Jacob Repp's Blog

Warning Deprecated

2008-01-16T22:17:00.001-08:00

This blog is complete and all future posts are at my new site jrepp.com.

Render targets, multipass glow buffers and more

2006-10-07T22:48:00.000-07:00

I've been trying to solidify the look of the shmup game and learning a lot more about how XNA (dx) interacts with HLSL. I have some issues still to work out but I'm almost done with the visual tweaks. One issue you'll run into quick is having to match your depth stencil buffer to your render target. There are also some issues with texel/pixel alignment (texels align in center, pixels align in the upper left). I did have some glowing bullet trails going for a bit which was nice and I'll hopefully have more progress to report soon.

Some other neat features that I've added gameplay wise are tracking missles and the start of a pretty full featured particle system. The tracking missles and bullets have been refactored to use the same particle system.

On another note, I got my old domain back jrepp.com and am pretty much finished with the migration of my recent content, links etc. I don't have all the old stuff from the previous jrepp.com (sources, cocoabb, arcane programming docs) but I'll be digging it up out of the archives to get things cool again. I also plan on writing a few short postmortum articles about XNA development when I hit my stopping point.

My kids are both really into playing the game right now. The key mechanics for them are the "star fox roll" and the debug camera. On a side note this months Retro Gamer has a couple good articles, one of which is about the making of Star Fox which is really a good read.

Holdem: Bug fixing career mode, UI tweaks

2006-09-29T11:09:00.000-07:00

I fixed a bunch of bugs in holdem last night. I got career mode working really well, both continue career and new career. I moved a bunch of the player game save logic out into it's own class called 'SaveData'. This aggregates the player basic information as well as extended stats. It uses a binary format with a version header tag to ensure consistency. I was smart about deserialization this time to avoid the unaligned memory read problem that I ran into with the pack file index.

On the UI side I cleaned up the main menu so continue career only shows up when you have a save game. From the in game options menu when you cash out or save and quit it does a nice transition back to the game and then either fades out to career or play now or shows the currently slightly broken quit confirmation.

I would love to get one more art pass over all the menus and background stuff. I may just experiment with altering the existing menu background to make it more color blend friendly and change to a larger font. I want the UI to feel very tangible and inviting.

XNA Shmup Update

2006-09-28T01:47:00.000-07:00

More progress as of late on the xna based shmup concept. All of the gameplay mentioned in the previous post has been implemented. Some of it is not quite 'fun' yet. The attack pod makes things entirely too one-sided and most of the weapons need to be tweaked.

Before ragging on the game any more I've gotten a bunch of neat things working. There's a few big things that currently don't exist in the XNA beta that will bite you as soon as you start to scratch the surface of the framework:

No support for model loading or animation
No support for fonts or UI

So I was pretty much okay with both of these not being there in the beta and just waiting for them to show up in a final version. Well the first thing I stumbled upon was the ZiggyWare XNA font generator and associated rendering code. This was super easy to throw into the code, it took me less than an hour to get the fonts support into the scene graph.

I then spent another hour and wrote a very small but usable UI/menuing system. When the debug camera is not enabled the left trigger brings up the menu. You use the DPAD to navigate the menu (A button also opens submenus). Certain items can have 'tweakables' attached to them which can be either a float, vector3 or vector4 value type. The tweakable fields (3 or 4 for vectors) can be selected using the shoulder buttons. The right analog stick adjusts the value in the field and an update event is sent to an attach IEventTarget object. I use eventing all over the engine already for animations, game logic etc. The one tweakable I have now for example is the LightDir tweakable which is wired to an UpdateLightDirection event on the scene. In the first picture you can see the specular highlights on the water (please excuse cheazy really bad shader code). You can tweak the lighting with the controller to get the desired effect.

So then that brings me to the issue of the model loading, which I was also content to let be and just use the standard cubes. I remembered that I had some old 3DS loader code laying around and porting C++ to C# is pretty darn easy IMO so I spent a few hours and ported the 3ds code. There were a few wierd things to work out in the translation but the C++ code was written with some nice abstractions so it went very smootly.

