Split shadow cascades through an orthographic camera's box

ARCHITECTURE.md

@@ -2691,7 +2691,7 @@ storage.
 |---|---|
 | Style | `dart format` |
 | Analysis | `flutter analyze` clean across the workspace, no warnings |
-| Unit tests | **11340 tests** across 43 packages and 10 applications |
+| Unit tests | **11343 tests** across 43 packages and 10 applications |
 | Structure rules | 35, `dart run tool/structure.dart`, the first CI step |
 | CI | GitHub Actions over `tool/ci.sh`, on `ubuntu-latest`, with no graphics card |
 
@@ -2731,7 +2731,7 @@ material parameter — is the case `doc/boundary-0.5.0.md` worked through for
 set belongs to whoever builds on the package rather than to the package
 itself.
 
-**Golden render tests.** 90 scenes against **four complete independent
+**Golden render tests.** 91 scenes against **four complete independent
 reference sets** — Impeller, the software rasteriser, WebGL2 and WebGPU — each
 held to zero differing pixels against its own set, with a per-channel tolerance
 of 8.
@@ -3143,7 +3143,7 @@ metres. The directional light's cascades fit the view up to that distance and
 nothing beyond it casts — a level whose far end matters visually wants the
 number raised, and pays for it in texels.
 
-**The web backend draws all ninety golden scenes the way Impeller does**,
+**The web backend draws all ninety-one golden scenes the way Impeller does**,
 between 0.01% and 0.42% of pixels differing by more than 8 per channel — the
 silhouette's worth of disagreement two rasterisers always have. Two of those
 numbers fell when the minification filter learned to read a sampler's
@@ -3259,7 +3259,7 @@ and charge each of them the bytes, and neither is a change to make on somebody
 else's behalf. A build that wants it says so in one flag, and the engine's own
 example takes the same answer from `?backend=webgpu` in the URL — a query
 parameter rather than a define, because the browser golden stand's whole saving
-is one dart2js run serving ninety scenes and both browser backends.
+is one dart2js run serving ninety-one scenes and both browser backends.
 
 **`flutter3d_shaders` is one text and no two backends take it the same way.**
 Impeller compiles the GLSL with `impellerc`; the WebGL2 generator translates it

README.md

@@ -158,9 +158,9 @@ Or one package at a time:
 (cd packages/flutter3d_physics && dart test)   # plain Dart, no Flutter needed
 ```
 
-There are 11340 tests across forty-three packages and nine applications. The
+There are 11343 tests across forty-three packages and nine applications. The
 only ones that need a GPU are the Impeller half of the golden set. The other
-half is rendered by the software backend, which is what makes 90 scenes
+half is rendered by the software backend, which is what makes 91 scenes
 checkable in a headless run.
 
 Several steps run in a browser. `flutter test --platform chrome` covers the two

packages/flutter3d/CHANGELOG.md

@@ -1,5 +1,9 @@
 ## Unreleased
 
+- `orthographic-shadow` in the reference set: a strategy board through an
+  isometric orthographic camera, its posts' shadows as sharp at the top of
+  the frame as at the bottom.
+
 - **`generatedMaterialPathFor`**: where the build hook writes a `.f3dmat`'s
   compiled bundle, `flutter3d_generated/<same path>.f3dshaders`.
 

packages/flutter3d/example/lib/src/spike/backend_web.dart

@@ -13,7 +13,7 @@ import 'golden_store.dart';
 ///
 /// Read from the URL, exactly the way the golden scene and the record/compare
 /// direction are read, and for exactly the same arithmetic: one dart2js run
-/// serves ninety scenes because the scene is a query parameter, and one
+/// serves ninety-one scenes because the scene is a query parameter, and one
 /// dart2js run serves the browser backends because this is one too. A
 /// `--dart-define` here would be a build per backend, which is the whole saving
 /// of the browser golden stand spent on a single word.

