From b5451bf0a6dec6d31caccf8f223e528b67fddb26 Mon Sep 17 00:00:00 2001
From: Bobby Smith <33353403+bslenul@users.noreply.github.com>
Date: Fri, 22 May 2026 14:59:57 +0200
Subject: [PATCH] Add a core option for opposite directions

---
 libretro.cpp            | 29 +++++++++++++++++++++++++++++
 libretro_core_options.h | 11 +++++++++++
 2 files changed, 40 insertions(+)

diff --git a/libretro.cpp b/libretro.cpp
index bbdcb4f..9353dc6 100644
--- a/libretro.cpp
+++ b/libretro.cpp
@@ -80,11 +80,23 @@ static const uint32 AnaglyphPreset_Colors[][2] =
 };
 
 #define STICK_DEADZONE 0x4000
+#define LEFT_DPAD_LEFT 0x0080
+#define LEFT_DPAD_RIGHT 0x0040
+#define LEFT_DPAD_UP 0x0200
+#define LEFT_DPAD_DOWN 0x0100
 #define RIGHT_DPAD_LEFT 0x1000
 #define RIGHT_DPAD_RIGHT 0x0020
 #define RIGHT_DPAD_UP 0x0010
 #define RIGHT_DPAD_DOWN 0x2000
 
+// D-Pads opposite directions
+#define LEFT_DPAD_LEFT_RIGHT (LEFT_DPAD_LEFT | LEFT_DPAD_RIGHT)
+#define LEFT_DPAD_UP_DOWN (LEFT_DPAD_UP | LEFT_DPAD_DOWN)
+#define RIGHT_DPAD_LEFT_RIGHT (RIGHT_DPAD_LEFT | RIGHT_DPAD_RIGHT)
+#define RIGHT_DPAD_UP_DOWN (RIGHT_DPAD_UP | RIGHT_DPAD_DOWN)
+
+static bool opposite_directions = false;
+
 static uint32 VB3DMode;
 
 static Blip_Buffer sbuf[2];
@@ -2213,6 +2225,11 @@ static void check_variables(void)
          setting_vb_right_analog_to_digital = false;
    }
 
+   var.key = "vb_opposite_directions";
+
+   if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)
+      opposite_directions = !strcmp(var.value, "enabled");
+
    var.key = "vb_cpu_emulation";
 
    if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)
@@ -2409,6 +2426,18 @@ static void update_input(void)
             input_buf[j] |= (analog_y < 0) ^ !setting_vb_right_invert_y ? RIGHT_DPAD_DOWN : RIGHT_DPAD_UP;
       }
 
+      if (!opposite_directions)
+      {
+         if ((input_buf[j] & LEFT_DPAD_LEFT_RIGHT) == LEFT_DPAD_LEFT_RIGHT)
+            input_buf[j] &= ~LEFT_DPAD_LEFT_RIGHT;
+         if ((input_buf[j] & LEFT_DPAD_UP_DOWN) == LEFT_DPAD_UP_DOWN)
+            input_buf[j] &= ~LEFT_DPAD_UP_DOWN;
+         if ((input_buf[j] & RIGHT_DPAD_LEFT_RIGHT) == RIGHT_DPAD_LEFT_RIGHT)
+            input_buf[j] &= ~RIGHT_DPAD_LEFT_RIGHT;
+         if ((input_buf[j] & RIGHT_DPAD_UP_DOWN) == RIGHT_DPAD_UP_DOWN)
+            input_buf[j] &= ~RIGHT_DPAD_UP_DOWN;
+      }
+
 #ifdef MSB_FIRST
       union {
          uint8_t b[2];
diff --git a/libretro_core_options.h b/libretro_core_options.h
index f97014b..4fd3eee 100644
--- a/libretro_core_options.h
+++ b/libretro_core_options.h
@@ -183,6 +183,17 @@ struct retro_core_option_definition option_defs_us[] = {
       },
       "disabled",
    },
+   {
+      "vb_opposite_directions",
+      "Allow Opposite Directions",
+      "Allow pressing up and down or left and right directions at the same time. This may cause glitches.",
+      {
+         { "disabled", NULL },
+         { "enabled", NULL },
+         { NULL, NULL },
+      },
+      "disabled",
+   },
    {
       "vb_cpu_emulation",
       "CPU emulation  (Restart)",