Subdivision tuning

Cells are all subdivided at the same level. One subdivision is added if: * the cell is on a pole * the cell is at a frontier of a base cells (and in collignon zona)
2025-12-12 07:40:26 -08:00 · 2025-04-01 14:31:57 +02:00
parent 62f9e61978
commit 645bab7cd9
81 changed files with 330 additions and 181 deletions
--- a/examples/al-artifact.html
+++ b/examples/al-artifact.html
@@ -4,7 +4,7 @@
 </head>
 <body>

-<div id="aladin-lite-div" style="width: 1024px; height: 256px;"></div>
+<div id="aladin-lite-div" style="width: 1024px; height: 768px;"></div>

 <script type="module">
    import A from '../src/js/A.js';
@@ -13,12 +13,14 @@
        var aladin = A.aladin(
            '#aladin-lite-div',
            {
-                survey: 'https://alasky.cds.unistra.fr/Pan-STARRS/DR1/color-z-zg-g/', // set initial image survey
+                survey: 'data/hips/wcs', // set initial image survey
                projection: 'SIN', // set a projection
-                fov: 114.19, // initial field of view in degrees
-                target: '19 24 51.556 +45 16 44.36', // initial target
-                cooFrame: 'equatorial', // set galactic frame
-                showCooGrid: true, // set the grid
+                fov: 80.0, // initial field of view in degrees
+                target: '96.5279427 -88.0037230', // initial target
+                cooFrame: 'galactic', // set galactic frame
+                showCooGrid: true, // set the grid,
+                fullScreen: true,
+                showSettingsControl: true,
            }
        );
    });
--- a/examples/data/hips/wcs/Norder0/Dir0/Npix10.png
+++ b/examples/data/hips/wcs/Norder0/Dir0/Npix10.png
--- a/examples/data/hips/wcs/Norder0/Dir0/Npix11.png
+++ b/examples/data/hips/wcs/Norder0/Dir0/Npix11.png
--- a/examples/data/hips/wcs/Norder0/Dir0/Npix4.png
+++ b/examples/data/hips/wcs/Norder0/Dir0/Npix4.png
--- a/examples/data/hips/wcs/Norder0/Dir0/Npix8.png
+++ b/examples/data/hips/wcs/Norder0/Dir0/Npix8.png
--- a/examples/data/hips/wcs/Norder0/Dir0/Npix9.png
+++ b/examples/data/hips/wcs/Norder0/Dir0/Npix9.png
--- a/examples/data/hips/wcs/Norder1/Dir0/Npix16.png
+++ b/examples/data/hips/wcs/Norder1/Dir0/Npix16.png
--- a/examples/data/hips/wcs/Norder1/Dir0/Npix32.png
+++ b/examples/data/hips/wcs/Norder1/Dir0/Npix32.png
--- a/examples/data/hips/wcs/Norder1/Dir0/Npix34.png
+++ b/examples/data/hips/wcs/Norder1/Dir0/Npix34.png
--- a/examples/data/hips/wcs/Norder1/Dir0/Npix36.png
+++ b/examples/data/hips/wcs/Norder1/Dir0/Npix36.png
--- a/examples/data/hips/wcs/Norder1/Dir0/Npix40.png
+++ b/examples/data/hips/wcs/Norder1/Dir0/Npix40.png
--- a/examples/data/hips/wcs/Norder1/Dir0/Npix44.png
+++ b/examples/data/hips/wcs/Norder1/Dir0/Npix44.png
--- a/examples/data/hips/wcs/Norder2/Dir0/Npix128.png
+++ b/examples/data/hips/wcs/Norder2/Dir0/Npix128.png
--- a/examples/data/hips/wcs/Norder2/Dir0/Npix139.png
+++ b/examples/data/hips/wcs/Norder2/Dir0/Npix139.png
--- a/examples/data/hips/wcs/Norder2/Dir0/Npix144.png
+++ b/examples/data/hips/wcs/Norder2/Dir0/Npix144.png
--- a/examples/data/hips/wcs/Norder2/Dir0/Npix160.png
+++ b/examples/data/hips/wcs/Norder2/Dir0/Npix160.png
--- a/examples/data/hips/wcs/Norder2/Dir0/Npix176.png
+++ b/examples/data/hips/wcs/Norder2/Dir0/Npix176.png
--- a/examples/data/hips/wcs/Norder2/Dir0/Npix64.png
+++ b/examples/data/hips/wcs/Norder2/Dir0/Npix64.png
--- a/examples/data/hips/wcs/Norder2/Dir0/Npix65.png
+++ b/examples/data/hips/wcs/Norder2/Dir0/Npix65.png
--- a/examples/data/hips/wcs/Norder3/Allsky.png
+++ b/examples/data/hips/wcs/Norder3/Allsky.png
--- a/examples/data/hips/wcs/Norder3/Dir0/Npix257.png
+++ b/examples/data/hips/wcs/Norder3/Dir0/Npix257.png
--- a/examples/data/hips/wcs/Norder3/Dir0/Npix260.png
+++ b/examples/data/hips/wcs/Norder3/Dir0/Npix260.png
--- a/examples/data/hips/wcs/Norder3/Dir0/Npix512.png
+++ b/examples/data/hips/wcs/Norder3/Dir0/Npix512.png
--- a/examples/data/hips/wcs/Norder3/Dir0/Npix513.png
+++ b/examples/data/hips/wcs/Norder3/Dir0/Npix513.png
--- a/examples/data/hips/wcs/Norder3/Dir0/Npix558.png
+++ b/examples/data/hips/wcs/Norder3/Dir0/Npix558.png
--- a/examples/data/hips/wcs/Norder3/Dir0/Npix576.png
+++ b/examples/data/hips/wcs/Norder3/Dir0/Npix576.png
--- a/examples/data/hips/wcs/Norder3/Dir0/Npix578.png
+++ b/examples/data/hips/wcs/Norder3/Dir0/Npix578.png
--- a/examples/data/hips/wcs/Norder3/Dir0/Npix640.png
+++ b/examples/data/hips/wcs/Norder3/Dir0/Npix640.png
--- a/examples/data/hips/wcs/Norder3/Dir0/Npix704.png
+++ b/examples/data/hips/wcs/Norder3/Dir0/Npix704.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix1029.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix1029.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix1031.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix1031.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix1040.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix1040.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix1041.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix1041.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2048.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2048.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2049.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2049.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2050.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2050.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2052.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2052.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2234.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2234.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2235.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2235.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2304.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2304.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2305.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2305.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2306.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2306.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2312.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2312.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2560.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2560.png