packages/flutter3d/example/lib/src/spike/golden_runner.dart

@@ -122,7 +122,7 @@ final class GoldenRunner {
       scene,
       // The store's answer wins where it has one. A desktop run takes the
       // direction from the environment and a browser run from the URL, for the
-      // same reason on both: one build has to serve ninety scenes in both
+      // same reason on both: one build has to serve ninety-one scenes in both
       // directions, and anything the compiler sees is another build.
       update:
           updateOverride ??

packages/flutter3d/example/lib/src/spike/golden_scenes.dart

@@ -1264,6 +1264,16 @@ final List<GoldenScene> kGoldenScenes = <GoldenScene>[
     configure: GoldenStages.orthographicMetalSettings,
   ),
 
+  // P7. A strategy board through an isometric orthographic camera, its
+  // shadows from cascades split through the box rather than from the eye.
+  const GoldenScene(
+    name: 'orthographic-shadow',
+    source: 'Cube',
+    bloom: false,
+    ground: false,
+    stage: GoldenStages.orthographicShadow,
+  ),
+
   // P6. `shadow-teapot` wiped at the middle: lit on the left, the shading
   // normal on the right.
   const GoldenScene(

packages/flutter3d/example/lib/src/spike/golden_stages.dart

@@ -1269,17 +1269,76 @@ abstract final class GoldenStages {
         fog: FogSettings(color: Vector3(0.7, 0.75, 0.8), density: 0.03),
       );
 
+  /// `orthographic-shadow`: a strategy board seen isometrically — a floor a
+  /// hundred and twenty metres on a side, a level far larger than the box
+  /// the camera sees, with blocks for buildings and thin posts for units in
+  /// rows from the near edge of the view to the far one, under the sun,
+  /// through an orthographic camera standing sixty metres back along its
+  /// axis.
+  ///
+  /// What it holds is `P7`'s cascade split: the near cascades fitted to the
+  /// box and shared evenly through its depth, so the posts at the top of the
+  /// frame cast as sharp a shadow as the ones at the bottom. Split from the
+  /// eye as a perspective camera's are, every shadow here fell to the last
+  /// cascade, the whole floor, and the posts cast none that could be seen.
+  static Future<GoldenStaged> orthographicShadow(GoldenStage stage) async {
+    final device = stage.device;
+    stage.sun.setLocalForward(Vector3(-1.0, -1.1, -0.45).normalized());
+    final stone = Material(baseColor: Vector4(0.78, 0.74, 0.68, 1.0));
+    final roof = Material(baseColor: Vector4(0.62, 0.34, 0.26, 1.0));
+    final unit = Material(baseColor: Vector4(0.25, 0.4, 0.7, 1.0));
+    return GoldenStaged(
+      nodes: <SceneNode>[
+        _slab(
+          device,
+          Vector3(120.0, 0.2, 120.0),
+          Vector3(0.0, -0.1, 0.0),
+          Material(baseColor: Vector4(0.5, 0.6, 0.42, 1.0), roughness: 0.95),
+        ),
+        for (final (x, z, height) in <(double, double, double)>[
+          (-4.0, -4.0, 2.5),
+          (3.0, -5.0, 1.5),
+          (-5.0, 3.0, 1.8),
+          (4.5, 4.0, 3.0),
+          (0.0, 0.0, 1.2),
+        ]) ...<SceneNode>[
+          _slab(
+            device,
+            Vector3(1.8, height, 1.8),
+            Vector3(x, height * 0.5, z),
+            stone,
+          ),
+          _slab(
+            device,
+            Vector3(2.0, 0.3, 2.0),
+            Vector3(x, height + 0.15, z),
+            roof,
+          ),
+        ],
+        for (var row = -3; row <= 3; row++)
+          for (var column = -1; column <= 1; column++)
+            _slab(
+              device,
+              Vector3(0.12, 1.0, 0.12),
+              Vector3(column * 2.4 + row * 0.6, 0.5, row * 2.6),
+              unit,
+            ),
+      ],
+      everyFrame: (_, _) => stage.camera
+        ..projection = const OrthographicProjection(height: 14.0, far: 200.0)
+        ..setPosition(34.6, 34.6, 34.6)
+        ..lookAt(Vector3.zero()),
+    );
+  }
+
   // ------------------------------------------------------------------ P6
 
   /// `debug-view-split`: the lit teapot left of the middle and its shading
   /// normal right of it, in one draw — the wipe `DebugViewSettings.split`
   /// makes, and the composite leaving the right half out of the tone curve.
