Volatile-Engine Rantings

Uniforms and Attributes

2009-01-02T18:16:00.003Z

Volatile-Engine's old way of doing uniforms was rather complicated. You stuck an annotation on the field that is a uniform, registered the class that the field belonged to and you were done; however the background stuff that made all this possible was rather hideous. Lots of reflection, lots of workarounds around Array stuff and in the end I quoted Sherwin Nulland: "Ahhh fuck it".

So what do to? Well, I stole MatthiasM's idea (with his permission). Get the list of uniforms from the shader after linking -> create an array of Uniforms and access the uniforms through getUniform(String);

This allows a few things to happen:

1) You can only set Uniforms to what are declared in the shader. No more exceptions saying that uniform isn't there at runtime...

2) Allows a context specific state to be stored in java to compare uniform values before uploading to GL. Each Uniform has a Handle which has a reference to the cache.

3) It now plays rather nicely with Surface and its shizzlness. Hurrah for easy multi-target rendering!

Happy '09 by the way.

Scripting and how your foot could be in danger!

2008-02-16T13:37:00.003Z

I was talking to MatthiasM last night regarding scripting and why, as game engine creators, we feel the need to restrict what the scriptee can do.

There are alot of arguments for and against scripting, the main one being is scope in my opinion. How much scope should you give the scriptee ?

On one hand, you definitely do not want your game engine crashing or even blue screening your computer (which OpenGL calls could do!), but on the other, you do not want to restrict the user's imagination in what they can and can't do.

I for one hand am going with the "give enough power to the scriptee so they can shoot their own foot off". Yes, they can access File. Yes, they can access GL_* calls, but so what? who cares? If they do and their game crashes, whos to blame?

Let me know your opinion if you have one.

The Bog

2008-02-15T19:23:00.003Z

I haven't been well in recent times and it seems that an increasing amount of my time is being spent on the throne...and it finally dawned on me.

Why am I making an XML based storage thing for Volatile-Engine?

I seemed to have lost track through the dark woods that is XML, but its clear now: having an index.xml file inside a .zip that loads the files surrounding the index.xml file...much like a website!

Afterall, whats a basic website? Just content and how to display it. Isn't that exactly what I need?

Just a question of how logic is going to fit into this equation, ruby or JSP anyone? Hmm?

So Close!

2008-02-01T02:34:00.000Z

Honestly, all I need to do now is 3 things:

Get VBOs implemented again. Had to take them out temporarily for design purposes.
Get MatthiasM's obj loader inserted somewhere with a nice design around it.
Get the DDS loader working again.

After that, hopefully Volatile-Engine v0.1 will be born!

View points

2008-01-30T21:32:00.000Z

It seems like everyone these days wants to force their viewpoint onto other people. I started noticing this about a year ago, maybe I was just naive or something, and it didn't bother me, I thought people were just expressing their point of view.

But the other day, I had this conversation about abortion with one of my peers at the university and they seemed adamant that they want to go to a country where abortion is illegal and force the currently acceptable British society values on this country. What is wrong with that I hear you say?

Well, a lot of people seem to forget history; It wasn't until a few decades ago that women were allowed to vote in this country (the UK) and be counted as equals. And now all of a sudden, this society is a beacon for equality and morality? I'm not saying that the current accepted views aren't morally correct by the current standards, but when has it become tradition for people to force their 30+ year old tradition on people who's culture has survived thousands of years?

Happy New Year!

2008-01-02T14:35:00.000Z

Yup, its 2008..boo hoo, like the first of january was ever going to be full of rainbows and unicorns. It was a freezing cold day and I stayed in and studied...Not really that bothered.

On a slightly cheery note, volatile-engine is in SVN at googlecode: http://code.google.com/p/volatileengine. So thats one step closer to an actual release.

