evanofsky

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About evanofsky

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  1. Thirteen Years of Bad Game Code

    I think we're in agreement; we just have different definitions of what a singleton is. To me, a singleton is defined as a function that lazily initializes a single global instance of an object. Without that lazy check, it's just... a regular global. I am totally cool with grouping global variables into a structure or object to "logically split them out and divy up code and responsibilities". I do it all the time. I only take issue when you put a singleton in front of it.
  2. Thirteen Years of Bad Game Code

    Alone on a Friday night, in need of some inspiration, you decide to relive some of your past programming conquests. The old archive hard drive slowly spins up, and the source code of the glory days scrolls by... Oh no. This is not at all what you expected. Were things really this bad? Why did no one tell you? Why were you like this? Is it even possible to have that many gotos in a single function? You quickly close the project. For a brief second, you consider deleting it and scrubbing the hard drive. What follows is a compilation of lessons, snippets, and words of warning salvaged from my own excursion into the past. Names have not been changed, to expose the guilty. 2004 I was thirteen. The project was called Red Moon -- a wildly ambitious third-person jet combat game. The few bits of code that were not copied verbatim out of Developing Games in Java were patently atrocious. Let's look at an example. I wanted to give the player multiple weapons to switch between. The plan was to rotate the weapon model down inside the player model, swap it out for the next weapon, then rotate it back. Here's the animation code. Don't think about it too hard.public void updateAnimation(long eTime) { if(group.getGroup("gun") == null) { group.addGroup((PolygonGroup)gun.clone()); } changeTime -= eTime; if(changing && changeTime = 0; i = Math.Min(this.bindings.Count - 1, i - 1)) this.bindings.OnChanged(this); } }} Every single field in the game, down to the last boolean, had an unwieldy dynamically allocated array attached to it. Take a look at the loop that notifies the bindings of a property change to get an idea of the issues I ran into with this paradigm. It has to iterate through the binding list backward, since a binding could actually add or delete UI elements, causing the binding list to change. Still, I loved data binding so much that I built the entire game on top of it. I broke down objects into components and bound their properties together. Things quickly got out of hand.jump.Add(new Binding(jump.Crouched, player.Character.Crouched));jump.Add(new TwoWayBinding(player.Character.IsSupported, jump.IsSupported));jump.Add(new TwoWayBinding(player.Character.HasTraction, jump.HasTraction));jump.Add(new TwoWayBinding(player.Character.LinearVelocity, jump.LinearVelocity));jump.Add(new TwoWayBinding(jump.SupportEntity, player.Character.SupportEntity));jump.Add(new TwoWayBinding(jump.SupportVelocity, player.Character.SupportVelocity));jump.Add(new Binding(jump.AbsoluteMovementDirection, player.Character.MovementDirection));jump.Add(new Binding(jump.WallRunState, wallRun.CurrentState));jump.Add(new Binding(jump.Rotation, rotation.Rotation));jump.Add(new Binding(jump.Position, transform.Position));jump.Add(new Binding(jump.FloorPosition, floor));jump.Add(new Binding(jump.MaxSpeed, player.Character.MaxSpeed));jump.Add(new Binding(jump.JumpSpeed, player.Character.JumpSpeed));jump.Add(new Binding(jump.Mass, player.Character.Mass));jump.Add(new Binding(jump.LastRollKickEnded, rollKickSlide.LastRollKickEnded));jump.Add(new Binding(jump.WallRunMap, wallRun.WallRunVoxel));jump.Add(new Binding(jump.WallDirection, wallRun.WallDirection));jump.Add(new CommandBinding(jump.WalkedOn, footsteps.WalkedOn));jump.Add(new CommandBinding(jump.DeactivateWallRun, (Action)wallRun.Deactivate));jump.FallDamage = fallDamage;jump.Predictor = predictor;jump.Bind(model);jump.Add(new TwoWayBinding(wallRun.LastWallRunMap, jump.LastWallRunMap));jump.Add(new TwoWayBinding(wallRun.LastWallDirection, jump.LastWallDirection));jump.Add(new TwoWayBinding(rollKickSlide.CanKick, jump.CanKick));jump.Add(new TwoWayBinding(player.Character.LastSupportedSpeed, jump.LastSupportedSpeed));wallRun.Add(new Binding(wallRun.IsSwimming, player.Character.IsSwimming));wallRun.Add(new TwoWayBinding(player.Character.LinearVelocity, wallRun.LinearVelocity));wallRun.Add(new TwoWayBinding(transform.Position, wallRun.Position));wallRun.Add(new TwoWayBinding(player.Character.IsSupported, wallRun.IsSupported));wallRun.Add(new CommandBinding(wallRun.LockRotation, (Action)rotation.Lock));wallRun.Add(new CommandBinding(wallRun.UpdateLockedRotation, rotation.UpdateLockedRotation));vault.Add(new