sunlight through atmosphere

crates/resolved-cli/tests/cli.rs

@@ -185,21 +185,24 @@ fn pretty_previews_lift_the_darks_and_leave_space_black() {
 
 #[cfg(feature = "astrokit")]
 #[test]
-fn lunar_eclipse_darkens_the_moon() {
-    // Mid-totality: at L1 the whole Moon is in Earth's umbra and reads the bias. At L0
-    // there are no eclipses on the bodies and it is a full Moon.
+fn lunar_eclipse_darkens_and_reddens_the_moon() {
+    // Mid-totality: at L1 the whole Moon is in Earth's umbra, lit only through Earth's
+    // atmosphere, red, and brighter at its northern edge, farther from the shadow's
+    // axis, than at its southern. At L0 there are no eclipses on the bodies, and the
+    // full Moon at the scene's L0 exposure, 300 times shorter, is bright but short of
+    // saturation.
     let scene = "examples/scenes/lunar-eclipse.toml";
     let l0 = render_at(scene, "gpu", "L0");
     let l1 = render_at(scene, "gpu", "L1");
-    assert!(
-        l0.get_pixel(960, 540).0.iter().all(|&v| v > 150),
-        "{:?}",
-        l0.get_pixel(960, 540)
-    );
-    assert!(
-        l1.pixels().all(|p| p.0 == [64; 3]),
-        "every pixel at the bias"
-    );
+    let full = l0.get_pixel(960, 540).0;
+    assert!(full.iter().all(|&v| v > 1000 && v < 4000), "{full:?}");
+    let [north, center, south] = [260, 540, 820].map(|y| l1.get_pixel(960, y).0);
+    // Measured: 695, 287, 145 DN at the north, 592, 164, 77 at the center, 208, 82, 65
+    // at the south, over a bias of 64.
+    for p in [north, center, south] {
+        assert!(p[0] > p[1] && p[1] >= p[2] && p[2] >= 64, "{p:?}");
+    }
+    assert!(north[0] > center[0] && center[0] > south[0] && south[0] > 100);
 }
 
 #[cfg(feature = "astrokit")]