More reasonable angular resolution based on the camera settings

Principia.sln.DotSettings

@@ -221,6 +221,7 @@
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=colour/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=colours/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=downsampling/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=equipotential/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Frenet/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=geopotential/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=gipfeli/@EntryIndexedValue">True</s:Boolean>

benchmarks/planetarium_benchmark.cpp

@@ -331,6 +331,7 @@ void BM_PlanetariumPlotMethod3(
         satellites.goes_8_trajectory().end(),
         now,
         /*t_max=*/InfiniteFuture,
+        /*tan_angular_resolution=*/0.00080,
         /*reverse=*/false,
         /*add_point=*/
         [&line](ScaledSpacePoint const& point) { line.push_back(point); },

ksp_plugin/interface_planetarium.cpp

@@ -50,6 +50,7 @@ Planetarium* __cdecl principia__PlanetariumCreate(
     double const focal,
     double const field_of_view,
     double const inverse_scale_factor,
+    double const tan_angular_resolution,
     XYZ const scaled_space_origin) {
   journal::Method<journal::PlanetariumCreate> m({plugin,
                                                  sun_world_position,
@@ -60,6 +61,7 @@ Planetarium* __cdecl principia__PlanetariumCreate(
                                                  focal,
                                                  field_of_view,
                                                  inverse_scale_factor,
+                                                 tan_angular_resolution,
                                                  scaled_space_origin});
   Renderer const& renderer = CHECK_NOTNULL(plugin)->renderer();
 
@@ -88,9 +90,13 @@ Planetarium* __cdecl principia__PlanetariumCreate(
                                    FromXYZ<Position<World>>(sun_world_position),
                                    plugin->PlanetariumRotation());
 