So now I've got some free 3ds models from the web running around in the engine with some more interesting lighting and it's actually looking a little bit more decent at this point. The next two shots are just of a free 3ds model I found that is composed of about 16 mesh chunks and has custom basic materials (no textures). To handle the materials I created a MeshMaterialGroup object that accepts the material with face indexes from the loader and resolves the faces into prim indexes. When you call Mesh.SubmitPrimitives() it looks to see if it has any material groups and if so it submits them in order instead of sumbitting the entire prim batch for the whole mesh.

Close ups of 3ds model:

XNA Shmup

2006-09-23T03:27:00.000-07:00

So for anyone who cares and hasn't heard me rant about what I wanted to do with the XNA stuff I'll just explain it now. Ryan inspired me to go in the direction of a shmup, I have wanted to do one for a long time but this new framework seems ideally suited to a game like this. There isn't any particular art style or theme set atm so I'm just laying out some really basic shmup gameplay elements that are pretty much 'required' to have a respectable game. One of the key ideas though is to completely leverage the 360 controller. I want to have a very natural action mapping to the controller that makes sense and gives you more control than simply shoot and move.

A few concepts that I am borrowing for the GD are:

Roll defense from starfox
Polarized attack for the enemies ala ikaruga (radiant silvergun), the difference here is that ground targets must be bombed, squigies must be railed with mass driver weapons and conventially shielded enemies require beam weapons.
All weapons are effective against all enemies but certain weaons are much more effective. This technique is vital to survival.
Ability to equip a small pod that can has limited controlled and it's own set of upgrades.
Clip/reload system for mass drivers/bombs, energy system for beam weapons. Ammo is plentiful but must actually be collected and you cannot hold the fire button the whole time.

Here's a screenshot debugging one of the triggers for a mob spawn and the new bullet system:

Again, not very impressive looking (it looks better in action) but I'll just layout a few of the things that are working now.
Follow camera
Scene trigger system that can fire proximity events
Mob controller with spawn/death management (hooked to trigger system)
Mob action scripting pcodes with time driven events (Fire, Rotate, Change properties etc)
Random terrain generator

I'm not trying to do a fully polished game currently. Just something that starts up allows you to play through a random level with increasing difficulty and records your high score. I will probably implement a few different types of weapons as well.

I don't know if I want to finish it all in one shot.. I have to get back to some other stuff.. really ;)

XNA: Yes I'm a bit addicted now

2006-09-22T19:47:00.000-07:00

This stuff is really nice. I'm actually a bit addicted to the whole thing. I finally got some shader issues sorted out. I have a few very basic shaders right now, one that renders color coded normals for debugging purposes and one that does a single directional light and diffuse shading. I picked up a good shader book and a new 20" LCD yesterday when I was hanging out with Mike. Here's a spinning cube inside a procedural landscape.

Migrating Outlook Express to a Mac

2006-09-21T21:58:00.000-07:00

So Lindsey is now migrating to a mac (Mac Mini) and I found the process of migrating her email to be relatively easy. First you get this program called dbconv and run it on all the dbx files in \Documents and Settings\UserName\Application Data\Identies\{BIG-GUID}\Microsoft\Outlook Express

dbxconv *.dbx

Copy all the mbox files to a windows file share.

On the mac in the finder 'Connect to Server (OpenApple-K)' enter the address:

smb://your.server.address

Import them in Mail.app.

Once the mailboxes are imported you export the contacts to a CSV file in outlook. Paste them into: Csv2Vcard and save the output to a vcf file.

Import it into Address Book as Vcards.

XNA rainbow mesh

2006-09-21T11:58:00.000-07:00

Well it's certainly not much to look at. I haven't put too much time into getting things pretty yet but I have ported a bunch of game engine concepts from rampart already. I've got a simple scene system with multiple vertex/pixel shader support and runtime switching between shaders. An animation system is hooked up to the avatar with event callbacks. Multiplayer support with actions wired into avatar. Debug mode with flying camera and ability to control scene rendering parameters (pictured wireframe mode). Oh and sound effect events.

The shader in the screenshot is the simple ffshader.fx that is shown as an example in the XNA docs. I have another shader that I put together off the template in NVIDIA's FX Composer. You can toggle between the two and there is a dynamic effect binding system that binds scene/object parameters automatically for the selected effect.

And yes the rainbow terrain mesh is super fruity!

The XNA docs overall are very good but they don't go very deep. I had to dig a bit deeper to discover how to handle the effect files more generic than in the examples which simply loaded a vertex shader function.

