Graphics › The frame
The frame budget on the graphics card
Know first: Shader: a function for every pixel, How an engine draws a frame: passes and the G-buffer, LOD, instancing and Nanite: drawing a million blades of grass
Every pass in this course draws on one budget: a few milliseconds per frame. This lesson adds up the bill. It explains why milliseconds measure a frame better than frames per second, and whether the CPU or the graphics card is the one that waits. It also shows where the time and the video memory go, why grass, shadows and transparency cost so much, and how to find the bottleneck instead of guessing. It is the thirteenth and last lesson of the course “How an engine draws a frame.”
Why this matters
Every lesson of the course named a price: shadows are the scene drawn one more time, transparency is layers on top of layers, Lumen is milliseconds in every frame. But prices on their own do not tell you whether the whole frame fits. Without this lesson, several things stay puzzling:
- why a game stutters even though every setting on its own is “cheap”;
- why lowering the resolution sometimes saves the frame and sometimes changes nothing;
- why textures suddenly turn blurry while the graphics card is not even busy;
- what an artist can do alone, without waiting for a programmer.