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Tom2D: Blitting

Part 2: 2D, Acceleration, And Windows: Aren't All Graphics Cards Equal?
By , Igor Wallossek

By blitting, we mean copying the contents of one bitmap into other bitmaps. In our test, we copy image clips.

Blitting benchmarkBlitting benchmark

Test  Content

For this test, we copy a total of 50,000 image clips ranging from 1x1 to 500x500 pixels in size, copied to a randomly-chosen position using block level transfer commands (blits). We alternate among the various copying styles, including copy, invert, and paint. As always, the seed for the random number generator is constant so that all test runs produce the same graphics information. And again, all objects are constrained to fit inside the display area, to make clipping unnecessary.

GDI Functions Called

Direct Block Level Transfer commands used:

BitBlt (copy, invert, paint)

Blt commands via the DIB buffer:

CreateCompatibleDC
CreateDIBSection
SelectObject
DeleteObject


Summary:

Block-level transfers show a general weakness in the Radeon HD 5000-series cards running XP in our tests. For buffered blitting, the Atom almost freezes completely, and the two top-rated cards are nearly unusable when running XP. In this case, both the GeForce GTX 285 and Radeon HD 5870 both perform at the same (poor) level.

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