--- a/examples/data/hips/wcs/Norder4/Dir0/Npix2816.png
+++ b/examples/data/hips/wcs/Norder4/Dir0/Npix2816.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix4119.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix4119.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix4125.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix4125.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix4160.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix4160.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix4161.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix4161.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix4162.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix4162.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix4163.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix4163.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix4164.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix4164.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix8192.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix8192.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix8193.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix8193.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix8194.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix8194.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix8195.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix8195.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix8196.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix8196.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix8197.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix8197.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix8198.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix8198.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix8200.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix8200.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix8208.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix8208.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix8939.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix8939.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix8942.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix8942.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix9216.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix9216.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix9217.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix9217.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix9218.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix9218.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix9219.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix9219.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix9222.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix9222.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix9224.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix9224.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix9225.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix9225.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix9226.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix9226.png
--- a/examples/data/hips/wcs/Norder5/Dir0/Npix9248.png
+++ b/examples/data/hips/wcs/Norder5/Dir0/Npix9248.png
--- a/examples/data/hips/wcs/Norder5/Dir10000/Npix10240.png
+++ b/examples/data/hips/wcs/Norder5/Dir10000/Npix10240.png
--- a/examples/data/hips/wcs/Norder5/Dir10000/Npix10242.png
+++ b/examples/data/hips/wcs/Norder5/Dir10000/Npix10242.png
--- a/examples/data/hips/wcs/Norder5/Dir10000/Npix11264.png
+++ b/examples/data/hips/wcs/Norder5/Dir10000/Npix11264.png
--- a/examples/data/hips/wcs/properties
+++ b/examples/data/hips/wcs/properties
@@ -0,0 +1,33 @@
+creator_did          = ivo://UNK.AUTH/P/474-2244-wcs
+obs_title            = 474-2244-wcs.fits
+hips_builder         = Aladin/HipsGen v12.135
+hips_version         = 1.4
+hips_frame           = galactic
+hips_order           = 10
+hips_order_min       = 0
+hips_tile_width      = 512
+hips_status          = public master clonableOnce
+hips_tile_format     = png
+hips_pixel_bitpix    = -32
+hips_pixel_cut       = -670.2 64044
+hips_data_range      = -38085 98627
+hips_initial_ra      = 11.66767
+hips_initial_dec     = -24.86479
+hips_initial_fov     = 5.90651
+hips_pixel_scale     = 1.118E-4
+s_pixel_scale        = 1.222E-4
+dataproduct_type     = image
+hipsgen_date         = 2024-11-13T17:07Z
+hipsgen_params       = in=NAROO/474-2244-wcs.fits out=/var/www/tmp/HiPS/474-2244-wcs id=474-2244-wcs maxThread=20
+data_pixel_bitpix    = -32
+hips_sampling        = bilinear
+hips_overlay         = overlayMean mergeOverwrite treeMean
+hips_release_date    = 2024-11-13T18:33Z
+hips_data_minmax     = -21385 73221
+moc_sky_fraction     = 0.001074
+hipsgen_date_1       = 2024-11-13T18:25Z
+hipsgen_params_1     = in=NAROO/474-2244-wcs.fits out=/var/www/tmp/HiPS/474-2244-wcs id=474-2244-wcs maxThread=20
+hips_creation_date   = 2024-11-13T18:25Z
+hips_estsize         = 24116525
+hips_nb_tiles        = 36636
+hips_check_code      = png:735272809
--- a/src/core/src/healpix/cell.rs
+++ b/src/core/src/healpix/cell.rs
@@ -76,15 +76,20 @@ impl HEALPixCell {
    }

