the fur is interesting. even more interesting to see that at least in the screenshots there seem to be no alpha sorting issues. is this a japanese trade secret or why do my ps2 games use lot's and lots of overlapping alpha's and on a typical pc game your character's hair should better not overlap with the background trees... grrrr!
btw. the google translation makes me dizzy. how are you supposed to read that? worse than some translated manuals from the 16bit era.
Japanese console games always have good alpha, the hair and stuff is always perfect. And they have less other gfx gliches too, compared to western games.
I think all consoles handle alpha pretty well. That's a hardware thing, the PC port of Phantasy Star Online has sorting issues, the GC version does not.
PS2 doesnt use OpenGL but proprietary API, ps3 will use OpenGL ES + Cg.
also alpha sorting is necessary in gl just as in dx, so that is not the reason. You can as well kill fillrate with lots of blends in GL just as in DX..
it really is just a matter of how much time or importance such a feature is being given.
The PS2 has always been a dog when it comes to Z-sorting alpha planes. I remember a coder explaining it to me one time. Basically it could be done, but required your engine to do some serious calculation, and that was a trade off - use the cycles to figure out the Z-depth of the alpha planes, or use it for something else like AI.
This isn't just limited to the PS2 though - again I'm PROBABLY wrong here, but as I understand it:
The engien will decide what it needs to draw by figuring out where all the objects (mountain, tree, building, crate, characer, another crate, character) are in z space, and draws them from the back forwards. However, alphas are on an object, and hair is not 20 seperate objects, so where it comes to drawing the hair you then have to stop and calculate the position of each polygon.
There are IDEs like CodeWarrior that let you use OpenGL or DirectX calls on consoles without actually using OGL in the end. At least that's what their feature page promises.
Alpha sorting fur is easy, always draw the shells from the inside out.
If sorting takes so much processing power you'd think they wouldn't let their modelers use so many overlapping alpha planes but I've seen games (pretty obvious in P.N.03, for example) on the GC that use strands with alpha textures, could it be that the GC can handle alpha sorting automatically? Or does Capcom just enjoy wasting cycles for that?
I cant speak for consoles, but for PC stuff it's like Rick explained. Basically you wouldnt want to transform every single tris and sort yourself. sometimes this is done for billboards, but then we just need to sort particles, as their billboards normally cant intersect.
as they all basically work similar, consoles would have to do the same. here is some info on gc http://www.segatech.com/gamecube/overview/
with modern gpu's this sorting can be done on the gpu with some hacks too (often referred to as gpgpu ).
but normally the best you can do is sort by object centers.
and about shells from inside out, as kdr said, it works for back-face culled objects, which is normally sufficient for fur, which doesnt stick out far.
Replies
http://translate.google.com/translate?u=...Flanguage_tools
you might need to copy the link and paste it into the address bar.
btw. the google translation makes me dizzy. how are you supposed to read that? worse than some translated manuals from the 16bit era.
also alpha sorting is necessary in gl just as in dx, so that is not the reason. You can as well kill fillrate with lots of blends in GL just as in DX..
it really is just a matter of how much time or importance such a feature is being given.
This isn't just limited to the PS2 though - again I'm PROBABLY wrong here, but as I understand it:
The engien will decide what it needs to draw by figuring out where all the objects (mountain, tree, building, crate, characer, another crate, character) are in z space, and draws them from the back forwards. However, alphas are on an object, and hair is not 20 seperate objects, so where it comes to drawing the hair you then have to stop and calculate the position of each polygon.
any. Yeah.
Great find.
Alpha sorting fur is easy, always draw the shells from the inside out.
If sorting takes so much processing power you'd think they wouldn't let their modelers use so many overlapping alpha planes but I've seen games (pretty obvious in P.N.03, for example) on the GC that use strands with alpha textures, could it be that the GC can handle alpha sorting automatically? Or does Capcom just enjoy wasting cycles for that?
as they all basically work similar, consoles would have to do the same. here is some info on gc http://www.segatech.com/gamecube/overview/
with modern gpu's this sorting can be done on the gpu with some hacks too (often referred to as gpgpu ).
but normally the best you can do is sort by object centers.
and about shells from inside out, as kdr said, it works for back-face culled objects, which is normally sufficient for fur, which doesnt stick out far.
http://www.ga-forum.com/showthread.php?t=78011
http://www.dyingduck.com/the_making_of_shadow_of_the_colossus.html