{"id":1971,"date":"2023-05-18T22:13:07","date_gmt":"2023-05-18T22:13:07","guid":{"rendered":"https:\/\/writingagame.com\/?p=1971"},"modified":"2026-04-09T17:00:25","modified_gmt":"2026-04-09T17:00:25","slug":"opengl-where-is-the-front-where-is-the-back","status":"publish","type":"post","link":"https:\/\/writingagame.com\/index.php\/2023\/05\/18\/opengl-where-is-the-front-where-is-the-back\/","title":{"rendered":"OpenGL: Where is the front, where is the back?"},"content":{"rendered":"\n

Tags:<\/strong> OpenGL, OpenGL ES 3.2, 3D Graphics, Coordinate Systems, Right-Handed System, Geometry, Game Engine Development, C++<\/em><\/p>\n\n\n\n

\n\n\n\n

For 3D modeling, this is actually a non-trivial question.<\/p>\n\n\n\n

When we talk about humans, our natural assumption is that “right” is relative to the back<\/strong>, not the front. For example, what is to the right of your face is actually your left<\/strong> hand:<\/p>\n\n\n\n

<\/p>\n\n\n\n

The same logic applies to cars: the “right” side is determined from the driver’s perspective (facing forward):<\/p>\n\n\n\n

<\/p>\n\n\n\n

However, this creates a Left-Handed Coordinate System<\/strong>!<\/p>\n\n\n\n

<\/p>\n\n\n\n

A quick reminder just in case:<\/p>\n\n\n\n

<\/p>\n\n\n\n

The catch? OpenGL is Right-Handed.<\/strong><\/p>\n\n\n\n

Some could say: what a stupid decision to use right handed system?!<\/p>\n\n\n\n

Well\u2026 It is NOT “stupid”.<\/p>\n\n\n\n

In real life we use BOTH. For example, when looking at buildings, we rely on RIGHT handed system where the right side is to the right of the FRONT:<\/p>\n\n\n\n

<\/p>\n\n\n\n

Both systems work. For example, MS in their DirectX choose to use the left handed. But since we picked OpenGL, let’s follow ITS standard. So, correct orientation in our case would be:<\/p>\n\n\n\n

<\/p>\n\n\n\n

Like for buildings, not like for cars or people.<\/p>\n\n\n\n

\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

Tags: OpenGL, OpenGL ES 3.2, 3D Graphics, Coordinate Systems, Right-Handed System, Geometry, Game Engine Development, C++ For 3D modeling, this is actually a non-trivial question. When we talk about humans, our natural assumption is that “right” is relative to the back, not the front. For example, what is to the right of your face is […]<\/p>\n","protected":false},"author":1,"featured_media":1973,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":["post-1971","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-side-notes"],"_links":{"self":[{"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/posts\/1971","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/comments?post=1971"}],"version-history":[{"count":10,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/posts\/1971\/revisions"}],"predecessor-version":[{"id":4298,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/posts\/1971\/revisions\/4298"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/media\/1973"}],"wp:attachment":[{"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/media?parent=1971"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/categories?post=1971"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/tags?post=1971"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}