Pass geometry of window with bell to custom shaders

docs/custom-shaders.rst

@@ -321,6 +321,11 @@ be combined with ``|`` — any one of them will trigger the action.
 
    * - ``bell-in-window``
      - A bell (BEL character) is received in any kitty window.
+       The geometry of the window in which the most recent bell occurred is
+       available in ``d.bell_window_geometry`` (UV co-ordinates, origin
+       bottom-left; ``.xy`` = lower-left corner, ``.zw`` = width and height).
+       If that window is not currently visible in the active tab or layout,
+       ``d.bell_window_geometry`` equals ``d.central_area``.
 
    * - ``user-activity``
      - Any keyboard or mouse input is received.

kitty/child-monitor.c

@@ -907,8 +907,10 @@ prepare_to_render_os_window(
             }
             if (send_cell_data_to_gpu(WD.vao_idx, WD.screen, os_window)) needs_render = true;
             if (WD.screen->start_visual_bell_at | WD.screen->start_drag_overlay_at) needs_render = true;
-            if (WD.screen->start_visual_bell_at && WD.screen->start_visual_bell_at > os_window->last_rendered_at)
+            if (WD.screen->start_visual_bell_at && WD.screen->start_visual_bell_at > os_window->last_rendered_at) {
                 os_window->shader_anim_event_registry |= (1u << SHADER_ANIM_EVENT_BELL_IN_WINDOW);
+                os_window->last_bell_window_id = w->id;
+            }
             // Prepare window title bar screen data for GPU
             WindowRenderData *trd = &w->window_title_render_data;
             if (trd->screen && trd->geometry.bottom > trd->geometry.top && trd->geometry.right > trd->geometry.left) {

kitty/shaders.c

@@ -2359,6 +2359,7 @@ run_custom_end_shader(OSWindow *os_window, float sx, float sy, monotonic_t now)
         float mouse_pos[4];
         float mouse_button_pressed[4];
         float active_window_geometry[4];
+        float bell_window_geometry[4];
         float central_area[4];
         float cursor_trail_corners_x[4];
         float cursor_trail_corners_y[4];
@@ -2486,6 +2487,27 @@ run_custom_end_shader(OSWindow *os_window, float sx, float sy, monotonic_t now)
         d->central_area[2] = 1.f;
         d->central_area[3] = 1.f;
     }
+    if (os_window->last_bell_window_id && os_window->num_tabs > 0 && vpw > 0 && vph > 0) {
+        WindowGeometry bell_win_geom = {0};
+        bool bell_win_found = false;
+        Tab *bt = os_window->tabs + os_window->active_tab;
+        for (unsigned i = 0; i < bt->num_windows; i++) {
+            Window *bw = bt->windows + i;
+            if (bw->id == os_window->last_bell_window_id && bw->visible) {
+                bell_win_geom = bw->render_data.geometry;
+                bell_win_found = true;
+                break;
+            }
+        }
+        if (bell_win_found && bell_win_geom.right > bell_win_geom.left) {
+            d->bell_window_geometry[0] = (float)bell_win_geom.left / vpw;
+            d->bell_window_geometry[1] = 1.f - (float)bell_win_geom.bottom / vph;
+            d->bell_window_geometry[2] = (float)(bell_win_geom.right - bell_win_geom.left) / vpw;
+            d->bell_window_geometry[3] = (float)(bell_win_geom.bottom - bell_win_geom.top) / vph;
+        } else {
+            memcpy(d->bell_window_geometry, d->central_area, sizeof(d->bell_window_geometry));
+        }
+    }
     unmap_vao_buffer(custom_end_vao_idx, 0);
     bind_vao_uniform_buffer(custom_end_vao_idx, 0, CUSTOM_END_DATA_BINDING_POINT);
 

kitty/shaders/custom/types.slang

@@ -22,6 +22,11 @@ public struct KittyCustomShaderData {
     // .xy = lower-left corner of the window, .zw = width and height.
     // All components are zero when no active window was rendered this frame.
     public float4 active_window_geometry;
+    // Geometry of the most recently belled window in UV co-ordinates (origin bottom-left).
+    // .xy = lower-left corner of the window, .zw = width and height.
+    // If the belled window is not currently visible in the active tab/layout, equals central_area.
+    // All components are zero until the first bell-in-window event occurs.
+    public float4 bell_window_geometry;
     // Geometry of the central content area of the OS window (the tab area, excluding any tab bar)
     // in UV co-ordinates (origin bottom-left).
     // .xy = lower-left corner, .zw = width and height.

kitty/state.h

@@ -563,6 +563,7 @@ typedef struct OSWindow {
         int last_v120_dir_x, last_v120_dir_y;
     } scroll;
     unsigned shader_anim_event_registry;
+    id_type last_bell_window_id; // ID of the most recent window that received a bell event
     struct {
         bool active;
         monotonic_t started_at;