This SVN entry is actually the 6th fork of VE...VE 2 is the most full featured, but the 6th is the one im happy about. Ive been making the comparison between VE and j2d recently and I think that stands. You create a Surface (be that a texture, or a window), get its rendering context, and call draw, clear, project, whatever on it. The rendering context will render onto that surface. And there is a CompositeSurface for MRT...

I've also had a Obj loader contributed to VE from MatthiasM. Its not in SVN yet, have to sort a few things out with VBOs and textures before that goes in. But nevertheless, thanks.

Also, had an idea regarding transformations from Riven that has helped with JNI overhead as well as some performance enhancements. It has to do with the way the engine handles transforms. Previously, each SceneObject had its own localTransform as well as a cumulative worldTransform. Now, a SceneObject returns the localTransform and the worldTransform of its parent. Only a TransformSceneNode has the ability to actually move anything.

This is useful in two ways:

Saves on glMatrixMode, glPushMatrix, glLoadMatrix and glPopMatrix calls if the transform is the same.
If a model has multiple parts to it, you can shove them in a single SceneNode and move that around. Other engines decided to have multiple Geometry(s) inside the equivilant of SceneMesh, but that has alot of hastle when it comes to passes.

So thanks to him for that contribution. All in all, I am very happy about the architecture of VE now. Hope this enthusiasm for coding stays for a while :)

Last but not least, Im still using alot of Gareth Jenkin-Jones' code (AKA ChaosDeathFish) especially the Array stuff. So thanks a bunch for that gareth.

New Stuff

2007-11-13T19:03:00.000Z

Its been a while, but alot has happened in that while. Yours truly has become a second year medical student in the top 10% of the year...w00p. Theres been little time to code, but things are progressing seriously slowly.

As a side note, went on placement with a friend of mine who has graduated and became a doc, it was quite nice to see actual patients that are living breathing things and not just some statistic in some book...

Side note two is that my music taste has somewhat slightly changed from the rock and roll to encompass alot of rock and roll, some acoustic guitar as well as funk. What will we ever do without james brown?!

Oh yeah, DOWN WITH FACEBOOK!

We love them really...

2007-06-03T00:39:00.001Z

Last year I upgraded Girlfriend 1.0 to Wife 1.0 and noticed that the new program began unexpected child processing that took up a lot of space and valuable resources. No mention of this phenomenon was included in the product brochure. In addition, Wife 1.0 installs itself into all other programs and launches during system initialization where it monitors all other system activity. Applications such as Pokernight 10.3 and Beerbash 2.5 no longer run, crashing the system whenever selected. I cannot seem to purge Wife 1.0 from my system. I am thinking about going back to Girlfriend 1.0 but un-install does not work on this program. Can you help me?

Dear Sir,
This is a very common problem men complain about but is mostly due to a primary misconception. Many people upgrade from Girlfriend 1.0 to Wife 1.0 with the idea that Wife 1.0 is merely a "UTILITIES & ENTERTAINMENT" program. Wife 1.0 is an OPERATING SYSTEM and designed by its creator to run everything. It is impossible to un-install, delete, or purge the program from the system once installed. You can not go back to Girlfriend 1.0 because Wife 1.0 is not designed to do this. Some have tried to install Girlfriend 2.0 or Wife 2.0 but end up with more problems than original system. Look in your manual under Warnings - Alimony / child Support. I recommend you keep Wife 1.0 and just deal with the situation. Having Wife 1.0 installed myself, I might also suggest you read the entire section regarding General Protection Faults (GPFs). You must assume all responsibility for faults and problems that might occur. The best course of action will be to push apologize button then reset button as soon as lock-up occurs. System will run smooth as long as you take the blame forall GPFs. Wife 1.0 is a great program but is very high maintenance.

My Guitar!

2007-04-30T15:25:00.000Z

Fear DP's guitar playing skilz! SKILZ I SAY! skilz...

Cats are lovely, yet EVIL!

2007-04-09T10:44:00.000Z

Its been a while folks, my excuse? Ummm...

