diff --git a/gsk/gpu/gskgpuboxshadowop.c b/gsk/gpu/gskgpuboxshadowop.c
index 46234aef67..5a404e62e9 100644
--- a/gsk/gpu/gskgpuboxshadowop.c
+++ b/gsk/gpu/gskgpuboxshadowop.c
@@ -10,6 +10,8 @@
 
 #include "gpu/shaders/gskgpuboxshadowinstance.h"
 
+#define VARIATION_INSET 1
+
 typedef struct _GskGpuBoxShadowOp GskGpuBoxShadowOp;
 
 struct _GskGpuBoxShadowOp
@@ -28,7 +30,7 @@ gsk_gpu_box_shadow_op_print (GskGpuOp    *op,
 
   instance = (GskGpuBoxshadowInstance *) gsk_gpu_frame_get_vertex_data (frame, shader->vertex_offset);
 
-  gsk_gpu_print_op (string, indent, instance->inset ? "inset-shadow" : "outset-shadow");
+  gsk_gpu_print_op (string, indent, shader->variation & VARIATION_INSET ? "inset-shadow" : "outset-shadow");
   gsk_gpu_print_rounded_rect (string, instance->outline);
   gsk_gpu_print_rgba (string, instance->color);
   g_string_append_printf (string, "%g %g %g %g ",
@@ -93,7 +95,7 @@ gsk_gpu_box_shadow_op (GskGpuFrame            *frame,
 
   gsk_gpu_shader_op_alloc (frame,
                            &GSK_GPU_BOX_SHADOW_OP_CLASS,
-                           0,
+                           inset ? VARIATION_INSET : 0,
                            clip,
                            NULL,
                            &instance);
@@ -105,6 +107,5 @@ gsk_gpu_box_shadow_op (GskGpuFrame            *frame,
   instance->shadow_offset[1] = shadow_offset->y;
   instance->shadow_spread = spread;
   instance->blur_radius = blur_radius;
-  instance->inset = inset ? 1 : 0;
 }
 
diff --git a/gsk/gpu/shaders/gskgpuboxshadow.glsl b/gsk/gpu/shaders/gskgpuboxshadow.glsl
index 5081e3cb02..8b0afc8b25 100644
--- a/gsk/gpu/shaders/gskgpuboxshadow.glsl
+++ b/gsk/gpu/shaders/gskgpuboxshadow.glsl
@@ -2,12 +2,13 @@
 
 /* blur radius (aka in_blur_direction) 0 is NOT supported and MUST be caught before */
 
+#define VARIATION_INSET ((GSK_VARIATION & 1u) == 1u)
+
 PASS(0) vec2 _pos;
 PASS_FLAT(1) RoundedRect _shadow_outline;
 PASS_FLAT(4) RoundedRect _clip_outline;
 PASS_FLAT(7) vec4 _color;
 PASS_FLAT(8) vec2 _sigma;
-PASS_FLAT(9) uint _inset;
 
 #ifdef GSK_VERTEX_SHADER
 
@@ -17,7 +18,6 @@ IN(4) vec4 in_color;
 IN(5) vec2 in_shadow_offset;
 IN(6) float in_shadow_spread;
 IN(7) float in_blur_radius;
-IN(8) uint in_inset;
 
 #define GAUSSIAN_SCALE_FACTOR ((3.0 * sqrt(2.0 * PI) / 4.0))
 
@@ -32,7 +32,7 @@ run (out vec2 pos)
   _clip_outline = outline;
 
   RoundedRect inside;
-  if (in_inset == 0u)
+  if (!VARIATION_INSET)
     {
       inside = outline;
       spread = -spread;
@@ -53,7 +53,6 @@ run (out vec2 pos)
   _shadow_outline = outline;
   _color = in_color;
   _sigma = GSK_GLOBAL_SCALE * 0.5 * in_blur_radius;
-  _inset = in_inset;
 }
 
 #endif
@@ -141,7 +140,7 @@ run (out vec4 color,
 {
   float clip_alpha = rounded_rect_coverage (_clip_outline, _pos);
 
-  if (_inset == 0u)
+  if (!VARIATION_INSET)
     clip_alpha = 1.0 - clip_alpha;
 
   if (clip_alpha == 0.0)
@@ -152,7 +151,7 @@ run (out vec4 color,
     }
 
   float blur_alpha = blur_rounded_rect (_shadow_outline, _pos);
-  if (_inset == 1u)
+  if (VARIATION_INSET)
     blur_alpha = 1.0 - blur_alpha;
 
   color = clip_alpha * _color * blur_alpha;