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    • By sausagejohnson
      Welcome to the 2D UFO game guide using the Orx Portable Game Engine. My aim for this tutorial is to take you through all the steps to build a UFO game from scratch.
      The aim of our game is to allow the player to control a UFO by applying physical forces to move it around. The player must collect pickups to increase their score to win.
      I should openly acknowledge that this series is cheekily inspired by the 2D UFO tutorial written for Unity.
      It makes an excellent comparison of the approaches between Orx and Unity. It is also a perfect way to highlight one of the major parts that makes Orx unique among other game engines, its Data Driven Configuration System.
      You'll get very familiar with this system very soon. It's at the very heart of just about every game written using Orx.
      If you are very new to game development, don't worry. We'll take it nice and slow and try to explain everything in very simple terms. The only knowledge you will need is some simple C++.
      I'd like say a huge thank you to FullyBugged for providing the graphics for this series of articles.
      What are we making?
      Visit the video below to see the look and gameplay of the final game:
      Getting Orx
      The latest up to date version of Orx can be cloned from github and set up with:
      git clone https://github.com/orx/orx.git After cloning, an $ORX environment variable will be created automatically for your system which will help with making game projects much easier. It will also create several IDE projects for your operating system: Visual Studio, Codelite, Code::Blocks, and gmake.
      These Orx projects will allow you to compile the Orx library for use in your own projects. And the $ORX environment variable means that your projects will know where to find the Orx library.
      For more details on this step, visit http://orx-project.org/wiki/en/tutorials/cloning_orx_from_github at the Orx learning wiki.
      Setting up a 2D UFO Project
      Now the you have the Orx libraries cloned and compiled, you will need a blank project for your game. Supported options are: Visual Studio, CodeLite, Code::Blocks, XCode or gmake, depending on your operating system.
      Once you have a game project, you can use it to work through the steps in this tutorial.
      Orx provides a very nice system for auto creating game projects for you. In the root of the Orx repo, you will find either the init.bat (for Windows) or init.sh (Mac/Linux) command.
      Create a project for our 2D game from the command line in the Orx folder and running:
      init c:\temp\ufo or
      init.sh ~/ufo Orx will create a project for each IDE supported by your OS at the specified location. You can copy this folder anywhere, and your project will always compile and link due to the $ORX environment variable. It knows where the libraries and includes are for Orx.
      Open your project using your favourite IDE from within the ufo/build folder.
      When the blank template loads, there are two main folders to note in your solution:
      config src Firstly, the src folder contains a single source file, ufo.cpp. This is where we will add the c++ code for the game. The config folder contains configuration files for our game.
        What is config?
      Orx is a data driven 2D game engine. Many of the elements in your game, like objects, spawners, music etc, do not need to be defined in code. They can be defined (or configured) using config files.
      You can make a range of complex multi-part objects with special behaviours and effects in Orx, and bring them into your game with a single line of code. You'll see this in the following chapters of this guide.
      There are three ufo config files in the config folder but for this guide, only one will actually be used in our game. This is:
      ufo.ini All our game configuration will be done there.
      Over in the Orx library repo folder under orx/code/bin, there are two other config files:
      CreationTemplate.ini SettingsTemplate.ini These are example configs and they list all the properties and values that are available to you. We will mainly concentrate on referring to the CreationTemplate.ini, which is for objects, sounds, etc. It's good idea to include these two files into your project for easy reference.
      Alternatively you can view these online at https://github.com/orx/orx/blob/master/code/bin/CreationTemplate.ini and here: https://github.com/orx/orx/blob/master/code/bin/SettingsTemplate.ini
      The code template
      Now to take a look at the basic ufo.cpp and see what is contained there.
      The first function is the Init() function.
      This function will execute when the game starts up. Here you can create objects have been defined in the config, or perform other set up tasks like handlers. We'll do both of these soon.
      The Run() function is executed every main clock cycle. This is a good place to continually perform a task. Though there are better alternatives for this, and we will cover those later. This is mainly used to check for the quit key.
      The Exit() function is where memory is cleaned up when your game quits. Orx cleans up nicely after itself. We won't use this function as part of this guide.
      The Bootstrap() function is an optional function to use. This is used to tell Orx where to find the first config file for use in our game (ufo.ini). There is another way to do this, but for now, we'll use this function to inform Orx of the config.
      Then of course, the main() function. We do not need to use this function in this guide.
      Now that we have everything we need to get start, you should be able to compile successfully. Run the program and an Orx logo will appear slowly rotating.