Essentially what I have is an scene effect object per .fx file. They derive from an abstract class with the following members:

OnEffectLoaded() -- called after the effect is loaded to get handles to the various parameters.

BindSceneParameters() -- called once per scene render to bind global scene parameters.

BindSceneObjectParameters() -- called once per scene object to bind local object parameters.

This is handy for switching effects on the fly.

I'll post some more XNA shader stuff later.

Goofing around with the XNA Framework

2006-09-20T16:22:00.000-07:00

I had to send my laptop into Dell again for repairs since they screwed up the initial repair so I spent some mess around time on non-beatbox, non-holdem related stuff.

So I downloaded XNA framework and so far I'm really happy with how things are setup. The API is really solid and easy to use. I had everything downloaded, installed and a spinning cube with 360 controller support in about 3 hours. Some things I like a lot and are worth mentioning:

360 controller support is awesome, no remapping wierd DINPUT Z-trigger or hats to in game actions. The game pad state that you read has members like Triggers.Left which is a floating point value. You can easily do things like Buttons.A == ButtonState.Pressed.
The Matrix object is very easy to use and has a bunch of very helpful static methods for getting various types of matrices.
C# is pretty fun to write game code in.
The framework is nice and lean and does things 'The Right Way', they don't eat all your CPU when you're running a basic idle loop or in the background.
All the heavy lifting is done in shaders via .fx files. This is very handy and works well with the VertexBuffer classes.

I couldn't get stuff to work initially on WinXP 64bit edition until I found this post

I'll probably post some screenshots before I go back to regular stuff. I don't know how far down the XNA path I'm willing to go just yet.

Jeff Minter gets his llama print undies in a bunch

2006-09-15T22:15:00.000-07:00

So it's been picked up on the indie gaming sites and beyond that Jeff Minter is working on a new game. I thought this was interesting in as much as the guy is an interesting character and I respect his seniority and work in the industry. Also, talking with some some other programmers around the office I heard some strange rumors when he was submitting early builds of neon to our group.

Rumor #1: There were some llamas that popped up and we made him take them out.
Rumor #2: There are still llama shapped buffers/backplanes used in the visualizer.

So tonight I followed a jump to his blog where he posted some test particle screenshots. These shots came out before the vids that clearly show he's doing a very tempest-like game. Now if you go and read the comments a fellow going by the name alanc5 asks him if he's just doing another tempest clone and Jeff flies off the handle. Alan has posted some retorts on his blog. I feel that Minter could have handled this much better than he did. Luckily nobody knows or cares about any of the stuff I'm working on so I will likely not have to prove that out ;)

Jeff is doing another tempest-y type thing which is boring but fine really yet he never did admit the guy called him out on it before he even showed off the game play. Alan might apparently have a history of goating Minter but at least he doesn't back down even when the whole yakyak forums come crashing down on him. I feel kinda bad for the guy.

Holdem: UI bug fixes

2006-09-14T00:00:00.000-07:00

Fixed a bunch of nagging UI bugs tonight. I'm still not totally happy with the fonts and some of the color blending. When you're a non-green background and you alpha blend a green menu it's a bit jarring. Even green on green is not very appealing.

At least on a green background it looks semi-decent. It looked better in 32bit color. I think that dithering to 12bit makes the colors harder to pick out. I 'skinnied' (if that's even a word) up the action menu which sacrificed the 'best hand' display and the bet ammount. That should make it more consistent with the other phone UI elements. The left action button is bound to the menu.

Career mode got some love. I fixed a bunch of character select bugs. But I think I'll the last glyph in the font should be swapped with a RUB button. Probably just a back arrow would be fine. The hiphen glyph is serving this purpose now.

I also fixed the career continue mode a bit. All menu animations have been cleaned up and are sliding in and out nice and smooth.

Funny quotes from IRC

2006-09-13T13:04:00.000-07:00

There are a bunch of great IRC quotes on this bash.org. This one had me in stiches:

#349567 +(9050)- [X]

Rabidplaybunny87: Okay, so my neighbors officially hate me
GarbageStan23: why?
Rabidplaybunny87: Well, me, david and andrew were having a bonfire in the backyard, and we were making s'mores and all... and suddenly we here sirens, and see a firetruck turn into the street in front of us.
Rabidplaybunny87: So we all went running to see what was up, and our neigbor's house was on fire!
GarbageStan23: oh shit!
Rabidplaybunny87: Yeah, and when we got there, the wife was crying into her husbands arms, and we were just kinda standing there, and then she saw us, and then like for 10 seconds, gave us the dirtiest look ever
Rabidplaybunny87: Turns out, we were still holding our sticks with marshmallows on it, watching the fire....
Rabidplaybunny87: talk about bad timing...

