Hi,

Just looking for a bit of a clarification on UpdatateSubresource()'s box parameter. I'm updating a subregion of a vertex buffer, and the box's left and right make perfect sense, for a 1D buffer, but bottom and back seem to make little difference, so long as they're nonzero. I just set them to 1 and it's all gravy (but anything positive seems to work too).

Thanks!

The box parameter for UpdateSubresource is a common source of confusion.

Depending on the dimension of the resource some values seems not relevant at all. But there is a problem. If you set both elements of a pair (left – right; top – bottom; front – back) to the same value the box is defined as empty. An empty box would not trigger a copy operation. Therefore you need to set some value to bottom and back.

Right, the empty box check makes sense.

It just seems a bit odd to be able to pass any positive number at all, only to pass some internal test. I expect a crash when I pass bogus values, and feel cheated otherwise ;-)

Thanks.

For any dimensions that are not representative of the Resource type, you set the low coord to 0 and high coord to 1.

For Buffers, you should set top & front to 0, and bottom & back to 1. I'm pretty sure the Debug Layer will complain about any random positive values. Out-of-bound coordinates are undefined (which includes crash or 'happens to work as intended').

Yes, the debug layer does indeed complain about an invalid box.

Thanks!