Make CMake download the prebuilt version of libmpv from our server; Add example asset that downloads its video on include

data/assets/examples/video_on_globe.asset

@@ -0,0 +1,35 @@
+local earth = asset.require("scene/solarsystem/planets/earth/earth")
+
+local data = asset.syncedResource({
+  Name = "Example Globe Video",
+  Type = "UrlSynchronization",
+  Identifier = "example_globe_video",
+  Url = "http://liu-se.cdn.openspaceproject.com/files/examples/test-video.mp4"
+})
+
+local layer = {
+  Identifier = "ExampleVideo",
+  Video = data .. "/test-video.mp4",
+  Name = "Example Video",
+  Enabled = true,
+  Type = "VideoTileLayer"
+}
+
+asset.onInitialize(function()
+  openspace.globebrowsing.addLayer(earth.Earth.Identifier, "ColorLayers", layer)
+end)
+
+asset.onDeinitialize(function()
+  openspace.globebrowsing.deleteLayer(earth.Earth.Identifier, "ColorLayers", layer)
+end)
+
+asset.export("layer", layer)
+
+asset.meta = {
+  Name = "Video Player Test",
+  Version = "1.0",
+  Description = "An example asset that shows how to include a video on Earth",
+  Author = "OpenSpace Team",
+  URL = "https://openspaceproject.com",
+  License = "MIT"
+}

modules/video/CMakeLists.txt

@@ -46,22 +46,52 @@ set(SOURCE_FILES
 source_group("Source Files" FILES ${SOURCE_FILES})
 
 # Libmpv
-if(WIN32)
+if (WIN32)
+  set(LIBMPV_ROOT "${CMAKE_CURRENT_BINARY_DIR}/ext/libmpv" CACHE INTERNAL "LIBMPV_ROOT")
+  if (NOT IS_DIRECTORY "${LIBMPV_ROOT}")
+    message(STATUS "Downloading LibMPV...")
+
+    # First download the SHA1 hash of the file
+    file(
+      DOWNLOAD
+      "http://data.openspaceproject.com/ext/libmpv/2.0/libmpv.zip.sha1"
+      "${LIBMPV_ROOT}/libmpv.zip.sha1"
+    )
+    file(READ "${LIBMPV_ROOT}/libmpv.zip.sha1" LIBMPV_SHA1)
+
+    # For some reason the SHA1 file contains extra linebreaks
+    string(STRIP ${LIBMPV_SHA1} LIBMPV_SHA1)
+
+    # Then download the file itself
+    file(
+      DOWNLOAD
+      "http://data.openspaceproject.com/ext/libmpv/2.0/libmpv.zip"
+      "${LIBMPV_ROOT}/libmpv.zip"
+      EXPECTED_HASH SHA1=${LIBMPV_SHA1}
+      SHOW_PROGRESS
+    )
+
+    execute_process(
+      COMMAND ${CMAKE_COMMAND} -E tar xzf "${LIBMPV_ROOT}/libmpv.zip"
+      WORKING_DIRECTORY ${LIBMPV_ROOT}
+    )
+  endif ()
+
   add_library(libmpv SHARED IMPORTED)
-  target_include_directories(libmpv SYSTEM INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}/ext/libmpv/include)
+  target_include_directories(libmpv SYSTEM INTERFACE ${LIBMPV_ROOT}/libmpv/include)
   set_target_properties(libmpv PROPERTIES
-    IMPORTED_LOCATION "${CMAKE_CURRENT_SOURCE_DIR}/ext/libmpv/bin/mpv-2.dll"
-    IMPORTED_IMPLIB "${CMAKE_CURRENT_SOURCE_DIR}/ext/libmpv/lib/mpv.lib"
+    IMPORTED_LOCATION "${LIBMPV_ROOT}/libmpv/bin/mpv-2.dll"
+    IMPORTED_IMPLIB "${LIBMPV_ROOT}/libmpv/lib/mpv.lib"
   )
 
   add_library(libopenh264 SHARED IMPORTED)
   set_target_properties(libopenh264 PROPERTIES
-    IMPORTED_LOCATION "${CMAKE_CURRENT_SOURCE_DIR}/ext/libmpv/bin/libopenh264.dll"
-    IMPORTED_IMPLIB "${CMAKE_CURRENT_SOURCE_DIR}/ext/libmpv/lib/mpv.lib"
+    IMPORTED_LOCATION "${LIBMPV_ROOT}/libmpv/bin/libopenh264.dll"
+    IMPORTED_IMPLIB "${LIBMPV_ROOT}/libmpv/lib/mpv.lib"
   )
 
   target_link_libraries(openspace-module-globebrowsing PUBLIC libmpv libopenh264)
-else(WIN32)
+else (WIN32)
   find_package(LIBMPV REQUIRED)
 
   target_include_directories(openspace-module-globebrowsing SYSTEM PRIVATE ${LIBMPV_INCLUDE_DIR})
@@ -74,4 +104,4 @@ create_new_module(
   video_module
   STATIC
   ${HEADER_FILES} ${SOURCE_FILES}
-)
+)