This is the part you pay for, and the one thing no other editor has at any price. Author a GLSL shader clip in a built-in code editor, or import one from ISF or Shadertoy with a click, and it receives the DonutStudio uniform contract every frame: a 128-voice note texture with pitch and cents, velocity, age, resolved frequency, JI ratio against the root, and prime-exponent lattice coordinates, plus the root path, chord aggregates, and about a bar of lookahead. Multipass and feedback buffers are first-class. That lookahead lets DonutStudio's visuals anticipate a note before it sounds.
The flagship, Harmonic Strings: notes appear as they play, and the link graph's strings vibrate as the a:b standing waves of their ratios. Pure just intonation stands perfectly still; temperament shimmers. The picture is literally a readout of the tuning.
The timeline takes many more clip types. Generator clips paint solids, gradients, and images; GPU particle clips are seeded by the notes themselves; SDF raymarch clips put 3D geometry in the timeline; adjustment clips grade everything beneath them; and HDR bloom finishes the composite. When a knob isn't enough, write the frame: per-clip Lua or JavaScript runs every frame with the full musical context in scope, including JI cents, the prime lattice, and note and chord state. A clip's parameters can be a function of the harmony.