How to get started on a custom scripting API?

DaruBrub · December 24, 2020, 2:53pm

Hello!

Let’s say I wan’t to use a programming language I am already comfortable with(like lua or javascript) and there is no plans for a official API, so, how can I get started on adding a custom scripting API? What tools do i need? What do I need to learn?

mafiesto4 · December 24, 2020, 3:42pm

To implement custom scripting language support (like haxe, js, python, lua) the best would be to follow how Visual Scripting is integrated into engine as it has been done as a plugin to the core so it’s nice and handy.

Source code references:

github.com

FlaxEngine/FlaxEngine/blob/master/Source/Engine/Content/Assets/VisualScript.h

// Copyright (c) 2012-2020 Wojciech Figat. All rights reserved.

#pragma once

#include "../BinaryAsset.h"
#include "Engine/Scripting/BinaryModule.h"
#include "Engine/Visject/VisjectGraph.h"

#define VISUAL_SCRIPT_GRAPH_MAX_CALL_STACK 250
#define VISUAL_SCRIPT_DEBUGGING USE_EDITOR

#define VisualScriptGraphNode VisjectGraphNode<>

class VisualScripting;
class VisualScriptingBinaryModule;

/// <summary>
/// The Visual Script graph data.
/// </summary>
class VisualScriptGraph : public VisjectGraph<VisualScriptGraphNode, VisjectGraphBox, VisjectGraphParameter>

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github.com

FlaxEngine/FlaxEngine/blob/master/Source/Engine/Content/Assets/VisualScript.cpp

// Copyright (c) 2012-2020 Wojciech Figat. All rights reserved.

#include "VisualScript.h"
#include "Engine/Core/Log.h"
#include "Engine/Core/Types/DataContainer.h"
#include "Engine/Content/Factories/BinaryAssetFactory.h"
#include "Engine/Scripting/MException.h"
#include "Engine/Scripting/Scripting.h"
#include "Engine/Scripting/ManagedCLR/MClass.h"
#include "Engine/Scripting/ManagedCLR/MMethod.h"
#include "Engine/Scripting/ManagedCLR/MField.h"
#include "Engine/Scripting/ManagedCLR/MUtils.h"
#include "Engine/Scripting/ManagedCLR/MType.h"
#include "Engine/Serialization/MemoryReadStream.h"
#include "Engine/Serialization/MemoryWriteStream.h"
#include "Engine/Serialization/Serialization.h"
#include "Engine/Serialization/JsonWriter.h"
#include "Engine/Utilities/StringConverter.h"
#include "FlaxEngine.Gen.h"

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github.com

FlaxEngine/FlaxEngine/blob/master/Source/Tools/Flax.Build/Build/Plugins/VisualScriptingPlugin.cs

// Copyright (c) 2012-2020 Wojciech Figat. All rights reserved.

using System.Text;
using Flax.Build.Bindings;

namespace Flax.Build.Plugins
{
    /// <summary>
    /// Flax.Build plugin for Visual Scripting support. Generates required bindings glue code for overriding native methods with Visual Scripts. 
    /// </summary>
    /// <seealso cref="Flax.Build.Plugin" />
    sealed class VisualScriptingPlugin : Plugin
    {
        /// <inheritdoc />
        public override void Init()
        {
            base.Init();

            BindingsGenerator.GenerateCppScriptWrapperFunction += OnGenerateCppScriptWrapperFunction;
            BindingsGenerator.CppScriptObjectVirtualWrapperMethodsPostfixes.Add("_VisualScriptWrapper");

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github.com

FlaxEngine/FlaxEngine/blob/master/Source/Editor/Content/Items/VisualScriptItem.cs

// Copyright (c) 2012-2020 Wojciech Figat. All rights reserved.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using FlaxEditor.Scripting;
using FlaxEngine;
using FlaxEngine.Json;
using Object = FlaxEngine.Object;

namespace FlaxEditor.Content
{
    sealed class VisualScriptParameterInfo : IScriptMemberInfo
    {
        private readonly VisualScriptType _type;
        private readonly VisjectGraphParameter _parameter;

        internal VisualScriptParameterInfo(VisualScriptType type, VisjectGraphParameter parameter)

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DaruBrub · December 24, 2020, 3:51pm

Is there anything in the documentation that could be helpful?

mafiesto4 · December 24, 2020, 5:27pm

I’m not sure. Rather source code has enough documentation for this.