220 reputation
17
bio website typeandflow.blogspot.com
location West Kelowna, Canada
age 24
visits member for 4 years
seen Mar 31 at 23:51

Feb
10
awarded  Yearling
Sep
4
awarded  Popular Question
Jul
19
accepted Optimizing gravity calculations
Jul
18
awarded  Popular Question
Nov
9
awarded  Nice Question
Nov
4
comment Optimizing gravity calculations
This is fundamentally what I'm doing. After I get all pairs involving X, I don't iterate over X again. I find the force between X and Y, X and Z, etc, and apply that force to both objects in the pair. After the loop completes, the ForceOfGravity vector is the sum of all the forces, and that is then converted into a velocity and new position. I'm not sure that the gravity calculation is particularly expensive, and checking if it exceeds a threshold first wouldn't save a noticeable amount of time, I don't think
Nov
4
awarded  Commentator
Nov
4
comment Optimizing gravity calculations
Thanks! I may use this :)
Nov
4
comment Optimizing gravity calculations
@JonPurdy that's a good point, but since XNA uses floats natively, I'm gonna stick with those unless it turns out that it's becoming a bottleneck.
Nov
4
comment Optimizing gravity calculations
@SamHocevar Because they still follow geodesics in a gravitational field -- rather than calculating the force on the massless particle (which would result in a non-real acceleration), it just calculates its acceleration using G * m / r^2 (where m is the mass of the massive body).
Nov
4
comment Optimizing gravity calculations
Separating the process into passes is an excellent idea, since the update interval is (as far as I know) a very small fraction of a second. The gravity field texture is AWESOME but perhaps a little beyond my reach right now.
Nov
4
comment Optimizing gravity calculations
I like this idea a lot. I had considered containing the objects in cells, but abandoned it when considering two nearby objects which were technically in different cells -- but I didn't make the mental leap to consider a few adjacent cells, as well as considering the combined mass of other cells. I think this should work really well if I do it right.
Nov
4
comment Optimizing gravity calculations
@chaosTechnician it doesn't have to be very accurate -- in fact if it's only accounting for the few most dominant forces then a system would be more stable, which is ideal. But it's finding out which of the forces are most dominant in an efficient way that I'm having trouble with. Also the gravitation calculation is already approximated, it's just G * m1 * m2 / r^2, where G is just to tweak the behavior. (although I can't just have them following a path, because the user can disturb the system)
Nov
4
comment Optimizing gravity calculations
@Drackir I think you're right. Part of the reason they're separated is because the math is different for massless objects, and part is because they originally didn't obey gravity at all, so it was more efficient to not include them. So it's vestigial
Nov
4
asked Optimizing gravity calculations
Feb
21
awarded  Scholar
Feb
21
accepted Understanding DeviceContext and Shaders in Direct3D/SlimDX
Feb
21
comment Understanding DeviceContext and Shaders in Direct3D/SlimDX
Well, I wouldn't use the triangle to build larger objects -- I'd also have a Cube class, etc -- it has a single vertex buffer and a Draw() method which takes the device context. It sets the layout, topology and shaders on the context and then draws all the vertices in the buffer. This isn't good?
Feb
21
awarded  Student
Feb
21
awarded  Supporter