   static RenderSettings debugViewSplit(RenderSettings settings) =>
       settings.copyWith(
-        debugView: const DebugViewSettings(
-          view: DebugView.normal,
-          split: 0.5,
-        ),
+        debugView: const DebugViewSettings(view: DebugView.normal, split: 0.5),
       );
 
   // ------------------------------------------------------------------ R6

packages/flutter3d/example/lib/src/spike/golden_store_web.dart

@@ -40,7 +40,7 @@ void reportLine(String message) {
 /// The scene named in the page's URL, if any.
 ///
 /// A run-time choice here, where the desktop path takes a compile-time define.
-/// The reason is arithmetic: the suite is ninety scenes, and rebuilding
+/// The reason is arithmetic: the suite is ninety-one scenes, and rebuilding
 /// the bundle for each is seventy-eight dart2js runs to compare seventy-eight
 /// pictures. One build and seventy-eight navigations is the same information
 /// in a fraction of the time.
@@ -58,7 +58,7 @@ String? get sceneOverride {
 /// Whether this run records rather than compares, from the page's URL.
 ///
 /// A run-time choice for the same reason [sceneOverride] is one: the suite is
-/// ninety scenes and rebuilding for each would be seventy-eight dart2js
+/// ninety-one scenes and rebuilding for each would be seventy-eight dart2js
 /// runs. One build serves both directions, and the URL says which.
 bool get updateOverride => Uri.base.queryParameters['update'] == '1';
 

packages/flutter3d/test/ambient_test.dart

@@ -141,7 +141,7 @@ void main() {
     // approximately, bit for bit.
     //
     // Mutation: default either end of the hemisphere to anything but white.
-    // Ninety goldens move at once.
+    // Ninety-one goldens move at once.
     final lit = await _pixels(_ball(), _noSky);
     final top = _band(lit, 0.15, 0.35);
     final bottom = _band(lit, 0.65, 0.85);

packages/flutter3d/test/anisotropy_test.dart

@@ -24,7 +24,7 @@
 /// which spends the taps and throws away what they bought — contrast drops
 /// *below* the trilinear baseline and the first assertion fails; and letting
 /// a sampler that asked for one reach the new path at all, which would move a
-/// backend ninety golden scenes are recorded on.
+/// backend ninety-one golden scenes are recorded on.
 ///
 /// **One they do not catch, said rather than hidden:** taking the taps along
 /// the *short* axis instead of the long one passes every line here. The
@@ -213,7 +213,7 @@ void main() {
   });
 
   test('asking for one tap is the old sampler exactly', () async {
-    // What makes this safe to add to the backend ninety golden scenes are
+    // What makes this safe to add to the backend ninety-one golden scenes are
     // recorded on. Not "close": the same bytes, because with `anisotropy` at
     // one the new path is not reached at all.
     expect(await _floorAt(1), await _floorAt(1));

packages/flutter3d/test/auto_batch_test.dart

@@ -22,7 +22,7 @@
 /// three backends.** It computes in Dart doubles; Impeller, WebGL and WebGPU
 /// compute in 32-bit floats, where those two expressions have far less room
 /// before they part. Nothing here can run them, so the setting stays off by
-/// default — which is also what keeps the ninety goldens where they are.