Anyways, onto today's subject. I love cats, dont get me wrong. I do! Ive had quite a few cats in my past time all of which have been adorable. But I can't stand them anymore!

Toxoplasmosis is a disease caused by cats. They are a host to Toxoplasma Gondii which is then secreted into their shit. The mice eat the shit/crap and then...all of a sudden...they start liking cats. I mean WTF! Serious brain melt...mice liking cats?

Anyways, the bacteria then gets into us and our unborn foetuses and it infects them. We dont start loving cats...but lets say it isn't pretty.

I might start a campaign against cats. Although a company has produces an allergen free cat.

Blast from the Past

2007-02-21T23:46:00.000Z

Remember this? Amazing isn't...

3 types of shadow volumes

2007-02-01T20:58:00.000Z

So yours truly got bored yesterday and decided to code Infinite Shadow Volumes that use the weight of the vertex to extrude the vertex to infinity, that was cool.

He then decided to code a version that uses GL_NV_depth_clamp, and that was also cool.

He then settled down for a nice cup of tea now that all 3 versions give the exact same result.

Ever seen green mixed with purple?

2007-01-29T23:00:00.000Z

Heres a question: Have you ever seen a green light, mixed with purple light, mixed with some directional yellow light on dirty terrain with a white box floating in mid air?

Well, now you have!

VE Points: What is this?

2007-01-28T23:15:00.000Z

2 VE Points to the person that can successfully guess What This Is and give a reason

When Linux Attacks

2007-01-28T19:49:00.000Z

Linux as bit my arse for the last time, but it took a big chunk of my fatty deposits with it as it chew helplessly on my harddisk.

The result is a complete format with the installation of Windows 2003 x64 Professional. And to my surprise, its dam quicker! The TestShadowVolumesStress used to run at 30ish FPS on Windows XP home edition (same HW and same driver, except this on is x64 the other was x86), it now runs at a smooth 83fps.

What I did manage to learn from this is two folds:

Always back your data (As mentioned last time by KappaOne on #lwjgl)
Repeat 1
Windows has some security feature in which you cannot access your Documents and Settings from another computer to back your data up if your username is password protected

Cool!

Getting close to 0.1!

2007-01-26T02:50:00.000Z

I know, I know! Ive cried wolf about VE 0.1 many times before; and as some of you might know, my new years resolution is to have 0.1 version of VE before march. But honestly now, things are shaping up nicely. Nice enough to have a release.

Ive taken out alot of experiemental/dodgy code today (that included frustum culling *gulp*), but it feels right. I honestly have 1 last thing to do with the handling of shadow volumes then I'm done for 0.1.

Development for 0.2 can start after 0.1. Ideas are already popping!

PS. I removed preRenderLogic in ImmutablePass. I figured out a much nicer way of doing the same thing.

So many changes, my head hurts!

2007-01-25T23:11:00.000Z

As usual, a build up to an exam results in massive stimulation of what I call "Wanting to Code Syndrome" (or WCS for short) and as usual, your truly has been developing VE. So what are the changes?

Profile now has a registerable Class-Renderatom situation; Register a class with a RenderAtom and whenever that class is rendered (it has to implement IRenderable), the renderatom you registered with that class gets used.
Added RenderAtom.getPriority(); You can now have multiple render atoms that render the same class; the one with the highest priority will be selected. The getPriority() returns a priority based on your hardwares capabilities.
Extracted Pass to Pass and ImmutablePass; this allows effects to extend ImmutablePass and not allow the user to override key variables.
Removed SceneVisitor.
Changed accept(...); in Spatial to traverse(SceneTraverser, int flags). This allows per spatial handling of traversal. Much nicer code.
Removed static members in RenderState (i.e. the RenderState type and all that). That is now handled by RenderStateType enum. This has implications on ImmutablePass and StateRenderBin
ImmutablePass now has 3 types: AMBIENT, ILLUMINANT or DECAL.
AbstractRenderBin now renders AMBIENT passes first of all shapes, followed by ILLUMINANT, followed by DECAL.
Added preRenderLogic(Shape, Light) to ImmutablePass. You can do some limited logic before rendering here. (I am considering removing this, but we'll see)
LWJGLProfile now registers the RenderAtoms/StateRenderAtoms in the EventQueue.
SceneTraverser now also has a render(Canvas) method. The Camera no longer renders, but is used at the SceneTraverser. This has complications for rendering as well as initialising a game.

