From 1ef8cb1111b63c06b2bd3cd567ab53195a38fac0 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Sun, 25 Jun 2023 17:40:25 -0500
Subject: [PATCH] Send feature flags in RTSP DESCRIBE response

---
 src/platform/common.h          | 15 +++++++++++++++
 src/platform/linux/input.cpp   |  9 +++++++++
 src/platform/macos/input.cpp   |  9 +++++++++
 src/platform/windows/input.cpp |  9 +++++++++
 src/rtsp.cpp                   |  4 ++++
 5 files changed, 46 insertions(+)

diff --git a/src/platform/common.h b/src/platform/common.h
index 91fced16..4d2ba921 100644
--- a/src/platform/common.h
+++ b/src/platform/common.h
@@ -160,6 +160,14 @@ namespace platf {
     int width, height;
   };
 
+  // These values must match Limelight-internal.h's SS_FF_* constants!
+  namespace platform_caps {
+    typedef uint32_t caps_t;
+
+    constexpr caps_t pen_touch = 0x01;  // Pen and touch events
+    constexpr caps_t controller_touch = 0x02;  // Controller touch events
+  };  // namespace platform_caps
+
   struct gamepad_state_t {
     std::uint32_t buttonFlags;
     std::uint8_t lt;
@@ -475,6 +483,13 @@ namespace platf {
   void
   free_gamepad(input_t &input, int nr);
 
+  /**
+   * @brief Returns the supported platform capabilities to advertise to the client.
+   * @return Capability flags.
+   */
+  platform_caps::caps_t
+  get_capabilities();
+
 #define SERVICE_NAME "Sunshine"
 #define SERVICE_TYPE "_nvstream._tcp"
 
diff --git a/src/platform/linux/input.cpp b/src/platform/linux/input.cpp
index d266ed5e..942d69e9 100644
--- a/src/platform/linux/input.cpp
+++ b/src/platform/linux/input.cpp
@@ -1833,4 +1833,13 @@ namespace platf {
 
     return gamepads;
   }
+
+  /**
+   * @brief Returns the supported platform capabilities to advertise to the client.
+   * @return Capability flags.
+   */
+  platform_caps::caps_t
+  get_capabilities() {
+    return 0;
+  }
 }  // namespace platf
diff --git a/src/platform/macos/input.cpp b/src/platform/macos/input.cpp
index 0ca85e75..b9b5b9b4 100644
--- a/src/platform/macos/input.cpp
+++ b/src/platform/macos/input.cpp
@@ -500,4 +500,13 @@ const KeyCodeMap kKeyCodesMap[] = {
 
     return gamepads;
   }
+
+  /**
+   * @brief Returns the supported platform capabilities to advertise to the client.
+   * @return Capability flags.
+   */
+  platform_caps::caps_t
+  get_capabilities() {
+    return 0;
+  }
 }  // namespace platf
diff --git a/src/platform/windows/input.cpp b/src/platform/windows/input.cpp
index c3067cb3..797c9d7e 100644
--- a/src/platform/windows/input.cpp
+++ b/src/platform/windows/input.cpp
@@ -825,4 +825,13 @@ namespace platf {
 
     return gps;
   }
+
+  /**
+   * @brief Returns the supported platform capabilities to advertise to the client.
+   * @return Capability flags.
+   */
+  platform_caps::caps_t
+  get_capabilities() {
+    return 0;
+  }
 }  // namespace platf
diff --git a/src/rtsp.cpp b/src/rtsp.cpp
index a2e4a2fc..28a029c6 100644
--- a/src/rtsp.cpp
+++ b/src/rtsp.cpp
@@ -492,6 +492,10 @@ namespace rtsp_stream {
     option.content = const_cast<char *>(seqn_str.c_str());
 
     std::stringstream ss;
+
+    // Tell the client about our supported features
+    ss << "a=x-ss-general.featureFlags: " << (uint32_t) platf::get_capabilities();
+
     if (video::active_hevc_mode != 1) {
       ss << "sprop-parameter-sets=AAAAAU"sv << std::endl;
     }