Portrait and square screens: world pixels, interface and zoom count on the shorter side

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

src/render3d.rs

@@ -85,12 +85,18 @@ impl Cam {
         vec3(self.rx, 0.0, self.rz)
     }
 
+    // visible world height in tiles: the zoom counts on the shorter side (upright screens: across)
+    pub fn view_h(&self) -> f32 {
+        let (w, h) = (screen_width().max(1.0), screen_height().max(1.0));
+        if h > w { self.zoom * h / w } else { self.zoom }
+    }
+
     pub fn camera(&self) -> Camera3D {
         Camera3D {
             position: self.target() + self.eye_dir() * 60.0,
             target: self.target(),
             up: Vec3::Y,
-            fovy: self.zoom,
+            fovy: self.view_h(),
             projection: Projection::Orthographics,
             z_near: 1.0,
             z_far: 200.0,
@@ -114,7 +120,7 @@ impl Cam {
 
     pub fn ray(&self, sx: f32, sy: f32) -> (Vec3, Vec3) {
         let (f, r, u) = self.basis();
-        let half_h = self.zoom * 0.5;
+        let half_h = self.view_h() * 0.5;
         let half_w = half_h * screen_width() / screen_height();
         let nx = sx / screen_width() * 2.0 - 1.0;
         let ny = 1.0 - sy / screen_height() * 2.0;
@@ -1468,7 +1474,7 @@ impl R3d {
     // Entity under the mouse (screen-space test against the projected sprite)
     pub fn pick_ent(&self, g: &Game, cam: &Cam, sx: f32, sy: f32, player_only: bool) -> Option<usize> {
         let m = cam.matrix();
-        let px_per_tile = screen_height() / cam.zoom;
+        let px_per_tile = screen_height() / cam.view_h();
         let mut best = None;
         let mut bd = (px_per_tile * 0.4).max(10.0);
         for (j, e) in g.ents.iter().enumerate() {
@@ -1494,7 +1500,9 @@ impl R3d {
         // on the virtual screen (ui.rs) the world takes exactly k x k interface pixels per pixel
         let vrows = crate::ui::virtual_rows();
         let pix = if vrows > 0 && self.pixel_rows > 0 {
-            let k = (vrows / self.pixel_rows).max(1);
+            // the pixel rows count on the shorter side (upright screens: across)
+            let short = vrows.min(crate::ui::sw().round() as u32);
+            let k = (short / self.pixel_rows).max(1);
             let th = vrows / k;
             Some(((crate::ui::sw() / k as f32).ceil() as u32, th, k as f32))
         } else {