This change is a bit pedantic, but it makes the ROMs run better in
DeSmuMe.
Some examples (particularly the dual 3D examples) used to flicker during
one or two seconds right after starting. In dual 3D examples the top and
bottom screen would start swapped, and they would eventually swap and
stop flickering. This would never happen in melonDS or real hardware.
I suspect this is because of the interaction between GFX_FLUSH and
swiWaitForVBlank(), where there would be some timing difference to reach
the first swiWaitForVBlank() or GFX_FLUSH, and that caused the desync.
This commit moves swiWaitForVBlank() to the beginning of the game loop.
This means that, even in the first iteration of the game loop, all
emulators and hardware will be synchronized. This doesn't actually
matter in any other situation, it just makes the first iteration
consistent.
Until now, a mesh was always owned by one single model. This made it
very difficult to clone models, because the mesh was always owned by one
of them. Whenever you deleted that model, the mesh was also deleted, and
all the cloned models would be unusable.
With the new system, there is a list of meshes with counters of how many
models use them. This way no matter how many models use the mesh, the
mesh will only be deleted when the last model is deleted.
In addition, in a similar way as before, a mesh has a flag that signals
if free() has to be called on the mesh data when the mesh is deleted.
This is useful when the mesh is loaded from a filesystem and stored in a
buffer allocated with malloc(), which is what Nitro Engine does.
Note that this code should be considered experimental for the time
being, until some tests are added.
