This is the Hello Tanvas demo rewritten in C using the TanvasTouch C API and SDL.  It targets TanvasTouch Windows SDK 3.0.0.

Download: HelloTanvasC.zip (3.1 MB)

Below is a copy of the example’s README.md file, converted to HTML from Markdown for Web viewing.

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The TanvasTouch C API example program

This program is a C implementation of the Hello Tanvas program described at https://tanvas.co/resources/api-reference/tanvastouch/dotnet-interface/articles/hello-tanvas.html. It has been tested in the following environments:

OS	Compiler
Windows 10	MSVC 2019 16.6
Kubuntu 20.04	clang 10.0.0
Kubuntu 20.04	gcc 9.3.0

Any recent C compiler should be able to build the program. If you find this is not the case, contact [email protected].

Installing dependencies on Windows

This example requires TanvasTouch Windows SDK v3.0.0 or later. You can download SDK v3.0.0 from https://tanvas.co/resources/tanvas-downloads.

This example contains a copy of the TanvasTouch C API library from SDK v3.0.0 in external\tanvastouch. If you have a newer version of the TanvasTouch Windows SDK installed, you can copy the contents of TanvasTouch SDK\API\C into that directory.

The TanvasTouch C API example program has additional dependencies on SDL and stb_image. Tanvas recommends using the Vcpkg package manager to install these dependencies.

To install dependencies via Vcpkg, follow the instructions at https://github.com/microsoft/vcpkg/blob/master/README.md#quick-start-windows to install Vcpkg. Then, in the Vcpkg directory, run

vcpkg integrate install

This command will output a path to a vcpkg.cmake file. Make a note of this path for later reference.

Next, run

vcpkg install sdl2 stb --triplet x64-windows

Building the program with Visual Studio 2019

To build this program with Visual Studio 2019, select File > Open > CMake… and select the directory containing this README file. If you are at the Visual Studio 2019 startup screen, select Open a local folder and select the directory containing this README file.

If File > Open > CMake… is not available, you may need to install additional Visual Studio components. In Visual Studio Installer, select Modify > Individual components and make sure that C++ CMake tools for Windows is checked.

With Visual Studio 2019, the vcpkg integrate install command you ran in the “Installing dependencies on Windows” section should allow Visual Studio to automatically detect Vcpkg. If it does not, you can supply the path to vcpkg.cmake in the CMake toolchain file field in Visual Studio’s CMake Settings dialog.

Running the program in Visual Studio 2019

Make sure that the TanvasTouch Engine is running. Afterwards, press the Start button in Visual Studio or select Debug > Start Debugging.

If you see Select Startup Item… in Visual Studio, press the down arrow next to the Select Startup Item… text and select tanvastouch-c-api-example.exe.

Building the program from the command line

This program can also be built from the command line using CMake:

mkdir build
cd build
cmake -DCMAKE_TOOLCHAIN_FILE=[vcpkg.cmake path] ..
cmake --build .

The text [vcpkg.cmake path] should be replaced by the path printed out by vcpkg integrate install.

Structure of the program

The program is split into the following parts:

File	Purpose
haptics.c	API context management and haptic scene creation
load_png.c	PNG loader
main.c	Startup code and main loop
stb_image.c	Implementation file for stb_image
visuals.c	Functions to create SDL surfaces from PNGs

Using the TanvasTouch C API in C++ programs

The TanvasTouch C API can be used as-is in C++ programs, or it can be wrapped with C++ constructs to relieve the programmer of manual tasks. For more information on this subject, please read the cpp_wrappers.md document in the docs directory.