diff --git a/backend/goglbackend/clip.go b/backend/goglbackend/clip.go
index be4d75a..3ccec5c 100644
--- a/backend/goglbackend/clip.go
+++ b/backend/goglbackend/clip.go
@@ -17,12 +17,11 @@ func (b *GoGLBackend) Clip(pts [][2]float64) {
 	b.activate()
 
 	b.ptsBuf = b.ptsBuf[:0]
-	min, max := extent(pts)
 	b.ptsBuf = append(b.ptsBuf,
-		float32(min[0]), float32(min[1]),
-		float32(min[0]), float32(max[1]),
-		float32(max[0]), float32(max[1]),
-		float32(max[0]), float32(min[1]))
+		0, 0,
+		0, float32(b.fh),
+		float32(b.fw), float32(b.fh),
+		float32(b.fw), 0)
 	for _, pt := range pts {
 		b.ptsBuf = append(b.ptsBuf, float32(pt[0]), float32(pt[1]))
 	}