diff --git a/util/test/tests/GL/GL_Separable_Geometry_Shaders.py b/util/test/tests/GL/GL_Separable_Geometry_Shaders.py
index 9a1908c2d..8f81845d3 100644
--- a/util/test/tests/GL/GL_Separable_Geometry_Shaders.py
+++ b/util/test/tests/GL/GL_Separable_Geometry_Shaders.py
@@ -82,7 +82,30 @@ class GL_Separable_Geometry_Shaders(rdtest.TestCase):
 
         pipe: rd.PipeState = self.controller.GetPipelineState()
 
-        out = pipe.GetOutputTargets()[0].resourceId
-        self.check_pixel_value(out, 0.5, 0.1, [1.0, 0.0, 0.0, 1.0])
-        self.check_pixel_value(out, 0.75, 0.5, [0.0, 1.0, 0.0, 1.0])
-        self.check_pixel_value(out, 0.25, 0.5, [1.0, 0.0, 1.0, 0.0])
+        rt = pipe.GetOutputTargets()[0].resourceId
+        self.check_pixel_value(rt, 0.5, 0.1, [1.0, 0.0, 0.0, 1.0])
+        self.check_pixel_value(rt, 0.75, 0.5, [0.0, 1.0, 0.0, 1.0])
+        self.check_pixel_value(rt, 0.25, 0.5, [1.0, 0.0, 1.0, 0.0])
+
+        out: rd.ReplayOutput = self.controller.CreateOutput(rd.CreateHeadlessWindowingData(100, 100), rd.ReplayOutputType.Texture)
+
+        tex = rd.TextureDisplay()
+        tex.resourceId = rt
+        tex.overlay = rd.DebugOverlay.Drawcall
+        out.SetTextureDisplay(tex)
+        out.Display()
+
+        eps = 1.0 / 256.0
+
+        overlay_id: rd.ResourceId = out.GetDebugOverlayTexID()
+
+        self.check_pixel_value(overlay_id, 200, 100, [0.8, 0.1, 0.8, 1.0], eps=eps)
+        self.check_pixel_value(overlay_id, 50, 150, [0.8, 0.1, 0.8, 1.0], eps=eps)
+        self.check_pixel_value(overlay_id, 350, 150, [0.8, 0.1, 0.8, 1.0], eps=eps)
+
+        self.check_pixel_value(overlay_id, 200, 150, [0.0, 0.0, 0.0, 0.5], eps=eps)
+        self.check_pixel_value(overlay_id, 200, 225, [0.0, 0.0, 0.0, 0.5], eps=eps)
+        self.check_pixel_value(overlay_id, 75, 50, [0.0, 0.0, 0.0, 0.5], eps=eps)
+        self.check_pixel_value(overlay_id, 350, 50, [0.0, 0.0, 0.0, 0.5], eps=eps)
+
+        out.Shutdown()