andongfan / diwocg

Course Project of Computer Graphics (2020-Spring-Summer)

diwoCG

Build

MinGW

cmake . -G "MinGW Makefiles"
mingw32-make
main.exe

Note that the program uses nativefiledialog, a C library that enables cross-platform file selection with native dialogs. The building process is, due to its cross-platform yet binary nature, somehow messy, taking advantage of prebuilt statically-linked libraries, located in the lib/ directory.

These libraries are prebuilt with instructions from the nfd repo, as well as various heuristics and trail-and-error, so it's literally impossible to provide an automatic build script to cover all possible platforms and build toolchains.

Currently, the supported platforms are MacOS / clang, Windows / MinGW and Windows / Visual Studio. If you're building this project under an unlisted platform, you'll have to figure out the build instructions yourself.

So, back to building process.

lib/nfd.lib is build with MinGW as instructed, however the original repo uses sprintf_s, which is an Windows-only function, and internally uses BufferOverflow.lib from Windows SDK.

MinGW, as a port of the GNU toolchain to Windows, contains a set of modified version of Windows header files as well as static libraries that work well on most cases, but not ALL cases. As of nfd, sprintf_s requires BufferOverflow.lib which is not shipped along with MinGW, so we have to get it out of Windows SDK manually.

The problem here is that the libraries in Windows SDK depends on other libraries, like ntdll.lib, which MinGW already has its own version, so if you try to link BufferOverflow.lib, the -lntdll option will instruct g++ to look for the symbols in libntdll.a, a file provided by MinGW. However, BufferOverflow.lib expects ntdll.lib from Windows SDK, which is not compatible with libntdll.a - and then came the infamous undefined reference.

Now you might want to replace libntdll.a with ntdll.lib, but even that won't work, because ntdll.lib - clearly compiled with the MSVC compiler - calls __aullshr, which is an internal function available in MSVC only. You'll get another undefined reference, and this time there's nothing to replace.

So our ultimate solution is to modify nfd source and change sprintf_s to snprintf, thus eliminating usage of BufferOverflow.lib and further problems. There's one problem left: undefined reference to _imp__SHCreateItemFromParsingName@16, which is located in shell32.lib, but not in the MinGW libshell32.a. So we removed libshell32.a and replaced it with shell32.lib, then everything worked.

Ugly as it might show, it's already the simplest solution we can find, and hopefully it'll work for you. If not, well, have fun dealing with compilers!

Usage

• Click and drag to rotate view
• WASD to navigate, Z for down, C for up
• Hover object (you will see a white frame), and hit Space to select it, or hit Space without selecting anything to cancel selection
• Hold G while selection to move the object around (keep it unchanged in your view)
• Hold F while selection to orbit an orbit (G will not work under this case)
• Hold P and drag to take screenshot (of a section of the screen)
• Hit R while selection to zoom to fit
• FPS is written to console output, once per second
• Hit K (globally) to enable/disable lighting
• Hit L while selecting a light source (which will appear as a bright white sphere) to enable/disable the light
• Use arrow keys and , . for moving a selected object
• Hit V B to increase / decrease diffuse of a selected object
• Hit N M to increase / decrease ambient of a selected object
• Hit H J to increase / decrease specular of a selected object
• Use U I O to rotate a selected object around x, y and z axis
• Hit T while selection to open a dialog and choose an image as texture. Hit again to clear it.