CODEWITHSUNDEEP
gpu
Max
Max

Reputation: 1232

Why do desktop GPUs typically use immediate mode rendering instead of tile based deferred rendering?

In other words, what are the advantages of immediate mode rendering vs. TBDR, assuming you have ample memory, bandwidth, and power (as found on a desktop GPU)?

Upvotes: 4

Views: 3566

Answers (1)

rpjohnst
rpjohnst

Reputation: 1642

The main drawback of TBDRs is that they struggle with large amounts of geometry, because they sort it before rendering in order to achieve zero overdraw. This is not a huge deal on low-power GPUs because they deal with simpler scenes anyway.

Modern desktop GPUs do have early-z tests, so if you sort the geometry and draw it front-to-back you can still get most of the bandwidth minimization of a TBDR, and many non-deferred mobile GPUs still do tiling even if they don't sort the geometry.

Upvotes: 5

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