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23. May 2018

I just realized that even though I have been developing a Godot 3 tutorial series and book for the last several months, I haven’t actually posted it here on the front page of GameFromScratch.  Each tutorial is published as pages instead of posts so it doesn’t appear on the front page or in the timeline!  Ooops…SeriesIntroduction

So anyways… I’m working on both a new tutorial series covering the recently released Godot 3.  If you followed my Godot 1/2 tutorial series you should have a good idea what to expect.  In this case the series is primarily video passed, but don’t worry if you prefer text I am publishing all code samples and assets here on GameFromScratch.  Additionally I am writing a book that parallels the videos published in the series.  While it is not available for purchase yet, I am making WIP chapters available to GFS Patreons as I finish them.

Currently the series covers the following topics:

  • Introduction
  • Getting Started
  • Nodes, Scenes and Trees
  • GDScript Programming 101
  • 2D Graphics, Sprites and Animation
  • Keyboard, Mouse and Joystick Input
  • User Interface Development

The series will expand to cover all aspects of Godot 3 development, including 3D, VR and Mobile development topics.  Expect a chapter on Godot 3 audio to be up shortly.

You can access the homepage to the tutorial series here which in addition to video links, also includes all of the code samples and assets used.  If you prefer to just watch the videos, you can find the YouTube playlist here.


18. May 2018

It’s not very often a game engine takes me completely by surprise.  Especially a full featured, open source, C++ based, cross platform, heavily documented, feature rich, high performance 3D game engine.  Well that’s exactly what happened with the G3D Innovation Engine.  The primary maintainers are Morgan McGuire (@CasualEffects) who is currently an educator as well as a VR scientist at NVIDIA and previously worked on games such as Skylanders, Titan Quest and the Unity game engine, as well as Michael Mara at Standard University and Oculus Research.

The G3D Engine is self described as:

The G3D Innovation Engine is a commercial-grade C++ 3D engine available as Open Source. ss

G3D supports hardware accelerated real-time rendering, off-line rendering like ray tracing, and general purpose computation on GPUs. Its design emphasizes rapid prototyping and innovation, particularly of rendering and game algorithms.

G3D provides a set of routines and structures so common that they are needed in almost every graphics program. It makes low-level libraries like OpenGL, network sockets, and audio channels easier to use without limiting functionality or performance. G3D is a carefully designed, feature-rich base on which to prototype your 3D application.

Beyond being a capable engine it is also an incredible learning resource.  The engine is bundled with over 6GB of assets to experiment with, as well as over a dozen robust ss2samples with thoroughly documented source code.  One of the samples is even a full blown first person shooter, while another demonstrates a Minecraft-esque voxel based level.  There are also examples that show you how to work at the lowest level directly with OpenGL as well as advanced examples showcasing functionality such as real-time raytracing, lighting effects, procedural geometry and even VR.

Additionally each example can easily embed a suite of tools directly, enabling you to screen shot or video capture, change camera settings on the fly or launch the built in profiler.  There is even a complete scene editor built in, allowing you to place entities directly in your scene via simple drag and drop, turning your application into a minimalistic level editor.

Remember back at the beginning I mentioned that the maintainer was also an educator?  He has also authored a companion called the Graphics Codex which goes hand in hand with the G3D game engine.  For a mere $10 you gain access to an advanced reference that may just be one of the single best ways of learning computer graphics GIF2topics such as ray casting, BSDF, rendering and more.  You can see a full chapter list here.  So if you are trying to learn more advanced graphics programming, G3D is certainly a great resource.  Keep in mind however, this material was used with a 300s level graphics course, so you are going to need a solid foundation in math to follow along.

Purchasing the Graphics Codex is by no means a requirement however.  One thing open source projects often suffer from is poor documentation.  Thankfully this certainly isn’t the case with the G3D engine.   There is an extensive manual available here, as well as a comprehensive set of API references.  As mentioned earlier, the engine is also loaded with well documented samples.

If you are looking for a low level foundation to build your game on, a framework to do some graphical experiments or simply are looking for a way to learn more about modern graphics programming, I can think of little reason not to suggest checking out the G3D Innovation Engine. 

If you are interested in learning more about the G3D Innovation Engine, be sure to check out our hands-on video available here and embedded below.  I am almost certain you will be amazed.

