{"id":236,"date":"2018-05-20T15:01:55","date_gmt":"2018-05-20T12:01:55","guid":{"rendered":"http:\/\/kadircenk.com\/blog\/?p=236"},"modified":"2019-02-07T19:37:15","modified_gmt":"2019-02-07T16:37:15","slug":"trace-the-ray-part-6-brdfs","status":"publish","type":"post","link":"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/","title":{"rendered":"Trace the Ray \u2013 Part 6 (BRDFs)"},"content":{"rendered":"<p>Hey trace-masters, <strong>Bidirectional Reflectance Distribution Functions<\/strong> are here! In this post, we will examine what those BRDFs are and how they are used.<\/p>\n<p><!--more--><\/p>\n<p>Bidirectional reflectance distribution functions (BRDFs) govern how<br \/>\nmuch a surface reflects lights for every incoming and outgoing light direction.<\/p>\n<p>There are many BRDFs used in practice, but in my sixth assignment, my task was to implement the BRDFs listed below:<\/p>\n<ul>\n<li>Phong BRDF<\/li>\n<li>Modified Phong BRDF<\/li>\n<li>Normalized Modified Phong BRDF<\/li>\n<li>Blinn-Phong BRDF<\/li>\n<li>Modified\u00a0Blinn-Phong BRDF<\/li>\n<li>Normalized Modified\u00a0Blinn-Phong BRDF<\/li>\n<li>Torrance-Sparrow BRDF<\/li>\n<\/ul>\n<p>My instructor, <a href=\"http:\/\/user.ceng.metu.edu.tr\/~akyuz\/\" target=\"_blank\" rel=\"noopener\">Assoc. Prof. Ahmet Oguz Akyuz<\/a>, has prepared a .pdf document with easy-to-understand figures that explains the details of the BRDFs listed above. The document can be downloaded by clicking\u00a0<a href=\"http:\/\/user.ceng.metu.edu.tr\/~kadircenk\/raytracing\/brdf.pdf\" target=\"_blank\" rel=\"noopener\">here<\/a>. The <strong>phi<\/strong> angle, which is used in the denominator of the Torrance-Sparrow BRDF in the document, is the angle between the\u00a0<strong>normal <\/strong>vector and\u00a0<strong>wo<\/strong> (eye) direction.<\/p>\n<p>Below are my results:<\/p>\n<h4>Phong BRDF<\/h4>\n<p><a href=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_original.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"238\" data-permalink=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/brdf_phong_original\/\" data-orig-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_original.png\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-title=\"brdf_phong_original\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_original.png\" class=\"aligncenter wp-image-238 size-full\" src=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_original.png\" alt=\"\" width=\"800\" height=\"800\" srcset=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_original.png 800w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_original-150x150.png 150w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_original-300x300.png 300w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_original-768x768.png 768w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_original-100x100.png 100w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/p>\n<pre>brdf_phong_original.xml\n(800x800)\n\/w 8 thrd, no MSAA\n1 sphere, 2 point lights.\nBRDF exponent 50.<\/pre>\n<h4>Modified Phong BRDF<\/h4>\n<p><a href=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified-1.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"240\" data-permalink=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/brdf_phong_modified-2\/\" data-orig-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified-1.png\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-title=\"brdf_phong_modified\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified-1.png\" class=\"aligncenter wp-image-240 size-full\" src=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified-1.png\" alt=\"\" width=\"800\" height=\"800\" srcset=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified-1.png 800w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified-1-150x150.png 150w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified-1-300x300.png 300w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified-1-768x768.png 768w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified-1-100x100.png 100w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/p>\n<pre>brdf_phong_modified.xml\n(800x800)\n\/w 8 thrd, no MSAA\n1 sphere, 2 point lights.\nBRDF exponent 50.<\/pre>\n<h4>Normalized\u00a0Modified Phong BRDF<\/h4>\n<p><a href=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified_normalized.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"241\" data-permalink=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/brdf_phong_modified_normalized\/\" data-orig-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified_normalized.png\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-title=\"brdf_phong_modified_normalized\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified_normalized.png\" class=\"aligncenter wp-image-241 size-full\" src=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified_normalized.png\" alt=\"\" width=\"800\" height=\"800\" srcset=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified_normalized.png 800w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified_normalized-150x150.png 150w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified_normalized-300x300.png 300w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified_normalized-768x768.png 768w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_phong_modified_normalized-100x100.png 100w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/p>\n<pre>brdf_phong_modified_normalized.xml\n(800x800)\n\/w 8 thrd, no MSAA\n1 sphere, 2 point lights.\nBRDF exponent 50.<\/pre>\n<h4>Blinn-Phong BRDF<\/h4>\n<p><a href=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_original.