      Great. So now you have everything you need to start building the UFO game.
      Setting up the game assets
      Our game will have a background, a UFO which the player will control, and some pickups that the player can collect.
      The UFO will be controlled by the player using the cursor keys.
      First you'll need the assets to make the game. You can download the file  assets-for-orx-ufo-game.zip which contains:
      The background file (background.png):

      The UFO and Pickup sprite images (ufo.png and pickup.png):
      And a pickup sound effect (pickup.ogg):
      Copy the .png files into your data/texture folder
      Copy the .ogg file into your data/sound folder.
      Now these files can be accessed by your project and included in the game.
      Setting up the Playfield
      We will start by setting up the background object. This is done using config.
      Open the ufo.ini config file in your editor and add the following:
      [BackgroundGraphic] Texture = background.png Pivot = center  
      The BackgroundGraphic defined here is called a Graphic Section. It has two properties defined. The first is Texture which has been set as background.png.
      The Orx library knows where to find this image, due to the properties set in the Resource section:
      [Resource] Texture = ../../data/texture  
      So any texture files that are required (just like in our BackgroundGraphic section) will be located in the ../../data/texture folder.
      The second parameter is Pivot. A pivot is the handle (or sometimes “hotspot” in other frameworks). This is set to be center. The position is 0,0 by default, just like the camera. The effect is to ensure the background sits in the center of our game window.
      There are other values available for Pivot. To see the list of values, open the CreationTemplate.ini file in your editor. Scroll to the GraphicTemplate section and find Pivot in the list. There you can see all the possible values that could be used.
      top left is also a typical value.
      We need to define an object that will make use of this graphic. This will be the actual entity that is used in the game:
      [BackgroundObject] Graphic = BackgroundGraphic Position = (0, 0, 0)  
      The Graphic property is the section BackgroundGraphic that we defined earlier. Our object will use that graphic.
      The second property is the Position. In our world, this object will be created at (0, 0, 0). In Orx, the coordinates are (x, y, z). It may seem strange that Orx, being a 2D game engine has a Z axis. Actually Orx is 2.5D. It respects the Z axis for objects, and can use this for layering above or below other objects in the game.
      To make the object appear in our game, we will add a line of code in our source file to create it.
      In the Init() function of ufo.cpp, remove the default line:
      orxObject_CreateFromConfig("Object"); and replace it with:
      orxObject_CreateFromConfig("BackgroundObject"); Compile and run.
      The old spinning logo is now replaced with a nice tiled background object.

      Next, the ufo object is required. This is what the player will control. This will be covered in Part 2.
    • By sausagejohnson
      Hi Guys, really pleased to announce that my 5 part series on creating a 2D UFO game using the Orx Portable Game Engine has been published in the articles section.

