So I'm trying to implement a photon mapping algorithm to simulate global illumination in my ray tracing program. However, I'm running into a few issues that are making it hard to complete the implementation.
My program already successfully traces photons throughout the scene, stores them in a balanced KD-Tree and can gather the k nearest photons near any given point p, so most of the work is complete. The issue is mostly when it comes time for the radiance estimate.
First, I can't seem to get the indirect illumination to be bright enough to make any noticeable difference in my scene. If my light source emits 100,000 photons, then the power of each stored photon (which for 100,000 emitted photons would be roughly around 500,000 stored photons in my program) must be scaled down by a factor of 100,000 which makes them very dim. I thought I could mitigate this when dividing by the area if the encapsulating circle (pi*rad^2) if I have a search radius much less than 1 but decreasing the search radius to such a small number leaves me with very few photons for the estimate and if I use a large radius I can get enough photons but i don't get the extra "power boost" of using a small radius and might wind up including incorrect photons. So I don't know what to do.
Additionally, my other problem is that if I were to artificially scale up the photon power to increase the indirect lighting contribution, the resulting illumination is splotchy, uneven and ugly and doesn't look at all realistic. I know this problem is vague but I don't know why it looks this way since I'm pretty sure I'm doing the radiance estimate and brdf calculations correctly.
