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Graphics Hardware Display Technologies

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Graphics Hardware Display Technologies Graphics Hardware Display Technologies Display (CRT, LCD,…) Front projection Graphics accelerator BkBack pro jtijection Scan controller Video Memory (frame buffer) Direct view Display/Graphics Processor Backlit CPU/Memory/Disk … Display Technologies Trade-offs CRT LED Cost, Weight, Size LCD Power consumption Plasma Panels Spatial & Color resolution DLP Peak brightness, Black, contrast OLED Etc. Etc. 1 Cathode Ray Tube (CRT) 1 2 3 4 5 6 1. Filament (generate heat) 2. Cathode (emit electrons) 3. Control grid (control intensity) 4. Focus 5. Deflector 6. Phosphor coating - Direct view Color CRT LED - backlight source 3 electron guns, 3 color phosphor dots at each pixel Color = (red, green, blue) Black = (0,0,0) White = (1,1,1) Red = 0 to 100% Red = (1,0,0) Green = 0 to 100% Green = (0,1,0) Blue = 0 to 100% Blue = (0,0,1) … 2 LCD: backlit Plasma Panels: emit light; soon extinct? DLP: http://www.dlp.com/includes/video_demo.aspx Trade-offs For digital projection Peak brightness Black level Digital Micromirror Device Contrast Rear projection Screen brightness FtFront pro jtijection Motion artifaces Direct view Aging Backlit Maximum resolution Thickness Weight Power consumption http://www.displaymate.com/ShootOut_Comparison.htm 3 Random Scan Order Vector graphics Display list Old way: No pixels - The electron gun Move (100,200) Draw(200,200) draws straight lines from location to Draw(200,100) location on the screen (vector graphics) Draw(100,100) a.k.a. calligraphic display, Random scan device, vector drawing display Use either display list or storage tube technology Raster Display graphics How CRT draws a picture Digital Display Based on (analog) raster-scan TV technology The screen (and a picture) consists of discrete pixels We have only one electron gun but many pixels in a picture need to be lit simultaneously… 4 Refresh of CRT Frame Buffer Refresh – the electron gun needs to come back to Frame buffer: the memory to hold the pixel intensity hit the pixel again before it fades out values Properties of a frame buffer that affect the graphics An appropriate fresh rate depends on the property of performance: phosphor coating Size: screen resolution Phosphor persistence: the time it takes for the Depth: color level emitted light to decay to 1/10 of the original intensity 1 bit/pixel: black and white 8 bits/pixel: 256 levels of gray Typical refresh rate: 60 – 80 times per second (Hz) 24 bits/pixel: 16 million colors (What will happen if refreshing is too slow or too Speed: refresh speed fast?) Raster Scan Order Raster Scan Order What we do now: the electron gun will The electron gun will scan through the scan through the pixels from left to pixels from left to right, top to bottom right, top to bottom (scanline by (scanline by scanline) scanline) Horizontal retrace 5 Raster Scan Order Progressive vs. Interlace The electron gun will scan through the Progressive: Scan every scan line pixels from left to right, top to bottom Interlace: Scan only every other scan (scanline by scanline) line (e ven ->odd> odd ->e> ev en ->odd> odd …) - so the refresh rate becomes twice as fast Vertical retrace 0 Even scan 1 2 3 Odd scan 4 5 Standards Raster Scan Control NTSC: Interlaced, 525 line, 59.94Hz, Scan Controller (video adaptor) and frame 4:3 buffer DTV: Digit al ve rsion of NTSC , 480i , 4 :3 x Scan controller y HDTV: e.g. 720p, 60Hz, 16:9 Blu-ray: 1080p Other standards? DAC Frame buffer 6 Color is expensive … Color Lookup Table At least used to be Say I am a poor man … I only have 3 bits per pixel The more color you want, the more bits you But I insist on having high quality pictures … will need for each pixel Use Color Look Up Table (LUT) Exercise: 1024 x 1280 screen with R G B 0 1 24 bits per pixel, how many bytes in the 2 You can still have 24 bits 3 in each of the color table frame buffer? 4 5 entries 6 24 bit wide 1024 x 1280 x 24 / 8 = 4M Byte 7 3 bits/pixel frame buffer @30fps = 120MB/sec A simple graphics system Dedicated memory Frame buffer can be part Video memory: On-board frame buffer: Scan much faster to access of the main memory Controller Scan Frame Controller buffer Frame CPU Main Memory buffer CPU Main Memory System bus System bus Problem? 7 Graphics Accelerator Graphics Accelerator Graphics Memory/ Frame buffer A dedicated processor Graphics Scan for graphics processing Processor Controller CPU Main Memory System bus Graphics Accelerator NVIDIA GPUs Quadro FX 5600 Quadro FX 4600 Memory Size 1.5GB GDDR3 768MB GDDR3 Memory Interface 384-bit 384-bit Memory 76.8 GB/sec. 67.2 GB/sec. Bandwidth Max Power 171W 134W Consumption Number of Slots 2 2 Display Connectors DVI-I DVI-I Stereo DVI-I DVI-I Stereo Dual-Link DVI 2 2 Price $2,999.00 $1,999.00 8 AMD GPUs Desktop vs Mobility Radeon Graphics Desktop Desktop Radeon HD Radeon HD Radeon HD 6990M 6990 6870 Transistors 5.28 billion 1.7 billion 1.7 billion Engine Clock 830 MHz 900 MHz 715 MHz Shader 3072 1120 1120 (ALUs) Texture Units 192 56 56 ROP Units643232 Compute 5.1 TFLOPS 2.01 TFLOPS 1.60 TFLOPS Performance DRAM Type GDDR5-5000 GDDR5-4200 GDDR5-3600 DRAM 256-bits per 256-bits 256-bits Interface GPU Memory 160 GB/s per 134 GB/s 115.2 GB/s Bandwidth GPU TDP 375 W 151 W 100 W GPUs The Graphics Pipeline The Evolution of GPUs ftp://download.nvidia.com/developer/presentations/2004/Perfect_Kitchen_Art/English_Evolution_of_GPUs.pdf THE GPU COMPUTING ERA http://sbel.wisc.edu/Courses/ME964/2011/Literature/onGPUcomputingDally2010.pdf 9 Graphics Bus Interface Graphics Bus Interface (2) PCI based technology PCI Bus becomes the bottleneck! Many devices are using it GaphicsMemoGraphics Memory / Other There is a lot of stuff needs to be Frame buffer Peripherals transmitted from main memory to graphics Graphics Scan memory (geometry, textures, etc) Processor Controller PCI Bus – 132 MB/s Example: 2M triangle, 90 Bytes each – 180MB > 132 MB (PCI bandwidth) System Bus – 800MB/s CPU Main Memory Accelerated Graphics Port (AGP) AGP A dedicated bus that allows direct access of main memory AGP 1x is four times as fast compared to PCI! (now we have AGP 8x) Grappy/hics Memory/ Other Frame buffer Peripherals No more llblocal bus congestion! Graphics Scan More geometry can be processed! Processor Controller PCI Bus – 132 MB/s Direct execution of many graphics AGP 1x: 518 MB/s operations from main memory Fast!!! CPU Main Memory 10 PCI Express Reading and Lab1 Bandwidth? Textbook Chapter 1, 2 Lab 1: Compile and run the sample OpenGL program posted on the class web site 11.
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