Build: add the WESTON compositor for Linux

WESTON is used when WITH_UI_TESTS is enabled.

Note that the system WESTON installation can be used by setting
WESTON_BIN to a path on the users system.

Ref !114164.

build_files/build_environment/CMakeLists.txt

@@ -168,6 +168,7 @@ if(UNIX AND NOT APPLE)
   # Can be removed when the build-bot upgrades to v1.20.x or newer.
   include(cmake/wayland.cmake)
   include(cmake/wayland_libdecor.cmake)
+  include(cmake/wayland_weston.cmake)
 endif()
 include(cmake/shaderc_deps.cmake)
 include(cmake/shaderc.cmake)

build_files/build_environment/cmake/download.cmake

@@ -137,6 +137,7 @@ download_source(XR_OPENXR_SDK)
 download_source(WL_PROTOCOLS)
 download_source(WAYLAND)
 download_source(WAYLAND_LIBDECOR)
+download_source(WAYLAND_WESTON)
 download_source(ISPC)
 download_source(GMP)
 download_source(POTRACE)

build_files/build_environment/cmake/harvest.cmake

@@ -191,6 +191,14 @@ else()
     harvest(wayland/bin wayland/bin "wayland-scanner")
     harvest(wayland/include wayland/include "*.h")
     harvest(wayland_libdecor/include wayland_libdecor/include "*.h")
+    # Only needed for running the WESTON compositor.
+    harvest(wayland/lib64 wayland/lib64 "*")
+
+    harvest(
+      wayland_weston/
+      wayland_weston/
+      "*"
+    )
   else()
     harvest(blosc/lib openvdb/lib "*.a")
     harvest(xml2/lib opencollada/lib "*.a")

build_files/build_environment/cmake/versions.cmake

@@ -574,6 +574,13 @@ set(WAYLAND_LIBDECOR_HASH 47b59eba76faa3787f0878bf8700e912)
 set(WAYLAND_LIBDECOR_HASH_TYPE MD5)
 set(WAYLAND_LIBDECOR_HOMEPAGE https://gitlab.freedesktop.org/libdecor/libdecor)
 
+set(WAYLAND_WESTON_VERSION 12.0.92)
+set(WAYLAND_WESTON_FILE weston-${WAYLAND_WESTON_VERSION}.tar.xz)
+set(WAYLAND_WESTON_URI https://gitlab.freedesktop.org/wayland/weston/-/releases/${WAYLAND_WESTON_VERSION}/downloads/weston-${WAYLAND_WESTON_VERSION}.tar.xz)
+set(WAYLAND_WESTON_HASH 44542b60bf9b9fe3add904af11bbad98)
+set(WAYLAND_WESTON_HASH_TYPE MD5)
+set(WAYLAND_WESTON_HOMEPAGE https://wayland.freedesktop.org)
+
 set(ISPC_VERSION v1.17.0)
 set(ISPC_URI https://github.com/ispc/ispc/archive/${ISPC_VERSION}.tar.gz)
 set(ISPC_HASH 4f476a3109332a77fe839a9014c60ca9)

build_files/build_environment/cmake/wayland_weston.cmake

@@ -0,0 +1,56 @@
+# SPDX-FileCopyrightText: 2023 Blender Authors
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+set(WAYLAND_WESTON_CONFIGURE_ENV ${CONFIGURE_ENV})
+set(WAYLAND_WESTON_PKG_ENV "PKG_CONFIG_PATH=\
+${LIBDIR}/wayland/lib64/pkgconfig:\
+${LIBDIR}/wayland-protocols/share/pkgconfig:\
+$PKG_CONFIG_PATH"
+)
+
+ExternalProject_Add(external_wayland_weston
+  URL file://${PACKAGE_DIR}/${WAYLAND_WESTON_FILE}
+  URL_HASH ${WAYLAND_WESTON_HASH_TYPE}=${WAYLAND_WESTON_HASH}
+  DOWNLOAD_DIR ${DOWNLOAD_DIR}
+  PREFIX ${BUILD_DIR}/wayland_weston
+
+  CONFIGURE_COMMAND ${WAYLAND_WESTON_CONFIGURE_ENV} &&
+  ${CMAKE_COMMAND} -E env ${WAYLAND_WESTON_PKG_ENV}
+  ${MESON} setup
+  ${MESON_BUILD_TYPE}
+  --prefix ${LIBDIR}/wayland_weston
+  --libdir lib
+  -Dbackend-default=headless  # For tests.
+  -Dbackend-drm-screencast-vaapi=false
+  -Dbackend-drm=false
+  -Dbackend-pipewire=false
+  -Dbackend-rdp=false
+  -Dcolor-management-lcms=false
+  -Ddemo-clients=false
+  -Dimage-jpeg=false
+  -Dimage-webp=false
+  -Dpipewire=false
+  -Dremoting=false
+  -Dshell-fullscreen=false
+  -Dshell-kiosk=false
+  -Dsimple-clients=
+  -Dsystemd=false
+  -Dtest-junit-xml=false
+  -Dwcap-decode=false
+  -Dxwayland=false
+  ${BUILD_DIR}/wayland_weston/src/external_wayland_weston-build
+  ${BUILD_DIR}/wayland_weston/src/external_wayland_weston
+
+  BUILD_COMMAND ninja
+  INSTALL_COMMAND ninja install
+  INSTALL_DIR ${LIBDIR}/wayland_weston
+)
+
+add_dependencies(
+  external_wayland_weston
+  external_wayland_protocols
+  external_wayland
+  # Needed for `MESON`.
+  external_python_site_packages
+)

build_files/build_environment/linux/linux_rocky8_setup.sh

@@ -109,6 +109,20 @@ PACKAGES_FOR_LIBS=(
     # Required by: `external_ssl` (build dependencies).
     perl-IPC-Cmd
     perl-Pod-Html
+
+    # Required by: `external_wayland_weston`
+    cairo-devel
+    libdrm-devel
+    pixman-devel
+    libffi-devel
+    libinput-devel
+    libevdev-devel
+    mesa-libEGL-devel
+    systemd-dev # for `libudev` (not so obvious!).
+    # Required by: `weston --headless` (run-time requirement for off screen rendering).
+    mesa-dri-drivers
+    mesa-libEGL
+    mesa-libGL
 )
 
 # Additional packages needed for building Blender.