Windows: Alt+Enter toggles fullscreen, as on Linux

.github/workflows/source-regressions.yml

@@ -55,6 +55,10 @@ on:
       - gpu/vk/movie_upscale_policy.h
       - tests/test_movie_upscale_policy.cpp
       - tests/test_movie_upscale_policy.py
+      - host/display.c
+      - host/posix/display_sdl.c
+      - host/nn_hid.c
+      - tests/test_alt_enter.py
       - nx2/test_import_windows.py
       - tests/test_handle_lookup.py
       - builder/linux/hookshot-launch
@@ -117,6 +121,10 @@ on:
       - gpu/vk/movie_upscale_policy.h
       - tests/test_movie_upscale_policy.cpp
       - tests/test_movie_upscale_policy.py
+      - host/display.c
+      - host/posix/display_sdl.c
+      - host/nn_hid.c
+      - tests/test_alt_enter.py
       - nx2/test_import_windows.py
       - tests/test_handle_lookup.py
       - builder/linux/hookshot-launch
@@ -227,6 +235,9 @@ jobs:
       - name: Check movie upscale fallback policy
         if: runner.os == 'Linux'
         run: python -I -B tests/test_movie_upscale_policy.py
+      - name: Check Alt+Enter is fullscreen, not Plus
+        if: runner.os == 'Linux'
+        run: python -I -B tests/test_alt_enter.py
       - name: Check import windows
         if: runner.os == 'Linux'
         run: python -I -B nx2/test_import_windows.py --cxx g++

host/display.c

@@ -4,7 +4,7 @@
    no emulated GPU, so the renderer is the only way to a picture.
    HOS_HEADLESS=1: no window (scripted runs; the renderer draws offscreen). Closing the window ends the run.
    HOS_WINDOW_NOACTIVATE=1: the window opens behind the one in front (test runs do not take the keyboard).
-   HOS_WINDOW_SIZE=<w>x<h>: the client area (default 1280x720 at 96 dpi). F11: fullscreen.
+   HOS_WINDOW_SIZE=<w>x<h>: the client area (default 1280x720 at 96 dpi). F11 or Alt+Enter: fullscreen.
    Mouse: a click in the window captures the mouse (hidden, kept in the window), Esc or leaving the window releases
    it (nn_hid.c reads its motion). */
 #include "hos.h"
@@ -113,6 +113,15 @@ static LRESULT CALLBACK wndproc(HWND w, UINT msg, WPARAM wp, LPARAM lp) {
         if (wp == VK_ESCAPE) mouse_capture(w, 0);
         if (wp == VK_F11 && !(lp & (1 << 30))) set_fullscreen(w, !fullscreen);
         return 0;
+    case WM_SYSKEYDOWN:   /* Alt+Enter, as on Linux (display_sdl.c); other Alt keys (Alt+F4) go on to Windows */
+        if (wp == VK_RETURN && (lp & (1 << 29))) {
+            if (!(lp & (1 << 30))) set_fullscreen(w, !fullscreen);
+            return 0;
+        }
+        break;
+    case WM_SYSCHAR:   /* (its character: without this Windows beeps, as for an Alt key with no menu) */
+        if (wp == '\r') return 0;
+        break;
     case WM_APP + 7:   /* (the Insert menu's row) */
         set_fullscreen(w, (int)wp);
         return 0;

host/nn_hid.c

@@ -169,6 +169,10 @@ static int mouse_stick(int32_t *rx, int32_t *ry, int pointing) {
     return 1;
 }
 
+/* A bound key is down: Enter held with Alt is no button (Alt+Enter is fullscreen, host/display.c and
+   host/posix/display_sdl.c). tests/test_alt_enter.py */
+static int kmap_down(int vk, int (*down)(int)) { return down(vk) && !(vk == VK_RETURN && down(VK_MENU)); }
+
 static int game_in_front(void) {
     DWORD pid = 0;
     HWND w = GetForegroundWindow();
@@ -543,7 +547,7 @@ static void read_input(uint64_t *buttons, int32_t stick[4]) {
     binds_load();   /* (the keys: key_default's, or hookshot_options.ini's) */
     for (int i = 0; i < HOS_SW_N; i++)
         for (int k = 0; k < 2; k++)
-            if (key_bind[i][k] && key(key_bind[i][k])) *buttons |= 1ULL << i;
+            if (key_bind[i][k] && kmap_down(key_bind[i][k], key)) *buttons |= 1ULL << i;
     int32_t mouse[4] = {0};
     /* left button Y (attack), right button ZL (shield, lock on), while the mouse is captured; a button held when
        the capture began counts only after it was let go (the click that captures never reaches the game) */

