diff --git a/autogen/lua_definitions/constants.lua b/autogen/lua_definitions/constants.lua
index 1209e9a0c..0d4414670 100644
--- a/autogen/lua_definitions/constants.lua
+++ b/autogen/lua_definitions/constants.lua
@@ -2982,7 +2982,8 @@ SHADER_FLAG_CONTRAST      = 3 --- @type ShaderFlag
 SHADER_FLAG_EXPOSURE      = 4 --- @type ShaderFlag
 SHADER_FLAG_DITHERING     = 5 --- @type ShaderFlag
 SHADER_FLAG_POSTERIZATION = 6 --- @type ShaderFlag
-SHADER_FLAG_MAX           = 7 --- @type ShaderFlag
+SHADER_FLAG_SCANLINES     = 7 --- @type ShaderFlag
+SHADER_FLAG_MAX           = 8 --- @type ShaderFlag
 
 --- @alias ShaderFlag
 --- | `SHADER_FLAG_HUE`
@@ -2992,6 +2993,7 @@ SHADER_FLAG_MAX           = 7 --- @type ShaderFlag
 --- | `SHADER_FLAG_EXPOSURE`
 --- | `SHADER_FLAG_DITHERING`
 --- | `SHADER_FLAG_POSTERIZATION`
+--- | `SHADER_FLAG_SCANLINES`
 --- | `SHADER_FLAG_MAX`
 
 --- @type integer
diff --git a/docs/lua/constants.md b/docs/lua/constants.md
index 42b541fa6..190d1738c 100644
--- a/docs/lua/constants.md
+++ b/docs/lua/constants.md
@@ -1340,7 +1340,8 @@
 | SHADER_FLAG_EXPOSURE | 4 |
 | SHADER_FLAG_DITHERING | 5 |
 | SHADER_FLAG_POSTERIZATION | 6 |
-| SHADER_FLAG_MAX | 7 |
+| SHADER_FLAG_SCANLINES | 7 |
+| SHADER_FLAG_MAX | 8 |
 
 [:arrow_up_small:](#)
 
diff --git a/src/pc/gfx/gfx_opengl.c b/src/pc/gfx/gfx_opengl.c
index 08f36676c..84d82b084 100644
--- a/src/pc/gfx/gfx_opengl.c
+++ b/src/pc/gfx/gfx_opengl.c
@@ -506,6 +506,12 @@ static struct ShaderProgram *gfx_opengl_create_and_load_new_shader(struct ColorC
         append_line(fs_buf, &fs_len, "int levels = int(uShaderFlagValues[6]);");
         append_line(fs_buf, &fs_len, "texel.rgb = floor(texel.rgb * levels) / levels;");
         append_line(fs_buf, &fs_len, "}");
+
+        // scan lines
+        append_line(fs_buf, &fs_len, "if (uShaderFlags[7] == 1) {");
+        append_line(fs_buf, &fs_len, "float scan = sin(gl_FragCoord.y * 1.5) * 0.04;");
+        append_line(fs_buf, &fs_len, "texel.rgb -= scan * uShaderFlagValues[7];");
+        append_line(fs_buf, &fs_len, "}");
     }
 
     if (opt_fog) {
diff --git a/src/pc/gfx/gfx_pc.c b/src/pc/gfx/gfx_pc.c
index 4f8f1fbb5..c166cf71c 100644
--- a/src/pc/gfx/gfx_pc.c
+++ b/src/pc/gfx/gfx_pc.c
@@ -126,7 +126,7 @@ Color gFogColor = { 0xFF, 0xFF, 0xFF };
 f32 gFogIntensity = 1;
 
 int gShaderFlags[SHADER_FLAG_MAX] = { 0 };
-f32 gDefaultShaderFlagValues[SHADER_FLAG_MAX] = { 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 8.0f };
+f32 gDefaultShaderFlagValues[SHADER_FLAG_MAX] = { 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 8.0f, 1.0f };
 f32 gShaderFlagValues[SHADER_FLAG_MAX] = { 0 };
 bool gShaderFlagsScreen = false;
 
diff --git a/src/pc/gfx/gfx_pc.h b/src/pc/gfx/gfx_pc.h
index f3047988c..649c8c95e 100644
--- a/src/pc/gfx/gfx_pc.h
+++ b/src/pc/gfx/gfx_pc.h
@@ -12,6 +12,7 @@ enum ShaderFlag {
     SHADER_FLAG_EXPOSURE,
     SHADER_FLAG_DITHERING,
     SHADER_FLAG_POSTERIZATION,
+    SHADER_FLAG_SCANLINES,
     SHADER_FLAG_MAX
 };
 
diff --git a/src/pc/lua/smlua_constants_autogen.c b/src/pc/lua/smlua_constants_autogen.c
index 7ac920737..a1be787a3 100644
--- a/src/pc/lua/smlua_constants_autogen.c
+++ b/src/pc/lua/smlua_constants_autogen.c
@@ -1547,7 +1547,8 @@ char gSmluaConstants[] = ""
 "SHADER_FLAG_EXPOSURE=4\n"
 "SHADER_FLAG_DITHERING=5\n"
 "SHADER_FLAG_POSTERIZATION=6\n"
-"SHADER_FLAG_MAX=7\n"
+"SHADER_FLAG_SCANLINES=7\n"
+"SHADER_FLAG_MAX=8\n"
 "GRAPH_RENDER_ACTIVE=(1 << 0)\n"
 "GRAPH_RENDER_CHILDREN_FIRST=(1 << 1)\n"
 "GRAPH_RENDER_BILLBOARD=(1 << 2)\n"