![\"Photographic](\"http:\/\/www.kevinbeason.com\/worklog\/wp-content\/uploads\/2008\/10\/image957.png\")
<\/a>Photographic DOF<\/p><\/div>\n
Previously I had limited support for Depth of Field (DOF) whose only input was the angle subtended by the lens relative to the center of the focal plane. In March 2008 I added a conventional photography-based “f-stop” parameter system (f\/2.8, f\/5.6, etc.). The reason for this was to more accurately simulate what a real 35mm camera would do for a real world focal distance. Now the focal length of the lens depends on the focus distance and the lens size on this f-stop parameter. As is my usual fashion I meticulously recreated someone else’s image, in this case Figure 14.2 in Shirley’s Realistic Ray Tracing 1st Ed.<\/a><\/p>\n That’s all well and fine. However, combining this efficiently<\/em> with Keller’s “Strictly Deterministic Sampling” and path tracing<\/em> forced me to implement deterministic ray trees with arbitrary depth. This was a bloody nightmare of brainstorming and code refactoring (which is still a mess to this day). Uhg. I think I spent like a week on that. But the pay off is huge in variance reduction when path tracing with a single explicit light sample and a large area light, thanks to maintaining sample stratification from path-to-path within a pixel.<\/p>\n The basic problem I was having was how to branch the ray tree arbitrarily but be on the same branch in a completely different path. The basic solution was to increment the ray tree dimension (d=d+1) each time I might branch, even if I don’t take samples from that branch. But don’t quote me on that… it’s in the Pane source. Which I will post sometime.<\/p>\n DOF w\/Bokeh effect and chromatic aperture<\/p><\/div>\n Taking inspiration from SunFlow<\/a> and Toshiya Hachisuka’s “Kitchen with Programmer’s Art”<\/em><\/a>, I added simple n-sided-polygon Bokeh effect and hacked-up chromatic aberration to produce the above image (click for full size). You can see the lens shape and aberration clearly from the bright dot I added in the scene under “.25m”. Together these features add noise and a color shift so they are disabled (commented out).<\/p>\n More to come.<\/p>\n","protected":false},"excerpt":{"rendered":" I’ve blockaded updating my log to wait for another project to complete for too long. So here is something unrelated. Previously I had limited support for Depth of Field (DOF) whose only input was the angle subtended by the lens relative to the center of the focal plane. In March 2008 I added a conventional […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-10","post","type-post","status-publish","format-standard","hentry","category-general"],"_links":{"self":[{"href":"https:\/\/www.kevinbeason.com\/worklog\/wp-json\/wp\/v2\/posts\/10","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.kevinbeason.com\/worklog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kevinbeason.com\/worklog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kevinbeason.com\/worklog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kevinbeason.com\/worklog\/wp-json\/wp\/v2\/comments?post=10"}],"version-history":[{"count":10,"href":"https:\/\/www.kevinbeason.com\/worklog\/wp-json\/wp\/v2\/posts\/10\/revisions"}],"predecessor-version":[{"id":22,"href":"https:\/\/www.kevinbeason.com\/worklog\/wp-json\/wp\/v2\/posts\/10\/revisions\/22"}],"wp:attachment":[{"href":"https:\/\/www.kevinbeason.com\/worklog\/wp-json\/wp\/v2\/media?parent=10"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kevinbeason.com\/worklog\/wp-json\/wp\/v2\/categories?post=10"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kevinbeason.com\/worklog\/wp-json\/wp\/v2\/tags?post=10"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/a>