Graphics › The frame
Anti-aliasing: stair-steps, flicker and TSR
Know first: How an engine draws a frame: passes and the G-buffer, UV: how a picture gets onto a model, Interpolation: lerp, smoothstep and remap
A screen is a mosaic of square tiles, and each tile can be only one color. That is where the stair-steps on edges come from, along with the sparkles on smooth metal and the flicker of wires and foliage when the camera moves. This lesson explains why it happens and how supersampling, MSAA, FXAA and temporal anti-aliasing differ. It shows where ghosting comes from, why upscalers such as TSR and DLSS use the same trick, and what an artist can do. This is the tenth lesson of the course “How an engine draws a frame.”
Why this matters
A model’s edge shimmers, a fence in the distance turns into a striped mess, and wires break into dashes. You turn on anti-aliasing, and now a trail follows the running character while the grass goes soft. Without this lesson, four things stay unclear:
- why stair-steps are not a modeling error but a property of every screen;
- why one kind of anti-aliasing removes stair-steps but not the sparkles on a shiny floor;
- where ghosting and blur in motion come from, and why they are also a price of anti-aliasing;
- how a game draws in 4K while computing a quarter as many pixels.