GameDev News Programming

14. May 2018


ZLib License

View On YouTube


Orx is a cross platform open sourced 2D game framework written in C and available on Github under the permissive ZLib source license.  What makes Orx somewhat unique among it’s peers is the data driven approach that Orx takes.  Instead of storing game data using a collection of objects in code, it is instead split out into data files.  This enables you to quickly change the content of your game without having to do a recompilation.   So for example you make have an entry like the following for defining the camera in your scene:

Camera            = Camera
BackgroundColor   = (255, 180, 0)

FrustumWidth  = 1024
FrustumHeight = 768
FrustumFar    = 1.0
FrustumNear   = 0.0
Position      = (0.0, 0.0, -1.0)
;Zoom          = 3.0

By editing this config file you can make major alterations to the camera without having to recompile your code.  Chance the FrustrumWidth in the ini file, and the next time you run your game’s window will be smaller.  Now let’s look at the code required to consume the Viewport/Camera data in your C/C++ application:


Yep, that’s it.  This will create the viewport, notice the camera property and create one of them as well, entirely driven by data. 

This approach has a couple of advantages.  First it creates a clean separation of code and data which should in theory make for easier to maintain code.  It also takes these values out of the compilation process, meaning changes do not require you to recompile your code.  Additionally, this data driven approach makes creating tools for you game a cinch, as you are simply writing out simple easily understood text files. 

There are of course disadvantages too.  Since you moved the code out from the compiler, you lose features such as intellisense as well as compile time error checking.  Moving more details off into data files can make hunting down bugs even more difficult.

Let’s take a quick look at one of the samples from the Orx tutorials, with the comments stripped down for brevity.

#include "orx.h"
orxOBJECT *pstSoldier;

orxSTATUS orxFASTCALL EventHandler(const orxEVENT *_pstEvent)
  orxANIM_EVENT_PAYLOAD *pstPayload;

  /* Gets event payload */
  pstPayload = (orxANIM_EVENT_PAYLOAD *)_pstEvent->pstPayload;

  /* Depending on event type */
    case orxANIM_EVENT_START:
      /* Logs info */
      orxLOG("Animation <%s>@<%s> has started!", pstPayload->zAnimName, orxObject_GetName(orxOBJECT(_pstEvent->hRecipient)));


    case orxANIM_EVENT_STOP:
      /* Logs info */
      orxLOG("Animation <%s>@<%s> has stopped!", pstPayload->zAnimName, orxObject_GetName(orxOBJECT(_pstEvent->hRecipient)));


    case orxANIM_EVENT_CUT:
      /* Logs info */
      orxLOG("Animation <%s>@<%s> has been cut!", pstPayload->zAnimName, orxObject_GetName(orxOBJECT(_pstEvent->hRecipient)));


    case orxANIM_EVENT_LOOP:
      /* Logs info */
      orxLOG("Animation <%s>@<%s> has looped!", pstPayload->zAnimName, orxObject_GetName(orxOBJECT(_pstEvent->hRecipient)));


       /* Logs info */
       orxLOG("Animation <%s>@<%s> has sent the event [%s]!", pstPayload->zAnimName, orxObject_GetName(orxOBJECT(_pstEvent->hRecipient)), pstPayload->stCustom.zName);


  /* Done! */
  return orxSTATUS_SUCCESS;

/** Update callback
void orxFASTCALL Update(const orxCLOCK_INFO *_pstClockInfo, void *_pstContext)
  orxVECTOR vScale;

  /* Is walk right active? */
    /* Sets walk right as target anim */
    orxObject_SetTargetAnim(pstSoldier, "WalkRight");
  /* Is walk left active? */
  else if(orxInput_IsActive("GoLeft"))
    /* Sets walk left as target anim */
    orxObject_SetTargetAnim(pstSoldier, "WalkLeft");
  /* No walk active */
    /* Removes target anim */
    orxObject_SetTargetAnim(pstSoldier, orxNULL);

  /* Is scale up active ? */
    /* Scales up the soldier */
    orxObject_SetScale(pstSoldier, orxVector_Mulf(&vScale, orxObject_GetScale(pstSoldier, &vScale), orx2F(1.02f)));
  /* Is scale down active? */
    /* Scales down the soldier */
    orxObject_SetScale(pstSoldier, orxVector_Mulf(&vScale, orxObject_GetScale(pstSoldier, &vScale), orx2F(0.98f)));