    #[inline(always)]
-    pub fn idx(&self) -> u64 {
+    pub(crate) const fn idx(&self) -> u64 {
        self.1
    }

    #[inline(always)]
-    pub fn depth(&self) -> u8 {
+    pub(crate) const fn depth(&self) -> u8 {
        self.0
    }

+    #[inline(always)]
+    pub fn nside(&self) -> u64 {
+        1 << self.depth()
+    }
+
    #[inline(always)]
    pub fn is_root(&self) -> bool {
        self.depth() == 0
@@ -168,6 +173,19 @@ impl HEALPixCell {
        HEALPixTilesIter::new(depth_children, first_idx..last_idx)
    }

+    #[inline]
+    pub(crate) const fn subdivide(&self) -> [HEALPixCell; 4] {
+        let children_depth = self.depth() + 1;
+        let children_idx = self.idx() << 2;
+
+        [
+            HEALPixCell(children_depth, children_idx),
+            HEALPixCell(children_depth, children_idx + 1),
+            HEALPixCell(children_depth, children_idx + 2),
+            HEALPixCell(children_depth, children_idx + 3),
+        ]
+    }
+
    #[inline]
    pub fn allsky(depth: u8) -> impl Iterator<Item = HEALPixCell> {
        let npix = 12 << ((depth as usize) << 1);
@@ -193,7 +211,7 @@ impl HEALPixCell {
    }

    #[inline(always)]
-    pub fn is_on_pole(&self) -> bool {
+    pub(crate) fn is_on_pole(&self) -> bool {
        let HEALPixCell(depth, idx) = *self;

        let two_times_depth = 2 * depth;
@@ -207,6 +225,40 @@ impl HEALPixCell {
        }
    }

+    #[inline(always)]
+    pub(crate) fn has_7_neigh(&self) -> bool {
+        let base_cell = self.ancestor(self.depth());
+        let nside_minus_one = (self.nside() - 1) as u32;
+
+        let (x, y) = self.offset_in_parent(&base_cell);
+
+        match base_cell.idx() {
+            0..=3 => (x == 0 && y == nside_minus_one) || (y == 0 && x == nside_minus_one),
+            4..=7 => (x == 0 && y == 0) || (x == nside_minus_one && y == nside_minus_one),
+            8..=11 => (x == 0 && y == nside_minus_one) || (y == 0 && x == nside_minus_one),
+            _ => unreachable!()
+        }
+    }
+
+    #[inline(always)]
+    pub(crate) fn is_on_base_cell_edges(&self) -> bool {
+        let base_cell = self.ancestor(self.depth());
+
+        let nside_minus_one = (self.nside() - 1) as u32;
+
+        let (x, y) = self.offset_in_parent(&base_cell);
+
+        if x == 0 || x == nside_minus_one {
+            return true;
+        }
+
+        if y == 0 || y == nside_minus_one {
+            return true;
+        }
+
+        false
+    }
+
    // Given in ICRS
    #[inline]
    pub fn new(depth: u8, theta: f64, delta: f64) -> Self {
--- a/src/core/src/renderable/hips/d2/mod.rs
+++ b/src/core/src/renderable/hips/d2/mod.rs
@@ -10,6 +10,7 @@ use al_core::colormap::Colormaps;
 use al_core::image::format::ChannelType;
 use cgmath::Vector3;

