GUI - add support for streaming the GUI via Spout on Windows

Author: samaaron

app/CMakeLists.txt

@@ -60,6 +60,15 @@ include(cmake/common.cmake)
 configure_file(${APP_ROOT}/cmake/config.h.cmake ${CMAKE_BINARY_DIR}/config.h)
 
 add_subdirectory(external)
+# Vendored Spout2 — Windows-only sibling to external/Syphon-Framework.
+if(WIN32)
+    add_subdirectory(external/Spout2)
+endif()
 add_subdirectory(api)
 add_subdirectory(api-tests)
 add_subdirectory(gui)
+
+option(BUILD_SPOUT_SMOKETEST "Build tools/spout-receiver smoke-test (Windows)" OFF)
+if(WIN32 AND BUILD_SPOUT_SMOKETEST)
+    add_subdirectory(tools/spout-receiver)
+endif()

app/external/Spout2/CMakeLists.txt

@@ -0,0 +1,45 @@
+# Vendored Spout2 (DirectX 11 sender subset). Windows only.
+# Exposes the `spout_vendored` static target. See README.md for
+# upstream version and local patches.
+
+if(NOT WIN32)
+    return()
+endif()
+
+set(SPOUTSDK_DIR ${CMAKE_CURRENT_SOURCE_DIR}/SPOUTSDK)
+
+add_library(spout_vendored STATIC
+    ${SPOUTSDK_DIR}/SpoutGL/SpoutCopy.cpp
+    ${SPOUTSDK_DIR}/SpoutGL/SpoutDirectX.cpp
+    ${SPOUTSDK_DIR}/SpoutGL/SpoutFrameCount.cpp
+    ${SPOUTSDK_DIR}/SpoutGL/SpoutSenderNames.cpp
+    ${SPOUTSDK_DIR}/SpoutGL/SpoutSharedMemory.cpp
+    ${SPOUTSDK_DIR}/SpoutGL/SpoutUtils.cpp
+    ${SPOUTSDK_DIR}/SpoutDirectX/SpoutDX/SpoutDX.cpp
+)
+
+# PUBLIC — both paths are needed:
+#  - SPOUTSDK/ resolves SpoutDX.h's `#include "SpoutGL\X.h"`
+#  - SPOUTSDK/SpoutDirectX/SpoutDX resolves `#include "SpoutDX.h"`
+target_include_directories(spout_vendored PUBLIC
+    ${SPOUTSDK_DIR}
+    ${SPOUTSDK_DIR}/SpoutDirectX/SpoutDX
+)
+
+# SPOUT_BUILD_DLL selects static-archive symbol decoration. Without it,
+# some Spout headers default to __declspec(dllimport) depending on
+# include order.
+target_compile_definitions(spout_vendored PRIVATE SPOUT_BUILD_DLL)
+
+# PUBLIC — system libs flow up to consumers.
+target_link_libraries(spout_vendored PUBLIC
+    d3d11 dxgi dxguid
+    ole32 oleaut32 uuid shlwapi advapi32 Version
+)
+
+target_compile_features(spout_vendored PUBLIC cxx_std_17)
+
+if(MSVC)
+    target_compile_options(spout_vendored PRIVATE
+        /W3 /D_CRT_SECURE_NO_WARNINGS)
+endif()

app/external/Spout2/LICENSE

@@ -0,0 +1,25 @@
+BSD 2-Clause License
+
+Copyright (c) 2020, Lynn Jarvis
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