/** Inits the tutorial
  orxCLOCK       *pstClock;
  orxINPUT_TYPE   eType;
  orxENUM         eID;
  orxINPUT_MODE   eMode;
  const orxSTRING zInputWalkLeft;
  const orxSTRING zInputWalkRight;
  const orxSTRING zInputScaleUp;
  const orxSTRING zInputScaleDown;

  /* Gets input binding names */
  orxInput_GetBinding("GoLeft", 0, &eType, &eID, &eMode);
  zInputWalkLeft  = orxInput_GetBindingName(eType, eID, eMode);

  orxInput_GetBinding("GoRight", 0, &eType, &eID, &eMode);
  zInputWalkRight = orxInput_GetBindingName(eType, eID, eMode);

  orxInput_GetBinding("ScaleUp", 0, &eType, &eID, &eMode);
  zInputScaleUp   = orxInput_GetBindingName(eType, eID, eMode);

  orxInput_GetBinding("ScaleDown", 0, &eType, &eID, &eMode);
  zInputScaleDown = orxInput_GetBindingName(eType, eID, eMode);

  /* Displays a small hint in console */
  orxLOG("\n- '%s' & '%s' will change the soldier's animations\n- '%s' & '%s' will scale the soldier", zInputWalkLeft, zInputWalkRight, zInputScaleUp, zInputScaleDown);

  /* Registers event handler */
  orxEvent_AddHandler(orxEVENT_TYPE_ANIM, EventHandler);

  /* Creates viewport */

  /* Creates soldier */
  pstSoldier = orxObject_CreateFromConfig("Soldier");

  /* Gets main clock */
  pstClock = orxClock_FindFirst(orx2F(-1.0f), orxCLOCK_TYPE_CORE);

  /* Registers our update callback */
  orxClock_Register(pstClock, Update, orxNULL, orxMODULE_ID_MAIN, orxCLOCK_PRIORITY_NORMAL);

  /* Done! */
  return orxSTATUS_SUCCESS;

/** Run function
  orxSTATUS eResult = orxSTATUS_SUCCESS;

  /* Should quit? */
    /* Updates result */
    eResult = orxSTATUS_FAILURE;

  /* Done! */
  return eResult;

/** Exit function
void orxFASTCALL Exit()
  /* We're a bit lazy here so we let orx clean all our mess! :) */

/** Main function
int main(int argc, char **argv)
  /* Executes a new instance of tutorial */
  orx_Execute(argc, argv, Init, Run, Exit);

  return EXIT_SUCCESS;

#ifdef __orxMSVC__

// Here's an example for a console-less program under windows with visual studio
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
  // Inits and executes orx
  orx_WinExecute(Init, Run, Exit);

  // Done!
  return EXIT_SUCCESS;

#endif // __orxMSVC__

This example illustrates a simple animation.  The game loop itself consists of implementing 3 simple functions, Init(), Run() and Exit() for handling various stages of the lifecycle.  The actual game loop itself is the Update callback function which is called continuously as your game is run.  Speaking of which, here is the code running.  The left and right arrow keys toggle between the animations, while up and down scale accordingly.


Now the “guts” of this example is actually in the ini file containing the data.  Let’s take a look:

; In this example, we use the same size for the screen display than our camera's frustum so as to obtain a 1:1 ratio
ScreenWidth   = @Camera.FrustumWidth
ScreenHeight  = @Camera.FrustumHeight
Title         = Anim Tutorial
Smoothing     = false
Texture = ../data/object 

SetList = MainInput


KEY_LEFT   = GoLeft
KEY_RIGHT  = GoRight
KEY_UP     = ScaleUp
KEY_DOWN   = ScaleDown

Camera = Camera

FrustumWidth  = 640
FrustumHeight = 480
FrustumFar    = 1.0
FrustumNear   = 0.0
Position      = (0.0, 0.0, -1.0)

Pivot = (15.0, 31.0, 0.0)

[[email protected]]
Texture = soldier.png

Graphic             = Graphic
AnimationSet        = AnimSet
Scale               = 4.0

Direction   = right # down
StartAnim   = IdleRight
KeyDuration = 0.1
Digits      = 1
FrameSize   = (32, 32, 0)

Texture     = soldier_full.png
Pivot       = @Pivot

IdleRight   = 1 ; <= We only want one frame
IdleLeft    = 1
WalkRight   = -1 ; <= We want as many frame that can fit in the texture defined by WalkRight
WalkLeft    = -1

IdleRight-> = IdleRight 
IdleLeft->  = IdleLeft 
WalkRight-> = WalkRight 
WalkLeft->  = WalkLeft 

Flip        = x

Flip        = x

Direction   = left

Direction   = left # up

KeyEvent    = !!Left!!