      The series is designed to help beginners download Orx, then use the tools to create your first project in your favourite IDE/OS.
      It then takes you step by step through numerous topics:
      Creating a playfield The ufo movement Keyboard controls Collisions Physics Scores Sounds and; Shadows The series starts over here:
      How to write a 2D UFO game using the Orx Portable Game Engine - Part 1
      If you find any problems, or enjoyed going through it, I'd love to hear about it.
      Graphics for the article series were kindly designed by my friend FullyBugged.
    • By Washantor
      Hello my name is Erik Reis i'm 15 and i just got into game development. I don't want to spend hundreds of bucks on online classes i just want someone to help me. Kinda like a mentor or another new developer I can learn with. I'm young and i'm new and stupid and would love to learn this is just don't know where to start there is so much. I do know some basic C# and i want to use unity. I can do some pixel art though it is not up to the standard i would like but that can be improved. I would really enjoy to meet someone who has knowledge of the subject and can teach me on their spare time. Thanks i really appreciate if your read this post.
    • By Mercury Gate
      Here is the scenario I have pertaining to a combat system I am jotting down on paper.
      The attacker has 100 soldiers each with 1 attack point and 3 health points. The defender has the same.
      All the player has to do is press a button and combat is all computed then the player is just shown the results. From my current example, I would have the attacker's soldiers do 100 points of damage to the defender resulting in 33 defenders being killed. The same happens to the attacker's soldiers. This continues until both sides defeat each other at the same time and it ends in a draw.
      I feel if I introduce a random factor, the battle could get lop-sided and the smaller side could not recover So I thought I would ask the community for their opinions of the very simple combat scenario.
      The game concept I am designing deals with combat from outside the actual conflict. Sort of like a coach and a sports team. You give orders and watch as your units perform them. The game does start small, with 100 to 200 soldiers (all the same) and could grow to larger numbers as well. I was just wanting to get a system in place for small conflict that could scale into larger ones.
      Each side has a unit type (soldier) a unit quantity (100). The player give the order, and the computer does the rest. After both players give their orders, the results are computed instantly. Keeping all things equal, Attack power, defensive power, etc. (I need a baseline) What would be the best way to determine damage? Static numbers, or RNG numbers?
      To use or not use RNG in combat?
    • By simco50
      I've stumbled upon Urho3D engine and found that it has a really nice and easy to read code structure.
      I think the graphics abstraction looks really interesting and I like the idea of how it defers pipeline state changes until just before the draw call to resolve redundant state changes.
      This is done by saving the state changes (blendEnabled/SRV changes/RTV changes) in member variables and just before the draw, apply the actual state changes using the graphics context.
      It looks something like this (pseudo):
      void PrepareDraw() { if(renderTargetsDirty) { pD3D11DeviceContext->OMSetRenderTarget(mCurrentRenderTargets); renderTargetsDirty = false } if(texturesDirty) { pD3D11DeviceContext->PSSetShaderResourceView(..., mCurrentSRVs); texturesDirty = false } .... //Some more state changes } This all looked like a great design at first but I've found that there is one big issue with this which I don't really understand how it is solved in their case and how I would tackle it.
      I'll explain it by example, imagine I have two rendertargets: my backbuffer RT and an offscreen RT.
      Say I want to render my backbuffer to the offscreen RT and then back to the backbuffer (Just for the sake of the example).
      You would do something like this:
      //Render to the offscreen RT pGraphics->SetRenderTarget(pOffscreenRT->GetRTV()); pGraphics->SetTexture(diffuseSlot, pDefaultRT->GetSRV()) pGraphics->DrawQuad() pGraphics->SetTexture(diffuseSlot, nullptr); //Remove the default RT from input //Render to the default (screen) RT pGraphics->SetRenderTarget(nullptr); //Default RT pGraphics->SetTexture(diffuseSlot, pOffscreenRT->GetSRV()) pGraphics->DrawQuad(); The problem here is that the second time the application loop comes around, the offscreen rendertarget is still bound as input ShaderResourceView when it gets set as a RenderTargetView because in Urho3D, the state of the RenderTargetView will always be changed before the ShaderResourceViews (see top code snippet) even when I set the SRV to nullptr before using it as a RTV like above causing errors because a resource can't be bound to both input and rendertarget.
      What is usually the solution to this?
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DX11 I need to learn DirectX. The examples for Introduction to 3D Programming with DirectX 11 by Frank D Luna does not work. Can anyone help me

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7 hours ago, GameDevCoder said:

Ok. I have removed a couple errors and am just left with one issue for the BOX example in chapter 6.