tests/test_alt_enter.py

@@ -0,0 +1,96 @@
+"""Alt+Enter toggles fullscreen and presses no button (Enter is Plus by default, and any button can be bound to it; issue #390).
+
+The bound keys' helper (host/nn_hid.c's kmap_down) is compiled alone against fake key states; the window
+procedures (host/display.c, host/posix/display_sdl.c) are checked to toggle on Alt+Enter, once per press, and to
+leave other Alt keys (Alt+F4) to Windows.
+
+python -I -B tests/test_alt_enter.py [--cc gcc]
+"""
+import argparse
+import subprocess
+import tempfile
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+def block(text, marker):
+    start = text.index(marker)
+    end = text.index("{", start) + 1
+    depth = 1
+    while depth:
+        depth += (text[end] == "{") - (text[end] == "}")
+        end += 1
+    return text[start:end]
+
+
+def case(text, label):
+    """The body of one `case label:` of a switch, up to the next case"""
+    start = text.index("case %s:" % label)
+    end = text.index("    case ", start + 1)
+    return text[start:end]
+
+
+def check_windows():
+    src = (ROOT / "host" / "display.c").read_text(encoding="utf-8")
+    sys_down = case(src, "WM_SYSKEYDOWN")
+    for need, why in (("VK_RETURN", "Enter"), ("1 << 29", "the Alt bit"), ("1 << 30", "a held key repeating"),
+                      ("set_fullscreen(w, !fullscreen)", "the toggle"), ("break;", "other Alt keys to DefWindowProc")):
+        if need not in sys_down:
+            raise SystemExit("display.c: WM_SYSKEYDOWN lacks %s (%s)" % (need, why))
+    if "'\\r'" not in case(src, "WM_SYSCHAR"):
+        raise SystemExit("display.c: Alt+Enter's WM_SYSCHAR is not taken (Windows beeps)")
+
+
+def check_linux():
+    src = (ROOT / "host" / "posix" / "display_sdl.c").read_text(encoding="utf-8")
+    if "scancode == 40 && (mod & 0x300)" not in src:
+        raise SystemExit("display_sdl.c: Alt+Enter no longer toggles fullscreen")
+
+
+FIXTURE = r'''#include <stdio.h>
+#include <stdlib.h>
+#define VK_RETURN 0x0D
+#define VK_MENU 0x12
+#define VK_TAB 0x09
+#define CHECK(x) do { if (!(x)) { fprintf(stderr, "FAIL:%d %s\n", __LINE__, #x); exit(1); } } while (0)
+static int held[256];
+static int down(int vk) { return held[vk & 255]; }
+@KMAP_DOWN@
+int main(void) {
+    held[VK_RETURN] = 1;
+    CHECK(kmap_down(VK_RETURN, down));            /* Enter alone is Plus */
+    held[VK_MENU] = 1;
+    CHECK(!kmap_down(VK_RETURN, down));           /* Alt+Enter is not */
+    held[VK_TAB] = 1;
+    CHECK(kmap_down(VK_TAB, down));               /* Alt does not hide the other keys */
+    held[VK_RETURN] = 0;
+    CHECK(!kmap_down(VK_RETURN, down));
+    held[VK_MENU] = 0;
+    CHECK(!kmap_down(VK_MENU, down) && kmap_down(VK_TAB, down));
+    printf("PASS: Alt+Enter is fullscreen, not Plus\n");
+    return 0;
+}
+'''
+
+
+def main():
+    p = argparse.ArgumentParser(description=__doc__)
+    p.add_argument("--cc", default="gcc")
+    a = p.parse_args()
+    check_windows()
+    check_linux()
+    hid = (ROOT / "host" / "nn_hid.c").read_text(encoding="utf-8")
+    fn = block(hid, "static int kmap_down(")
+    if "kmap_down(key_bind[i][k], key)" not in hid:
+        raise SystemExit("nn_hid.c: the bound keys no longer go through kmap_down")
+    with tempfile.TemporaryDirectory(prefix="alt-enter-") as tmp:
+        c = Path(tmp) / "fixture.c"
+        exe = Path(tmp) / "fixture"
+        c.write_text(FIXTURE.replace("@KMAP_DOWN@", fn), encoding="utf-8")
+        subprocess.run([a.cc, "-std=c11", "-Wall", "-Wextra", "-Werror", str(c), "-o", str(exe)], check=True)
+        subprocess.run([str(exe)], check=True)
+
+
+if __name__ == "__main__":
+    main()