GLFW example with dirty region management (flutter#35057)

* Update the GLFW example callbacks.

* Update the dart example.

* Update CMakeLists

* Update library dependencies in the BUILD file.

* Documenting.

* Formatting.

* Update the callback name.

* Move glfw_drm example to a new folder.

* Create new example folder for drm_embedder.

* Add the flutter spinkit dependency

* Update BUILD files.

* Do not compile glfw_drm example if running it on mac.

* Update the executable name for the glfw_drm example.

* Avoid looking for the surface and display every time since they are always the same.

* Formatting.

* GN formatting.

* Update the way the user malloc's the existing damage

* Update comment

* Update example and add gitignore.

Co-authored-by: Bernardo Eilert Trevisan <[email protected]>

BUILD.gn

@@ -84,6 +84,10 @@ group("flutter") {
       "//flutter/examples/glfw",
       "//flutter/examples/vulkan_glfw",
     ]
+
+    if (!is_mac) {
+      public_deps += [ "//flutter/examples/glfw_drm" ]
+    }
   }
 
   # If enbaled, compile the SDK / snapshot.

examples/glfw_drm/.gitignore

@@ -0,0 +1 @@
+debug/

examples/glfw_drm/BUILD.gn

@@ -0,0 +1,20 @@
+# Copyright 2013 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//flutter/examples/examples.gni")
+
+if (build_embedder_examples) {
+  executable("glfw_drm") {
+    output_name = "embedder_example_drm"
+
+    sources = [ "FlutterEmbedderGLFW.cc" ]
+
+    deps = [
+      "//flutter/shell/platform/embedder:embedder",
+      "//third_party/glfw",
+    ]
+
+    libs = [ "EGL" ]
+  }
+}

examples/glfw_drm/CMakeLists.txt

@@ -0,0 +1,35 @@
+cmake_minimum_required(VERSION 3.15)
+project(FlutterEmbedderGLFW)
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11" )
+
+add_executable(flutter_glfw FlutterEmbedderGLFW.cc)
+
+############################################################
+# GLFW
+############################################################
+option(GLFW_BUILD_EXAMPLES "" OFF)
+option(GLFW_BUILD_TESTS "" OFF)
+option(GLFW_BUILD_DOCS "" OFF)
+option(GLFW_INSTALL "" OFF)
+find_package(OpenGL REQUIRED COMPONENTS EGL)
+include_directories(${OPENGL_INCLUDE_DIRS})
+add_subdirectory(${CMAKE_SOURCE_DIR}/../../../third_party/glfw glfw)
+target_link_libraries(flutter_glfw glfw OpenGL::EGL)
+include_directories(${CMAKE_SOURCE_DIR}/../../../third_party/glfw/include)
+
+############################################################
+# Flutter Engine
+############################################################
+# This is assuming you've built a local version of the Flutter Engine.  If you
+# downloaded yours is from the internet you'll have to change this.
+include_directories(${CMAKE_SOURCE_DIR}/../../shell/platform/embedder)
+find_library(FLUTTER_LIB flutter_engine PATHS ${CMAKE_SOURCE_DIR}/../../../out/host_debug_unopt)
+target_link_libraries(flutter_glfw ${FLUTTER_LIB})
+
+# Copy the flutter library here since the shared library
+# name is `./libflutter_engine.dylib`.
+add_custom_command(
+        TARGET flutter_glfw POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy
+                ${FLUTTER_LIB}
+                ${CMAKE_CURRENT_BINARY_DIR})