Add new sokol_poll.h layer

sokol_poll.h

@@ -0,0 +1,139 @@
+#ifndef SOKOL_APP_INCLUDED
+#error Please include sokol_app.h before sokol_poll.h
+#endif
+
+#if defined(SOKOL_IMPL) && !defined(SOKOL_POLL_IMPL)
+#define SOKOL_POLL_IMPL
+#endif
+#ifndef SOKOL_POLL_INCLUDED
+/*
+    sokol_poll.h -- polling layer for sokol_app input
+
+    Project URL: https://github.com/floooh/sokol
+
+    Do this:
+        #define SOKOL_IMPL or
+        #define SOKOL_POLL_IMPL
+    before you include this file in *one* C or C++ file to create the
+    implementation.
+
+    OVERVIEW
+    ========
+    This header provides a supplementary poll-based input API for sokol_app.h
+
+    When a program that uses sokol_app.h needs to check whether a key
+    is currently down, it must manage a boolean flag that gets set or
+    reset upon KEYUP/KEYDOWN events. This header provides convenience
+    functions that manage such flags, along with a simple API to check
+    them.
+
+    PROVIDED FUNCTIONS
+    ==================
+
+    bool spoll_handle_event(const sapp_event* evt);
+    bool spoll_keydown(sapp_keycode key);
+
+    LICENSE
+    =======
+    zlib/libpng license
+
+    Copyright (c) 2023 Octave Crespel
+
+    This software is provided 'as-is', without any express or implied warranty.
+    In no event will the authors be held liable for any damages arising from the
+    use of this software.
+
+    Permission is granted to anyone to use this software for any purpose,
+    including commercial applications, and to alter it and redistribute it
+    freely, subject to the following restrictions:
+
+        1. The origin of this software must not be misrepresented; you must not
+        claim that you wrote the original software. If you use this software in a
+        product, an acknowledgment in the product documentation would be
+        appreciated but is not required.
+
+        2. Altered source versions must be plainly marked as such, and must not
+        be misrepresented as being the original software.
+
+        3. This notice may not be removed or altered from any source
+        distribution.
+
+*/
+#define SOKOL_POLL_INCLUDED
+
+#if defined(SOKOL_API_DECL) && !defined(SOKOL_POLL_API_DECL)
+#define SOKOL_POLL_API_DECL SOKOL_API_DECL
+#endif
+#ifndef SOKOL_POLL_API_DECL
+#if defined(_WIN32) && defined(SOKOL_DLL) && defined(SOKOL_POLL_IMPL)
+#define SOKOL_POLL_API_DECL __declspec(dllexport)
+#elif defined(_WIN32) && defined(SOKOL_DLL)
+#define SOKOL_POLL_API_DECL __declspec(dllimport)
+#else
+#define SOKOL_POLL_API_DECL extern
+#endif
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+    spoll_handle_event : must be called in the event callback that was
+    provided at sokol_app initialization. Returns `true` if the event
+    was used to update the internal keyboard state.
+*/
+bool spoll_handle_event(const sapp_event* evt);
+
+/*
+    spoll_keydown : returns whether the key `key` is currently being held down.
+*/
+bool spoll_keydown(sapp_keycode key);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+#endif /* SOKOL_POLL_INCLUDED */
+
+/*-- IMPLEMENTATION ----------------------------------------------------------*/
+#ifdef SOKOL_POLL_IMPL
+#define SOKOL_POLL_IMPL_INCLUDED
+
+#include <stdint.h>
+
+#define SOKOL_KEYCODE_MAXIMUM 512
+
+static uint8_t g_key_down[SOKOL_KEYCODE_MAXIMUM / 8];
+
+#define BIT_INDEX(key) ((key) / 8)
+#define BIT_MASK(key) (1 << ((key) % 8))
+
+bool spoll_handle_event(const sapp_event* evt)
+{
+    switch (evt->type) {
+    case SAPP_EVENTTYPE_KEY_DOWN:
+        g_key_down[BIT_INDEX(evt->key_code)] |= BIT_MASK(evt->key_code);
+        return true;
+    case SAPP_EVENTTYPE_KEY_UP:
+        g_key_down[BIT_INDEX(evt->key_code)] &= ~BIT_MASK(evt->key_code);
+        return true;
+    case SAPP_EVENTTYPE_UNFOCUSED:
+    case SAPP_EVENTTYPE_SUSPENDED:
+    case SAPP_EVENTTYPE_ICONIFIED:
+        memset(g_key_down, 0, sizeof(g_key_down));
+        return true;
+    default:
+        return false;
+    }
+}
+
+bool spoll_keydown(sapp_keycode key)
+{
+    return g_key_down[BIT_INDEX(key)] & BIT_MASK(key);
+}
+
+/* Macro cleanup */
+#undef BIT_INDEX
+#undef BIT_MASK
+
+#endif