+use crate::math::angle::ToAngle;
 use crate::downloader::query;

 use al_core::image::Image;
@@ -31,10 +32,7 @@ use crate::{math::lonlat::LonLatT, utils};

 use crate::downloader::request::allsky::Allsky;
 use crate::healpix::{cell::HEALPixCell, coverage::HEALPixCoverage};
-use crate::renderable::utils::index_patch::DefaultPatchIndexIter;
 use crate::time::Time;
-use crate::math::angle::ToAngle;
-

 use super::config::HiPSConfig;
 use std::collections::HashSet;
@@ -451,7 +449,15 @@ impl HiPS2D {

        // Retrieve the model and inverse model matrix
        let mut off_indices = 0;
+        // Define a global level of subdivisions for all the healpix tile cells in the view
+        // This should prevent seeing many holes
+        // We compute it from the first cell in the view but it might be an under/over estimate for the other cells in the view
+        let num_sub = self.hpx_cells_in_view.iter()
+            .map(|cell| super::subdivide::num_hpx_subdivision(cell, camera, projection))
+            .max().unwrap();

+        //let num_sub =
+        //    super::subdivide::num_hpx_subdivision(&self.hpx_cells_in_view[0], camera, projection);
        for cell in &self.hpx_cells_in_view {
            // filter textures that are not in the moc
            let cell_in_cov = if let Some(moc) = self.footprint_moc.as_ref() {
@@ -559,64 +565,70 @@ impl HiPS2D {
                let d01e = uv_1[TileCorner::BottomRight].x - uv_1[TileCorner::BottomLeft].x;
                let d02e = uv_1[TileCorner::TopLeft].y - uv_1[TileCorner::BottomLeft].y;

+                let sub_cells =
+                    super::subdivide::subdivide_hpx_cell(cell, num_sub, camera);

-                let num_subdivision =
-                    super::subdivide::num_hpxcell_subdivision(cell, camera, projection);
+                let mut pos = Vec::with_capacity(sub_cells.len() * 4);

-                let n_segments_by_side: usize = 1 << (num_subdivision as usize);
-                let n_segments_by_side_f32 = n_segments_by_side as f32;
+                let mut idx = 0;

-                let n_vertices_per_segment = n_segments_by_side + 1;
+                for sub_cell in sub_cells {
+                    let (i, j) = sub_cell.offset_in_parent(cell);
+                    let nside = (1 << (sub_cell.depth() - cell.depth())) as f32;

-                let mut pos = Vec::with_capacity((n_segments_by_side + 1) * 4);
+                    for ((lon, lat), (di, dj)) in
+                        sub_cell
+                            .vertices()
+                            .iter()
+                            .zip([(0, 0), (1, 0), (1, 1), (0, 1)])
+                    {
+                        let hj0 = ((j + dj) as f32) / nside;
+                        let hi0 = ((i + di) as f32) / nside;

-                let grid_lonlat =
-                    healpix::nested::grid(cell.depth(), cell.idx(), n_segments_by_side as u16);
-                let grid_lonlat_iter = grid_lonlat.iter();
+                        let uv_start = [
+                            uv_0[TileCorner::BottomLeft].x + hj0 * d01s,
+                            uv_0[TileCorner::BottomLeft].y + hi0 * d02s,
+                            uv_0[TileCorner::BottomLeft].z,
+                        ];

-                for (idx, &(lon, lat)) in grid_lonlat_iter.enumerate() {
-                    let i: usize = idx / n_vertices_per_segment;
-                    let j: usize = idx % n_vertices_per_segment;
+                        let uv_end = [
+                            uv_1[TileCorner::BottomLeft].x + hj0 * d01e,
+                            uv_1[TileCorner::BottomLeft].y + hi0 * d02e,
+                            uv_1[TileCorner::BottomLeft].z,
+                        ];

-                    let hj0 = (j as f32) / n_segments_by_side_f32;
-                    let hi0 = (i as f32) / n_segments_by_side_f32;
+                        self.uv_start.extend(uv_start);
+                        self.uv_end.extend(uv_end);
+                        self.time_tile_received.push(start_time);