Holdem: bugs, bugs, bugs

2006-09-12T12:16:00.000-07:00

I've gotten a lot of bugs fixed in holdem in a short ammount of time. I have to rework the in-game overlay UI as it covers up important information right now. I'm considering cutting the in game AI chatter. I am reluctant to do it though because I think it breaths a lot of life into the game. One thing I was considering is still having an AI chat system but making it more event based. When an AI character has something important to say or a key event is triggered in career mode.

Holdem: Nokia 6682 photo

2006-09-10T19:11:00.000-07:00

This picture is of a pretty low quality. I'll just blame the camera.. the display on the phone is nice and makes the game look pretty sharp. I think I need to scale the fonts up a bit though as they seem a little on the small side.

Massimo says:

so what are you up to now? working on getting the animation running? Cuz I know what you're not doing :) you're not posting pictures of Hold'em running on your phone :)

Well somebody has to keep me honest.

Holdem is finally running, woot!

2006-09-10T03:05:00.000-07:00

And it looks amazing! For the record Dragonfly by Lemon D was the song that was playing when the app actually started up and ran and the time is 3am. I have been pursuing this goal of having this game engine run on a symbian smart phone for some time now. I finally tracked down the finaly serious problem pretty much by accident.

The line that was crashing first was:

if(path.compare(rec->name, rec->namelen))

This looks totally innocent.. I'll just say right away that it wasn't any of the usual suspects. Keep in mind that this ran fine on other hardware architectures. The problem was actually memory alignment.

The records that are being referenced here are part of a block of index records stored in the resource file. I have a tool that transforms and packs files into a single file and creates one block of memory to be used as a searchable index. The structure in memory used to look like this:

struct RecordRef
{
uint32 offset;
uint16 nextrec;
uint16 namelen;
// char name[namelen + 1]
};

If I tried to access offset or nextrec and the field didn't lay on a 4 or 2 byte boundary respectively my application would crash. This kind of problems are pretty hard to track down without a debugger. I used loglines traced to a text file on the phones internal memory through multiple builds to track this down.

The new structure looks like this:

struct RecordRef
{
uint32 offset;
uint16 nextrec;
uint16 namelen;
uint16 padding;
uint16 reserved;
// char name[namelen + 1]
};

I calculate the padding when the records are built in memory and before they are stored into the resource file. When they load from the file they are all nicely aligned and the code that searches the index just has to take into account padding when doing any pointer/index math.

Seeing the title screen on my phone makes me very happy!

Holdem: More progress

2006-09-09T15:37:00.000-07:00

So the game is running on my phone and I'm getting closer to tracking down what is stopping the game from starting.

..\..\..\..\..\DEV\ZTEAM\HOLDEM\S60\SRC\Series60.cpp(220): Starting window session
..\..\..\..\..\DEV\ZTEAM\HOLDEM\S60\SRC\Series60.cpp(232): Setting up direct screen access
..\..\..\..\..\DEV\ZTEAM\HOLDEM\S60\SRC\Series60.cpp(236): Creating double buffered drawable
..\..\..\..\..\DEV\ZTEAM\HOLDEM\S60\SRC\Series60.cpp(270): Initializating game engine with data path: E:\System\Apps\Holdem\data
..\..\..\..\..\DEV\ZTEAM\CORE\SRC\Gameengine.cpp(56): GameEngine::initialize(): game engine data path: E:\System\Apps\Holdem\data
..\..\..\..\..\DEV\ZTEAM\CORE\SRC\Gamearchive.cpp(68): GRPIndex::_reserve(): reserving: 1409 bytes, buffer: 0x00000000
..\..\..\..\..\DEV\ZTEAM\CORE\SRC\Gamearchive.cpp(95): GRPIndex::_reserve(): finished, buffer: 0x004121c4
..\..\..\..\..\DEV\ZTEAM\CORE\SRC\Gamearchive.cpp(734): GRPFileSystem: loading file: default.ini, packfile: E:\System\Apps\Holdem\data.grp

Could be a few things right now but pretty promising that game engine startup has gotten this far. Now if I can get that config file to load it will be on like donkey kong.

