move update_cursor_trail out of child_monitor_c

kitty/child-monitor.c

@@ -705,63 +705,6 @@ change_menubar_title(PyObject *title UNUSED) {
 #endif
 }
 
-inline static float
-norm(float x, float y) {
-    return sqrtf(x * x + y * y);
-}
-
-static bool
-update_cursor_trail(CursorTrail *ct, Window *w, monotonic_t now) {
-#define WD w->render_data
-    // the trail corners move towards the cursor corner at a speed proportional to their distance from the cursor corner.
-    // equivalent to exponential ease out animation.
-    static const int ci[4][2] = {{1, 0}, {1, 1}, {0, 1}, {0, 0}};
-    float cursor_edge_x[2], cursor_edge_y[2];
-    cursor_edge_x[0] = WD.xstart + WD.screen->cursor_render_info.x * WD.dx;
-    cursor_edge_x[1] = cursor_edge_x[0] + WD.dx;
-    cursor_edge_y[0] = WD.ystart - WD.screen->cursor_render_info.y * WD.dy;
-    cursor_edge_y[1] = cursor_edge_y[0] - WD.dy;
-
-    // todo - make these configurable
-    // the decay time for the trail to reach 1/1024 of its distance from the cursor corner
-    float decay_fast = 0.10f;
-    float decay_slow = 0.40f;
-
-    if (OPT(input_delay) < now - WD.screen->cursor->updated_at && ct->updated_at < now) {
-        float cursor_center_x = (cursor_edge_x[0] + cursor_edge_x[1]) * 0.5f;
-        float cursor_center_y = (cursor_edge_y[0] + cursor_edge_y[1]) * 0.5f;
-        float cursor_diag_2 = norm(cursor_edge_x[1] - cursor_edge_x[0], cursor_edge_y[1] - cursor_edge_y[0]) * 0.5;
-        float dt = monotonic_t_to_s_double(now - ct->updated_at);
-
-        for (int i = 0; i < 4; ++i) {
-            float dx = cursor_edge_x[ci[i][0]] - ct->corner_x[i];
-            float dy = cursor_edge_y[ci[i][1]] - ct->corner_y[i];
-            float dist = norm(dx, dy);
-            if (dist == 0) {
-                continue;
-            }
-            float dot = (dx * (cursor_edge_x[ci[i][0]] - cursor_center_x) +
-                dy * (cursor_edge_y[ci[i][1]] - cursor_center_y)) /
-                cursor_diag_2 / dist;
-
-            float decay_seconds = decay_slow + (decay_fast - decay_slow) * (1.0f + dot) * 0.5f;
-            float step = 1.0f - 1.0f / exp2f(10.0f * dt / decay_seconds);
-
-            ct->corner_x[i] += dx * step;
-            ct->corner_y[i] += dy * step;
-        }
-    }
-    ct->updated_at = now;
-    for (int i = 0; i < 4; ++i) {
-        float dx = cursor_edge_x[ci[i][0]] - ct->corner_x[i];
-        float dy = cursor_edge_y[ci[i][1]] - ct->corner_y[i];
-        if (dx * dx + dy * dy >= 1e-6) {
-            return true;
-        }
-    }
-    return false;
-}
-
 static bool
 prepare_to_render_os_window(OSWindow *os_window, monotonic_t now, unsigned int *active_window_id, color_type *active_window_bg, unsigned int *num_visible_windows, bool *all_windows_have_same_bg, bool scan_for_animated_images) {
 #define TD os_window->tab_bar_render_data
@@ -785,6 +728,7 @@ prepare_to_render_os_window(OSWindow *os_window, monotonic_t now, unsigned int *
     color_type first_window_bg = 0;
     for (unsigned int i = 0; i < tab->num_windows; i++) {
         Window *w = tab->windows + i;
+#define WD w->render_data
         if (w->visible && WD.screen) {
             screen_check_pause_rendering(WD.screen, now);
             *num_visible_windows += 1;
@@ -865,7 +809,7 @@ render_prepared_os_window(OSWindow *os_window, unsigned int active_window_id, co
             w->cursor_opacity_at_last_render = WD.screen->cursor_render_info.opacity; w->last_cursor_shape = WD.screen->cursor_render_info.shape;
         }
     }
-    if (true) draw_trail(&tab->cursor_trail);
+    if (true) draw_cursor_trail(&tab->cursor_trail);
     if (os_window->live_resize.in_progress) draw_resizing_text(os_window);
     swap_window_buffers(os_window);
     os_window->last_active_tab = os_window->active_tab; os_window->last_num_tabs = os_window->num_tabs; os_window->last_active_window_id = active_window_id;