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"242\" data-permalink=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/brdf_blinnphong_original\/\" data-orig-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_original.png\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-title=\"brdf_blinnphong_original\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_original.png\" class=\"aligncenter wp-image-242 size-full\" src=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_original.png\" alt=\"\" width=\"800\" height=\"800\" srcset=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_original.png 800w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_original-150x150.png 150w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_original-300x300.png 300w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_original-768x768.png 768w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_original-100x100.png 100w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/p>\n<pre>brdf_blinnphong_original.xml\n(800x800)\n\/w 8 thrd, no MSAA\n1 sphere, 2 point lights.\nBRDF exponent 50.<\/pre>\n<h4>Modified\u00a0Blinn-Phong BRDF<\/h4>\n<p><a href=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"243\" data-permalink=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/brdf_blinnphong_modified\/\" data-orig-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified.png\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-title=\"brdf_blinnphong_modified\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified.png\" class=\"aligncenter wp-image-243 size-full\" src=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified.png\" alt=\"\" width=\"800\" height=\"800\" srcset=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified.png 800w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified-150x150.png 150w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified-300x300.png 300w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified-768x768.png 768w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified-100x100.png 100w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/p>\n<pre>brdf_blinnphong_modified.xml\n(800x800)\n\/w 8 thrd, no MSAA\n1 sphere, 2 point lights.\nBRDF exponent 50.<\/pre>\n<h4>Normalized\u00a0Modified\u00a0Blinn-Phong BRDF<\/h4>\n<p><a href=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified_normalized.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"244\" data-permalink=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/brdf_blinnphong_modified_normalized\/\" data-orig-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified_normalized.png\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-title=\"brdf_blinnphong_modified_normalized\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified_normalized.png\" class=\"aligncenter wp-image-244 size-full\" src=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified_normalized.png\" alt=\"\" width=\"800\" height=\"800\" srcset=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified_normalized.png 800w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified_normalized-150x150.png 150w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified_normalized-300x300.png 300w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified_normalized-768x768.png 768w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_blinnphong_modified_normalized-100x100.png 100w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/p>\n<pre>brdf_blinnphong_modified_normalized.xml\n(800x800)\n\/w 8 thrd, no MSAA\n1 sphere, 2 point lights.\nBRDF exponent 50.<\/pre>\n<h4>Torrance-Sparrow BRDF<\/h4>\n<p><a href=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_torrancesparrow.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"245\" data-permalink=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/brdf_torrancesparrow\/\" data-orig-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_torrancesparrow.png\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-title=\"brdf_torrancesparrow\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_torrancesparrow.png\" class=\"aligncenter wp-image-245 size-full\" src=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_torrancesparrow.png\" alt=\"\" width=\"800\" height=\"800\" srcset=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_torrancesparrow.png 800w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_torrancesparrow-150x150.png 150w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_torrancesparrow-300x300.png 300w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_torrancesparrow-768x768.png 768w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/brdf_torrancesparrow-100x100.png 100w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/p>\n<pre>brdf_torrancesparrow.xml\n(800x800)\n\/w 8 thrd, no MSAA\n1 sphere, 2 point lights.\nBRDF exponent 50,\nBRDF refractiveIndex 0.370 .<\/pre>\n<h4>Killeroo Renders<\/h4>\n<p><a href=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong-1.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"247\" data-permalink=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/killeroo_blinnphong-2\/\" data-orig-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong-1.png\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-title=\"killeroo_blinnphong\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong-1.png\" class=\"aligncenter wp-image-247 size-full\" src=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong-1.png\" alt=\"\" width=\"800\" height=\"800\" srcset=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong-1.png 800w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong-1-150x150.png 150w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong-1-300x300.png 300w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong-1-768x768.png 768w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong-1-100x100.png 100w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/p>\n<pre>killeroo_blinnphong.xml\n(800x800)\n\/w 8 thrd, 16MSAA,\nPhotographic Tonemapping,\n3% burn-out,\nOriginal Blinn-Phong BRDF,\nBRDF exponent 50.