Orion Engine Blog

I’ve been making changes to the base scene object.  Now there is a flag that you can use to render the current scene object after all of the children have been rendered, instead of the other way around.  This was needed due to the way mesh skinning is performed.  All of the bones (i.e. matrices used to influence the vertices) are added as children to the mesh itself.  The combined transform for all of these bones need to be calculated prior to rendering the skinned mesh.  A new object called a Matrix Palette was added to the mesh scene object.  It’s used to setup, and update, all of these bone transforms.

For the blend indices, we need to compensate for the lack of UBYTE4 on older hardware, so we use the UINT32 data type instead of UBYTE4.  In the shader hardware it’s going to end up being interpreted as a color and converted into 4 floats, instead of a single 32-bit integer. Thus, we will need to swizzle and scale the components back into the original 4 unsigned bytes.  This really feels like a serious hack to me; but after hours of searching the Internet, it’s apparently the only way it can be done using older hardware.

Some small changes were made to the helper functions that handle vertex declarations.  There were some instances where en element would not be detected, if the data type is different than normally expected.  For example, a position element may have been padded into a 4 element tuple; instead of using a 3 element tuple, the default.

I’ve been working a lot on the skinned mesh support in the engine lately.  I was having a problem with the engine’s 3ds Max exporter crashing when you exported a mesh that contained physique, but I have that fixed now.  If you tried to export a skinned mesh that was not already triangulated (i.e. a NURBs surface), then the number of skinned vertices would not match the number of vertices actually in the mesh data.

I also added some new features to the .fx effect file importer in the world builder.  There were some issues that needed worked out, so that I could load the effect file that is going to be used to render the skinned meshes.

So, I finally have all of the data that I need.  Now I just need to finish the skinned mesh support in the mesh object itself.

I’m currently updating the mesh scene object hierarchy to support skinning data.  The skin weights, and the bone data, are already exported by the custom 3ds Max exporter.  All of this data can be successfully loaded by the engine.  I’ve also been working on the HLSL vertex shader in the effect file that will be used to render the skinned meshes.  I may need to make some small changes to the effect system, to make things work out exactly the way that I want.  I hope to be testing this all out very soon.