-                    let uv_start = [
-                        uv_0[TileCorner::BottomLeft].x + hj0 * d01s,
-                        uv_0[TileCorner::BottomLeft].y + hi0 * d02s,
-                        uv_0[TileCorner::BottomLeft].z,
-                    ];
+                        let xyz = crate::math::lonlat::radec_to_xyz(lon.to_angle(), lat.to_angle());
+                        pos.push([xyz.x as f32, xyz.y as f32, xyz.z as f32]);
+                    }

-                    let uv_end = [
-                        uv_1[TileCorner::BottomLeft].x + hj0 * d01e,
-                        uv_1[TileCorner::BottomLeft].y + hi0 * d02e,
-                        uv_1[TileCorner::BottomLeft].z,
-                    ];
+                    // GL TRIANGLES
+                    self.idx_vertices.extend([
+                        idx + off_indices,
+                        idx + 1 + off_indices,
+                        idx + 2 + off_indices,
+                        idx + off_indices,
+                        idx + 2 + off_indices,
+                        idx + 3 + off_indices,
+                    ]);
+                    // GL LINES
+                    /*self.idx_vertices.extend([
+                        idx + off_indices,
+                        idx + 1 + off_indices,
+                        idx + 1 + off_indices,
+                        idx + 2 + off_indices,
+                        idx + 2 + off_indices,
+                        idx + 3 + off_indices,
+                        idx + 3 + off_indices,
+                        idx + off_indices,
+                    ]);*/

-                    self.uv_start.extend(uv_start);
-                    self.uv_end.extend(uv_end);
-                    self.time_tile_received.push(start_time);
-
-                    let xyz = crate::math::lonlat::radec_to_xyz(lon.to_angle(), lat.to_angle());
-                    pos.push([xyz.x as f32, xyz.y as f32, xyz.z as f32]);
+                    idx += 4;
                }

-                let patch_indices_iter = DefaultPatchIndexIter::new(
-                    &(0..=n_segments_by_side),
-                    &(0..=n_segments_by_side),
-                    n_vertices_per_segment,
-                )
-                .flatten()
-                .map(|indices| {
-                    [
-                        indices.0 + off_indices,
-                        indices.1 + off_indices,
-                        indices.2 + off_indices,
-                    ]
-                })
-                .flatten();
-                self.idx_vertices.extend(patch_indices_iter);
-
                off_indices += pos.len() as u16;

                // Replace options with an arbitrary vertex
@@ -773,6 +785,7 @@ impl HiPS2D {
                    .bind_vertex_array_object_ref(&self.vao)
                    .draw_elements_with_i32(
                        WebGl2RenderingContext::TRIANGLES,
+                        //WebGl2RenderingContext::LINES,
                        Some(self.num_idx as i32),
                        WebGl2RenderingContext::UNSIGNED_SHORT,
                        0,
--- a/src/core/src/renderable/hips/d3/mod.rs
+++ b/src/core/src/renderable/hips/d3/mod.rs
@@ -28,7 +28,6 @@ use crate::math::lonlat::LonLatT;

 use crate::downloader::request::allsky::Allsky;
 use crate::healpix::{cell::HEALPixCell, coverage::HEALPixCoverage};
-use crate::renderable::utils::index_patch::DefaultPatchIndexIter;
 use crate::time::Time;

 use super::config::HiPSConfig;
@@ -94,47 +93,6 @@ pub fn get_raster_shader<'a>(
    }
 }

-/*
-pub fn get_raytracer_shader<'a>(
-    cmap: &Colormap,
-    gl: &WebGlContext,
-    shaders: &'a mut ShaderManager,
-    config: &HiPSConfig,
-) -> Result<&'a Shader, JsValue> {
-    //let colored_hips = config.is_colored();
-    if config.get_format().is_colored() && cmap.label() == "native" {
-        crate::shader::get_shader(
-            gl,
-            shaders,
-            "hips_raytracer_raytracer.vert",
-            "hips_raytracer_color.frag",
-        )
-    } else {
-        if config.tex_storing_unsigned_int {
-            crate::shader::get_shader(
-                gl,
-                shaders,
-                "hips_raytracer_raytracer.vert",
-                "hips_raytracer_grayscale_to_colormap_u.frag",
-            )
-        } else if config.tex_storing_integers {
-            crate::shader::get_shader(
-                gl,
-                shaders,
-                "hips_raytracer_raytracer.vert",
-                "hips_raytracer_grayscale_to_colormap_i.frag",
-            )
-        } else {
-            crate::shader::get_shader(
-                gl,
-                shaders,
-                "hips_raytracer_raytracer.vert",
-                "hips_raytracer_grayscale_to_colormap.frag",
-            )
-        }
-    }
-}*/
-
 pub struct HiPS3D {
    //color: Color,
    // The image survey texture buffer
@@ -355,6 +313,15 @@ impl HiPS3D {

        let channel = self.get_config().get_format().get_channel();