Now why all those changes? I realised the engine isn't up to scratch yet and now I'm fairly happy with the current code.

Generics are confusing!

2007-01-23T00:29:00.000Z

;ALSDKH;ABNOI;OSGABSODFGASNBAGUNHAHAGBOATBWOH;

Thats how I feel about Generics at the moment!

The method getRenderAtom(Class) in the type Profile is not applicable for the arguments (Class)

Although Directional-f***ing-Light extends a class that implements IRenderable. Go F yourself up the arsehol Java Generics/Eclipse (who ever is at fault)

11.171us

2007-01-21T19:05:00.000Z

11 microseconds to calculate the shadow volume of a box! Beat that carmack :P

Really happy about the performance of the silhouette extractor as you can tell

Shadow Volumes/Map interactions

2007-01-21T12:23:00.000Z

Been a while huh? Ive been too busy studying about the breast/axilla and various other organs of the body. Tis pretty neat. Anyways, onto the meat of this post.

With shadow maps, after calculating which point is in complete shadow and which point isn't, you add a small ambient value so that things look half decent (*cough* unlike Doom3 *cough*). All nice and rosy. Until you meet shadow volumes. Shadow volumes require that you have an ambient pass, then render an alpha'd full screen quad with certain alpha values to get the ambient you want. Can you see the problem?

If you mix both maps and volumes, getting the same colour for both volumes and maps is going to be dam hard since the alpha value doesn't directly correspond to a colour per say.

The solution to the problem is to render the stencil buffer to texture, and sample from a fragment shader and add the ambient factor just like shadow maps. However, FBOs dont support rendering to stencil alone. Apparently, OGL implementations interleave depth and stencil since depth is usually 24bits and stencil 8bits => fits perfectly into 32bits

EXT_packed_depth_stencil to the rescue. You can have 1 texture that is both depth and stencil, which means that the shadow map is the depth value and the stencil buffer for stencil shadows is the stencil 8bit packed value. Tis very neat.

In the wise words of borat: I like!

Uniforms and java fields

2007-01-08T00:42:00.000Z

Not sure if you know, but there is another shading language out there (yes, besides HLSL, GLSL and Cg) called SH. What it does is it allows uniforms and attributes to be treated just like normal C/C++ fields...which is nice!

What I'm working on now is a step in that direction. You extend Pass for your particular appearance/pass; declare a few Uniforms and use them just like java fields. Notice I didn't say declare, instantiate then use them just like java fields; the actual instantiation happens behind the scenes.

So, you declare a field name of type Uniform (e.g: protected Uniform4f pointSize;) the name that Volatile-Engine will use to query the location of the Uniform is pointSize. So the field in java is bound to the field in shader code...neat huh? This required a few modifications to the way Shaders and Uniforms are handled in Volatile-Engine, but I think its a step forwards...

Credit goes to MatthiasM for this one with slight modification on implementation by yours truly...

Conspiracies I say!

2007-01-03T17:15:00.000Z

Thats right, new year is a conspiracy in order for us to leave the comfort of our homes and go look at shiny things that like to go pop. I am ofcourse talking about firewoks. What happens in your home while you are gone is a completely different story. Little minions crawl out of the pores on your couch and re-arrange your pots of chocolate into a less decorated mess...

Aaaanyway, I finally found a solution to the RenderBin bug; Each Shape has a Material which inturn has many Passes. The problem was extracting the Pass and coupling it with the shape it represents. This eventually meant that a new Shape/Pass pairing had to be per pass per object per frame! The number of objects that were created was herrendous.

