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ZBethel

Member Since 10 Jan 2011
Offline Last Active Today, 11:02 AM

Posts I've Made

In Topic: Skeletal animation - apply rotation matrices from Collada

21 December 2014 - 02:15 PM

You want to build a local transformation matrix for each joint. As you stated, the component transforms are in SRT order (for post multiplication). For clarify, that means you first apply the scaling matrix, then the rotation matrices, then the translation matrix. You can treat each Euler rotation as a separate matrix, with the result being (S * Rz * Ry * Rx * T). The order of multiplication is actually defined by the Collada file (you'll notice that the order is Rotate Z/Y/X).

 

Finally, in Collada, the skeletons can be instanced, which is where the offset matrix comes into play. In short, you have to apply the offset matrix to the root of the joint skeleton.


In Topic: Help me build a PC

07 October 2014 - 03:54 PM

The nVidia 970GTX is the biggest bang for the buck these days. I bought a 780GTX when they went on sale for about $330, thinking that it would be faster. Turns out the 970 is still faster than the 780, despite having fewer compute units, less bandwidth, and nearly 100W less TDP.

 

I'm kicking myself now.


In Topic: Having trouble with energy conservation with IBL.

02 September 2014 - 11:52 AM

Another problem I'm having is that the G term in the brdf is going to infinity at the edges of my model. (if I use an implicit G term it goes away).

 

Attached File  Black2.png   535.06KB   1 downloads

 

I suspect this might be because normals being smoothed incorrectly across grazing angles. I assume this is a common problem with using the microfacet brdf model. I could use clamping to fix the problem, but how is this typically addressed in production scenarios?


In Topic: Having trouble with energy conservation with IBL.

02 September 2014 - 11:41 AM

Here's what Uffizi looks like now. It looks much more like yours, MJP.


In Topic: Having trouble with energy conservation with IBL.

02 September 2014 - 11:37 AM

I believe I found the problem. I was gamma correcting the HDR input texture by performing a pow(value, 2.2). That definitely isn't going to do what I want for values  > 1.

 

Question: are these HDR probes gamma corrected already? When I leave off the pow(2.2) factor but use an SRGB default framebuffer, the colors of the probe get desaturated (see attached).


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