Does anyone know how I can fix this please?  https://ibb.co/gstKvw

I've no idea what to do about this problem.

Put the code back to its original state.  It was not trying to use a pointer to a color.  You can't use pointer as vertex data.

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11 hours ago, Infinisearch said:

Put the code back to its original state.  It was not trying to use a pointer to a color.  You can't use pointer as vertex data.

Thanks for the post. I haven't altered the original code in anyway. I have only tinkered with the project settings/properties. Any chance you can elaborate on for me please? If you might know how I can solve this issue?

Edited by GameDevCoder

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My mistake, I thought you had been messing around with the code and assumed.  Follow what ericrrichards22 mentions.  Basically this is to just manually stick some xmfloat4's in there with what ever values you find for RGBA whereever "Colors::" is defined.

edit - you can also use Colors:: in the same way.... sorry I edited my post and made it confusing.

Edited by Infinisearch

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2 hours ago, Infinisearch said:

My mistake, I thought you had been messing around with the code and assumed.  Follow what ericrrichards22 mentions.  Basically this is to just manually stick some xmfloat4's in there with what ever values you find for RGBA whereever "Colors::" is defined.

edit - you can also use Colors:: in the same way.... sorry I edited my post and made it confusing.

;) it's ok. Thanks for the post Infinsearch. I will be trying out some stuff with getting these examples to work over the weekend I plan too. Will see if I can get this BOX example working.

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7 hours ago, GameDevCoder said:

2015 i'm using

Then I take back what I said about not having to change anything.

See here: https://blogs.msdn.microsoft.com/chuckw/2012/04/24/wheres-dxerr-lib/

IIRC If you want to make things real easy just use VS2013 and the 2010 SDK.  It will get you up and running with the demo's from the book... and once you feel comfortable with the basics you can either move past using the legacy libraries or use their replacements.

On 11/9/2017 at 10:46 PM, ericrrichards22 said:

Not overly familiar with DirectXMath, and it has been quite a while since I was digging through the Luna DX11 book, but it looks like you probably need to use the constructor for XMFLOAT4, rather than rely on an implicit conversion


This really should work for you in your older version.  You should try it.

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Before I carry on. I just want to say how I over came this issue https://ibb.co/gstKvw .

Like people suggested it was regarding the constructor. So like this https://ibb.co/f0vXHb that part of the code is now working. It's just https://ibb.co/hG0gSb being my last hurdle now. 


I will download VS13 and give that a shot. Thanks for this suggestion. I totally agree with what you say to that if this goes well I can then become familiar with it all then later I can move onto using VS15 for DirectX when I have built up my confidence more from learning it.


PS - it's a bit annoying to really as I was able to remove this error in one version of me trying to get the example to work. It has appeared again though this error and now I'm not sure how to remove it. I will start downloading VS13 also now.

Edit - Finding it hard to download VS13. Where I should be able to get it, this page won't let me download it. Where I scroll down to the download I need something to load and it just isn't loading. It's like they aren't fussed with older content being viewed by anyone now.

Edit 2- I can download the express version I think, I was trying to download the community version. I'll try the express version and see how it goes.... I think getting VS13 is going to be a struggle too. I've tried doing this and I'm just getting webpages thrown at me saying error and to get in touch with Microsoft. I had this pop up on my screen when I tried downloading VS13 express "We are sorry, but our system is detecting a problem with your account and we are unable to validate access to your subscription". Such a pain in the backside to get anything done :l . I just tried going on live chat with support but they only open Mon-Fri :(.

I'll see if I can download VS13 still otherwise I'll have to try and get it working using VS15 that I am currently using.

I've emailed the support team also now to see why I can't download VS13. Hopefully they show me a fix for this.

Edited by GameDevCoder

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I know you want to stick with Luna but just so you know there are some tutorials here:


Oh and why did you delete the older version you were working on?

edit - BTW on the front page of d3dcoder.net is frank luna's email address.

Edited by Infinisearch

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