<\/pre>\n<p><a href=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong_closeup.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"248\" data-permalink=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/killeroo_blinnphong_closeup\/\" data-orig-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong_closeup.png\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-title=\"killeroo_blinnphong_closeup\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong_closeup.png\" class=\"aligncenter wp-image-248 size-full\" src=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong_closeup.png\" alt=\"\" width=\"800\" height=\"800\" srcset=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong_closeup.png 800w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong_closeup-150x150.png 150w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong_closeup-300x300.png 300w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong_closeup-768x768.png 768w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_blinnphong_closeup-100x100.png 100w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/p>\n<pre>killeroo_blinnphong_closeup.xml\n(800x800)\n\/w 8 thrd, 16MSAA,\nPhotographic Tonemapping,\n3% burn-out,\nOriginal Blinn-Phong BRDF,\nBRDF exponent 50.<\/pre>\n<p><a href=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"249\" data-permalink=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/killeroo_torrancesparrow\/\" data-orig-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow.png\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-title=\"killeroo_torrancesparrow\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow.png\" class=\"aligncenter wp-image-249 size-full\" src=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow.png\" alt=\"\" width=\"800\" height=\"800\" srcset=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow.png 800w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow-150x150.png 150w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow-300x300.png 300w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow-768x768.png 768w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow-100x100.png 100w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/p>\n<pre>killeroo_torrancesparrow.xml\n(800x800)\n\/w 8 thrd, 16MSAA,\nPhotographic Tonemapping,\n3% burn-out,\nTorrance-Sparrow BRDF,\nBRDF exponent 50,\nBRDF refractiveIndex 0.370 .<\/pre>\n<p><a href=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow_closeup.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"250\" data-permalink=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/killeroo_torrancesparrow_closeup\/\" data-orig-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow_closeup.png\" data-orig-size=\"800,800\" data-comments-opened=\"1\" data-image-title=\"killeroo_torrancesparrow_closeup\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow_closeup.png\" class=\"aligncenter wp-image-250 size-full\" src=\"http:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow_closeup.png\" alt=\"\" width=\"800\" height=\"800\" srcset=\"https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow_closeup.png 800w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow_closeup-150x150.png 150w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow_closeup-300x300.png 300w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow_closeup-768x768.png 768w, https:\/\/kadircenk.com\/blog\/wp-content\/uploads\/2018\/05\/killeroo_torrancesparrow_closeup-100x100.png 100w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/p>\n<pre>killeroo_torrancesparrow_closeup.xml\n(800x800)\n\/w 8 thrd, 16MSAA,\nPhotographic Tonemapping,\n3% burn-out,\nTorrance-Sparrow BRDF,\nBRDF exponent 50,\nBRDF refractiveIndex 0.370 .\nBrightness being too high is caused by\na small bug in my tonemapping\n(to create .png file) implementation;\nstill working on to fix it.\n.exr files below do not have this bug.<\/pre>\n<h4>EXR Outputs<\/h4>\n<p>You can visualize my .exr outputs of the killeroo scene by following the links below (move the handles of the slider to right step by step, while \u201cGamma 2.0\u201d option is selected):<\/p>\n<ul>\n<li><a href=\"http:\/\/kadircenk.com\/hdr\/exrvisualizer?exrname=killeroo_blinnphong\" target=\"_blank\" rel=\"noopener\">killeroo_blinnphong.exr<\/a><\/li>\n<li><a href=\"http:\/\/kadircenk.com\/hdr\/exrvisualizer?exrname=killeroo_blinnphong_closeup\" target=\"_blank\" rel=\"noopener\">killeroo_blinnphong_closeup.exr<\/a><\/li>\n<li><a href=\"http:\/\/kadircenk.com\/hdr\/exrvisualizer?exrname=killeroo_torrancesparrow\" target=\"_blank\" rel=\"noopener\">killeroo_torrancesparrow.exr<\/a><\/li>\n<li><a href=\"http:\/\/kadircenk.com\/hdr\/exrvisualizer?exrname=killeroo_torrancesparrow_closeup\" target=\"_blank\" rel=\"noopener\">killeroo_torrancesparrow_closeup.exr<\/a><\/li>\n<\/ul>\n<p>That&#8217;s the end of my sixth assignment!<\/p>\n<p>Hope to see you in the next one!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Hey trace-masters, Bidirectional Reflectance Distribution Functions are here! In this post, we will examine what those BRDFs are and how they are used.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[4],"tags":[],"class_list":["post-236","post","type-post","status-publish","format-standard","hentry","category-ray-tracing"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Trace the Ray \u2013 Part 6 (BRDFs) - kadircenk<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/kadircenk.com\/blog\/trace-the-ray-part-6-brdfs\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Trace the Ray \u2013 Part 6 (BRDFs) - kadircenk\" \/>\n<meta property=\"og:description\" content=\"Hey trace-masters, Bidirectional Reflectance Distribution Functions are here! 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