CommandBinding(wallRun.Vault, delegate() { vault.Go(true); }));wallRun.Predictor = predictor;wallRun.Add(new Binding(wallRun.Height, player.Character.Height));wallRun.Add(new Binding(wallRun.JumpSpeed, player.Character.JumpSpeed));wallRun.Add(new Binding(wallRun.MaxSpeed, player.Character.MaxSpeed));wallRun.Add(new TwoWayBinding(rotation.Rotation, wallRun.Rotation));wallRun.Add(new TwoWayBinding(player.Character.AllowUncrouch, wallRun.AllowUncrouch));wallRun.Add(new TwoWayBinding(player.Character.HasTraction, wallRun.HasTraction));wallRun.Add(new Binding(wallRun.LastWallJump, jump.LastWallJump));wallRun.Add(new Binding(player.Character.LastSupportedSpeed, wallRun.LastSupportedSpeed));player.Add(new Binding(player.Character.WallRunState, wallRun.CurrentState));input.Bind(rollKickSlide.RollKickButton, settings.RollKick);rollKickSlide.Add(new Binding(rollKickSlide.EnableCrouch, player.EnableCrouch));rollKickSlide.Add(new Binding(rollKickSlide.Rotation, rotation.Rotation));rollKickSlide.Add(new Binding(rollKickSlide.IsSwimming, player.Character.IsSwimming));rollKickSlide.Add(new Binding(rollKickSlide.IsSupported, player.Character.IsSupported));rollKickSlide.Add(new Binding(rollKickSlide.FloorPosition, floor));rollKickSlide.Add(new Binding(rollKickSlide.Height, player.Character.Height));rollKickSlide.Add(new Binding(rollKickSlide.MaxSpeed, player.Character.MaxSpeed));rollKickSlide.Add(new Binding(rollKickSlide.JumpSpeed, player.Character.JumpSpeed));rollKickSlide.Add(new Binding(rollKickSlide.SupportVelocity, player.Character.SupportVelocity));rollKickSlide.Add(new TwoWayBinding(wallRun.EnableEnhancedWallRun, rollKickSlide.EnableEnhancedRollSlide));rollKickSlide.Add(new TwoWayBinding(player.Character.AllowUncrouch, rollKickSlide.AllowUncrouch));rollKickSlide.Add(new TwoWayBinding(player.Character.Crouched, rollKickSlide.Crouched));rollKickSlide.Add(new TwoWayBinding(player.Character.EnableWalking, rollKickSlide.EnableWalking));rollKickSlide.Add(new TwoWayBinding(player.Character.LinearVelocity, rollKickSlide.LinearVelocity));rollKickSlide.Add(new TwoWayBinding(transform.Position, rollKickSlide.Position));rollKickSlide.Predictor = predictor;rollKickSlide.Bind(model);rollKickSlide.VoxelTools = voxelTools;rollKickSlide.Add(new CommandBinding(rollKickSlide.DeactivateWallRun, (Action)wallRun.Deactivate));rollKickSlide.Add(new CommandBinding(rollKickSlide.Footstep, footsteps.Footstep)); I ran into tons of problems. I created binding cycles that caused infinite loops. I found out that initialization order is often important, and initialization is a nightmare with data binding, with some properties getting initialized multiple times as bindings are added. When it came time to add animation, I found that data binding made it difficult and non-intuitive to animate between two states. And this isn't just me. Watch this Netflix talk which gushes about how great React is before explaining how they have to turn it off any time they run an animation. I too realized the power of turning a binding on or off, so I added a new field:class Binding{ public bool Enabled;} Unfortunately, this defeated the purpose of data binding. I wanted to get rid of UI state, and this code actually added some. How can I eliminate this state? I know! Data binding!class Binding{ public Property Enabled = new Property { Value = true };} Yes, I really did try this briefly. It was bindings all the way down. I soon realized how crazy it was. How can we improve on data binding? Try making your UI actually functional and stateless. dear imgui is a great example of this. Separate behavior and state as much as possible. Avoid techniques that make it easy to create state. It should be a pain for you to create state. Conclusion There are many, many more embarrassing mistakes to discuss. I discovered another "creative" method to avoid globals. For some time I was obsessed with closures. I designed an "entity" "component" "system" that was anything but. I tried to multithread a voxel engine by sprinkling locks everywhere. Here's the takeaway: Make decisions upfront instead of lazily leaving them to the computer. Separate behavior and state. Write pure functions. Write the client code first. Write boring code. That's my story. What horrors from your past are you willing to share? If you enjoyed this article, try these: The Poor Man's Voxel Engine The Poor Man's Character Controller One Weird Trick to Write Better Code
  3. Best explanation I've seen of quaternions, complete with Blender practical application tips https://t.co/MVxF1Pb5cE
  4. RT @MarkPuente: The best letter to the editor in today's @TB_Times. https://t.co/E60kou9BXw
  5. woah guys i actually kinda did an animation https://t.co/6Q7hoBIm1R
  6. YES! More awesome devs coming to the Midwest! We live cheap! And we don't even mind if you pick that state up north https://t.co/R1Dhjdq22V
