Dom's Blog

Shaders

If you have been writing PostFX shaders in Virtools, you may have waited long for this, but here it is: overriding techniques for rendering into RenderTargets!!! You can has Tron, yay! Here's a simple example for a masked glow PostFX:

Overriding techniques allows you to specify a technique name that shall be used when rendering the scene using the Render Scene in RT View BuildingBlock. Previously one was only able to use one shader/material for all objects. That's ok for some tasks but if you need need per-material masking, there was no easy way for doing so. I first expressed the need for a better way in 2005 – that's 4 years ago! In 2006 I tried manual techniques switching and hit another barrier. Now, finally, it's a smooth process. Better late than never!

Some help with hiding or unhiding elements of the scene (i.e. something like RenderLayers) has unfortunately not yet been added. Also some other aspects like include management still needs improvements.

There are a few new shader semantics available:

AlphaTestEnable, AlphaBlendEnable, AlphaRef and for OpenGL only: SingleSided, DoubleSided

If you check the SDK, you will  find traces of WIP (work in progress) for shader-based shadow maps: a new shader semantic, a new BB, a new Rendstate and maybe a future built-in shadow-shader. You will also notice that support for hardware shadow texture formats has been added.

LUA

LUA has been added as scripting language. LUA is a widely used scripting language in the games industry. In contrast to VSL (Vitools Scripting language) LUA is not strongly typed and not JITed (Just-In-Time compiled). It's therefore to be considered to be slower than VSL. So why add it? VSL is very focused on implementing new BuidlingBlocks via scripting. It's not very strong with custom data types and working in a global scope is very limited.

Moreover not everybody likes to use the concept of Schematic Programming. By using the SDK it's possible to bypass it, but of course it makes development slower again. Using LUA one is now able to script a game without using the schematic a lot. This is possible because all LUA scripts share the same context. ( A bit of schematic is still a required though).

As LUA is known by a wider audience, new (script) developers can pick up 3DVIA Virtools much faster without worrying a lot  about the schematic. A good example for this are the 2 last adventure games by City Interactive. Moreover there is a new example game (a BoulderDash clone) entirely writtin in LUA. I think it's also a good starting point for Virtools users that still need to learn LUA!

As LUA is a dynamic language there is no help from a compiler but a button for checking the syntax is available. Setting breakpoints and stepping through the code is possible! There is a small input field in the right side of the toolbar for calling LUA functions directly but i think it's a bit small. From my Maxscripting experience a big input console that allows to prototype interactively is a big plus and hopefully it will come in a later release.

You can't yet use LUA for action scripts and therefore you don't have direct access to the selection. But using the run-button LUA scripts can be executed at any time in authoring mode too.

Personally I am not much attracted by the LUA syntax. Further more I saw some articles on how to implement OO in LUA and they scare me off 😉 Currently I think using C# as embedded scripting language is my favorite! AngelScript recently got simple inheritance and interfaces – it's also a strongly typed language with JITC – might be an interesting alternative to LUA and Co.

The LUA editor control is the same from the shader editor and VSL editor and thereore suffers from the same problems i.e. long scripts slow the entire editor down (due it's slow syntax highlighting I guess).

Blend Shape Support

Blend Shape Support basically means morph targets mixable with skinning (bone-based deformation). So you can have facial animation or body deformations/customizations using morph targets ( blend shapes in Maya) at the same time with your standard bone-based character animations.

Probably most people will think "finally facial animations!" … yeah, cool … but I think you can do much more with it…

😎

What about muscle deformation? Here is a simple example of what I mean: an arm deformed by bones can be morphed simultaneously to bulge it for the muscles effects …

Above you see two arm entities, both are referring to the same mesh, but one is using the morph weights differently. The great thing is: it's still only ONE mesh. You don't need to copy the mesh for each entity! Thus it even works independently for GPU skinned characters – only one mesh and full individual weight control .. I tested it and it seems to work!

Currently when exporting from 3ds max, you need to do a "export selected" that excludes the morph targets otherwise they will be added as additional body parts. Hopefully in future those will be detected and skipped automatically.

I think this is probably one of the new feature that really gives a solid advantage over other 3d authoring solutions! Flexible and simple workflow, nice!

To be continued …

There are more new features but it's getting late (bedtime!). Please note that this is beta experience and some things might be different with the final release. I hope it gives some more insights about 3DVIA Virtools 5's new features as benefits are not always clear via a plain listing of "what's new?" items. Feel free to add informations or to ask questions. Till next part, cheers!