From 023d2cb9a913ad5b291ed6a9f20386f87c31994b Mon Sep 17 00:00:00 2001
From: twinaphex <libretro@gmail.com>
Date: Fri, 21 Jun 2019 11:21:07 +0200
Subject: [PATCH] (Libretro) implement new environment callback
 RETRO_ENVIRONMENT_GET_INPUT_BITMASKS

---
 dynamic.c                          |  4 ++++
 libretro-common/include/libretro.h | 16 +++++++++++++++-
 retroarch.c                        | 11 +++++++++++
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/dynamic.c b/dynamic.c
index 3fed3dce28..82c491d023 100644
--- a/dynamic.c
+++ b/dynamic.c
@@ -1842,6 +1842,10 @@ bool rarch_environment_cb(unsigned cmd, void *data)
          break;
       }
 
+      case RETRO_ENVIRONMENT_GET_INPUT_BITMASKS:
+         /* Just falldown, the function will return true */
+         break;
+
       case RETRO_ENVIRONMENT_GET_TARGET_REFRESH_RATE:
       {
          /* Try to use the polled refresh rate first.  */
diff --git a/libretro-common/include/libretro.h b/libretro-common/include/libretro.h
index a096eacef4..8daec83601 100644
--- a/libretro-common/include/libretro.h
+++ b/libretro-common/include/libretro.h
@@ -202,6 +202,8 @@ extern "C" {
 #define RETRO_DEVICE_ID_JOYPAD_L3      14
 #define RETRO_DEVICE_ID_JOYPAD_R3      15
 
+#define RETRO_DEVICE_ID_JOYPAD_MASK    256
+
 /* Index / Id values for ANALOG device. */
 #define RETRO_DEVICE_INDEX_ANALOG_LEFT       0
 #define RETRO_DEVICE_INDEX_ANALOG_RIGHT      1
@@ -1092,10 +1094,22 @@ enum retro_mod
                                             * refresh rate/framerate.
                                             */
 
+#define RETRO_ENVIRONMENT_GET_INPUT_BITMASKS (51 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+                                            /* bool * --
+                                            * Boolean value that indicates whether or not the frontend supports
+                                            * input bitmasks being returned by retro_input_state_t. The advantage
+                                            * of this is that retro_input_state_t has to be only called once to 
+                                            * grab all button states instead of multiple times.
+                                            *
+                                            * If it returns true, you can pass RETRO_DEVICE_ID_JOYPAD_MASK as 'id'
+                                            * to retro_input_state_t (make sure 'device' is set to RETRO_DEVICE_JOYPAD).
+                                            * It will return a bitmask of all the digital buttons.
+                                            */
+
 /* VFS functionality */
 
 /* File paths:
- * File paths passed as parameters when using this api shall be well formed UNIX-style,
+ * File paths passed as parameters when using this API shall be well formed UNIX-style,
  * using "/" (unquoted forward slash) as directory separator regardless of the platform's native separator.
  * Paths shall also include at least one forward slash ("game.bin" is an invalid path, use "./game.bin" instead).
  * Other than the directory separator, cores shall not make assumptions about path format:
diff --git a/retroarch.c b/retroarch.c
index 9cc885d27b..9366ba9de8 100644
--- a/retroarch.c
+++ b/retroarch.c
@@ -2541,6 +2541,17 @@ int16_t input_state(unsigned port, unsigned device,
       is in action for that button*/
    bool reset_state    = false;
 
+   if (  (device == RETRO_DEVICE_JOYPAD) &&
+         (id == RETRO_DEVICE_ID_JOYPAD_MASK))
+   {
+      unsigned i;
+
+      for (i = 0; i < RARCH_FIRST_CUSTOM_BIND; i++)
+         if (input_state(port, device, idx, i))
+            res |= (1 << i);
+      return res;
+   }
+
    device &= RETRO_DEVICE_MASK;
 
    if (bsv_movie_get_input(&bsv_result))