Graphics Cards Bryan Duggan
Overview • Resolutions & memory • What does a graphics card do? • Features • Texturing • Anti-aliasing • Ansiphromorphic filtering • Bump mapping • Z Buffering • Benchmarking & diagnostics • Manufacturers • Low end cards • Mid range cards • High end cards • Direct X • Open GL • AGP • PCI Express
Terminology • Pixel – Picture element - the basic unit of programmable color on a computer display or in a computer image • Resolution – how many pixels wide and tall • Bit depth or colour depth or Bits per pixel – How many bits are required to represent a pixel • The larger the bit depth, the more colours can be represented
BPP • 1 = Monochrome (0 = white, 1=black) • 4 = 16 colours • 8 = 256 colours (+ pallette) • 16 = 65536 colours (+ pallette) • 24 = 16M colours (true colour) red, green, blue • 32 = 16M colours (true colour) red, green, blue, transparency
Display devices • CRT – Cathode Ray Tube • Maximum resolution • Refresh rate (min 60 Hz) • LCD – Liquid Crystal Display • Optimum resolution • Refresh rate is less important • Response time (<25ms for games)
Resolutions & Memory • Originally, graphics memory was a factor of the resolution and colour depth supported • VGA 16 Colours @ 640 x 480 or 256 colours @ 320 x 200 x • SVGA 800 x 600 • XGA 16 million colors @ 800 x 600 or 1024 x 768 @ 65,536 • Super Extended Graphics Array (SXGA) and Ultra Extended Graphics Array (UXGA) 1280 x 1024 resolution • UXGA refers to a resolution of 1600 by 1200. • Palette info also stored
Memory was a factor of resolution & pallet size • E.g. 16 colours can be represented by 4 bits therefore 4 BPP (or 1 nibble or .5 of a byte) • VGA 640 x 480 x .5 = 153600 = 150k • VGA 320 * 200 = 64000 = 62.5k • SVGA 800 * 600 * 2 (16 bits per pixel) = 960000 + pallet 196608 = 393216 = 384k • Nowadays graphics cards have a between 32MB Ram and 256Mb • So what is all the extra memory used for??
What does a 3d graphics card do with all that memory!! • A 2d point can be represented by 2 numbers, X, Y • A 2d object is called a polygon. For example: • This can be easily manipulated by • Modifying the X, Y coords • Transformed • Scaled • Rotated • Etc.
3d objects • A 3d point can be represented by 3 numbers, X, Y, Z • 3d polygons are made up of a number of 2d polygons • Usually triangles
Primitives • Polygons are combined to make primitives. • Spheres • Cones • Cubes etc
Textures • Textures are then applied to the models • Textures are just bitmaps drawn onto a 3d object to make them more realistic • Games support different size textures for graphics cards with different capeabilities
Scenes • Games are set in virtual worlds known as scenes • Scenes can contain hundreds of 3d objects, thosands of polygons • A graphics card must render the scene at least 30 times per second to give the impression of fluid motion. • A typical scene from half life 2
Transformation • Transformation involves taking position data as it's stored in a vertex structure and transforming it into a 'screenspace' position. • 'Screenspace' refers to the 2D plane that represents the viewer's window onto the world
Lighting • Graphics cards also apply lighting effects to a scene, to create shadows in real time:
Depth of vision This can be used to optomise rendering. Faraway objects require less detail and therefore less work to render
Z Buffering • Z-buffering is an algorithm used in 3-D graphics to ensure that perspective works the same way in the virtual world as it does in the real one: a solid object in the foreground will block the view of one behind it.
Anti-aliasing • Adds intermediate pixels to reduce the staircase effect. • Up to 8 samples • Can slow down games, reducing frame rate
Bump Mapping • Bump mapping is a technique used in graphics programs to produce the appearance of textured surfaces. • It works by altering the brightnesses of the pixels in specific patterns. The result is similar to that produced when light shines at an angle on a surface. • By means of bump mapping, a sphere can be made to look like an orange. • An apparently horizontal plane can be given the appearance of a pond with ripples, an asphalt parking lot, or a grassy lawn. Bump mapping is used in gaming programs to produce the illusion of relief.
