The pixel shader is cool, but consumes too much resources. On my 1080Ti, uses about 20% of GPU to render, which is too expensive for such a simple graphics.

I’ve looked at the source, and it seems you’re doing too much computations there. Metaballs are usually rather simple, and they don’t require any trigonometric functions. Compute something like `sum( ball.z / length( pixel - ball.xy ) )` and apply the threshold. If you want anti-aliasing, use fwidth() for the screen-space partial derivative of that value after the loop, compute two thresholds around the iso-value, then smoothstep() instead of a hard threshold.

Also, consider moving the ball parameters (center and size) into a constant buffer and update them on CPU. Because there’s just a few balls, JavaScript is good enough for the job. Your current version computes these things from time for each pixel for each frame. There’re about 8 megapixels on my display, so these computation costs are escalating very quickly.