+/// default — which is also what keeps the ninety-one goldens where they are.
 library;
 
 import 'dart:math' as math;
@@ -191,7 +191,7 @@ void main() {
   });
 
   test('nothing is batched unless it is asked for', () async {
-    // Which is what keeps the ninety goldens where they are: the default
+    // Which is what keeps the ninety-one goldens where they are: the default
     // frame is the frame it always was, to the byte.
     final device = _device();
     final scene = _field(device, count: 100);

packages/flutter3d/test/fog_test.dart

@@ -151,7 +151,7 @@ void main() {
 
   test('no fog is byte-identical to the fog nobody asked for', () async {
     // The early return at zero density is not an optimisation. The golden sets
-    // — ninety scenes, zero-pixel threshold, three backends — are all
+    // — ninety-one scenes, zero-pixel threshold, three backends — are all
     // recorded with the default `FogSettings()`, and this is the property that
     // lets them stay recorded.
     final none = FogSettings();

packages/flutter3d/test/grade_test.dart

@@ -63,7 +63,7 @@ Future<List<int>> _ramp(LookSettings look, {int width = 256}) async {
 
 void main() {
   test('every default is an exact identity', () async {
-    // The promise ninety goldens rest on. Neutral for these three is
+    // The promise ninety-one goldens rest on. Neutral for these three is
     // (0,0,0) added, (1,1,1) as an exponent and (1,1,1) multiplied, and the
     // composite has to take all three without moving a byte.
     final plain = await _ramp(const LookSettings());

packages/flutter3d/test/halation_test.dart

@@ -87,7 +87,7 @@ void main() {
 
   test('zero is an exact identity, and is the default', () async {
     // The multiplier is one on every channel at zero, so the chain comes out
-    // byte for byte as it did — which is what ninety goldens need.
+    // byte for byte as it did — which is what ninety-one goldens need.
     expect(const BloomSettings().halation, 0.0);
     final a = await _glow(halation: 0.0);
     final b = await _glow(halation: 0.0);

packages/flutter3d/test/irradiance_bounce_test.dart

@@ -136,7 +136,7 @@ double _tint(Uint8List rgba) {
 void main() {
   test('off, the picture is the bytes it was', () async {
     // The clause every recorded frame depends on. A field is null by default,
-    // so this is the path ninety goldens take.
+    // so this is the path ninety-one goldens take.
     final a = await _draw(field: false, redWall: true);
     final b = await _draw(field: false, redWall: true);
     expect(a, orderedEquals(b));

packages/flutter3d/test/masked_shadow_test.dart

@@ -223,7 +223,7 @@ void main() {
   test('a caster with no map keeps the shadow it always cast', () async {
     // **The half that lets this land.** A material that is not cut out goes
     // through the stage it has always gone through, with no sampler in the
-    // pipeline and no texture bound per draw, so the ninety goldens
+    // pipeline and no texture bound per draw, so the ninety-one goldens
     // recorded against that stage cannot move. Asking for MASK with no map to
     // read is the same case: there is nothing to cut out.
     final plain = await _frame(masked: false, withTexture: false);

packages/flutter3d/test/material_vertex_stage_test.dart

@@ -172,7 +172,7 @@ void main() {
     // **The half that lets this land**, and the reason the seam is a null field
     // rather than a new required one: a material saying nothing about its vertex
     // stage goes through the pipeline it has always gone through, which is also
-    // why the ninety goldens cannot move.
+    // why the ninety-one goldens cannot move.
     final withSeam = await _draw(lighting: _plain);
 
     final device = CpuDevice(

packages/flutter3d/test/per_view_exposure_test.dart

@@ -157,7 +157,7 @@ void main() {
       // **The strongest form of "this costs nothing where it is not wanted".**
       // One view is the whole frame, so its rectangle is the whole histogram
       // and its exposure is the frame's. The composite takes its single-draw
-      // path, and ninety goldens stay where they are.
