03/18/2003
15-462 Graphics I
11
Displays and Framebuffers
•Image
stored in memory as 2D pixel array, called framebuffer
•Value
of each pixel controls color
•Video
hardware scans the framebuffer at 60Hz
•Depth of framebuffer is information per pixel
–1 bit:
black and white display (cf. Smithsonian)
–8 bit:
256 colors at any given time via colormap
–16
bit: 5, 6, 5 bits (R,G,B), 216 = 65,536 colors
–24 bit: 8, 8, 8 bits (R,G,B), 224 = 16,777,216 colors