The solution was, as kindly donated by kevglass, was to get rid of Material and introduce the Passes straight into Shape. But, when introducting this, you create a Map.Entry that takes the shape and the pass you want to add. Then, the RenderBin can use these pairings to render. Near zero objection creation! Yay!

Game Idea!

2006-12-12T19:49:00.000Z

I don't know how I didn't think of this game idea before, but it combines pretty much all of the techy stuff I've made so far. So, heres a quick summary on what it is:

Procedurally created planets
Satellites deploy characters on planet
Planet is split into equal countries (so a grid)
Players take turns to deploy characters on the grid at any unoccupied country
When two occupied countries join that are not of the same team a final fantasy type fight occurs
Winning party gets to deploy another character on the losing country
The currency of a block is how long you have occupied this block for.
Slopes give you a height advantage which leads to having a surprise attack on your enemy
Characters are elemental, each character has a very big weakness that another character has as a very big strength. Think water beats fire, fire beats tree...etc

The actual fight system is free flowing, time unit cost based, heres a quick summary:

3 slots that are occupied with verbs. So Attack Attack Defend for example.
Your slots are independent of the enemy, you insert 3 verbs into the slots, then the character does the attacks in the correct order, then you rinse and repeat. Both characters go at the same time and if you attack and the other person attacks, both players get a miss; same for defensive moves.
Attack moves cost more than defensive moves, this is to encourage the use of defensive moves.
All moves have the same time frame, I am considering having very powerful moves that take up more than 1 slot...

What do you guys think of this?

Insulin, Fog, Lights...Action!

2006-12-01T14:16:00.000Z

Box, green point light, yellow directional light, blue directional light and some blue fog! Yes...blue fog. It is a naturally occurring fog that is localised around me...

In any case, it looks half decent, still no mipmapping or normal mapping and thats mainly because I've been studying about how diabetes is associated with ethnicity. Which leads to how many sugars I have in my tea: 8

Thats right, 8 sugars and thats little to what I used to have! Which sorta begs the question about insulin resistance...

I'll report back when I found more shizzle on the subject.

PS. Click on the image to enlarge

Dawn Terrain

2006-11-27T01:56:00.000Z

Today is the official world wide 'make your own terrain' day as christened by yours truly. Anyway, here is my 20 minute contribution. Its lit by two directional lights to give that morning breeze factor to it. Unfortunetly, I couldn't be arsed with a skybox just yet so I've managed with a clear colour.

For those with a mind hellbent on performance, it runs at about 2400fps on a 7900GT, I'm pretty sure I could squeeze that to near 3000, but thats for another time. Hope you like it

RAW-FP32 and RAW16

2006-11-25T15:19:00.001Z

Just created two more height map modes which are probably going to be the mostly widely used ones. The first loads from a RAW 32bit file which gives excellent accuracy with literally no visual differences in height maps between the file and the WorldMachine internal view on the height map. The RAW16 is a slightly different matter, there are pretty obvious visual errors especially around the edges. And since 16bits wasn't enough, I decided against writing an 8bit importer...

In other news, found a bug in the renderbins and its fix is rather expensive. It was originally put there to minimize object creation to minimize GC significantly, but it made a few objects pop in and out which was rather strange. I've added this issue onto my TODO list but its near the bottom at the moment, I have a few other more exciting bits to code first.

Time to code the NormalMapFilter (hint hint)

"Performancing" blog tool

2006-11-25T12:40:00.001Z

Found this cool blog posting/editing tool for firefox. Instead of going to the website, logging in, clicking on Post then typing; all you need to do is click on the little pencil icon near the bottom and write away...

Rather neat I thought.

Volatile-Engine's blog has moved here

2006-11-25T12:16:00.000Z

I got really really tired of those spammers on the www.volatile-engine.com website, so I decided to move my rantings here in the hope of having more control...

I guess I'll see whether that was a good move soon enough...