Jump to content
  • Advertisement
Sign in to follow this  
psastras

Simple Photon Mapping Question

This topic is 3073 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

So I was just reading Jensen's 2004 paper http://portal.acm.org/citation.cfm?id=1103920, A practical guide to global illumination using ray tracing and photon mapping.

My question is how exactly he goes from equation (2.5) to (2.6) on page 25. Equation 2.5 is an integral over the hemisphere, which is approximated using the sum of the photons in the photon map in 2.6.

My question is why is he not dividing by the probability of seeing the photon coming from that direction, in equation 2.6? ie. Why is does he not dividing by p(\omega_p) = 1 / 2Pi?

Equation 2.5:

L_r(x,\omega) = \int_\Omega f_r(x,\omega',\omega) \frac{d^2\Phi_i(x,\omega')}{dA_i}

Equation 2.6:
L_r(x,\omega) \approx \sum_{p=1}^n f_r(x,\omega_p,\omega) \frac{\Delta\Phi_p(x,\omega_p)}{\Delta A}

[Edited by - psastras on July 16, 2010 1:07:04 PM]

Share this post


Link to post
Share on other sites
Advertisement
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

GameDev.net is your game development community. Create an account for your GameDev Portfolio and participate in the largest developer community in the games industry.

Sign me up!