How images are produced.
WHAT THE RASTERISATION PIPELINE DOES
Transforms geometry into screen space Determines which pixels each triangle covers Computes a colour for each Resolves visibility between overlapping surfaces
WHAT A VERTEX SHADER DOES
Transforms each vertex, typically into screen coordinates.
WHAT A FRAGMENT SHADER DOES
Computes the colour of each covered pixel.
WHAT THE DEPTH BUFFER DOES
Records depth per pixel, so nearer surfaces occlude farther ones.
WHAT RAY TRACING DOES INSTEAD
Traces rays from the camera into the scene, computing what they strike.
WHAT IT PROVIDES
Physically accurate reflection, refraction and shadows.
WHAT IT COSTS
Far more computation.
WHAT MODERN HARDWARE PROVIDES
Acceleration for parts of it, enabling hybrid approaches.
WHAT PHYSICALLY BASED RENDERING MEANS
Material models derived from how light actually behaves.
WHY IT MATTERS
Materials look correct under any lighting, rather than being tuned per scene.
WHAT DOMINATES PERFORMANCE
Overdraw, texture bandwidth, and the number of separate draw calls.
WHAT TO MEASURE
Frame time, not frame rate.
WHY
Frame time is linear and reveals variance; frame rate conceals it.