Beatbox: Sound is back

2006-09-07T01:09:00.000-07:00

I got sound hooked up again, fixed texture binding/uploading and got the combo meter and song position indicator working again. Yeah it's still rough but it's coming along. There are some pretty big things to do still and I think I'm going to change gears back onto texas holdem to nail down my framebuffer initialization problems.

Since music and sound is at the core of the game I'm considering building a specialized sound library/sequencer for the game. It would use an existing format and tracker for the editor probably screamtracker3 since I'm most comfortable writing tracks in that. Right now I'm using fmod which actually allows you to get event callbacks from the sequence. I'll probably just play with that for now.

I wrote a really nice scene graph when I was on vacation in mexico so that eventually needs to make it into the gfxlib but it's a pretty big change at this point so I may put that off too..

Oh well, lots of stuff to put off per-the-usual. I really am trying to keep the tasks smaller and more achievable but at some point I know I need to make bigger bets to make sure the stuff can be finished, polished and pushed out the door.

Globals are still considered harmful to your health

2006-09-07T00:55:00.000-07:00

Sometimes there are well defined technical reasons for this. Some people detest them because they have been told they are bad. Other more thoughtful people understand some of the serious problems that globals have. Many times in rapid prototyping (ala beatbox) or in general game dev people get a bit too global-happy and it can be a serious problem... I'll list a few of my main reasons for really not liking them:

Globals can hide bugs, if you don't name them intelligently they can be overriden by locally scoped variables.
Globals don't have well defined access patterns, anything in any thread can access them. This can make porting a single-threaded app to multi-core a super fun hairpulling exercise.
Globals enable sloppy coding and can ruin layering.
Globally defined classes don't have deterministic initialization order, you better not count on one class being ready before another one. Go for two-phase construction if you need a global class.

It's not all bad though:

Having your root system(s) as objects at global scope simplifies your life.
Pre/Static allocation is your friend. Many applications can be designed to require vary little dynamic allocation and this can really improve speed.
Sometimes when you're maintaining code it is less intrusive to add a global or static method then touch every method on down the call stack.

They're there for a reason. What's yours?

It's coming along

2006-09-05T21:45:00.000-07:00

Well there is more or less something there now. It is actually playable, although not being able to see scores and combos is a bit of a drag. Also the thing is completely full of bugs. It has gotten a lot funner to work on now though. Much less doing the boring plumbing that runs the show and more doing the AI and gameplay that I enjoy.

Beatbox: A story

2006-09-04T21:24:00.000-07:00

Okay well this isn't the sky falling but screenshots are so much fun, especially really dumb ones during development. What was at one point actually a fairly fun playable little game is currently a shadow of itself living on top of all new (actually rehashed I get to that in a minute) stuff.

Now I'll provide a little story about beatbox, mostly for my own benefit. About a year ago I was having a lot of trouble getting any coding done after our second kid came along. I still had time but I just couldn't really get myself motivated to do anything good. Discouragement mostly came from the fact that I didn't figure that I had time to really write anything of any good quality.

So I got this idea to just hack, not worry much about proper design or object orientation or really doing anything right at all. I wanted to get back to the root of what I loved, the thing that made me write reams of code in Jr and Sr High School. Just get something up and going no matter how sloppy or lame it was and have fun doing it. So I put some 3d graphics to music using glut, and it was a blast.

After awhile just doing different 3d scenes at different sample points in the song became a bit mundane for my own personal enjoyment so I decided to make the blocks fall down and controllable. And that's more or less how beatbox was born. I wanted to have poyupoyu style gameplay with my own individual twists because that was really what I wanted to play and I didn't have a poyupoyu game on hand to enjoy.

This whole time I was still hacking. The entire game logic was in poyu.cpp and the rendering was in render.cpp. It was a pretty mess. I copy-pasted chunks of code that I dragged in from all kinds of personal projects from as far back as 2002, yeah a glorius mess. At some point I just dropped the binaries in a folder and called it good. I realized this was a dead end and I was re-inventing and ruining all kinds of work I had already done for the past few years as well as writing some code that would never again be useful. So I made a big choice. I was going to take 5 years of code and make it into a set of consistent usable libraries and make all my games compile off of that. I knew this was a huge project but I decided that it would be fun and good for me.

