952661474501111808, 1021907146475069440

2026-08-27 20:51:06 -04:00
1 parent b0af9a5e05
commit 17ad2e1f82
@@ -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 :)
@@ -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]]
@@ -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]]
@@ -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]]
@@ -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]]
@@ -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]]
@@ -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]]
@@ -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]]