+  // Angular resolution: My display has a height of 401 mm and 1600 pixels
+  // vertically.  My eye is at least 550 mm from the centre.  Hence the
+  // wolframalpha.com query: "ArcTan[(401/1600)/550] in arcmin" which yields
+  // 1.567'.
   Planetarium::Parameters parameters(
       /*sphere_radius_multiplier=*/1.0,
-      /*angular_resolution=*/0.4 * ArcMinute,
+      /*angular_resolution=*/1.567 * ArcMinute,
       field_of_view * Radian);
   Perspective<Navigation, Camera> perspective(
       world_to_plotting_affine_map *
@@ -130,11 +136,19 @@ void __cdecl principia__PlanetariumPlotFlightPlanSegment(
     char const* const vessel_guid,
     int const index,
     double const* const t_max,
+    double const tan_angular_resolution,
     ScaledSpacePoint* const vertices,
     int const vertices_size,
     int* const vertex_count) {
   journal::Method<journal::PlanetariumPlotFlightPlanSegment> m(
-      {planetarium, plugin, vessel_guid, index, t_max, vertices, vertices_size},
+      {planetarium,
+       plugin,
+       vessel_guid,
+       index,
+       t_max,
+       tan_angular_resolution,
+       vertices,
+       vertices_size},
       {vertex_count});
   CHECK_NOTNULL(plugin);
   CHECK_NOTNULL(planetarium);
@@ -156,6 +170,7 @@ void __cdecl principia__PlanetariumPlotFlightPlanSegment(
         segment->end(),
         plugin->CurrentTime(),
         t_max == nullptr ? InfiniteFuture : FromGameTime(*plugin, *t_max),
+        tan_angular_resolution,
         /*reverse=*/false,
         [vertices, vertex_count](ScaledSpacePoint const& vertex) {
           vertices[(*vertex_count)++] = vertex;
@@ -172,11 +187,18 @@ void __cdecl principia__PlanetariumPlotPrediction(
     Plugin const* const plugin,
     char const* const vessel_guid,
     double const* const t_max,
+    double const tan_angular_resolution,
     ScaledSpacePoint* const vertices,
     int const vertices_size,
     int* const vertex_count) {
   journal::Method<journal::PlanetariumPlotPrediction> m(
-      {planetarium, plugin, vessel_guid, t_max, vertices, vertices_size},
+      {planetarium,
+       plugin,
+       vessel_guid,
+       t_max,
+       tan_angular_resolution,
+       vertices,
+       vertices_size},
       {vertex_count});
   CHECK_NOTNULL(plugin);
   CHECK_NOTNULL(planetarium);
@@ -189,6 +211,7 @@ void __cdecl principia__PlanetariumPlotPrediction(
       prediction->end(),
       plugin->CurrentTime(),
       t_max == nullptr ? InfiniteFuture : FromGameTime(*plugin, *t_max),
+      tan_angular_resolution,
       /*reverse=*/false,
       [vertices, vertex_count](ScaledSpacePoint const& vertex) {
         vertices[(*vertex_count)++] = vertex;
@@ -207,6 +230,7 @@ void __cdecl principia__PlanetariumPlotPsychohistory(
     char const* const vessel_guid,
     double const max_history_length,
     double const* const t_max,
+    double const tan_angular_resolution,
     ScaledSpacePoint* const vertices,
     int const vertices_size,
     int* const vertex_count) {
@@ -216,6 +240,7 @@ void __cdecl principia__PlanetariumPlotPsychohistory(
        vessel_guid,
        max_history_length,
        t_max,
+       tan_angular_resolution,
        vertices,
        vertices_size},
       {vertex_count});
@@ -246,6 +271,7 @@ void __cdecl principia__PlanetariumPlotPsychohistory(
         psychohistory->end(),
         /*now=*/plugin->CurrentTime(),
         t_max == nullptr ? InfiniteFuture : FromGameTime(*plugin, *t_max),
+        tan_angular_resolution,
         /*reverse=*/true,
         [vertices, vertex_count](ScaledSpacePoint const& vertex) {
           vertices[(*vertex_count)++] = vertex;
@@ -264,6 +290,7 @@ void __cdecl principia__PlanetariumPlotCelestialPastTrajectory(
     Plugin const* const plugin,
     int const celestial_index,
     double const max_history_length,
+    double const tan_angular_resolution,
     ScaledSpacePoint* const vertices,
     int const vertices_size,
     double* const minimal_distance_from_camera,
@@ -273,6 +300,7 @@ void __cdecl principia__PlanetariumPlotCelestialPastTrajectory(
        plugin,
        celestial_index,
        max_history_length,
+       tan_angular_resolution,
        vertices,
        vertices_size},
       {minimal_distance_from_camera, vertex_count});
@@ -303,6 +331,7 @@ void __cdecl principia__PlanetariumPlotCelestialPastTrajectory(
         first_time,
         /*last_time=*/plugin->CurrentTime(),
         /*now=*/plugin->CurrentTime(),
+        tan_angular_resolution,
         /*reverse=*/true,
         [vertices, vertex_count](ScaledSpacePoint const& vertex) {
           vertices[(*vertex_count)++] = vertex;
@@ -323,6 +352,7 @@ void __cdecl principia__PlanetariumPlotCelestialFutureTrajectory(
     Plugin const* const plugin,
     int const celestial_index,
     char const* const vessel_guid,
+    double const tan_angular_resolution,
     ScaledSpacePoint* const vertices,
     int const vertices_size,
     double* const minimal_distance_from_camera,
@@ -332,6 +362,7 @@ void __cdecl principia__PlanetariumPlotCelestialFutureTrajectory(
        plugin,
        celestial_index,
        vessel_guid,
+       tan_angular_resolution,
        vertices,
        vertices_size},
       {minimal_distance_from_camera, vertex_count});
@@ -362,6 +393,7 @@ void __cdecl principia__PlanetariumPlotCelestialFutureTrajectory(
         /*first_time=*/plugin->CurrentTime(),
         /*last_time=*/final_time,
         /*now=*/plugin->CurrentTime(),
+        tan_angular_resolution,
         /*reverse=*/false,
         [vertices, vertex_count](ScaledSpacePoint const& vertex) {
           vertices[(*vertex_count)++] = vertex;
@@ -379,11 +411,17 @@ void __cdecl principia__PlanetariumPlotEquipotential(
     Planetarium const* const planetarium,
     Plugin const* const plugin,
     int const index,
+    double const tan_angular_resolution,
     ScaledSpacePoint* const vertices,
     int const vertices_size,
     int* const vertex_count) {
   journal::Method<journal::PlanetariumPlotEquipotential> m(
-      {planetarium, plugin, index, vertices, vertices_size},
+      {planetarium,
+       plugin,
+       index,
+       tan_angular_resolution,
+       vertices,
+       vertices_size},
       {vertex_count});
   CHECK_NOTNULL(plugin);
   CHECK_NOTNULL(planetarium);
@@ -401,6 +439,7 @@ void __cdecl principia__PlanetariumPlotEquipotential(
       equipotential.front().time,
       equipotential.back().time,
       plugin->CurrentTime(),
+      tan_angular_resolution,
       /*reverse=*/false,
       [vertices, vertex_count](ScaledSpacePoint const& vertex) {
         vertices[(*vertex_count)++] = vertex;

ksp_plugin/planetarium.cpp

@@ -271,6 +271,7 @@ void Planetarium::PlotMethod3(
     DiscreteTrajectory<Barycentric>::iterator end,
     Instant const& now,
     Instant const& t_max,
+    double const tan_angular_resolution,
     bool const reverse,
     std::function<void(ScaledSpacePoint const&)> const& add_point,
     int max_points) const {
@@ -281,8 +282,14 @@ void Planetarium::PlotMethod3(
   auto const begin_time = std::max(begin->time, plotting_frame_->t_min());
   auto const last_time =
       std::min({last->time, plotting_frame_->t_max(), t_max});
-  PlotMethod3(
-      trajectory, begin_time, last_time, now, reverse, add_point, max_points);
+  PlotMethod3(trajectory,
+              begin_time,
+              last_time,
+              now,
+              tan_angular_resolution,
+              reverse,
+              add_point,
+              max_points);
 }
 
