Hello world!

```
void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1).
    vec2 uv = fragCoord / iResolution.xy;

    // Output to screen as (r, g, b, alpha).
    fragColor = vec4(uv.x, uv.y, 0.0, 1.0);
}
```

“` void mainImage(out vec4 fragColor, in vec2 fragCoord) { // Normalized pixel coordinates (from 0 to 1). vec2 uv = fragCoord / iResolution.xy; // Output to screen as (r, g, b, alpha). fragColor = vec4(uv.x, uv.y, 0.0, 1.0); } “`