tag:blogger.com,1999:blog-8350257063773144600.post824601802797434713..comments2024-03-29T04:22:20.467-07:00Comments on Pete Shirley's Graphics Blog: Random diffuse raysPeter Shirleyhttp://www.blogger.com/profile/17871569418798062417noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-8350257063773144600.post-11551169220080879752016-05-28T12:17:43.786-07:002016-05-28T12:17:43.786-07:00I don't understand why you say the method on t...I don't understand why you say the method on the right is probably closer to being Lambertian than the one on the left. Isn't a Lambertian BRDF simply one that "scatters incident illumination equally in all directions"? (Physically Based Rendering, 2nd ed, Pharr & Humphreys, p. 446.) So isn't the one on the left (the hemisphere) actually just purely Lambertian, ignoring any side effects of drand48? Is it maybe because the sampling occurs inside the volume of a sphere rather than on the surface of a sphere?Anonymoushttps://www.blogger.com/profile/08605009491912886012noreply@blogger.comtag:blogger.com,1999:blog-8350257063773144600.post-65880703748808556562015-01-26T03:09:29.252-08:002015-01-26T03:09:29.252-08:00Simply desire to say your article is as astonishin...Simply desire to say your article is as astonishing. The clearness in your post is just excellent and i could assume you are an expert on this subject. Fine with your permission let me to grab your feed to keep up to date with forthcoming post. Thanks a million and please continue the rewarding work. <a href="http://graphicexpertsindia.com/" rel="nofollow">clipping path</a><br /><br />Anonymoushttps://www.blogger.com/profile/10488101347045813881noreply@blogger.comtag:blogger.com,1999:blog-8350257063773144600.post-69840127499675735872015-01-26T00:24:19.917-08:002015-01-26T00:24:19.917-08:00After a long time I got something fresh and qualit...After a long time I got something fresh and quality content on massage therapy services. I searched a lot for the related material but got almost replica work. Keep it up! It is really very informative. <a href="http://graphicexpertsbd.com/photoshop-clipping-path" rel="nofollow">clipping path</a><br /> Andrew P. Agostohttps://www.blogger.com/profile/07131899134572089030noreply@blogger.comtag:blogger.com,1999:blog-8350257063773144600.post-14038006418955658502014-09-12T17:48:38.917-07:002014-09-12T17:48:38.917-07:00I like that logic. My only concern is the "b...I like that logic. My only concern is the "beams" in a certain direction get fatter so it may grow faster than cosine theta. Let's put our programming hat on and figure out a way to test it empirically. Some numercal integration of a known integral maybe?<br />Peter Shirleyhttps://www.blogger.com/profile/17871569418798062417noreply@blogger.comtag:blogger.com,1999:blog-8350257063773144600.post-13755009752205490522014-09-12T14:34:12.652-07:002014-09-12T14:34:12.652-07:00I came up with the same technique some years back....I came up with the same technique some years back. My reasoning was that a cosine plotted in polar coordinates looks like a circle, which would be the equivalent of a cosine distribution in 2D. In 3D that would be it would look like a sphere (mumble, handwave, something about the cross section and rotational symmetry around the normal). Treat that sphere as a PDF, uniformly sample inside the sphere, and you're using rejection sampling to generate directions with a cosine distribution about the normal. I didn't try a more formal proof, but it looked good enough in the toy path tracer I was writing.friedlinguinihttps://www.blogger.com/profile/16254798224837016192noreply@blogger.com