diff --git a/Data/Sys/Shaders/crt_pi.glsl b/Data/Sys/Shaders/crt_pi.glsl
index 8bd1334f26..dcdb3725f3 100644
--- a/Data/Sys/Shaders/crt_pi.glsl
+++ b/Data/Sys/Shaders/crt_pi.glsl
@@ -159,12 +159,12 @@ much the mask type darkens the screen.
 [MASK_TYPE has been replaced with SHADOW_MASK and MASK_TRINITRON]
 */
 
-vec2 CURVATURE_DISTORTION = vec2(GetOption(CURVATURE_X), GetOption(CURVATURE_Y));
-// Barrel distortion shrinks the display area a bit, this will allow us to counteract that.
-vec2 barrelScale = 1.0 - (0.23 * CURVATURE_DISTORTION);
-
 vec2 Distort(vec2 coord)
 {
+    vec2 CURVATURE_DISTORTION = vec2(GetOption(CURVATURE_X), GetOption(CURVATURE_Y));
+    // Barrel distortion shrinks the display area a bit, this will allow us to counteract that.
+    vec2 barrelScale = 1.0 - (0.23 * CURVATURE_DISTORTION);
+
 //  coord *= screenScale; // not necessary in slang
     coord -= vec2(0.5);
     float rsq = coord.x * coord.x + coord.y * coord.y;