Reusable 3D Earth globe widget (pure OCaml + WebGL)
Add Earth occlusion for picking and filter hover by brightness
Satellites behind the Earth are no longer hoverable or clickable.
Hover highlight only shows for satellites with brightness > 0.05,
preventing invisible satellites from popping in on mouseover.
+36
-12
+5
lib/raycast.ml
+5
lib/raycast.ml
···
81
81
match intersect_sphere ray ~center:Math.Vec3.zero ~radius:1.0 with
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| None -> None
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83
| Some t -> Some (Math.Vec3.add ray.origin (Math.Vec3.scale t ray.direction))
84
+
85
+
let occluded_by_earth ray ~hit_distance =
86
+
match intersect_sphere ray ~center:Math.Vec3.zero ~radius:1.0 with
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+
| None -> false
88
+
| Some earth_t -> earth_t < hit_distance
+4
lib/raycast.mli
+4
lib/raycast.mli
···
44
44
val pick_earth : ray -> Math.Vec3.t option
45
45
(** [pick_earth ray] returns where the ray hits the unit sphere (Earth surface),
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46
or [None] if it misses. *)
47
+
48
+
val occluded_by_earth : ray -> hit_distance:float -> bool
49
+
(** [occluded_by_earth ray ~hit_distance] is [true] if the Earth (unit sphere)
50
+
blocks the ray before [hit_distance]. *)
+27
-12
lib/webgl/scene.ml
+27
-12
lib/webgl/scene.ml
···
264
264
let cam_pos = camera_position t in
265
265
Orbit.draw gl t.orbit ~projection:p ~view:v ~camera_pos:cam_pos ~far:12.0
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~dots;
267
-
(* Draw hovered satellite larger *)
267
+
(* Draw hovered satellite larger, but only if it's visible *)
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match t.hovered with
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| Some idx -> (
270
-
match List.nth_opt (satellite_positions t) idx with
271
-
| Some pos ->
272
-
let color =
273
-
match List.nth_opt t.satellites idx with
274
-
| Some sat -> Globe.Satellite.color sat
275
-
| None -> Globe.Color.white
276
-
in
270
+
match List.nth_opt t.satellites idx with
271
+
| Some sat when Globe.Satellite.brightness sat > 0.05 ->
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+
let dt = sat_dt sat t.current_unix in
273
+
let pos = Globe.Satellite.position_at sat ~dt in
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+
let color = Globe.Satellite.color sat in
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275
Orbit.draw_dot gl t.orbit
278
276
~proj:(Tarray.of_float_array Tarray.Float32 p)
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277
~vw:(Tarray.of_float_array Tarray.Float32 v)
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278
pos ~color ~size:14.0 ~alpha:1.0
281
-
| None -> ())
279
+
| _ -> ())
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| None -> ()
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end;
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282
List.iter (fun f -> f ~projection:p ~view:v) layers.custom;
···
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297
| Some ray -> (
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let positions = satellite_positions t in
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match Globe.Raycast.pick_nearest ray positions ~threshold:0.05 with
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-
| Some hit -> `Satellite hit.Globe.Raycast.index
303
-
| None -> (
300
+
| Some hit
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+
when not
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+
(Globe.Raycast.occluded_by_earth ray
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+
~hit_distance:hit.Globe.Raycast.distance) ->
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+
`Satellite hit.Globe.Raycast.index
305
+
| _ -> (
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match Globe.Raycast.pick_earth ray with
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307
| Some pos -> `Earth pos
306
308
| None -> `Miss))
···
337
339
let positions = satellite_positions t in
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t.hovered <-
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(match Globe.Raycast.pick_nearest ray positions ~threshold:0.08 with
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-
| Some hit -> Some hit.Globe.Raycast.index
342
+
| Some hit ->
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+
(* Skip satellites behind the Earth *)
344
+
let occluded =
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+
Globe.Raycast.occluded_by_earth ray
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+
~hit_distance:hit.Globe.Raycast.distance
347
+
in
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+
(* Only hover satellites that are visibly bright *)
349
+
let visible =
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+
match List.nth_opt t.satellites hit.Globe.Raycast.index with
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+
| Some sat -> Globe.Satellite.brightness sat > 0.05
352
+
| None -> false
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+
in
354
+
if (not occluded) && visible then Some hit.Globe.Raycast.index
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+
else None
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| None -> None))
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357
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let click t ~screen_x ~screen_y =