KeyEvent    = !!Right!!

KeyEvent    = !!Right!!

KeyEvent    = !!Left!!

As you can see, just about every aspect of the game is data driven here, from the animation names, the source graphic files, to the camera, viewport and even keys pressed and the corresponding binding to call for each key.

This post only scratched the service of how Orx works, but should give you an idea of the data driven approach they have taken.  It certainly wont be for everyone, but it could be a great fit for many people.  If you are interested in giving Orx a shot, be sure to check out our video, which is also embedded below, to walk through the installation process and get you up and running.  Then it’s time to jump into the extremely thorough getting started guide and tutorials available on the Orx website.


17. April 2018

If you are a Blender Game Engine (BGE) fan, I have some bad news for you.  Earlier today BGE was removed from the Blender 2.8 branch of source code.  This means in the next version of Blender and beyond, there will no longer be an in-built game engine.  The game engine was never particularly popular and apparently caused a bit of a code maintenance nightmare, so the decision was made to remove it.  Then changes to the game engine are massive, touching 916 files in the code base.

Details of the change from the Blender code commit comments:

Removing Blender Game Engine from Blender 2.8

Folders removed entirely:

  • //extern/recastnavigation
  • //intern/decklink
  • //intern/moto
  • //source/blender/editors/space_logic
  • //source/blenderplayer
  • //source/gameengine

This includes DNA data and any reference to the BGE code in Blender itself.
We are bumping the subversion.

Pending tasks:

  • Tile/clamp code in image editor draw code.
  • Viewport drawing code (so much of this will go away because of BI removal that we can wait until then to remove this.

You can learn more about the change in this video, also embedded below.

Art Programming GameDev News

15. April 2018

A couple days back AppGameKit v2018.4.12 was released with the major new feature being AR (Augmented Reality) support.  I decided to give the new AR functionality a shot and it was really impressive how easy it was.  In order to get started with AR and AppGameKit you are going to need an AR compatible device.  On iOS, this means an ARKit compatible device, which basically means an iPhone 6S or newer device, while on Android device you need an ARCore compatible device from this list of phones.

I modified the AR example slightly, to remove a bit of functionality and to instead load a simple Tie Fighter model I downloaded off the web and converted to .X format.  AppGameKit can be coded using either C++ or their higher level Basic like script, which is what was used in this example.  Here is the slightly modified source code used:

// set window properties
SetWindowTitle( "AR Tie Fighter" )
SetWindowSize( 1024, 768, 0 )

// set display properties
SetVirtualResolution( 1024, 768 )
SetOrientationAllowed( 1, 1, 1, 1 )
SetClearColor( 101,120,154 )
SetGenerateMipmaps( 1 )

// camera range from 0.1 meters to 40 meters
SetCameraRange( 1, 0.1, 40 )
SetAmbientColor( 128,128,128 )
SetSunColor( 255,255,255 )

// load tie fighter
LoadObject( 1, "tie.x")
SetObjectPosition( 1, 0,0.1,0 )
LoadImage(1, "diffuse.jpg")
SetObjectImage (1,1,0) 

function ShowModel( show as integer )
  SetObjectVisible( 1, show )

ShowModel( 0 )

function ScaleModel( amount as float )
  SetObjectScalePermanent( 1, amount, amount, amount )

ScaleModel( 0.025 )

// create some planes to show detected surfaces, initially hidden
for i = 101 to 150
  CreateObjectPlane( i, 1,1 )
  SetObjectRotation( i, 90,0,0 )
  FixObjectPivot( i )
  SetObjectVisible( i, 0 )
  SetObjectColor( i, 255,255,255,128 ) // 50% transparent
  SetObjectTransparency( i, 1 )
next i

