Fix #19

app/src/main/java/com/kyant/glass/playground/Preview.kt

@@ -131,6 +131,11 @@ fun Preview() {
             float refractedDistance = circleMap(1.0 - -sd / height) * amount;
             float2 refractedDirection = normalize(normal + eccentricFactor * normalize(centeredCoord));
             float2 refractedCoord = coord + refractedDistance * refractedDirection;
+            if (refractedCoord.x < -0.5 || refractedCoord.x > size.x + 0.5 ||
+                refractedCoord.y < -0.5 || refractedCoord.y > size.y + 0.5) {
+                return half4(0.0, 0.0, 0.0, 1.0);
+            }
+            
             return image.eval(refractedCoord);
         } else {
             return image.eval(coord);