From 17ad2e1f82ea85a766da16c722734fc738246b23 Mon Sep 17 00:00:00 2001 From: Ed_ Date: Thu, 27 Aug 2026 20:51:06 -0400 Subject: [PATCH] 952661474501111808, 1021907146475069440 --- .../index.md | 52 +++++++++++++++++++ archive/threads/EricLengyel/index.md | 1 + ...diagram-is-clearly-talking-about-the-up.md | 37 +++++++++++++ ...-made-the-right-decision-to-use-z-up-in.md | 37 +++++++++++++ ...ink-the-best-is-x-into-z-up-and-y-right.md | 37 +++++++++++++ .../index.md | 44 ++++++++++++++++ archive/threads/TimSweeneyEpic/index.md | 12 +++++ archive/threads/index.md | 1 + 8 files changed, 221 insertions(+) create mode 100644 archive/threads/EricLengyel/2018-07-24-the-final-figure-got-even-crazier/index.md create mode 100644 archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2018-01-14-EricLengyel-also-this-diagram-is-clearly-talking-about-the-up.md create mode 100644 archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2018-01-14-EricLengyel-tim-you-made-the-right-decision-to-use-z-up-in.md create mode 100644 archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2020-10-04-tom_forsyth-i-still-think-the-best-is-x-into-z-up-and-y-right.md create mode 100644 archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/index.md create mode 100644 archive/threads/TimSweeneyEpic/index.md diff --git a/archive/threads/EricLengyel/2018-07-24-the-final-figure-got-even-crazier/index.md b/archive/threads/EricLengyel/2018-07-24-the-final-figure-got-even-crazier/index.md new file mode 100644 index 0000000..4d09265 --- /dev/null +++ b/archive/threads/EricLengyel/2018-07-24-the-final-figure-got-even-crazier/index.md @@ -0,0 +1,52 @@ +--- +title: "The final figure got even crazier." +type: archive +source: twitter +source_url: "https://x.com/EricLengyel/status/1021907146475069440" +author: "Eric Lengyel" +handle: EricLengyel +post_id: "1021907146475069440" +date: 2018-07-24 +archived: 2026-08-27 +draft: false +tags: + - archive + - twitter + - EricLengyel +description: "The final figure got even crazier." +in_reply_to: "" +--- + +## Source + +- URL: https://x.com/EricLengyel/status/1021907146475069440 +- Author: Eric Lengyel (@EricLengyel) +- Posted: 2018-07-24 23:57:04 + +## Thread + +**1/** **@EricLengyel** ^1021907146475069440 + +The final figure got even crazier. This is the minimum amount of detail necessary to fully explain a complete solution to the problem (depth bounds for a point light in a view frustum with an oblique near clipping plane). + +![](https://pbs.twimg.com/media/Di6KfWzU0AAIKXK?format=jpg&name=orig) + +**2/** **@bugshake** ^1022045432279719936 + +**@EricLengyel** + +I wish mathematicians would use more meaningful variable names! As a programmer, this is hard enough, but now I have to also figure out what a, c, d, k, f, h, l, A, B, C, D, E and especially z mean. The image does look very clear though :) + +**3/** **@EricLengyel** ^1022255281168732160 + +**@bugshake** + +Here, I fixed it for you! + +![](https://pbs.twimg.com/media/Di_HoqhVAAA-aa2?format=jpg&name=orig) + +**4/** **@bugshake** ^1022347082680676352 + +**@EricLengyel** + +Haha, that's amazing! Maybe the area of 'math with proper variable names' needs a little more exploration but it's a step :) diff --git a/archive/threads/EricLengyel/index.md b/archive/threads/EricLengyel/index.md index b56a62a..94e839e 100644 --- a/archive/threads/EricLengyel/index.md +++ b/archive/threads/EricLengyel/index.md @@ -21,5 +21,6 @@ tags: - [[archive/threads/EricLengyel/2017-05-26-needs-repeating-you-can-always-perform-a-signed]] - [[archive/threads/EricLengyel/2017-11-17-one-advantage-to-not-including-any-os-headers-or]] - [[archive/threads/EricLengyel/2017-12-29-i-know-a-lot-of-people-are-against-software]] +- [[archive/threads/EricLengyel/2018-07-24-the-final-figure-got-even-crazier]] - [[archive/threads/EricLengyel/2018-08-14-thread]] - [[archive/threads/EricLengyel/2026-01-23-ive-worked-very-hard-over-many-years-to-develop-a]] diff --git