So I've come to a summit of that work. I actually have the original beatbox code retrofit into the new set of libraries with a new resource system thrown in for good measure. It feels good but all I have to show for it is a white triangle on a grey background. At least I'm happy.

Beatbox: Was it.. nope

2006-09-04T21:14:00.000-07:00

I thought I saw a triangle on the screen but it was just some wierd food stuff stuck to my laptop LCD. It really looked promising for a second or two. I'll post screenshots when there's blocks falling from the sky again. I had a really neat visual idea for the combo system the other night as I was falling asleep. We'll see how it pans out... but for now back to getting a triangle back onto the screen.

Some things are running again

2006-09-03T23:48:00.000-07:00

The UI widget test app is up and running again. This time using the final resource system from the game library. I took a screenshot to prove how unimpressive this actually is ;) This is some of that TDD stuff that I posted about earlier. There is a unit test framework (built using a command line system that is part of the game engine) for testing object models and what not but this is a simple test graphics app. It doesn't do anything besides create a view, add some UI components, test strings and setup the layout. This makes it really easy to get up and running fast and find a variety of little bugs.

Ich Pwne Newbs

2006-08-29T17:22:00.000-07:00

Blogging is so advanced now it's going back to the future. Ol' E never sounded so good.

This is Hardcore

2006-08-28T22:23:00.000-07:00

I was listening to pandora and it chose a very appropriate song. I had to look over my shoulder just to make sure.

PULP LYRICS

"This Is Hardcore"

You are hardcore, you make me hard.
You name the drama and I'll play the part.
It seems I saw you in some teenage wet dream.
I like your get up if you know what I mean.
I want it bad. I want it now.
Oh can't you see I'm ready now.
I've seen all the pictures,
I've studied them forever.
I wanna make a movie so let's star in it
together.
Don't make a move 'til I say, "Action."
Oh, here comes the Hardcore life.
Put your money where your mouth is tonight.
Leave your make-up on & I'll leave on the light.
Come over here babe & talk in the mic. Oh yeah I hear you now.
It's gonna be one hell of a night.
You can't be a spectator. Oh no.
You got to take these dreams & make them whole.
Oh this is Hardcore -
there is no way back for you.
Oh this is Hardcore -
this is me on top of you &
I can't believe that it took me this long. That it took me this long.

This is the eye of the storm.
It's what men in stained raincoats pay for but in here it is pure.
Yeah. This is the end of the line.
I've seen the storyline played out so many times before.
Oh that goes in there.
Then that goes in there.
Then that goes in there.
Then that goes in there. & then it's over. Oh, what a hell of a show
but what I want to know:
what exactly do you do for an encore? 'Cos this is Hardcore.

Beatbox: Track names

2006-08-28T21:41:00.000-07:00

Mass and I had some good lunch game design conversation today. Made a stop by gamestop and bought 'Trauma Center: Under the Knife' for Nintendo DS. It's one of those titles you don't see that often although the counter guy said they got a restock of 2 copies so that may indicate that Atlus is responding to the demand. Speaking of hard to find (at least for me) DS titles that I got recently:

Bomberman DS
Pheonix Wright: Ace Attorney

The general lesson seems to be: if you hear a DS game is good and you see it, swoop it yo.

Oh back to the topic, so we're talking about beatbox which is my music based puzzle game I sent out to a few people and the tracks so far which are named:

I Was a Teenage Mecha (MkII)
Luxury Carpet Comparison (bitwise)
Siding is Exciting

I'm going for a bit of an abstract techno feel with these tracks but the names are inspired by local Seattle band Minus the Bear who have great song names such as:

Hey! Is that a Ninja up There?
Monkey!!!Knife!!!Fight!!!
Thanks for the Killer Game of Crisco® Twister
I Lost All My Money at the Cock Fights -

I mistakenly said one of their songs was 'Monkey Monkey!!!Knife!!!Knife!!!Knife!!!' and for that I'm sorry because I really think that is a much funnier title anyways ;)

And while I'm at it I might as well thank Ryan Blinsky for introducing Minus the Bear to me.. As well as tons of other awesome music.