 std::vector<Sphere<Navigation>> Planetarium::ComputePlottableSpheres(

ksp_plugin/planetarium.hpp

@@ -60,9 +60,10 @@ class Planetarium {
   class Parameters final {
    public:
     // `sphere_radius_multiplier` defines the "dark area" around a celestial
-    // where we don't draw trajectories.  `angular_resolution` defines the limit
-    // beyond which spheres don't participate in hiding.  `field_of_view`
-    // is the half-angle of a cone outside of which not plotting takes place.
+    // where we don't draw trajectories.  For methods 0 to 2,
+    // `angular_resolution` defines the limit beyond which spheres don't
+    // participate in hiding.  `field_of_view` is the half-angle of a cone
+    // outside of which not plotting takes place.
     explicit Parameters(double sphere_radius_multiplier,
                         Angle const& angular_resolution,
                         Angle const& field_of_view);
@@ -124,13 +125,16 @@ class Planetarium {
       Length* minimal_distance = nullptr) const;
 
   // A method similar to PlotMethod2, but which produces a three-dimensional
-  // trajectory in scaled space instead of projecting and hiding.
+  // trajectory in scaled space instead of projecting and hiding.  Note that the
+  // angular resolution passed at construction is ignored and the parameter
+  // `tan_angular_resolution` is used instead.
   void PlotMethod3(
       Trajectory<Barycentric> const& trajectory,
       DiscreteTrajectory<Barycentric>::iterator begin,
       DiscreteTrajectory<Barycentric>::iterator end,
       Instant const& now,
       Instant const& t_max,
+      double tan_angular_resolution,
       bool reverse,
       std::function<void(ScaledSpacePoint const&)> const& add_point,
       int max_points) const;
@@ -143,6 +147,7 @@ class Planetarium {
       Instant const& first_time,
       Instant const& last_time,
       Instant const& now,
+      double tan_angular_resolution,
       bool reverse,
       std::function<void(ScaledSpacePoint const&)> const& add_point,
       int max_points,

ksp_plugin/planetarium_body.hpp

@@ -54,12 +54,12 @@ void Planetarium::PlotMethod3(
     Instant const& first_time,
     Instant const& last_time,
     Instant const& now,
+    double const tan_angular_resolution,
     bool const reverse,
     std::function<void(ScaledSpacePoint const&)> const& add_point,
     int const max_points,
     Length* const minimal_distance) const {
-  double const tan²_angular_resolution =
-      Pow<2>(parameters_.tan_angular_resolution_);
+  double const tan²_angular_resolution = Pow<2>(tan_angular_resolution);
   auto const final_time = reverse ? first_time : last_time;
   auto previous_time = reverse ? last_time : first_time;
 

ksp_plugin_adapter/gl_lines.cs

@@ -75,6 +75,7 @@ public static DisposablePlanetarium NewPlanetarium(IntPtr plugin,
         focal:1,
         field_of_view,
         ScaledSpace.InverseScaleFactor,
+        Plotter.TanAngularResolution(),
         scaled_space_origin: (XYZ)ScaledSpace.ScaledToLocalSpace(
             Vector3d.zero));
   }

ksp_plugin_adapter/main_window.cs

@@ -25,6 +25,8 @@ public MainWindow(PrincipiaPluginAdapter adapter,
     flight_planner_ = flight_planner;
     orbit_analyser_ = orbit_analyser;
     plotting_frame_selector_ = plotting_frame_selector;
+    cheeze_c.value = 0.65;
+    cheeze_x.value = -0.31;
     Show();
   }
 
@@ -167,8 +169,28 @@ public override void Save(ConfigNode node) {
 
   protected override string Title => "Principia";
 
-  protected override void RenderWindowContents(int window_id) {
+  public static DifferentialSlider cheeze_c = new DifferentialSlider("c", "", -5, -1,
+  (x) => x.ToString("0.000"), zero_value: 0.65, min_value: 0.1, max_value: 4);
+  public static DifferentialSlider cheeze_x = new DifferentialSlider("x", "", -5, -1,
+  (x) => x.ToString("0.000"), zero_value: -0.31, min_value: -2, max_value: 0);
+
+      protected override void RenderWindowContents(int window_id) {
     using (new UnityEngine.GUILayout.VerticalScope()) {
+      UnityEngine.GUILayout.Label("Cheeze constants: ");
+      cheeze_c.Render(true);
+      cheeze_x.Render(true);
+
+      UnityEngine.Camera camera = PlanetariumCamera.Camera;
+      float vertical_fov = camera.fieldOfView;
+      float horizontal_fov =
+          UnityEngine.Camera.VerticalToHorizontalFieldOfView(
+              vertical_fov,
+              camera.aspect);
+      UnityEngine.GUILayout.Label("vfov=" + vertical_fov);
+      UnityEngine.GUILayout.Label("hfov=" + horizontal_fov);
+      UnityEngine.GUILayout.Label("pixh=" + camera.pixelHeight);
+      UnityEngine.GUILayout.Label("pixw=" + camera.pixelWidth);
+
       if (!adapter_.PluginRunning()) {
         UnityEngine.GUILayout.Label(
             text : L10N.CacheFormat("#Principia_MainWindow_PluginNotStarted"),