Skinning solutions and body animation

[Ingemar]

I am looking for advice on methods, code and model formats suitable to do body animations with skinning.

I know how skinning works, and I could implement it from scratch (I have even authored a student lab on skinning), but time is limited so I would like to avoid detours on not-so-good formats, and if there is good (modern) code around then it would be wise not to miss it. I fear that what I know is aging and I want to be updated.

Let's say, what is the current state on the subject? How do you work on body animation?

[User137]

My game engine is actually not that far yet to do bone based animation, but i know little about formats:
OBJ: Does support multiple objects and textures but no frames or bones.
MS3D(Milkshape3D): Propably supports it all but the format itself is weird. There is binary and ASCII versions, and i suppose different versions for the binary.
3DS: One of the most popular ones to support all. If you find a good model reader for this you can do alot.

Then there is also formats from other games like HalfLife 1 and 2, and Quake, was it MD2 and MD3 which had i guess compact bone animation format for gaming. I'm not sure how much Unreal-engines format is used, but graphics and models in their games are outstanding.

[Ingemar]

AFAIK MD2 and MD3 are a bit too old-fashioned these days. OBJ is nice for rigid objects but no animation data.

3DS is popular, no doubt about that. How about Collada, B3D? Any nice loaders/renderers around?

[AirPas]

xproger wrote an excellent tutorial about that http://xproger.mentalx.org/old/?id=1&page=2&doc=anim3d

you will find also a source code + 3DS max exporter

i personally used it

[Stoney]

While I never wrote my own model loader, when I used Unity3D and Horde3D I generally used Collada (and sometimes FBX in Unity) and I was really satisfied with it.
Collada shouldn't be too difficult to parse, since it's just a big XML file. But I don't think there are any Collada loader written in Pascal though.
There is also Restless, a model loader and format written in Pascal with a Blender exporter and it should support everything you for looking for. Unfortunately I haven't been able to get it working properly on Mac OS X as of yet. (Compiling the dynamic library works with some added compiler defines, but somehow it crashes in the example application.)

[Ingemar]

Collada shouldn't be too difficult to parse, since it's just a big XML file. But I don't think there are any Collada loader written in Pascal though.

On the negative side, I understand that Collada is a very complex format so writing that loader might take a lot of time.

There is also Restless, a model loader and format written in Pascal with a Blender exporter and it should support everything you for looking for. Unfortunately I haven't been able to get it working properly on Mac OS X as of yet. (Compiling the dynamic library works with some added compiler defines, but somehow it crashes in the example application.)

As you say, the library compiles with a few tweaks (Delphi mode + replacing dglOpenGL by GL + GLext), which is a very good sign. Most packages I find that are written for Delphi tend to be littered with dependencies and Win32 calls, so I am happy that that wasn't the case here.

So now I can try a demo though the debugger and see what happens.

[mobilus]

The longer I use GLScene, the longer I wonder why it was created, and since it was established why it is not used. You have the best format there - MD5 (I tried all) - just a few lines of code:

  With TGLActor.CreateAsChild(GLScene.Objects) do
  begin
    Name:= 'Actor1';
    LoadFromFile('actormesh.md5mesh');
    MeshObjects.BuildTangentSpace(True, True);
    StructureChanged;
    TransformationChanged;
    AddDataFromFile('actoranim.md5anim');
    SwitchToAnimation('actoranim');
    AnimationMode:= aamLoop;
  end;

[Ingemar]

As you say, the library compiles with a few tweaks (Delphi mode + replacing dglOpenGL by GL + GLext), which is a very good sign. Most packages I find that are written for Delphi tend to be littered with dependencies and Win32 calls, so I am happy that that wasn't the case here.

So now I can try a demo though the debugger and see what happens.

It finds the file, but crashes in CreateVBO. Something is nil, and it looks like it is the current object. Or I am not allowed to take the address of a variable in the TRLS object. It is the @FVBO parameter to glGenBuffersARB that breaks.

glGenBuffersARB, BTW. Isn't it well overdue to drop ARB from glGenBuffers? Not that I have cleaned up every code snippet I have but in a library like this I think I would. But it shouldn't matter, of course.

[Ingemar]

Now I think I was all wrong; the problem must be that I don't initialize OpenGL properly.

I can't seem to use dglOpenGL, it doesn't compile, and the error "Generating PIC, but reference is not PIC-safe" is not understandable to me. But dglOpenGL shouldn't be needed anyway.

So I'll have to figure out how to initialize OpenGL in a way that enables glGenBuffersARB. Should be trivial.

PS: And it was: load_GL_ARB_vertex_buffer_object

So my current status is that is compiles, finds the files, runs... but doesn't draw anything.

Stoney, how far did you get? Where did it crash for you?

[Stoney]

Using Mac OS X Lion and FreePascal 2.7.1 I get this error while compiling and linking one of the examples:

Assertion failed: (_dependentDylibs.size() != 0), function File, file /SourceCache/ld64/ld64-123.2.1/src/ld/parsers/macho_dylib_file.cpp, line 391.
0  0x102efd71c  __assert_rtn + 76
1  0x102f562c1  mach_o::dylib::File<x86>::File(unsigned char const*, unsigned long long, char const*, long, unsigned int, bool, bool, bool, ld::MacVersionMin, ld::IPhoneVersionMin, bool) + 2721
2  0x102f4abe2  mach_o::dylib::parse(unsigned char const*, unsigned long long, char const*, long, Options const&, unsigned int, bool) + 706
3  0x102f5c0a5  ld::tool::InputFiles::makeFile(Options::FileInfo const&) + 709
4  0x102f5d6f9  ld::tool::InputFiles::InputFiles(Options&, char const**) + 665
5  0x102efd947  main + 311

I used dglOpenGL to build the library, but integrated those changes in dglOpenGL to get it working properly on Mac OS X.


I'm pretty sure I was able to compile it on Mac OS Snow Leopard, but it crashed when I tried to execute one of the examples.