just add everything!

assets/test.frag

@@ -23,5 +23,5 @@ void main()
     // float x = fract(fragTexCoord.s);
     // float final = smoothstep(divider - 0.1, divider + 0.1, x);
 
-    finalColor = vec4(fragTexCoord, 0.0, 1.0);
+    finalColor = fragColor;
 }