// add some buttons to control various features
AddVirtualButton( 1, 100,565,100 )
AddVirtualButton( 2, 100,665,100 )
SetVirtualButtonText( 1, "Scale +" )
SetVirtualButtonText( 2, "Scale -" )

AddVirtualButton( 3, 924,665,100 )
SetVirtualButtonText( 3, "Hide" )

function ShowHUD( show as integer )
  SetVirtualButtonVisible( 1, show )
  SetVirtualButtonVisible( 2, show )
  SetVirtualButtonVisible( 3, show )
  SetVirtualButtonActive( 1, show )
  SetVirtualButtonActive( 2, show )
  SetVirtualButtonActive( 3, show )

// initialize AR, if possible
while( ARGetStatus() = 1 )
  // wait while user is being prompted to install ARCore

AnchorID as integer = 0
ShowPlanes as integer = 1
ambientScale# = 1.0

  // get light estimation
  ambient = ARGetLightEstimate() * 255 * ambientScale#
  SetAmbientColor( ambient,ambient,ambient )
  // check screen tap for plane hits, but only if buttons are visible
  if ( GetPointerReleased() and ShowPlanes = 1 )
    // check the point that the user tapped on the screen
    numHits = ARHitTest( GetPointerX(), GetPointerY() )
    if ( numHits > 0 )
      ShowModel( 1 )
      // delete any previous anchor, could keep it around instead
      if ( AnchorID > 0 ) then ARDeleteAnchor( AnchorID )
      // hit test results are ordered from closest to furthest
      // place the object at result 1, the closest
      AnchorID = ARCreateAnchorFromHitTest( 1 )
      ARFixObjectToAnchor( 1, AnchorID )
      // if the user didn't tap on any planes then hide the object
      ShowModel( 0 )
    // clean up some internal resources
  // place the buttons at the edge of the screen
  // needs to be done regularly in case orientation changes
  SetVirtualButtonPosition( 1, GetScreenBoundsLeft()+105, GetScreenBoundsBottom()-210 )
  SetVirtualButtonPosition( 2, GetScreenBoundsLeft()+105, GetScreenBoundsBottom()-105 )
  SetVirtualButtonPosition( 3, GetScreenBoundsRight()-105, GetScreenBoundsBottom()-105 )
  // detect button presses if they are visible
  if ( ShowPlanes = 1 )
    if ( GetVirtualButtonPressed(1) )
      ScaleModel( 1.05 )
    if ( GetVirtualButtonPressed(2) )
      ScaleModel( 0.95 )
    if ( GetVirtualButtonPressed(3) )
      ShowPlanes = 1 - ShowPlanes
      ShowHUD( 0 )
    // screen tap whilst button are hidden shows them again
    if ( GetPointerReleased() )
      ShowPlanes = 1 - ShowPlanes
      ShowHUD( 1 )
  // hide old planes
    for i = 101 to 150
    SetObjectVisible( i, 0 )
  next i
  // show detected planes
  if ( ShowPlanes )
    numPlanes = ARGetPlanes(0)
    // this demo stops at 50 planes, but there is no internal limit
    if numPlanes > 50 then numPlanes = 50
    for i = 1 to numPlanes
      SetObjectPosition( i+100, ARGetPlaneX(i), ARGetPlaneY(i), ARGetPlaneZ(i) )
      SetObjectRotation( i+100, ARGetPlaneAngleX(i), ARGetPlaneAngleY(i), ARGetPlaneAngleZ(i) )
      SetObjectScale( i+100, ARGetPlaneSizeX(i), 1, ARGetPlaneSizeZ(i) )
      SetObjectVisible( i+100, 1 )
    next i
    if ( ShowPlanes )
    Print( "FPS: " + str(ScreenFPS()) )
    select( ARGetStatus() )
      case 2 :  Print( "AR Active" ) : endcase
      case -1 :  Print( "AR Not Available" ) : endcase
      case -2 :  Print( "AR Install Rejected" ) : endcase
    Print( "Number of Planes Detected: " + str(numPlanes) )
    Print( "Light Estimation: " + str(ARGetLightEstimate()) )
    Print( "Light Boost: " + str(ambientScale#,1) )
  // draw the camera feed, and then the rest of the scene

You can see the results of this code and get a bit more detail by watching the video below:

If you are interested in learning more about AppGameKit, be sure to check out our Closer Look available here.


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