+        // Define a global level of subdivisions for all the healpix tile cells in the view
+        // This should prevent seeing many holes
+        // We compute it from the first cell in the view but it might be an under/over estimate for the other cells in the view
+        //let num_sub = super::subdivide::num_hpx_subdivision(&self.hpx_cells_in_view[0], camera, proj);
+
+        let num_sub = self.hpx_cells_in_view.iter()
+            .map(|cell| super::subdivide::num_hpx_subdivision(cell, camera, proj))
+            .max().unwrap();
+
        for cell in &self.hpx_cells_in_view {
            // filter textures that are not in the moc
            let cell = if let Some(moc) = self.footprint_moc.as_ref() {
@@ -405,62 +372,68 @@ impl HiPS3D {
                    let d01e = uv_1[TileCorner::BottomRight].x - uv_1[TileCorner::BottomLeft].x;
                    let d02e = uv_1[TileCorner::TopLeft].y - uv_1[TileCorner::BottomLeft].y;

-                    let num_subdivision =
-                        super::subdivide::num_hpxcell_subdivision(cell, camera, proj);
+                    let sub_cells = super::subdivide::subdivide_hpx_cell(cell, num_sub, camera);

-                    let n_segments_by_side: usize = 1 << (num_subdivision as usize);
-                    let n_segments_by_side_f32 = n_segments_by_side as f32;
+                    let mut pos = Vec::with_capacity(sub_cells.len() * 4);

-                    let n_vertices_per_segment = n_segments_by_side + 1;
+                    let mut idx = 0;

-                    let mut pos = Vec::with_capacity((n_segments_by_side + 1) * 4);
+                    let tmp = self.idx_vertices.len();

-                    let grid_lonlat =
-                        healpix::nested::grid(cell.depth(), cell.idx(), n_segments_by_side as u16);
-                    let grid_lonlat_iter = grid_lonlat.iter();
+                    for sub_cell in sub_cells {
+                        let (i, j) = sub_cell.offset_in_parent(cell);
+                        let nside = (1 << (sub_cell.depth() - cell.depth())) as f32;

-                    for (idx, &(lon, lat)) in grid_lonlat_iter.enumerate() {
-                        let i: usize = idx / n_vertices_per_segment;
-                        let j: usize = idx % n_vertices_per_segment;
+                        for ((lon, lat), (di, dj)) in sub_cell.vertices().iter().zip([(0, 0), (1, 0), (1, 1), (0, 1)]) {
+                            let hj0 = ((j + dj) as f32) / nside;
+                            let hi0 = ((i + di) as f32) / nside;

-                        let hj0 = (j as f32) / n_segments_by_side_f32;
-                        let hi0 = (i as f32) / n_segments_by_side_f32;
+                            let uv_end = [
+                                uv_1[TileCorner::BottomLeft].x + hj0 * d01e,
+                                uv_1[TileCorner::BottomLeft].y + hi0 * d02e,
+                                uv_1[TileCorner::BottomLeft].z,
+                            ];

-                        let uv_end = [
-                            uv_1[TileCorner::BottomLeft].x + hj0 * d01e,
-                            uv_1[TileCorner::BottomLeft].y + hi0 * d02e,
-                            uv_1[TileCorner::BottomLeft].z,
-                        ];
+                            self.uv.extend(uv_end);

-                        self.uv.extend(uv_end);
+                            pos.push([*lon as f32, *lat as f32]);
+                        }

-                        pos.push([lon as f32, lat as f32]);
+                        // GL TRIANGLES
+                        self.idx_vertices.extend([
+                            idx + off_indices,
+                            idx + 2 + off_indices,
+                            idx + 1 + off_indices,
+
+                            idx + off_indices,
+                            idx + 3 + off_indices,
+                            idx + 2 + off_indices,
+                        ]);
+                        // GL LINES
+                        /*self.idx_vertices.extend([
+                            idx + off_indices,
+                            idx + 1 + off_indices,
+
+                            idx + 1 + off_indices,
+                            idx + 2 + off_indices,
+
+                            idx + 2 + off_indices,
+                            idx + 3 + off_indices,
+
+                            idx + 3 + off_indices,
+                            idx + off_indices,
+                        ]);*/
+
+                        idx += 4;
                    }

-                    let patch_indices_iter = DefaultPatchIndexIter::new(
-                        &(0..=n_segments_by_side),
-                        &(0..=n_segments_by_side),
-                        n_vertices_per_segment,
-                    )
-                    .flatten()
-                    .map(|indices| {
-                        [
-                            indices.0 + off_indices,
-                            indices.1 + off_indices,
-                            indices.2 + off_indices,
-                        ]
-                    })
-                    .flatten();
-                    let tmp = self.idx_vertices.len();
-                    self.idx_vertices.extend(patch_indices_iter);
+                    off_indices += pos.len() as u16;

                    self.num_indices.push(self.idx_vertices.len() - tmp);
-                    off_indices += pos.len() as u16;

                    // Replace options with an arbitrary vertex
                    let position_iter = pos
                        .into_iter()
-                        //.map(|ndc| ndc.unwrap_or([0.0, 0.0]))
                        .flatten();
                    self.position.extend(position_iter);
                }
--- a/src/core/src/renderable/hips/subdivide.rs
+++ b/src/core/src/renderable/hips/subdivide.rs
@@ -3,9 +3,9 @@ use crate::math::projection::ProjectionType;
 use crate::math::vector::dist2;
 use crate::HEALPixCell;
 use crate::math::angle::ToAngle;
-const M: f64 = 280.0 * 280.0;
-const N: f64 = 150.0 * 150.0;
-const RAP: f64 = 0.7;
+
+const M: f64 = 220.0 * 220.0;
+
 fn is_too_large(cell: &HEALPixCell, camera: &CameraViewPort, projection: &ProjectionType) -> bool {
    let vertices = cell
        .vertices()
@@ -21,47 +21,128 @@ fn is_too_large(cell: &HEALPixCell, camera: &CameraViewPort, projection: &Projec
    } else {
        let d1 = dist2(vertices[0].as_ref(), &vertices[2].as_ref());
        let d2 = dist2(vertices[1].as_ref(), &vertices[3].as_ref());
-        if d1 > M || d2 > M {
-            true
-        } else if d1 < N && d2 < N {
-            false
-        } else {
-            let rap = if d2 > d1 { d1 / d2 } else { d2 / d1 };

-            rap < RAP
-        }
+        d1 > M || d2 > M
    }
 }

-pub fn num_hpxcell_subdivision(
+pub(crate) fn num_hpx_subdivision(
    cell: &HEALPixCell,
    camera: &CameraViewPort,
    projection: &ProjectionType,
 ) -> u8 {
-    let d = cell.depth();
-    // Subdivide all cells at least one time.
-    // TODO: use a single subdivision number computed from the current cells inside the view
-    // i.e. subdivide all cells in the view with the cell that has to be the most subdivided
-    let mut num_sub = 1;
-    if d < 2 {
-        num_sub = 2 - d;
+    let d0 = cell.depth();
+
+    let num_sub = num_hpx_subdivision_rec(cell, d0, camera, projection);
+
+    // Ensure that the HEALPix cells wireframe is at least composed of order 3 cells
+    let sub_cells_depth = d0 + num_sub;
+
+    if sub_cells_depth < 3 {
+        num_sub + (3 - sub_cells_depth)
+    } else {
+        num_sub
    }
-
-    // Largest deformation cell among the cells of a specific depth
-    let largest_center_to_vertex_dist =
-        healpix::largest_center_to_vertex_distance(d, 0.0, healpix::TRANSITION_LATITUDE);
-    let smallest_center_to_vertex_dist =
-        healpix::largest_center_to_vertex_distance(d, 0.0, healpix::LAT_OF_SQUARE_CELL);
-
-    let (lon, lat) = cell.center();
-    let center_to_vertex_dist = healpix::largest_center_to_vertex_distance(d, lon, lat);
-
-    let skewed_factor = (center_to_vertex_dist - smallest_center_to_vertex_dist)
-        / (largest_center_to_vertex_dist - smallest_center_to_vertex_dist);
-
-    if skewed_factor > 0.25 || is_too_large(cell, camera, projection) || cell.is_on_pole() {
-        num_sub += 1;
-    }
-
-    num_sub
+}
+
+fn num_hpx_subdivision_rec(
+    cell: &HEALPixCell,
+    d0: u8,
+    camera: &CameraViewPort,
+    projection: &ProjectionType,
+) -> u8 {
+    if (cell.depth() - d0) < MAX_HPX_CELL_SUBDIVISION
+        && cell.depth() < 29
+        && is_too_large(cell, camera, projection)
+    {
+        let sub_cells = cell.subdivide();
+
+        1 + [
+            num_hpx_subdivision_rec(&sub_cells[0], d0, camera, projection),
+            num_hpx_subdivision_rec(&sub_cells[1], d0, camera, projection),
+            num_hpx_subdivision_rec(&sub_cells[2], d0, camera, projection),
+            num_hpx_subdivision_rec(&sub_cells[3], d0, camera, projection),
+        ]
+        .iter()
+        .max()
+        .unwrap()
+    } else {
+        0
+    }
+}
+
+const MAX_HPX_CELL_SUBDIVISION: u8 = 4;
+/// Subdivide a HEALPix cell that is directly mapped to a tile image in many sub cells
+/// taking into account the distortion occuring when projecting its vertices into the screen pixel space
+pub(crate) fn subdivide_hpx_cell(
+    cell: &HEALPixCell,
+    num_subdivisions: u8,
+    camera: &CameraViewPort,
+) -> Box<[HEALPixCell]> {
+    cell.get_children_cells(num_subdivisions)
+        .map(|child_cell| {
+            /*let cell_depth = child_cell.depth();
+
+            // Largest deformation cell among the cells of a specific depth
+            let largest_center_to_vertex_dist = healpix::largest_center_to_vertex_distance(
+                cell_depth,
+                0.0,
+                healpix::TRANSITION_LATITUDE,
+            );
+            let smallest_center_to_vertex_dist = healpix::largest_center_to_vertex_distance(
+                cell_depth,
+                0.0,
+                healpix::LAT_OF_SQUARE_CELL,
+            );
+
+            let (lon, lat) = child_cell.center();
+            let center_to_vertex_dist =
+                healpix::largest_center_to_vertex_distance(cell_depth, lon, lat);
+
+            let skewed_factor = (center_to_vertex_dist - smallest_center_to_vertex_dist)
+                / (largest_center_to_vertex_dist - smallest_center_to_vertex_dist);*/
+
+            let lat = child_cell.center().1;
+
+
+            let c0 = child_cell.ancestor(child_cell.depth()).idx();
+
+            let c3 = child_cell.ancestor(child_cell.depth() - 3);
+            let (x3i, y3i) = c3.get_offset_in_texture_cell(c3.depth());
+            let nside3i = c3.nside() as u32;
+            let c3_s = (x3i, y3i) == (0, nside3i - 1) || (x3i, y3i) == (nside3i - 1, 0);
+
+            let (x, y) = child_cell.get_offset_in_texture_cell(child_cell.depth());
+            let nside = child_cell.nside() as u32;
+
+            let collignon_equatorial_frontier = ((0..=3).contains(&c0) || (8..=11).contains(&c0)) && ((x + y) as i32 - (nside as i32) + 1).abs() <= 1;
+
+            // A HEALPix cell would be distorted if
+            let hpx_num_sub = if camera.get_aperture() >= 15.0_f64.to_radians() &&
+                    // cells at the frontier between collignon and equatorial HEALpix zones
+                    ((0..=3).contains(&c0) || (8..=11).contains(&c0)) &&
+                    // neighbors of cells having only 7 neighbors (the most distorted ones)
+                    c3_s
+                {
+                    // more specific cells needing a subdivision
+                    2
+                } else if collignon_equatorial_frontier && c3_s {
+                    // on the collignon/equatorial fence and part of a 3 order cell having only 7 neighbors
+                    1
+                } else if child_cell.is_on_pole() {
+                    // it lies on a pole
+                    1
+                } else if child_cell.is_on_base_cell_edges() && lat.abs() >= healpix::TRANSITION_LATITUDE {
+                    // it lies on a frontier between base cells and at a high absolute latitude
+                    1
+                } else {
+                    0
+                };
+
+            // Subdivide one more time if the HEALPix cell is distorted
+            child_cell.get_children_cells(hpx_num_sub)
+        })
+        .flatten()
+        .collect::<Vec<_>>()
+        .into_boxed_slice()
 }
--- a/src/js/View.js
+++ b/src/js/View.js
@@ -658,11 +658,6 @@ export let View = (function () {
                        if (typeof footprintClickedFunction === 'function') {
                            footprintClickedFunction(o, xy);
                        }
-                        // If this footprint has a catalog then it will be selected from its source
-                        // so we will not add it
-                        if (!cat) {
-                            footprints.push(o);
-                        } 
                    }

                    // If this shape has a catalog then it will be selected from its source