+      // path, and ninety-one goldens stay where they are.
       final off = await frame(
         const RenderSettings(autoExposure: AutoExposureSettings(enabled: true)),
       );

packages/flutter3d/test/render_scale_test.dart

@@ -36,7 +36,7 @@ import 'package:vector_math/vector_math.dart';
 
 void main() {
   test('one is the whole resolution, and is the default', () {
-    // Ninety goldens are recorded at the size they asked for. A default
+    // Ninety-one goldens are recorded at the size they asked for. A default
     // that shrank anything would move every one of them.
     expect(const RenderSettings().renderScale, 1.0);
     expect(_drawn(1.0), (width: 64, height: 64));

packages/flutter3d/test/sharpen_test.dart

@@ -95,7 +95,7 @@ int _steepest(List<int> row) {
 
 void main() {
   test('zero is an exact identity, and is the default', () async {
-    // Ninety goldens go through this pass. The shader returns the centre
+    // Ninety-one goldens go through this pass. The shader returns the centre
     // untouched at zero rather than running a kernel that rounds to nothing,
     // because "rounds to nothing" is a claim about the target's bit depth.
     expect(const AntiAliasSettings().sharpen, 0.0);

packages/flutter3d/test/sky_procedural_test.dart

@@ -167,7 +167,7 @@ double _mean(Uint8List rgba, {required int channel}) {
 void main() {
   _hardEdgedSun();
   test('no sky is byte-identical to the sky nobody asked for', () async {
-    // The property ninety goldens rest on: a frame with no sky in it is
+    // The property ninety-one goldens rest on: a frame with no sky in it is
     // the frame this renderer has always drawn.
     //
     // Mutation: drop the early return. The sky is drawn into every scene that

packages/flutter3d/test/ssao_blur_test.dart

@@ -75,7 +75,7 @@ void main() {
   test('no taps is no pass, and is the default', () async {
     // The occlusion is already off by default, and this is a second
     // full-screen pass over it — so nothing pays for either until two things
-    // are switched on. Ninety goldens depend on the frame being what it
+    // are switched on. Ninety-one goldens depend on the frame being what it
     // was.
     expect(const AmbientOcclusionSettings().blurTaps, 0);
     expect(await _frame(blurTaps: 0), await _frame(blurTaps: 0));

packages/flutter3d_core/CHANGELOG.md

@@ -1,5 +1,17 @@
 ## Unreleased
 
+- **Shadow cascades under an orthographic camera.** They were split by
+  distance from the eye, mostly logarithmically, as a perspective camera
+  wants; through an orthographic lens the eye is only where the camera was
+  put along its axis, so the near cascades covered the air in front of the
+  board and every shadow fell to the last, the whole level. Now the near
+  cascades share the depth the camera's box and the casters have in common,
+  evenly, since a pixel needs the same texel at every depth, and each is a
+  sphere fitted to the slab of the box its threshold can send to it. The
+  last stays the whole scene, for mirrors and probes. Perspective cameras
+  split as before. `Renderer.debugCascadeSplits` reads where the near
+  cascades end. `orthographic-shadow` is in all four golden sets.
+
 - **Caustics.** `ShadowSettings.caustics` (with `translucentCasters`, off by
   default) follows the sun's light through every caster with a volume — a
   transmission and a thickness. Each is drawn from the sun into two small

packages/flutter3d_core/lib/src/engine/render/render_settings.dart

@@ -1462,7 +1462,7 @@ final class RenderSettings {
   /// eight-bit answer — `auto_batch_test.dart` holds a hundred cubes, turned and
   /// scaled, to byte equality. Impeller, WebGL and WebGPU compute in 32-bit
   /// floats, where those expressions have far less room before they part, and
-  /// nothing headless can run them. So the ninety goldens keep the frame
+  /// nothing headless can run them. So the ninety-one goldens keep the frame
   /// they have, and an application that wants the draw calls back asks.
   ///
   /// Shadows and picking are unaffected: both walk the scene themselves and
@@ -2246,7 +2246,7 @@ final class DisplayTransform {
 /// **Everything here defaults to doing nothing, exactly.** Not nearly nothing:
 /// a vignette of zero multiplies by one and grain of zero adds zero, so a scene
 /// that asks for none of it composites to the same bytes it did before this
-/// existed. Ninety goldens depend on that being exact, and the composite
+/// existed. Ninety-one goldens depend on that being exact, and the composite
 /// pass already keeps the same promise for ambient occlusion.
 ///
 /// Applied in the composite rather than as passes of their own, which is the