Packages/MoonriseKit/Tests/SkyRendererTests/PointingTests.swift

 1import CoreGraphics
 2import Testing
 3import SkyEngine
 4@testable import SkyRenderer
 5
 6// Rows of the rotation matrix are the device axes in reference coordinates
 7// (x north, y west, z up); the third row is the device z axis, toward the user.
 8
 9@Test func uprightFacingNorth() {
10    // Screen faces south, so device z = south = (-1, 0, 0).
11    let h = Pointing.direction(m31: -1, m32: 0, m33: 0)
12    #expect(abs(h.altitude) < 1e-9)
13    #expect(abs(h.azimuth) < 1e-9)
14}
15
16@Test func uprightFacingEast() {
17    // Screen faces west: device z = (0, 1, 0).
18    let h = Pointing.direction(m31: 0, m32: 1, m33: 0)
19    #expect(abs(h.azimuth - 90) < 1e-9)
20}
21
22@Test func flatFaceUpPointsDown() {
23    let h = Pointing.direction(m31: 0, m32: 0, m33: 1)
24    #expect(abs(h.altitude + 90) < 1e-9)
25}
26
27@Test func tiltedUpToward45DegreesSouth() {
28    // Camera toward south and 45° up: −z = (−s, 0, s), so z = (s, 0, −s).
29    let s = 0.5.squareRoot()
30    let h = Pointing.direction(m31: s, m32: 0, m33: -s)
31    #expect(abs(h.altitude - 45) < 1e-9)
32    #expect(abs(h.azimuth - 180) < 1e-9)
33}
34
35@Test func polarProjectionPutsPoleAtCentreAndObserverBelow() {
36    let p = PolarProjection(north: true, centerLongitude: -87.6, size: CGSize(width: 200, height: 200))
37    let pole = p.point(lon: 0, lat: 90)!
38    #expect(abs(pole.x - 100) < 1e-9 && abs(pole.y - 100) < 1e-9)
39    let you = p.point(lon: -87.6, lat: 41.9)!
40    #expect(abs(you.x - 100) < 1e-9 && you.y > 180)
41    #expect(p.point(lon: 0, lat: 20) == nil)
42}