From b453e661ba9253708f7a9848c56981a876224a48 Mon Sep 17 00:00:00 2001
From: Apaczer <94932128+Apaczer@users.noreply.github.com>
Date: Tue, 18 Mar 2025 14:49:26 +0100
Subject: [PATCH] libretro: add "Interlace mode" to UNAI options

---
 frontend/libretro.c              | 12 ++++++++++++
 frontend/libretro_core_options.h | 14 ++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/frontend/libretro.c b/frontend/libretro.c
index 8571c458..03db4b40 100644
--- a/frontend/libretro.c
+++ b/frontend/libretro.c
@@ -949,6 +949,7 @@ static bool update_option_visibility(void)
          struct retro_core_option_display option_display;
          char gpu_unai_option[][40] = {
             "pcsx_rearmed_gpu_unai_blending",
+            "pcsx_rearmed_gpu_unai_skipline",
             "pcsx_rearmed_gpu_unai_lighting",
             "pcsx_rearmed_gpu_unai_fast_lighting",
             "pcsx_rearmed_gpu_unai_scale_hires",
@@ -2696,6 +2697,17 @@ static void update_variables(bool in_flight)
          pl_rearmed_cbs.gpu_unai.old_renderer = 0;
    }
 
+   var.key = "pcsx_rearmed_gpu_unai_skipline";
+   var.value = NULL;
+
+   if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)
+   {
+      if (strcmp(var.value, "disabled") == 0)
+         pl_rearmed_cbs.gpu_unai.ilace_force = 0;
+      else if (strcmp(var.value, "enabled") == 0)
+         pl_rearmed_cbs.gpu_unai.ilace_force = 1;
+   }
+
    var.key = "pcsx_rearmed_gpu_unai_lighting";
    var.value = NULL;
 
diff --git a/frontend/libretro_core_options.h b/frontend/libretro_core_options.h
index 3e80968b..de65b475 100644
--- a/frontend/libretro_core_options.h
+++ b/frontend/libretro_core_options.h
@@ -781,6 +781,20 @@ struct retro_core_option_v2_definition option_defs_us[] = {
       },
       "enabled",
    },
+   {
+      "pcsx_rearmed_gpu_unai_skipline",
+      "(GPU) Skip every 2nd line",
+      "Skip every 2nd line",
+      "Skips every second scanline. Can be enabled to improve performance at the expense of display inaccuracies (artifacts etc.).",
+      NULL,
+      "gpu_unai",
+      {
+         { "disabled", NULL },
+         { "enabled",  NULL },
+         { NULL, NULL},
+      },
+      "disabled",
+   },
    {
       "pcsx_rearmed_gpu_unai_lighting",
       "(GPU) Lighting Effects",
-- 
2.39.5