kitty/cursor_trail.c

@@ -0,0 +1,58 @@
+#include "state.h"
+
+inline static float
+norm(float x, float y) {
+    return sqrtf(x * x + y * y);
+}
+
+bool
+update_cursor_trail(CursorTrail *ct, Window *w, monotonic_t now) {
+#define WD w->render_data
+    // the trail corners move towards the cursor corner at a speed proportional to their distance from the cursor corner.
+    // equivalent to exponential ease out animation.
+    static const int ci[4][2] = {{1, 0}, {1, 1}, {0, 1}, {0, 0}};
+    float cursor_edge_x[2], cursor_edge_y[2];
+    cursor_edge_x[0] = WD.xstart + WD.screen->cursor_render_info.x * WD.dx;
+    cursor_edge_x[1] = cursor_edge_x[0] + WD.dx;
+    cursor_edge_y[0] = WD.ystart - WD.screen->cursor_render_info.y * WD.dy;
+    cursor_edge_y[1] = cursor_edge_y[0] - WD.dy;
+
+    // todo - make these configurable
+    // the decay time for the trail to reach 1/1024 of its distance from the cursor corner
+    float decay_fast = 0.10f;
+    float decay_slow = 0.40f;
+
+    if (OPT(input_delay) < now - WD.screen->cursor->updated_at && ct->updated_at < now) {
+        float cursor_center_x = (cursor_edge_x[0] + cursor_edge_x[1]) * 0.5f;
+        float cursor_center_y = (cursor_edge_y[0] + cursor_edge_y[1]) * 0.5f;
+        float cursor_diag_2 = norm(cursor_edge_x[1] - cursor_edge_x[0], cursor_edge_y[1] - cursor_edge_y[0]) * 0.5;
+        float dt = monotonic_t_to_s_double(now - ct->updated_at);
+
+        for (int i = 0; i < 4; ++i) {
+            float dx = cursor_edge_x[ci[i][0]] - ct->corner_x[i];
+            float dy = cursor_edge_y[ci[i][1]] - ct->corner_y[i];
+            float dist = norm(dx, dy);
+            if (dist == 0) {
+                continue;
+            }
+            float dot = (dx * (cursor_edge_x[ci[i][0]] - cursor_center_x) +
+                dy * (cursor_edge_y[ci[i][1]] - cursor_center_y)) /
+                cursor_diag_2 / dist;
+
+            float decay_seconds = decay_slow + (decay_fast - decay_slow) * (1.0f + dot) * 0.5f;
+            float step = 1.0f - 1.0f / exp2f(10.0f * dt / decay_seconds);
+
+            ct->corner_x[i] += dx * step;
+            ct->corner_y[i] += dy * step;
+        }
+    }
+    ct->updated_at = now;
+    for (int i = 0; i < 4; ++i) {
+        float dx = cursor_edge_x[ci[i][0]] - ct->corner_x[i];
+        float dy = cursor_edge_y[ci[i][1]] - ct->corner_y[i];
+        if (dx * dx + dy * dy >= 1e-6) {
+            return true;
+        }
+    }
+    return false;
+}

kitty/shaders.c

@@ -1145,7 +1145,7 @@ init_trail_program(void) {
 }
 
 void
-draw_trail(CursorTrail *trail) {
+draw_cursor_trail(CursorTrail *trail) {
     glEnable(GL_BLEND);
     // BLEND_PREMULT
     /*glBlendFuncSeparate(GL_ONE, GL_ONE_MINUS_SRC_ALPHA, GL_ZERO, GL_ONE);*/

kitty/state.h

@@ -359,7 +359,8 @@ ssize_t create_border_vao(void);
 bool send_cell_data_to_gpu(ssize_t, float, float, float, float, Screen *, OSWindow *);
 void draw_cells(ssize_t, const WindowRenderData*, OSWindow *, bool, bool, bool, Window*);
 void draw_centered_alpha_mask(OSWindow *w, size_t screen_width, size_t screen_height, size_t width, size_t height, uint8_t *canvas, float);
-void draw_trail(CursorTrail *trail);
+void draw_cursor_trail(CursorTrail *trail);
+bool update_cursor_trail(CursorTrail *ct, Window *w, monotonic_t now);
 void update_surface_size(int, int, uint32_t);
 void free_texture(uint32_t*);
 void free_framebuffer(uint32_t*);