a/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2018-01-14-EricLengyel-also-this-diagram-is-clearly-talking-about-the-up.md b/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2018-01-14-EricLengyel-also-this-diagram-is-clearly-talking-about-the-up.md new file mode 100644 index 0000000..767da8f --- /dev/null +++ b/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2018-01-14-EricLengyel-also-this-diagram-is-clearly-talking-about-the-up.md @@ -0,0 +1,37 @@ +--- +title: "@tom_forsyth @TimSweeneyEpic Also, this diagram is clearly talking about the up direction in world space, but neither DirectX nor OpenGL define a world-space up direction *at all*." +type: archive +source: twitter +source_url: "https://x.com/EricLengyel/status/952672665818427393" +author: "Eric Lengyel" +handle: EricLengyel +post_id: "952672665818427393" +date: 2018-01-14 +archived: 2026-08-27 +draft: false +tags: + - archive + - twitter + - TimSweeneyEpic +description: "@tom_forsyth @TimSweeneyEpic Also, this diagram is clearly talking about the up direction in world space, but neither DirectX nor OpenGL define a world-space up direction *at all*." +in_reply_to: "" +parent_post_id: "952669960593027072" +--- + +## Source + +- URL: https://x.com/EricLengyel/status/952672665818427393 +- Author: Eric Lengyel (@EricLengyel) +- Posted: 2018-01-14 22:43:57 + +## Branch + +**1/** **@EricLengyel** ^952672665818427393 + +**@tom_forsyth** **@TimSweeneyEpic** + +Also, this diagram is clearly talking about the up direction in world space, but neither DirectX nor OpenGL define a world-space up direction *at all*. Those APIs do not belong here. People use this to defend Y-up all the time, and they're completely misunderstanding. + +## Related + +- Spine: [[archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system]] diff --git a/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2018-01-14-EricLengyel-tim-you-made-the-right-decision-to-use-z-up-in.md b/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2018-01-14-EricLengyel-tim-you-made-the-right-decision-to-use-z-up-in.md new file mode 100644 index 0000000..7c0f1b0 --- /dev/null +++ b/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2018-01-14-EricLengyel-tim-you-made-the-right-decision-to-use-z-up-in.md @@ -0,0 +1,37 @@ +--- +title: "@tom_forsyth @TimSweeneyEpic Tim, you made the right decision to use Z-up in world space." +type: archive +source: twitter +source_url: "https://x.com/EricLengyel/status/952671193936441345" +author: "Eric Lengyel" +handle: EricLengyel +post_id: "952671193936441345" +date: 2018-01-14 +archived: 2026-08-27 +draft: false +tags: + - archive + - twitter + - TimSweeneyEpic +description: "@tom_forsyth @TimSweeneyEpic Tim, you made the right decision to use Z-up in world space." +in_reply_to: "" +parent_post_id: "952669960593027072" +--- + +## Source + +- URL: https://x.com/EricLengyel/status/952671193936441345 +- Author: Eric Lengyel (@EricLengyel) +- Posted: 2018-01-14 22:38:07 + +## Branch + +**1/** **@EricLengyel** ^952671193936441345 + +**@tom_forsyth** **@TimSweeneyEpic** + +Tim, you made the right decision to use Z-up in world space. Own that, and be an influence that steers gamedev in the right direction. + +## Related + +- Spine: [[archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system]] diff --git a/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2020-10-04-tom_forsyth-i-still-think-the-best-is-x-into-z-up-and-y-right.md b/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2020-10-04-tom_forsyth-i-still-think-the-best-is-x-into-z-up-and-y-right.md new file mode 100644 index 0000000..2559150 --- /dev/null +++ b/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2020-10-04-tom_forsyth-i-still-think-the-best-is-x-into-z-up-and-y-right.md @@ -0,0 +1,37 @@ +--- +title: "@EricLengyel @TimSweeneyEpic I still think the best is X into, Z up and Y right." +type: archive +source: twitter +source_url: "https://x.com/tom_forsyth/status/1312698521087143936" +author: "Tom Forsyth (TODO: fix my heart or die)" +handle: tom_forsyth +post_id: "1312698521087143936" +date: 2020-10-04 +archived: 2026-08-27 +draft: false +tags: + - archive + - twitter + - TimSweeneyEpic +description: "@EricLengyel @TimSweeneyEpic I still think the best is X into, Z up and Y right." +in_reply_to: "" +parent_post_id: "952669960593027072" +--- + +## Source + +- URL: https://x.com/tom_forsyth/status/1312698521087143936 +- Author: Tom Forsyth (TODO: fix my heart or die) (@tom_forsyth) +- Posted: 2020-10-04 10:18:10 + +## Branch + +**1/** **@tom_forsyth** ^1312698521087143936 + +**@EricLengyel** **@TimSweeneyEpic** + +I still think the best is X into, Z up and Y right. Because it's symmetrically consistent - all the axes are equally wrong. + +## Related + +- Spine: [[archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system]] diff --git a/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/index.md b/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/index.md new file mode 100644 index 0000000..0e11108 --- /dev/null +++ b/archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/index.md @@ -0,0 +1,44 @@ +--- +title: "Sorry y’all I was young and this coordinate system stuff was confusing https://x.com/dj_link/status/952185276218200065" +type: archive +source: twitter +source_url: "https://x.com/TimSweeneyEpic/status/952661474501111808" +author: "Tim Sweeney" +handle: TimSweeneyEpic +post_id: "952661474501111808" +date: 2018-01-14 +archived: 2026-08-27 +draft: false +tags: + - archive + - twitter + - TimSweeneyEpic +description: "Sorry y’all I was young and this coordinate system stuff was confusing https://x.com/dj_link/status/952185276218200065" +in_reply_to: "" +--- + +## Source + +- URL: https://x.com/TimSweeneyEpic/status/952661474501111808 +- Author: Tim Sweeney (@TimSweeneyEpic) +- Posted: 2018-01-14 21:59:29 + +## Thread + +**1/** **@TimSweeneyEpic** ^952661474501111808 + +Sorry y’all I was young and this coordinate system stuff was confusing https://x.com/dj_link/status/952185276218200065 + +**2/** **@tom_forsyth** ^952667638072619008 + +**@TimSweeneyEpic** + +Nothing wrong with Z=up. One of those things that at first glance looks insane, then you explain it to people, and it's actually quite sensible. + +**3/** **@EricLengyel** ^952669960593027072 + +**@tom_forsyth** **@TimSweeneyEpic** + +These kinds of diagrams always fail to make a distinction between camera space and world space, and it makes my blood boil. Z-up makes waaaay more sense in world space, and Y-up makes sense in camera space or screen space. + +Branches: [[archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2018-01-14-EricLengyel-tim-you-made-the-right-decision-to-use-z-up-in]], [[archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2018-01-14-EricLengyel-also-this-diagram-is-clearly-talking-about-the-up]], [[archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system/2020-10-04-tom_forsyth-i-still-think-the-best-is-x-into-z-up-and-y-right]] diff --git a/archive/threads/TimSweeneyEpic/index.md b/archive/threads/TimSweeneyEpic/index.md new file mode 100644 index 0000000..6caef8a --- /dev/null +++ b/archive/threads/TimSweeneyEpic/index.md @@ -0,0 +1,12 @@ +--- +title: TimSweeneyEpic +type: note +draft: false +description: Archived threads by TimSweeneyEpic. +tags: + - archive + - twitter + - TimSweeneyEpic +--- + +- [[archive/threads/TimSweeneyEpic/2018-01-14-sorry-yall-i-was-young-and-this-coordinate-system]] diff --git a/archive/threads/index.md b/archive/threads/index.md index 8cfbe8c..1f48529 100644 --- a/archive/threads/index.md +++ b/archive/threads/index.md @@ -53,6 +53,7 @@ Example of the note shape (single spine, no branches): [[archive/threads/How to - [[archive/threads/simplex_fx]] - [[archive/threads/TheGingerBill]] - [[archive/threads/ThePrimeagen]] +- [[archive/threads/TimSweeneyEpic]] - [[archive/threads/tom_forsyth]] - [[archive/threads/Triang3l]] - [[archive/threads/valigo]]