Wunderchu said:[the specs of PS3 and Xbox 360 have not been finalized yet (athough, in Xbox 360 's case, it's specs will have to be finalized very soon)]..
but, as of now;
- Xenos' limit is 500 million triangles/sec. , according to the spec. sheet
- RSX 's limit is 1100 million vertices/sec. , if one extrapolates from G70 's specs., (G70 @ 430 MHz has limit of 860 million vertices/sec. .. and RSX is slated to run @ 550 MHz)
hasanahmad said:whats the difference between triangles/sec and vertices/sec
Titanio said:AFAIK, for these purposes, they are the same. If you "push" x number of vertices per sec you can pretty much claim to push the same x number of triangles. 1 triangle can = 1 vertex, effectively.
I'm confused though, if G70's figures are the transform rate or setup limit.
sure you can..BenQ said:But you can NOT claim that "1 triangle can = 1 vertex, effectively."
Wunderchu said:sure you can..
take, for example a 3 sided pyramid, with a triangular base, like in this pic.:
[source: http://www.jaist.ac.jp/~g-kampis/Lecture_One ]
there are 4 vertices, & 4 triangles in this pic.
heh ... I guess my example does not really apply too well to what we are discussing .. I apologizeBenQ said:That's not fair, unless the only thing your planning on rendering is pyramids. You can't claim a 1:1 ratio with anything more complex than a pyramid.
Wunderchu said:sure you can..
take, for example a 3 sided pyramid, with a triangular base, like in this pic.:
[source: http://www.jaist.ac.jp/~g-kampis/Lecture_One ]
there are 4 vertices, & 4 triangles in this pic.
Shifty Geezer said:When creating a mesh, you can add a triangle by adding just 1 vertex. Think of a ribbon. You start with the first triangle made of 3 vertices. The ratio triangles:vertices = 1:3. The next triangle uses two already existing verticies and adds one more. The ratio's now 2:4. Same with the next triangle, giving 3:5. Continue this on and on, and the ratio triangles:vertices gets closer and closer to 1:1. It has been said on this forum by others that you can even get a ratio of less than 1 vertex per triangle. Someone posted the average triangle:vertex ratio for a game too, which was between 1 and 2 if memeory serves. But in peak rates it's fair to consider 1 vertex=1 triangle as that's an ideal situation for pushing polygons.
BenQ said:That's not fair, unless the only thing your planning on rendering is pyramids. You can't claim a 1:1 ratio with anything more complex than a pyramid.
if one takes the dotted line as behind the solid ones, the pic. can be seen as a 3D representation of a triangular prism with a triangular base (AKA: a tetrahedron)hasanahmad said:that shape is of a quadrilateral, not a triangle
BenQ said:That's not fair, unless the only thing your planning on rendering is pyramids. You can't claim a 1:1 ratio with anything more complex than a pyramid.
Titanio said:Yes, you can. Or virtually so. As Shifty points out, if constructing a mesh, you can add new triangles by simply adding one vertex. Every triangle has 3 vertices, but in a mesh they are rarely unique, non-shared vertices. The more triangles you have sharing vertices, the closer you get to that 1:1 ratio.
Wunderchu said:if one takes the dotted line as behind the solid ones, the pic. can be seen as a 3D representation of a triangular prism with a triangular base (AKA: a tetrahedron)
but, yes, it can also be seen as a quadrilateral
if one takes that pic. I posted as a 3D shape, then there are 4 triangles therehasanahmad said:yes but there is an important difference: triangle has 3 sides, quadrilateral has 4 sides. If you take that into account, the numbers end up same in terms of efficiency as well as triangles vs quadrilaterals
BenQ said:That is true, but is it fair to simply not account for the increased complexity of those vertices?
Something smells fishy to me.
For every other console in the past, they release how manys poly per second it can push in the spec sheet, this is the first time I have seen vertices/second rather than polys/second. Which leads me to wonder why.
The answer I come up with is that M$ released their numbers first and then Sony's PR team decided using vertices/second rather than polys ( and most people don't even know the difference ) looks much better on paper.
I want to see how many polys the PS3 an push OR how many vertices the Xbox 360 can push. Comparing polys to vertices seems designed purely to misslead.