Getting started

A script is a class in a .hot file. It derives from a native engine class.

A script can also be a plain C++ file, a .cpp script. It compiles unchanged in a normal build. See C++ scripts.

Write a class

using pulls in a native header. A method with override replaces a native virtual method. A bare name reaches a script member or a native member of the base. Use this. only when a parameter has the same name.

using "Actor.h";
using "Math.h";

class Player : Actor {
    float hp = 100.0;
    float speed = 5.0;

    override void Tick(float dt) {
        Move(Vec3(speed * dt, 0, 0));
        heal(1.0);
    }

    void heal(float amount) {
        hp = Math.Min(hp + amount, 100.0);
    }
}

Check and compile

The first command translates the script to C++ and prints it. The second command builds a shared library for generation 1.

hotc --emit-cpp player.hot --gen 1 -I include -I tests/engine
hotc player.hot --gen 1 -I include -I tests/engine -o player.so

The scripts of this page use the headers of the test host in tests/engine (Actor.h). For your own project, use your own native headers. The folder tests/engine is a test host and is not a model for a user project. Copy from samples/ (see samples/README.md).

Build a program with the SDK

To use scripts in a C++ program, install the Hot++ SDK. A project then needs only find_package(Hot REQUIRED) and hot_add_host(...) in its CMakeLists.txt. You do not need the Hot++ source tree. See CMake, the sections Quick start with an installed SDK and Install the SDK.