From afac587aab5265fda4c198f40ae054c74115f12b Mon Sep 17 00:00:00 2001
From: neonloop
Date: Wed, 9 Feb 2022 06:55:47 +0000
Subject: Adds frameskip interval for limiting max skipped frames

---
 libretro.c              | 17 ++++++++++++-----
 libretro_core_options.h | 29 ++++++++++++++++++++++++++---
 2 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/libretro.c b/libretro.c
index f64b71c..5e4dc31 100644
--- a/libretro.c
+++ b/libretro.c
@@ -70,13 +70,11 @@ static int32_t audio_low_pass_range = (60 * 65536) / 100;
 static unsigned frameskip_type             = 0;
 static unsigned frameskip_threshold        = 0;
 static uint16_t frameskip_counter          = 0;
+static unsigned frameskip_interval         = 0;
 
 static bool retro_audio_buff_active        = false;
 static unsigned retro_audio_buff_occupancy = 0;
 static bool retro_audio_buff_underrun      = false;
-/* Maximum number of consecutive frames that
- * can be skipped */
-#define FRAMESKIP_MAX 30
 
 static unsigned retro_audio_latency        = 0;
 static bool update_audio_latency           = false;
@@ -488,6 +486,7 @@ void retro_deinit(void)
    audio_low_pass_enabled     = false;
    audio_low_pass_range       = (60 * 65536) / 100;
 #endif
+   frameskip_interval         = 0;
    retro_audio_buff_active    = false;
    retro_audio_buff_occupancy = 0;
    retro_audio_buff_underrun  = false;
@@ -562,7 +561,7 @@ static void check_variables(bool first_run)
    {
       if (strcmp(var.value, "auto") == 0)
          frameskip_type = 1;
-      else if (strcmp(var.value, "manual") == 0)
+      else if (strcmp(var.value, "auto_threshold") == 0)
          frameskip_type = 2;
    }
 
@@ -593,6 +592,14 @@ static void check_variables(bool first_run)
       audio_low_pass_range = (strtol(var.value, NULL, 10) * 0x10000) / 100;
 #endif
 
+   var.key = "snes9x_2005_frameskip_interval";
+   var.value = NULL;
+
+   frameskip_interval = 4;
+
+   if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)
+      frameskip_interval = strtol(var.value, NULL, 10);
+
    var.key = "snes9x_2005_overclock_cycles";
    var.value = NULL;
 
@@ -690,7 +697,7 @@ void retro_run(void)
 
       if (skip_frame)
       {
-         if(frameskip_counter < FRAMESKIP_MAX)
+         if(frameskip_counter < frameskip_interval)
          {
             IPPU.RenderThisFrame = false;
             frameskip_counter++;
diff --git a/libretro_core_options.h b/libretro_core_options.h
index 28bb210..409590c 100644
--- a/libretro_core_options.h
+++ b/libretro_core_options.h
@@ -87,9 +87,9 @@ struct retro_core_option_v2_definition option_defs_us[] = {
       NULL,
       NULL,
       {
-         { "disabled", NULL },
-         { "auto",     "Auto" },
-         { "manual",   "Manual" },
+         { "disabled",       NULL },
+         { "auto",           "Auto" },
+         { "auto_threshold", "Threshold" },
          { NULL, NULL },
       },
       "disabled"
@@ -169,6 +169,29 @@ struct retro_core_option_v2_definition option_defs_us[] = {
       "60"
    },
 #endif
+   {
+      "snes9x_2005_frameskip_interval",
+      "Frameskip Interval",
+      NULL,
+      "The maximum number of frames that can be skipped before a new frame is rendered.",
+      NULL,
+      NULL,
+      {
+         { "0",  NULL },
+         { "1",  NULL },
+         { "2",  NULL },
+         { "3",  NULL },
+         { "4",  NULL },
+         { "5",  NULL },
+         { "6",  NULL },
+         { "7",  NULL },
+         { "8",  NULL },
+         { "9",  NULL },
+         { "10", NULL },
+         { NULL, NULL },
+      },
+      "4"
+   },
    {
       "snes9x_2005_overclock_cycles",
       "Reduce Slowdown (Hack, Unsafe, Restart)",
-- 
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