That should be the mantra of every graphics programmer ... at least, that's what some professor told me one time.
I worked up a direct visualization of the photon emission stage by simply drawing points in space for each photon. I set the color of each point to the power of the photon and now I'm seeing something very important. The power is not attenuating ... AT ALL. That's why we aren't getting any shadows and that's probably why everything is a constant power and too dim.
I thought that I could safely ignore the photon power until milestone 2 but I think I need to deal with it now so that's going to be the current task.
Here's the visualizations:
Note: the number of photons listed is the number of emitted photons. Since photons are recorded each bounce there are actually MANY more being added to the map and drawn. With russian roulette in play, the photons are bouncing about 5 times on average so multiply the number of emitted photons by 6 to get the number being drawn and the number of rays being traced. This is all still happing quite efficiently. The last case has about 6M rays to trace and it does so in only a few minutes. Not bad! Unfortunately, the splatting/final gather phase is painfully slow still. I think it's because the kd-Tree for the photon map is not being properly balanced.
Some Observations about these images:
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Info about progress on my Google Summer of Code 2009 project on Advanced Lighting & Shading in CrystalSpace.
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