Last active
August 11, 2024 03:43
-
-
Save drewolbrich/284d92eb3df5580cb635a50cbe49dab5 to your computer and use it in GitHub Desktop.
SIMD look-at functions
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| // | |
| // SIMD+LookAt.swift | |
| // | |
| // Created by Drew Olbrich on 11/10/23. | |
| // Copyright © 2023 Lunar Skydiving LLC. All rights reserved. | |
| // | |
| // MIT License | |
| // | |
| // Permission is hereby granted, free of charge, to any person obtaining a copy | |
| // of this software and associated documentation files (the "Software"), to deal | |
| // in the Software without restriction, including without limitation the rights | |
| // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| // copies of the Software, and to permit persons to whom the Software is | |
| // furnished to do so, subject to the following conditions: | |
| // | |
| // The above copyright notice and this permission notice shall be included in all | |
| // copies or substantial portions of the Software. | |
| // | |
| // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
| // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
| // SOFTWARE. | |
| // | |
| import simd | |
| /// Creates a 4x4 matrix that orients the +Z axis in the direction of `at`, and the | |
| /// +Y axis toward `up`. | |
| func simd_look(at: SIMD3<Float>, up: SIMD3<Float> = SIMD3<Float>(0, 1, 0)) -> simd_float4x4 { | |
| let zAxis = normalize(at) | |
| let xAxis = normalize(cross(up, zAxis)) | |
| let yAxis = normalize(cross(zAxis, xAxis)) | |
| return simd_float4x4( | |
| SIMD4(xAxis, w: 0), | |
| SIMD4(yAxis, w: 0), | |
| SIMD4(zAxis, w: 0), | |
| SIMD4(0, 0, 0, 1) | |
| ) | |
| } | |
| /// Creates a 4x4 matrix that positions the origin at `from`, orienting the +Z axis | |
| /// so it points at `at`, and the +Y axis in the direction of `up`. | |
| func simd_look(at: SIMD3<Float>, from: SIMD3<Float>, up: SIMD3<Float> = SIMD3<Float>(0, 1, 0)) -> simd_float4x4 { | |
| let zAxis = normalize(at - from) | |
| let xAxis = normalize(cross(up, zAxis)) | |
| let yAxis = normalize(cross(zAxis, xAxis)) | |
| return simd_float4x4( | |
| SIMD4(xAxis, w: 0), | |
| SIMD4(yAxis, w: 0), | |
| SIMD4(zAxis, w: 0), | |
| SIMD4(from, 1) | |
| ) | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment