Imp in 64x64 when close, 32x32 at normal zoom; detailed sprites in their own texture

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

art/generated/imp-sprite/PROMPTS.md

@@ -108,3 +108,18 @@ The game copies `imp-32.png` and `imp-hack-32.png` to `assets/sprites/`.
 
 The gold sack is not generated: it is a small hand-made pixel pattern (`SACK_HD`, `SACK_SMALL`
 in `src/gfx.rs`) that the game places on every frame when the atlas is built.
+
+## 64x64 (2026-11-07)
+
+The high-res style shows the imp in 64x64 when close and in 32x32 at the normal zoom (both from
+the same raw sheets; a 64x64 sprite shown smaller would lose pixels and flicker). The 64x64
+sheets use the body scale 60 pixels, the feet row 63, 24 colours plus the iron greys:
+
+```bash
+python3 $T raw-1.png imp --views 5 --size 64 --colors 24 --crop 0,0.27,1,0.72 --step 9.217 --feet 63 \
+    --add-colors "150,152,168;104,106,122"
+# hack rows: --size 64 --step <body height>/60 --feet 63 --palette imp-64.png --outline-weight 0.6
+```
+
+Results: `imp-64.png`, `imp-hack-64.png`, preview `imp-hack-64-preview.png` (idle views in the
+right column). The game copies them to `assets/sprites/`.

src/gfx.rs

@@ -98,6 +98,7 @@ pub const T_MOSS: u32 = 216; // 4 variants: mushroom grove ground, moss with glo
 pub struct Gfx {
     pub atlas: Texture2D,
     pub sprites: Texture2D,
+    pub hd_sprites: Texture2D, // detailed sprites (see HD_SPRITES, hd_cell_view)
     pub cursors: Texture2D, // mouse pointer frames, 16x16 each (see CURSOR_*)
     pub badges: Texture2D, // achievement badges, 32x32 each (see badges.rs)
     pub font: Texture2D, // Dinowyde (glyphs of 6x8 px ordered by Unicode, see font_slot) and DINOBYTE
@@ -1368,36 +1369,46 @@ fn gen_atlas() -> Image {
 
 const SPR: usize = 10;
 const SPR_CELL: u32 = 12;
-// the atlas holds every sprite pixel as SPR_K x SPR_K texels, so detailed sprites (HD_SPRITES)
-// fit into the same cells: a cell is SPR_CELL * SPR_K = 36 texels
+// the atlas holds every sprite pixel as SPR_K x SPR_K texels: a cell is SPR_CELL * SPR_K texels
 const SPR_K: u32 = 3;
 pub const ACELL: u32 = SPR_CELL * SPR_K;
 
-// Detailed 32x32 sprites (generated, see art/generated/), used instead of the 10x10 ones in the
-// high-res graphics style when close enough (render3d::billboards). Transparent background, the
-// feet on the bottom row. `idle`: the five views side by side (VIEWS); `hack`: the digging
-// animation, HACK_FRAMES frames side by side, one row per view. No gear yet.
+// Detailed sprites (generated, see art/generated/) in their own texture, used instead of the
+// 10x10 ones in the high-res graphics style (render3d::billboards). Two levels of detail from
+// the same pictures: 64x64 when the sprite gets enough screen pixels (close), 32x32 otherwise,
+// so neither loses pixels nor flickers. Sheets: transparent, the feet on the bottom row;
+// `idle*`: the five views side by side (VIEWS); `hack*`: the digging animation, HACK_FRAMES
+// frames side by side, one row per view. No gear yet.
 struct HdSprite {
     kind: EK,
     idle: &'static [u8],
     hack: &'static [u8],
+    idle_32: &'static [u8],
+    hack_32: &'static [u8],
 }
 const HD_SPRITES: [HdSprite; 1] = [HdSprite {
     kind: EK::Worker,
-    idle: include_bytes!("../assets/sprites/imp-32.png"),
-    hack: include_bytes!("../assets/sprites/imp-hack-32.png"),
+    idle: include_bytes!("../assets/sprites/imp-64.png"),
+    hack: include_bytes!("../assets/sprites/imp-hack-64.png"),
+    idle_32: include_bytes!("../assets/sprites/imp-32.png"),
+    hack_32: include_bytes!("../assets/sprites/imp-hack-32.png"),
 }];
-const HD: u32 = 32;
 pub const HACK_FRAMES: u32 = 4;
-// atlas columns of a detailed sprite: idle and the hack frames, each without and with the sack
+// a detailed sprite's cell: the same shape as a 10x10 sprite's 12x12 cell (6 texels per pixel),
+// so the billboard is the same; the 64x64 picture sits where the 10x10 sprite would
+pub const HD_CELL: u32 = SPR_CELL * 6;
+// columns per detailed sprite and detail level: idle and the hack frames, each without and with
+// the sack; then the same for the 32x32 level
 const HD_COLS: u32 = (1 + HACK_FRAMES) * 2;
+pub const HD_TEX_W: f32 = (HD_SPRITES.len() as u32 * HD_COLS * 2 * HD_CELL) as f32;
+pub const HD_TEX_H: f32 = (VIEWS * 2 * HD_CELL) as f32;
 
 // kinds that carry treasure in a sack on the back (instead of the coin sign over the head);
 // their 10x10 sprite with the sack gets an own atlas column after SPRITE_KINDS
 const SACK_KINDS: [EK; 1] = [EK::Worker];
 // the sack (k outline, B burlap, b its shade and the rope, y/Y gold coins at the opening)
 const SACK_SMALL: [&str; 5] = [".kk.", "kyYk", "kBbk", "kBBk", ".kk."];
-const SACK_HD: [&str; 12] = [
+const SACK_32: [&str; 12] = [
     "....kkkk....",
     "...kyYYyk...",
     "..kyYyyYyk..",
@@ -1411,6 +1422,31 @@ const SACK_HD: [&str; 12] = [
     "..kBBBBBBk..",
     "...kkkkkk...",
 ];
+// the same, finer for the 64x64 sprites (d: the shadow side)
+const SACK_64: [&str; 22] = [
+    ".......kkkkkk.......",
+    ".....kkyYYYyykk.....",
+    "....kyYYyYYyyYyk....",
+    "...kyYyyYyYYyyYyk...",
+    "...kkyYYyyyYYyykk...",
+    "....kkbbbbbbbbkk....",
+    ".....kbBbbbbBbk.....",
+    "......kBBBBBBk......",
+    ".....kBBBBBBBBk.....",
+    "....kBBBBBBBBBBk....",
+    "...kBBBBbBBBBBBBk...",
+    "..kBBBBBBBBBbBBBBk..",
+    "..kBBbBBBBBBBBBBBk..",
+    ".kBBBBBBBBBBBBbBBBk.",
+    ".kBBBBBBBbBBBBBBBBk.",
+    ".kBBBBBBBBBBBBBBBdk.",
+    ".kBBbBBBBBBBBBBBddk.",
+    ".kBBBBBBBBBBBBBdddk.",
+    "..kBBBBBBBBBBBdddk..",
+    "..kdBBBBBBBBBddddk..",
+    "...kkddddddddddkk...",
+    ".....kkkkkkkkkk.....",
+];
 
 fn sprite_rows(k: EK) -> [&'static str; 10] {
     match k {
@@ -1868,7 +1904,7 @@ pub const SPRITE_KINDS: [EK; 31] = [
     EK::Inquisitor,
 ];
 // width of the sprite texture in pixels
-pub const SPRITE_TEX_W: f32 = ((SPRITE_KINDS.len() + SACK_KINDS.len()) as u32 * ACELL + HD_SPRITES.len() as u32 * HD_COLS * ACELL) as f32;
+pub const SPRITE_TEX_W: f32 = ((SPRITE_KINDS.len() + SACK_KINDS.len()) as u32 * ACELL) as f32;
 pub const SPRITE_TEX_H: f32 = (2 * VIEWS * GEAR_TIERS * ACELL) as f32;
 
 pub fn sprite_index(k: EK) -> u32 {
@@ -2105,6 +2141,7 @@ fn add_sack(g: &mut Cell, view: u32, pat: &[&str], front_dx: (f32, f32)) {
                 'b' => c(108, 70, 40),
                 'y' => c(232, 176, 48),
                 'Y' => c(255, 232, 120),
+                'd' => c(112, 74, 42),
                 _ => continue,
             };
             let (x, y) = (x0 + px as i32, y0 + py as i32);
@@ -2119,30 +2156,32 @@ fn add_sack(g: &mut Cell, view: u32, pat: &[&str], front_dx: (f32, f32)) {
     }
 }
 
-// writes a cell into the atlas: column, cell row (the white silhouette goes into the row below),
-// every cell pixel as k x k texels
-fn put_cell(img: &mut Image, col: u32, row: u32, g: &Cell, k: u32) {
+// writes a cell into an atlas of `cell` x `cell` texel cells: column, cell row (the white
+// silhouette goes into the row below), every cell pixel as k x k texels
+fn put_cell(img: &mut Image, col: u32, row: u32, g: &Cell, k: u32, cell: u32) {
     for (y, line) in g.iter().enumerate() {
         for (x, p) in line.iter().enumerate() {
             let Some(c) = p else { continue };
             for d in 0..k * k {
-                let (px, py) = (col * ACELL + x as u32 * k + d % k, row * ACELL + y as u32 * k + d / k);
+                let (px, py) = (col * cell + x as u32 * k + d % k, row * cell + y as u32 * k + d / k);
                 img.set_pixel(px, py, *c);
-                img.set_pixel(px, py + ACELL, WHITE);
+                img.set_pixel(px, py + cell, WHITE);
             }
         }
     }
 }
 
-// a 32x32 picture from a sheet into a 36x36 cell (the feet on the 10x10 sprite's bottom row)
-fn hd_cell(src: &Image, sx: u32, sy: u32) -> Cell {
-    let mut g = vec![vec![None; ACELL as usize]; ACELL as usize];
-    for y in 0..HD {
-        for x in 0..HD {
+// an n x n picture from a sheet into a cell grid of `size` (centred, the feet on the bottom row
+// of a 10x10 sprite: 11/12 of the cell)
+fn hd_cell(src: &Image, sx: u32, sy: u32, n: u32, size: u32) -> Cell {
+    let mut g = vec![vec![None; size as usize]; size as usize];
+    let (ox, oy) = ((size - n) / 2, size * 11 / 12 - n);
+    for y in 0..n {
+        for x in 0..n {
             if sx + x < src.width as u32 && sy + y < src.height as u32 {
                 let p = src.get_pixel(sx + x, sy + y);
                 if p.a > 0.5 {
-                    g[1 + y as usize][2 + x as usize] = Some(Color::new(p.r, p.g, p.b, 1.0));
+                    g[(oy + y) as usize][(ox + x) as usize] = Some(Color::new(p.r, p.g, p.b, 1.0));
                 }
             }
         }
@@ -2150,9 +2189,9 @@ fn hd_cell(src: &Image, sx: u32, sy: u32) -> Cell {
     g
 }
 
-// The sprite atlas. Columns: SPRITE_KINDS, SACK_KINDS (with the sack), then HD_COLS per
-// detailed sprite. 10x10 sprites: row (view * GEAR_TIERS + tier) * 2 with the gear of the tier,
-// the row after it the white silhouette (hit flash). Detailed sprites: row view * 2 (+1 white).
+// The sprite atlas of the 10x10 sprites. Columns: SPRITE_KINDS, then SACK_KINDS with the sack.
+// Row (view * GEAR_TIERS + tier) * 2 with the gear of the tier, the row after it the white
+// silhouette (hit flash).
 fn gen_sprites() -> Image {
     let n = SPRITE_KINDS.len() as u32;
     let mut img = Image::gen_image_color(SPRITE_TEX_W as u16, SPRITE_TEX_H as u16, Color::new(0.0, 0.0, 0.0, 0.0));
@@ -2161,27 +2200,40 @@ fn gen_sprites() -> Image {
         for tier in 0..GEAR_TIERS {
             let row = (view * GEAR_TIERS + tier) * 2;
             for (i, &k) in SPRITE_KINDS.iter().enumerate() {
-                put_cell(&mut img, i as u32, row, &small(k, tier, view), SPR_K);
+                put_cell(&mut img, i as u32, row, &small(k, tier, view), SPR_K, ACELL);
             }
             for (i, &k) in SACK_KINDS.iter().enumerate() {
                 let mut g = small(k, tier, view);
                 add_sack(&mut g, view, &SACK_SMALL, (-0.5, -0.5));
-                put_cell(&mut img, n + i as u32, row, &g, SPR_K);
+                put_cell(&mut img, n + i as u32, row, &g, SPR_K, ACELL);
             }
         }
     }
-    let base = n + SACK_KINDS.len() as u32;
+    img
+}
+
+// The texture of the detailed sprites (HD_SPRITES): per sprite HD_COLS columns of 64x64
+// pictures, then HD_COLS of 32x32 ones (two texels per pixel); row view * 2, the row after it
+// the white silhouette.
+fn gen_hd_sprites() -> Image {
+    let mut img = Image::gen_image_color(HD_TEX_W as u16, HD_TEX_H as u16, Color::new(0.0, 0.0, 0.0, 0.0));
+    let png = |b: &[u8]| Image::from_file_with_format(b, Some(ImageFormat::Png)).expect("hd sprite");
     for (j, hd) in HD_SPRITES.iter().enumerate() {
-        let idle = Image::from_file_with_format(hd.idle, Some(ImageFormat::Png)).expect("hd sprite");
-        let hack = Image::from_file_with_format(hd.hack, Some(ImageFormat::Png)).expect("hd sprite");
-        for view in 0..VIEWS {
-            for f in 0..1 + HACK_FRAMES {
-                let g = if f == 0 { hd_cell(&idle, view * HD, 0) } else { hd_cell(&hack, (f - 1) * HD, view * HD) };
-                let col = base + j as u32 * HD_COLS + f * 2;
-                put_cell(&mut img, col, view * 2, &g, 1);
-                let mut s = g;
-                add_sack(&mut s, view, &SACK_HD, (0.7, -0.65));
-                put_cell(&mut img, col + 1, view * 2, &s, 1);
+        // (idle, hack, picture size, cell grid, texels per pixel, sack, where the sack shows from the front)
+        let levels = [
+            (png(hd.idle), png(hd.hack), 64, HD_CELL, 1, &SACK_64[..], (0.7, -0.65)),
+            (png(hd.idle_32), png(hd.hack_32), 32, HD_CELL / 2, 2, &SACK_32[..], (0.7, -0.65)),
+        ];
+        for (l, (idle, hack, n, size, k, sack, dx)) in levels.iter().enumerate() {
+            for view in 0..VIEWS {
+                for f in 0..1 + HACK_FRAMES {
+                    let g = if f == 0 { hd_cell(idle, view * n, 0, *n, *size) } else { hd_cell(hack, (f - 1) * n, view * n, *n, *size) };
+                    let col = (j as u32 * 2 + l as u32) * HD_COLS + f * 2;
+                    put_cell(&mut img, col, view * 2, &g, *k, HD_CELL);
+                    let mut s = g;
+                    add_sack(&mut s, view, sack, *dx);
+                    put_cell(&mut img, col + 1, view * 2, &s, *k, HD_CELL);
+                }
             }
         }
     }
@@ -2308,7 +2360,9 @@ impl Gfx {
         cursors.set_filter(FilterMode::Nearest);
         let badges = Texture2D::from_image(&crate::badges::gen_badges());
         badges.set_filter(FilterMode::Nearest);
-        Gfx { atlas, sprites, cursors, badges, font, font_map }
+        let hd_sprites = Texture2D::from_image(&gen_hd_sprites());
+        hd_sprites.set_filter(FilterMode::Nearest);
+        Gfx { atlas, sprites, hd_sprites, cursors, badges, font, font_map }
     }
 
     pub fn cell(id: u32) -> Rect {
@@ -2335,14 +2389,15 @@ impl Gfx {
     }
 
     // the cell of a detailed sprite's view, if the kind has one (same layout as sprite_cell_view)
-    // the cell of a detailed sprite, if the kind has one: a view, standing (`hack` None) or a
-    // frame of the digging animation, with or without the sack
-    pub fn hd_cell_view(k: EK, white: bool, view: u32, hack: Option<u32>, sack: bool) -> Option<Rect> {
+    // the cell of a detailed sprite in `hd_sprites`, if the kind has one: a view, standing
+    // (`hack` None) or a frame of the digging animation, with or without the sack; `fine`: the
+    // 64x64 level, else the 32x32 one
+    pub fn hd_cell_view(k: EK, white: bool, view: u32, hack: Option<u32>, sack: bool, fine: bool) -> Option<Rect> {
         let j = HD_SPRITES.iter().position(|h| h.kind == k)? as u32;
         let f = hack.map_or(0, |f| 1 + f % HACK_FRAMES);
-        let col = (SPRITE_KINDS.len() + SACK_KINDS.len()) as u32 + j * HD_COLS + f * 2 + sack as u32;
+        let col = (j * 2 + !fine as u32) * HD_COLS + f * 2 + sack as u32;
         let row = view.min(VIEWS - 1) * 2 + white as u32;
-        Some(Rect::new((col * ACELL) as f32, (row * ACELL) as f32, ACELL as f32, ACELL as f32))
+        Some(Rect::new((col * HD_CELL) as f32, (row * HD_CELL) as f32, HD_CELL as f32, HD_CELL as f32))
     }
 
     // whether a kind carries its treasure in a sack on the back
@@ -2582,36 +2637,46 @@ mod sprite_tests {
     use super::*;
 
     fn opaque(img: &Image, r: Rect) -> usize {
-        (0..ACELL * ACELL).filter(|i| img.get_pixel(r.x as u32 + i % ACELL, r.y as u32 + i / ACELL).a > 0.5).count()
+        let n = r.w as u32;
+        (0..n * n).filter(|i| img.get_pixel(r.x as u32 + i % n, r.y as u32 + i / n).a > 0.5).count()
     }
 
     // texels that differ between two cells
     fn differ(img: &Image, a: Rect, b: Rect) -> usize {
-        (0..ACELL * ACELL)
+        let n = a.w as u32;
+        (0..n * n)
             .filter(|i| {
-                let p = img.get_pixel(a.x as u32 + i % ACELL, a.y as u32 + i / ACELL);
-                let q = img.get_pixel(b.x as u32 + i % ACELL, b.y as u32 + i / ACELL);
+                let p = img.get_pixel(a.x as u32 + i % n, a.y as u32 + i / n);
+                let q = img.get_pixel(b.x as u32 + i % n, b.y as u32 + i / n);
                 (p.r, p.g, p.b, p.a) != (q.r, q.g, q.b, q.a)
             })
             .count()
     }
 
     #[test]
-    fn detailed_sprites_in_the_atlas() {
-        let img = gen_sprites();
-        assert_eq!((img.width as f32, img.height as f32), (SPRITE_TEX_W, SPRITE_TEX_H));
-        for view in 0..VIEWS {
-            for hack in [None, Some(0), Some(1), Some(2), Some(3)] {
-                let r = Gfx::hd_cell_view(EK::Worker, false, view, hack, false).expect("the imp has a detailed sprite");
-                let w = Gfx::hd_cell_view(EK::Worker, true, view, hack, false).unwrap();
-                let s = Gfx::hd_cell_view(EK::Worker, false, view, hack, true).unwrap();
-                assert!(opaque(&img, r) > 150, "view {view} {hack:?} drawn");
-                assert_eq!(opaque(&img, r), opaque(&img, w), "white silhouette matches");
-                assert!(differ(&img, s, r) > 15, "view {view} {hack:?}: the sack shows");
+    fn detailed_sprites() {
+        let img = gen_hd_sprites();
+        assert_eq!((img.width as f32, img.height as f32), (HD_TEX_W, HD_TEX_H));
+        for fine in [true, false] {
+            for view in 0..VIEWS {
+                for hack in [None, Some(0), Some(1), Some(2), Some(3)] {
+                    let r = Gfx::hd_cell_view(EK::Worker, false, view, hack, false, fine).expect("the imp has a detailed sprite");
+                    let w = Gfx::hd_cell_view(EK::Worker, true, view, hack, false, fine).unwrap();
+                    let s = Gfx::hd_cell_view(EK::Worker, false, view, hack, true, fine).unwrap();
+                    assert!(opaque(&img, r) > 600, "view {view} {hack:?} {fine} drawn");
+                    assert_eq!(opaque(&img, r), opaque(&img, w), "white silhouette matches");
+                    assert!(differ(&img, s, r) > 60, "view {view} {hack:?} {fine}: the sack shows");
+                }
             }
         }
-        assert!(Gfx::hd_cell_view(EK::Knight, false, 0, None, false).is_none());
-        // the 10x10 sprites: every pixel a 3x3 block; the imp's sack variant
+        assert!(Gfx::hd_cell_view(EK::Knight, false, 0, None, false, true).is_none());
+    }
+
+    #[test]
+    fn small_sprites_and_sack() {
+        let img = gen_sprites();
+        assert_eq!((img.width as f32, img.height as f32), (SPRITE_TEX_W, SPRITE_TEX_H));
+        // every pixel a 3x3 block
         let r = Gfx::sprite_cell_view(EK::Knight, false, 1, 0);
         for y in 0..SPR_CELL {
             for x in 0..SPR_CELL {
@@ -2628,32 +2693,30 @@ mod sprite_tests {
         }
     }
 
-    // `cargo test --bins dump_imp_cells -- --ignored` writes the imp's cells to /tmp for a look:
-    // rows: 10x10, 10x10 with sack, then idle and the hack frames without and with sack
+    // `cargo test --bins dump_imp_cells -- --ignored` writes the imp's detailed cells to /tmp for
+    // a look: rows idle and the hack frames, without and with sack; 64x64 left, 32x32 right
     #[test]
     #[ignore]
     fn dump_imp_cells() {
-        let img = gen_sprites();
-        let mut cells: Vec<Vec<Rect>> = Vec::new();
-        for sack in [false, true] {
-            let r: Vec<Rect> = (0..VIEWS).map(|v| if sack { Gfx::sprite_cell_sack(EK::Worker, false, 1, v).unwrap() } else { Gfx::sprite_cell_view(EK::Worker, false, 1, v) }).collect();
-            cells.push(r);
-        }
+        let img = gen_hd_sprites();
+        let mut rows: Vec<Vec<Rect>> = Vec::new();
         for sack in [false, true] {
             for hack in [None, Some(0), Some(1), Some(2), Some(3)] {
-                cells.push((0..VIEWS).map(|v| Gfx::hd_cell_view(EK::Worker, false, v, hack, sack).unwrap()).collect());
+                let mut r: Vec<Rect> = (0..VIEWS).map(|v| Gfx::hd_cell_view(EK::Worker, false, v, hack, sack, true).unwrap()).collect();
+                r.extend((0..VIEWS).map(|v| Gfx::hd_cell_view(EK::Worker, false, v, hack, sack, false).unwrap()));
+                rows.push(r);
             }
         }
-        let z = 3;
-        let (w, h) = (ACELL * z * VIEWS, ACELL * z * cells.len() as u32);
+        let c = HD_CELL;
+        let (w, h) = (c * VIEWS * 2, c * rows.len() as u32);
         let mut out = Image::gen_image_color(w as u16, h as u16, Color::new(0.35, 0.33, 0.38, 1.0));
-        for (row, list) in cells.iter().enumerate() {
-            for (view, r) in list.iter().enumerate() {
-                for y in 0..ACELL * z {
-                    for x in 0..ACELL * z {
-                        let p = img.get_pixel(r.x as u32 + x / z, r.y as u32 + y / z);
+        for (row, list) in rows.iter().enumerate() {
+            for (i, r) in list.iter().enumerate() {
+                for y in 0..c {
+                    for x in 0..c {
+                        let p = img.get_pixel(r.x as u32 + x, r.y as u32 + y);
                         if p.a > 0.5 {
-                            out.set_pixel(view as u32 * ACELL * z + x, h - 1 - (row as u32 * ACELL * z + y), p);
+                            out.set_pixel(i as u32 * c + x, h - 1 - (row as u32 * c + y), p);
                         }
                     }
                 }

src/render3d.rs

@@ -1563,8 +1563,9 @@ impl R3d {
         // sprites as billboards
         // the world's pixel rows (detailed sprites only where they get enough pixels)
         let world_rows = pix.map_or(screen_height() * screen_dpi_scale(), |(_, th, _)| th as f32);
-        if let Some(mesh) = self.billboards(g, gfx, cam, t, world_rows) {
-            draw_mesh(&mesh);
+        let (small, detailed) = self.billboards(g, gfx, cam, t, world_rows);
+        for mesh in [small, detailed].iter().flatten() {
+            draw_mesh(mesh);
         }
         // solid unlit objects (default material, depth tested)
         gl_use_default_material();
@@ -1638,7 +1639,8 @@ impl R3d {
         self.draw_2d(g, gfx, cam, &m, t);
     }
 
-    fn billboards(&self, g: &Game, gfx: &Gfx, cam: &Cam, t: f32, world_rows: f32) -> Option<Mesh> {
+    // the units as billboards: the 10x10 sprites and the detailed ones (two textures)
+    fn billboards(&self, g: &Game, gfx: &Gfx, cam: &Cam, t: f32, world_rows: f32) -> (Option<Mesh>, Option<Mesh>) {
         let (_, r, _) = cam.basis();
         let toward = cam.eye_dir();
         let amb = |x: f32, z: f32| {
@@ -1656,6 +1658,7 @@ impl R3d {
         let rg = vec2(r.x, r.z).normalize_or_zero();
         let tg = vec2(toward.x, toward.z).normalize_or_zero();
         let mut mb = MB::new();
+        let mut mb_hd = MB::new();
         let sw = SPRITE_TEX_W;
         let sh = SPRITE_TEX_H;
         // detailed sprites only in the high-res style, and only where a sprite's cell (1.2 sizes
@@ -1761,19 +1764,24 @@ impl R3d {
             }
             let white = e.flash > 0.07;
             let v = if e.captive != 0 { 0 } else { view };
-            let detailed = hd && w * 1.2 * px_per_tile >= crate::gfx::ACELL as f32 * 0.85;
+            // screen pixels of the cell per texel of a detailed cell (64x64 level), the 32x32
+            // level has two texels per pixel
+            let texel = w * 1.2 * px_per_tile / crate::gfx::HD_CELL as f32;
+            let detailed = hd && texel * 2.0 >= 0.85;
+            let fine = texel >= 0.85;
             // treasure in a sack on the back; digging as a drawn animation (detailed sprites),
             // frame by frame with the same rhythm as the swing below
             let sack = e.carry > 0 && Gfx::has_sack(e.kind);
             let hacking = e.working && !e.moving && !sleeping && matches!(e.job, Job::Dig(_) | Job::TearBridge(_));
             let frame = ((ph * 1.3 / std::f32::consts::TAU).rem_euclid(1.0) * crate::gfx::HACK_FRAMES as f32) as u32;
-            let hd = if detailed { Gfx::hd_cell_view(e.kind, white, v, hacking.then_some(frame), sack) } else { None };
+            let hd = if detailed { Gfx::hd_cell_view(e.kind, white, v, hacking.then_some(frame), sack, fine) } else { None };
             if hd.is_some() && hacking {
                 // the frames swing the pickaxe: no tilting of the whole figure
                 rot = 0.0;
                 lunge = 0.0;
             }
             let src = hd.or_else(|| sack.then(|| Gfx::sprite_cell_sack(e.kind, white, e.level, v)).flatten()).unwrap_or_else(|| Gfx::sprite_cell_view(e.kind, white, e.level, v));
+            let (sw, sh) = if hd.is_some() { (crate::gfx::HD_TEX_W, crate::gfx::HD_TEX_H) } else { (sw, sh) };
             let (mut u0, v0) = (src.x / sw, src.y / sh);
             let (mut u1, v1) = ((src.x + src.w) / sw, (src.y + src.h) / sh);
             if mirror {
@@ -1813,6 +1821,7 @@ impl R3d {
             };
             // the 12x12 cell (sprite with a one pixel border for the gear): the sprite's feet
             // (bottom of its 11th pixel row) stay on the ground
+            let mb = if hd.is_some() { &mut mb_hd } else { &mut mb };
             mb.quad(
                 [corner(-w * 0.6, h * 1.1), corner(w * 0.6, h * 1.1), corner(w * 0.6, -h * 0.1), corner(-w * 0.6, -h * 0.1)],
                 [vec2(u0, v0), vec2(u1, v0), vec2(u1, v1), vec2(u0, v1)],
@@ -1820,11 +1829,8 @@ impl R3d {
                 [toward; 4],
             );
         }
-        if mb.v.is_empty() {
-            None
-        } else {
-            Some(Mesh { vertices: mb.v, indices: mb.i, texture: Some(gfx.sprites.clone()) })
-        }
+        let mesh = |mb: MB, tex: &Texture2D| if mb.v.is_empty() { None } else { Some(Mesh { vertices: mb.v, indices: mb.i, texture: Some(tex.clone()) }) };
+        (mesh(mb, &gfx.sprites), mesh(mb_hd, &gfx.hd_sprites))
     }
 
     fn draw_2d(&self, g: &Game, gfx: &Gfx, cam: &Cam, m: &Mat4, t: f32) {