This illustrates a simple ray marcher in action. Press the flag to render, press the [ + ] to add spheres https://turbowarp.org/507129553 runs between 10 - 20x faster. Shows how much better raymarchers scale with more shapes.
A Distance field ray marcher works very simply. for spheres, you measure the distance to the center of the sphere and subtract the radius. You then move that distance forward, rinse, and repeat. I eventually want to ray march some volumetric clouds.