++
 src/steamcompmgr.cpp | 21 +++++++++++++++++++++
 src/xwayland_ctx.hpp |  1 +
 3 files changed, 28 insertions(+)

diff --git a/src/drm.hpp b/src/drm.hpp
index 8242ac8..850dad7 100644
--- a/src/drm.hpp
+++ b/src/drm.hpp
@@ -42,6 +42,12 @@ enum GamescopeAppTextureColorspace {
 };
 const uint32_t GamescopeAppTextureColorspace_Bits = 2;
 
+inline bool ColorspaceIsHDR( GamescopeAppTextureColorspace colorspace )
+{
+	return colorspace == GAMESCOPE_APP_TEXTURE_COLORSPACE_SCRGB ||
+		   colorspace == GAMESCOPE_APP_TEXTURE_COLORSPACE_HDR10_PQ;
+}
+
 extern struct drm_t g_DRM;
 void drm_destroy_hdr_metadata_blob(struct drm_t *drm, uint32_t blob);
 
diff --git a/src/steamcompmgr.cpp b/src/steamcompmgr.cpp
index 598e326..6f1dff5 100644
--- a/src/steamcompmgr.cpp
+++ b/src/steamcompmgr.cpp
@@ -6100,6 +6100,7 @@ void init_xwayland_ctx(uint32_t serverId, gamescope_xwayland_server_t *xwayland_
 	ctx->atoms.gamescopeColorSDRGamutWideness = XInternAtom( ctx->dpy, "GAMESCOPE_COLOR_SDR_GAMUT_WIDENESS", false );
 	ctx->atoms.gamescopeColorNightMode = XInternAtom( ctx->dpy, "GAMESCOPE_COLOR_NIGHT_MODE", false );
 	ctx->atoms.gamescopeColorManagementDisable = XInternAtom( ctx->dpy, "GAMESCOPE_COLOR_MANAGEMENT_DISABLE", false );
+	ctx->atoms.gamescopeColorAppWantsHDRFeedback = XInternAtom( ctx->dpy, "GAMESCOPE_COLOR_APP_WANTS_HDR_FEEDBACK", false );
 
 	ctx->atoms.gamescopeCreateXWaylandServer = XInternAtom( ctx->dpy, "GAMESCOPE_CREATE_XWAYLAND_SERVER", false );
 	ctx->atoms.gamescopeCreateXWaylandServerFeedback = XInternAtom( ctx->dpy, "GAMESCOPE_CREATE_XWAYLAND_SERVER_FEEDBACK", false );
@@ -6606,6 +6607,26 @@ steamcompmgr_main(int argc, char **argv)
 				}
 			}
 
+			{
+				GamescopeAppTextureColorspace current_app_colorspace = GAMESCOPE_APP_TEXTURE_COLORSPACE_SRGB;
+				if ( g_HeldCommits[HELD_COMMIT_BASE] )
+					current_app_colorspace = g_HeldCommits[HELD_COMMIT_BASE]->colorspace();
+
+				bool app_wants_hdr = ColorspaceIsHDR( current_app_colorspace );
+
+				static bool s_bAppWantsHDRCached = false;
+
+				if ( app_wants_hdr != s_bAppWantsHDRCached )
+				{
+					uint32_t app_wants_hdr_prop = app_wants_hdr ? 1 : 0;
+
+					XChangeProperty(root_ctx->dpy, root_ctx->root, root_ctx->atoms.gamescopeColorAppWantsHDRFeedback, XA_CARDINAL, 32, PropModeReplace,
+							(unsigned char *)&app_wants_hdr_prop, 1 );
+
+					s_bAppWantsHDRCached = app_wants_hdr;
+				}
+			}
+
 			currentOutputWidth = g_nOutputWidth;
 			currentOutputHeight = g_nOutputHeight;
 			currentHDROutput = g_bOutputHDREnabled;
diff --git a/src/xwayland_ctx.hpp b/src/xwayland_ctx.hpp
index b21944c..7b3dcf1 100644
--- a/src/xwayland_ctx.hpp
+++ b/src/xwayland_ctx.hpp
@@ -191,6 +191,7 @@ struct xwayland_ctx_t
 		Atom gamescopeColorSDRGamutWideness;
 		Atom gamescopeColorNightMode; // amount, hue, saturation
 		Atom gamescopeColorManagementDisable;
+		Atom gamescopeColorAppWantsHDRFeedback;
 
 		Atom gamescopeCreateXWaylandServer;
 		Atom gamescopeCreateXWaylandServerFeedback;