Graphic Card Companies • In 1998 there were more than 50 companies developing graphics chips • Today this number is much smaller • NVIDIA and ATI are two of the largest graphic card companies around now • NVIDIA and ATI are rivals that are always fighting for market share, and this is good for the end-user
Video Card Needs • Main categories of computer usage: • Casual computing • Graphic design • Light gaming • Heavy gaming
Casual Computing • Word processing, web browsing, watching a DVD, listening to music • Video card should support: • 32-bit colour depth – allows the display of over 16.7 million colours • 1280 x 1024 colour depth resolution • 85 Hz refresh rate – reduces eye fatigue over extended usage • ATI Radeon 9200 or NVIDIA GeForceFX 5200 processors
Graphic Design • Video card should support the following: • 1600 x 1200 depth resolution • Multi-monitor support - allows the card to support two computer displays at once, expanding the graphical workspace • For video editing • Video in/video out (VIVO) – allows a video source to be plugged into the computer for digitizing of analog video sources such as TV or VHS tapes as well as exporting a video signal back to those devices.
Light Gaming • Games that use 3D graphics acceleration • NVIDA GeForceFX 5700 and ATI Radeon 9600 are both excellent processors since they both support: • AGP 8x • DirectX 9 • 128 MB VRAM
Heavy Gaming • ATI Radeon 9800 and NVIDIA GeForceFX 5900 processors support: • DirectX 9 • 128 MB of VRAM • 256 MB of memory for future game support
ATI Graphics Processors • The R350 graphics processor is the direct successor to the R300 and is used in the highperformance Radeon 9700 line of graphics cards • The R350 is similar to the R300 in some ways: • They both use the 0.15 micron chip process • They both have 8 pixel pipelines and a 256 bit memory bus
ATI Graphics Processors • The R350 has advantages over the R300: • Increased clock speed • Pixel and vertex shader code • Refined and optimised Z-buffer code • There are three versions of the Radeon 9800 cards based on the R350 core: • Radeon 9800 w/128 MB • Radeon 9800 Pro w/128 MB • Radeon 9800 Pro w/256 MB
ATI Graphics Processors • The RV350 is ATI’s mid-range chip • RV350 uses the new 0.13 micron chip • Improved performance of the pixel and vertex shaders • 4 pixel pipelines • 128-bit memory bus • Used in the Radeon 9600 and Radeon Pro 9600 boards
ATI Graphics Processors • The Radeon 9200 are ATI’s value boards • They use the same features and functions of the older RV250, but now includes an AGP 8x compatible interface • Supports DirectX 8.1 pixel and vertex shaders so has limited future potential as more and more games are developed around DirectX 9
NVIDIA Graphics Processors • The GeForceFX 5600 boards based on the NV31 core are part of NVIDIA’s mid-range of boards • Performance of the GeForceFX 5600 Ultra boards is 25% faster than GeForce 4600 boards • Fully compatible with DirectX 9 and has the same vertex and pixel shaders as the 6800 Ultra processor
NVIDIA Graphics Processors • The NVIDIA budget range also has a fully DirectX 9 compliant video board with the same graphics features as the higher end processors • The NV34 based GeForceFX 5200 is built on a 0.15 micron chip • Performance features such as colour and z-compression are absent from these boards
Benchmarking • 3d Mark 2001 • 3d Mark 2003 • Aquamark • Quake 3 • Unreal tournament • DXDIAG • Sis Soft Sandra
DirectX • an application program interface (API) for creating and managing graphic images and multimedia effects in applications • Windows Only • Currently at Version 9.0b • Allows programs written to the DirectX standard to work with a variety of hardware • Use DXDIAG to diagnose problems
OpenGL • Silicon Graphics, DEC, Intel, IBM, Microsoft, and Sun Microsystems • Open, cross platform Standard
Game types • FPS – First Person Shooter • TPS – Third Person Shooter • RTS – Real Time Strategy • MMORPG – Massivly Multi-player Online Role Playing Game • Turn Based Strategy • Guess the following titles and their genres: