add nix build system

.envrc

@@ -0,0 +1 @@
+use_nix

.gitignore

@@ -0,0 +1,3 @@
+result
+.DS_Store
+/result

README.md

@@ -21,6 +21,25 @@ section of the developer's website. Please visit
 the [Latest Version Information](https://developer.dji.com/doc/payload-sdk-tutorial/en/)
 to get the latest version information.
 
+## Use Docker & Nix to build
+
+
+
+```bash
+docker pull nixpkgs/nix-flakes:latest
+docker run --name payload -it -v {SOMEWHERE}/Payload-SDK:/workspace docker.io/nixpkgs/nix-flakes:latest bash
+```
+(inside docker)
+```bash
+cd /workspace
+nix develop
+mkdir build && cd build
+cmake ..
+make
+```
+
+then output will appears in `build/bin/dji_sdk_demo_linux` and `build/bin/dji_sdk_demo_linux_cxx`
+
 ## Latest Release
 
 The latest release version of PSDK is 3.9.0. This version of Payload SDK mainly add some new features support and fixed some

default.nix

@@ -0,0 +1,30 @@
+{
+  pkgs ? import <nixpkgs> { },
+}:
+pkgs.stdenv.mkDerivation rec {
+  pname = "dji-payload-sdk";
+  version = "1.0";
+
+  src = ./.;
+
+  enableParallelBuilding = true;
+  # 此选项禁用了对 CMake 软件包的一些自动修正
+  # dontFixCmake = true;
+
+  nativeBuildInputs = with pkgs; [
+    cmake
+    libusb1
+    libopus
+    gcc
+    ffmpeg_4-full
+    opencv3
+  ];
+
+  # 传给 CMake 的配置参数，控制 liboqs 的功能
+  cmakeFlags = [ ];
+
+  postInstall = ''
+    mkdir -p $out/bin
+    install -m755 bin/* $out/bin
+  '';
+}

samples/sample_c++/platform/linux/manifold2/application/dji_sdk_app_info.h.bak

@@ -0,0 +1,55 @@
+/**
+ ********************************************************************
+ * @file    dji_sdk_app_info.h
+ * @brief   This is the header file for defining the structure and (exported) function prototypes.
+ *
+ * @copyright (c) 2018 DJI. All rights reserved.
+ *
+ * All information contained herein is, and remains, the property of DJI.
+ * The intellectual and technical concepts contained herein are proprietary
+ * to DJI and may be covered by U.S. and foreign patents, patents in process,
+ * and protected by trade secret or copyright law.  Dissemination of this
+ * information, including but not limited to data and other proprietary
+ * material(s) incorporated within the information, in any form, is strictly
+ * prohibited without the express written consent of DJI.
+ *
+ * If you receive this source code without DJI’s authorization, you may not
+ * further disseminate the information, and you must immediately remove the
+ * source code and notify DJI of its removal. DJI reserves the right to pursue
+ * legal actions against you for any loss(es) or damage(s) caused by your
+ * failure to do so.
+ *
+ *********************************************************************
+ */
+
+/* Define to prevent recursive inclusion -------------------------------------*/
+#ifndef DJI_SDK_APP_INFO_H
+#define DJI_SDK_APP_INFO_H
+
+/* Includes ------------------------------------------------------------------*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Exported constants --------------------------------------------------------*/
+// ATTENTION: User must goto https://developer.dji.com/user/apps/#all to create your own dji sdk application, get dji sdk application
+// information then fill in the application information here.
+#define USER_APP_NAME               "Campus security"
+#define USER_APP_ID                 "148693"
+#define USER_APP_KEY                "63dcfdc7dd50ada8821724aefc4b240"
+#define USER_APP_LICENSE            "iup9qipeflyvYzTWP6EYghlaODONDAqY4J7NwCSRXCqve3VHZ9HoQh7Ar85GCRaSEpDZ2H1Z9w54m65/K21EzwOsJvKZBmGPtL7xlzeP5iax+3wVqL7RmDYmZrPhLrONcGeHlRpls/HP+KzNMFsFvrIIKmsTFJywxaKloO2gd3K5iv2teltk3XjZJFTNKaLB1TX7aC9qf3/NZFES6z4rYDBsTHHAU+z9dz9beLGvf0YSLSZSIXhq2LPkw1cbC+o3KrbMDPRWzSD+oj8NsLmc9NJxydjhPehabt504I8itEIdFLfU/AYDLPAGLZzTt/mJRoDaDG/HcI0lGWAKPYI7/A=="
+#define USER_DEVELOPER_ACCOUNT      "[email protected]"
+#define USER_BAUD_RATE              "460800"
+
+/* Exported types ------------------------------------------------------------*/
+
+/* Exported functions --------------------------------------------------------*/
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // DJI_SDK_APP_INFO_H
+/************************ (C) COPYRIGHT DJI Innovations *******END OF FILE******/