{"id":1077,"date":"2015-03-17T10:47:36","date_gmt":"2015-03-17T17:47:36","guid":{"rendered":"http:\/\/otherthings.com\/blog\/?p=1077"},"modified":"2025-12-17T14:21:30","modified_gmt":"2025-12-17T22:21:30","slug":"fun-with-pseudocolor","status":"publish","type":"post","link":"https:\/\/otherthings.com\/blog\/2015\/03\/fun-with-pseudocolor\/","title":{"rendered":"Fun with Pseudocolor"},"content":{"rendered":"
\n
\"Screen<\/a>

A shader experiment gone horribly, beautifully wrong.<\/center><\/figcaption><\/figure>\n<\/div>\n\n\n

 <\/p>\n\n\n\n

I was tinkering with some GLSL shaders in Processing, and I needed a way to visualize a value that smoothly changes from 0 to 1, showing a lot more than the 256 levels of gray that you’d normally see. So I wrote a little pseudocolor function that spirals through colorspace from black to white, hitting various hues along the way. It’s fun, and pretty, and very rungy-chungy<\/a>, so I thought I’d post it here.<\/p>\n\n\n\n

vec4 pseudo3(float val) {<\/code>float reps = 20.0;
float pi = 3.14159256;
float bright = val;
float con = 0.25 – 0.20 * cos(val * pi * 2.0);
float sat = 0.66 – 0.25 * cos(val * pi * 2.0);<\/p>\n\n\n\n

return vec4(sin(val*pi*reps)*con+bright,
sin(val*pi*reps – pi*0.663 * sat)*con+bright,
sin(val*pi*reps – pi*1.333 * sat)*con+bright,
1.0);
}

<\/p>\n\n\n

\n
\"Here's<\/a>
Here’s the path the above function traces through the RGB cube of colorspace.<\/center><\/figcaption><\/figure>\n<\/div>","protected":false},"excerpt":{"rendered":"

  I was tinkering with some GLSL shaders in Processing, and I needed a way to visualize a value that smoothly changes from 0 to 1, showing a lot more than the 256 levels of gray that you’d normally see. So I wrote a little pseudocolor function that spirals through colorspace from black to white, … Continue reading Fun with Pseudocolor<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,123,27],"tags":[],"class_list":["post-1077","post","type-post","status-publish","format-standard","hentry","category-fun","category-graphics","category-visualization"],"_links":{"self":[{"href":"https:\/\/otherthings.com\/blog\/wp-json\/wp\/v2\/posts\/1077","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/otherthings.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/otherthings.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/otherthings.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/otherthings.com\/blog\/wp-json\/wp\/v2\/comments?post=1077"}],"version-history":[{"count":10,"href":"https:\/\/otherthings.com\/blog\/wp-json\/wp\/v2\/posts\/1077\/revisions"}],"predecessor-version":[{"id":1866,"href":"https:\/\/otherthings.com\/blog\/wp-json\/wp\/v2\/posts\/1077\/revisions\/1866"}],"wp:attachment":[{"href":"https:\/\/otherthings.com\/blog\/wp-json\/wp\/v2\/media?parent=1077"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/otherthings.com\/blog\/wp-json\/wp\/v2\/categories?post=1077"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/otherthings.com\/blog\/wp-json\/wp\/v2\/tags?post=1077"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}