  7. What percentage of a relationship would you say happens over text these days?
  8. Anyone planning on attending Handmade Con 2016? https://t.co/x3Rs6ruCdw
  9. Allow me to regale you with an exciting tale: the birth of a janky dialogue and voice system. I have a JSON file with all the localized strings in my game, like this:{ "danger": "Danger", "level": "Level %d", ...} A preprocessor takes this and generates a header file with integer constants for each string, like this:namespace strings{ const int danger = 0; const int level = 1; // ...} At runtime, it loads the JSON file and hooks up the integer IDs to localized strings. A function called "_" takes an integer ID and returns the corresponding localized string. I use it like this:draw_string(_(strings::danger), position); This all worked (and still works) pretty well for UI strings. Not so much for dialogue. To write dialogue, I had to come up with a unique ID for each line, then add it to the strings file, like this:{ "hello_penelope": "Hello! I am Penelope.", "nice_meet_you": "Nice to meet you.", ...} Yes, the preprocessor generated a new integer ID in the header file every time I added a line of dialogue. Gross. I construct dialogue trees in Dialogger. With this setup, I had to use IDs like "hello_penelope" rather than actual English strings. Also gross. A better way I keep the string system, but extend it to support "dynamic" strings loaded at runtime that do not have integer IDs in the header file. Now I can write plain English in the dialogue trees. The preprocessor goes through all of them and extracts the strings into a separate JSON file, using the SHA-1 hash of each string for its ID. Once everything is loaded, I discard all string IDs in favor of integer IDs. I couldn't find a simple straightforward SHA-1 implementation that worked on plain C strings, so here's one for you. The point of all this is: I now have a single JSON file containing all the dialogue in the game. Ripe for automation... Speak and spell Penelope is an AI character. I'm using text-to-speech for her voice, at least for now. I don't want to integrate a text-to-speech engine in the game; that's way too much work. And I don't want to manually export WAVs from a text-to-speech program. Also too much work. I create a free IBM Bluemix account. They have a dead simple text-to-speech API: make an HTTP request with basic HTTP authentication, get a WAV file back. I write an 82-line Python script that goes through all the dialogue strings and makes an HTTP request for each one. It keeps track of which strings have previously been voiced, to facilitate incremental updates. Now I have a folder of WAV files, each one named after a SHA-1 hash. I'm using Wwise for audio, so the next step requires a bit of manual involvement. I drag all the WAVs into the project and batch create events for them. Now when I display a dialogue string, I just have to look up the SHA-1 hash and play the audio event. Easy. Disaster strikes I don't hear anything. All signs indicate the audio is playing correctly, but nothing comes out of my speakers. I look at one of the audio files in Wwise. Looks like the file is corrupted. I play the WAV in a number of different programs. Some play it fine, others don't play it at all. I edit my text-to-speech script to use Python's wave library to load the WAV file after downloading it from IBM. Sure enough, the library doesn't know what to make of it. Too lazy to care, I edit the wave library in-place in my Python distribution. YOLO. After a bit of printf debugging, I pinpoint the issue. The WAV format is based on RIFF, a binary format which breaks the file into "chunks". According to Wikipedia, the format of each chunk is as follows: 4 bytes: an ASCII identifier for this chunk (examples are "fmt " and "data"; note the space in "fmt "). 4 bytes: an unsigned, little-endian 32-bit integer with the length of this chunk (except this field itself and the chunk identifier). variable-sized field: the chunk data itself, of the size given in the previous field. a pad byte, if the chunk's length is not even. Turns out, IBM's text-to-speech API generates streaming WAV files, which means it sets the "length" field to 0. Some WAV players can handle it, while others choke. Wwise falls in the latter category. Fortunately, I can easily figure out the chunk length based on the file size, modify it using the wave library, and write it back out to the WAV file. Like so. Problem solved. Wwise is happy. Next I set up some Wwise callbacks to detect the current volume of Penelope's voice, and when she's done speaking. Here's the result, along with some rope physics in the background being destroyed by the wonky framerate caused by my GIF recorder: If you want to hear it, check out the IBM text-to-speech demo here. Thanks for reading! Mirrored on my blog
  10. RT @ADAMATOMIC: @fasterthanlime "dada are you just randomly trying different sin() / cos() -1/1 variations until you get what you want" "..…
  11. It's not just cygwin, it's actual Linux binaries running on Windows. It intercepts and translates Linux syscalls. https://t.co/YlloZZTGwl
  12. nav mesh generation now under 30 seconds https://t.co/5SW9aPp5om