app/external/Spout2/README.md

@@ -0,0 +1,93 @@
+# Spout2 (vendored subset)
+
+This directory contains a vendored, minimal subset of [Spout2](https://github.com/leadedge/Spout2)
+— the server-side DirectX 11 sender used by Sonic Pi's *Publish Window via Spout* feature
+on Windows. Counterpart to the macOS `Syphon-Framework/` vendor.
+
+## Upstream
+
+- Repo: <https://github.com/leadedge/Spout2>
+- Version: **2.007.010**
+- Source commit: `62362774c96547d63b502d7efd5cfbf138eb7570`
+- License: BSD-2-Clause (`LICENSE`)
+
+## Subset
+
+Only the SpoutDX (DirectX 11 sender) path is shipped. The OpenGL helpers, GL-based
+Spout/SpoutSender/SpoutReceiver wrappers, demos, examples and the SpoutPanel /
+SpoutSettings tools are deliberately omitted.
+
+```
+SPOUTSDK/
+├── SpoutGL/                     ← runtime backing (despite the "GL" dir name,
+│   ├── SpoutCommon.h               these files are the DX subset's deps)
+│   ├── SpoutCopy.{h,cpp}
+│   ├── SpoutDirectX.{h,cpp}
+│   ├── SpoutFrameCount.{h,cpp}
+│   ├── SpoutSenderNames.{h,cpp}
+│   ├── SpoutSharedMemory.{h,cpp}
+│   └── SpoutUtils.{h,cpp}
+└── SpoutDirectX/SpoutDX/
+    └── SpoutDX.{h,cpp}          ← the public facade we consume
+```
+
+## Local modifications
+
+Three patches applied directly to the source — they do **not** exist as separate
+`.patch` files in this tree because the vendored copy is checked in already-patched.
+
+### 1. fix-include-path
+
+`SpoutDirectX/SpoutDX/SpoutDX.h` uses quote-form includes like
+`#include "SpoutGL\SpoutCommon.h"`. Upstream's CMake builds `SpoutDX` as a
+separate target with its own private include path that lets `..\..\SpoutGL\X.h`
+resolve. In our in-tree build the headers come from this directory's structure
+directly, so the relative paths were normalised to single-segment form.
+
+### 2. fix-dx-keyed
+
+`spoutDX::spoutDX()` ctor: explicitly initialises `m_bKeyed = false` so the
+keyed-mutex code path is deterministic without depending on whatever a default
+caller may have set.
+
+### 3. fix-arm64 (Sonic Pi specific)
+
+Spout's `SpoutCopy.{h,cpp}` uses SSE2/SSSE3 intrinsics (`<emmintrin.h>`,
+`<tmmintrin.h>`, `__m128i`, `_mm_*`) for fast pixel copies, plus 3 `__movsd`
+calls in `SpoutCopy.cpp` and 3 in `SpoutSenderNames.cpp` for the 280-byte
+shared-sender-info struct. None of those compile for MSVC on ARM64.
+
+Modifications:
+
+- SSE includes guarded with `#if defined(_M_IX86) || defined(_M_AMD64)`,
+  defining `SPOUT_HAS_SSE` to 1 / 0.
+- `spoutCopy::memcpy_sse2`, `rgba_bgra_sse2`, `rgba_bgra_sse3` and
+  `rgb_to_bgrx_sse` function bodies wrapped in `#if SPOUT_HAS_SSE`, with
+  scalar `memcpy` (or no-op) fallbacks on ARM64. The call sites are already
+  runtime-guarded by `m_bSSE2 / m_bSSSE3` flags which stay `false` on ARM64
+  because `CheckSSE()`'s `__cpuid` calls are also gated out.
+- Six `__movsd(dst, src, n)` calls replaced with `memcpy(dst, src, n*4)`.
+  Semantically equivalent. On x64 / x86 modern MSVC `memcpy` is heavily
+  optimised (often emits the same `rep movs` instruction internally).
+
+On x86 / x64 the patches are inert — `SPOUT_HAS_SSE` is 1, all SSE bodies
+compile as upstream, runtime SSE-detection works, behaviour is identical.
+
+The `__movsd` -> `memcpy` swap is unconditional but the perf difference is
+sub-microsecond on a 280-byte struct copied once per sender event — not on
+any hot path.
+
+## Updating
+
+To pull a new upstream Spout2 release:
+
+1. Download `https://github.com/leadedge/Spout2/archive/<commit>.tar.gz`
+2. Diff against this tree to see what's drifted in the subset above.
+3. Re-apply the three modifications above (the `fix-arm64` one is the only
+   non-trivial diff).
+4. Bump the version + commit references in this README.
+
+Long term: upstreaming the ARM64 changes to `leadedge/Spout2` would eliminate
+the third patch entirely. The mods follow the same `_M_IX86 || _M_AMD64`
+pattern Spout already uses internally in some places, so a PR should be
+mechanical.