1. UBI 516 Advanced Computer Graphics Aydın Öztürk ozturk@ube.ege.edu.tr http://www.ube.ege.edu.tr/~ozturk Aydın Öztürk ozturk@ube.ege.edu.tr http://www.ube.ege.edu.tr/~ozturk

2. Administrivia Syllabus Instructor/TA coordinatesInstructor/TA coordinates PrereqsPrereqs TextsTexts AssignmentsAssignments Topic listTopic listSyllabus Instructor/TA coordinatesInstructor/TA coordinates PrereqsPrereqs TextsTexts AssignmentsAssignments Topic listTopic list

3. Textbook Computer Graphics with OpenGLComputer Graphics with OpenGL –Third Edition –Hearn and Baker Computer Graphics with OpenGLComputer Graphics with OpenGL –Third Edition –Hearn and Baker

4. The Basics Computer graphics: generating 2D images of a 3D world represented in a computer. Main tasks: modeling: creating and representing the geometry of objects in the 3D worldmodeling: creating and representing the geometry of objects in the 3D world rendering: generating 2D images of the objectsrendering: generating 2D images of the objects animation: describing how objects change in timeanimation: describing how objects change in time Computer graphics: generating 2D images of a 3D world represented in a computer. Main tasks: modeling: creating and representing the geometry of objects in the 3D worldmodeling: creating and representing the geometry of objects in the 3D world rendering: generating 2D images of the objectsrendering: generating 2D images of the objects animation: describing how objects change in timeanimation: describing how objects change in time

5. Why Study Computer Graphics? Graphics is cool I like to see what I’m doingI like to see what I’m doing I like to show people what I’m doingI like to show people what I’m doing Graphics is interesting Involves simulation, algorithms, architecture…Involves simulation, algorithms, architecture… I’ll never get an Oscar for my acting But maybe I’ll get one for my CG special effectsBut maybe I’ll get one for my CG special effects Graphics is fun Graphics is cool I like to see what I’m doingI like to see what I’m doing I like to show people what I’m doingI like to show people what I’m doing Graphics is interesting Involves simulation, algorithms, architecture…Involves simulation, algorithms, architecture… I’ll never get an Oscar for my acting But maybe I’ll get one for my CG special effectsBut maybe I’ll get one for my CG special effects Graphics is fun

6. Graphics Applications Entertainment: Cinema Pixar: Monster’s Inc. Square: Final Fantasy

7. Final Fantasy (Square, USA) Graphics Applications Entertainment: Cinema

8. Graphics Applications GT Racer 3 Polyphony Digital: Gran Turismo 3, A Spec Entertainment: Games

9. Graphics Applications Video Games

10. Graphics Applications Medical Visualization MIT: Image-Guided Surgery Project The Visible Human Project

11. Graphics Applications Computer Aided Design (CAD)

12. Graphics Applications Scientific Visualization

13. Graphics Applications Everyday Use Microsoft’s Whistler OS will use graphics seriouslyMicrosoft’s Whistler OS will use graphics seriously Graphics visualizations and debuggersGraphics visualizations and debuggers Visualize complex software systemsVisualize complex software systems Everyday Use Microsoft’s Whistler OS will use graphics seriouslyMicrosoft’s Whistler OS will use graphics seriously Graphics visualizations and debuggersGraphics visualizations and debuggers Visualize complex software systemsVisualize complex software systems

14. Everyday use

15. Window system and large-screen interaction metaphors (François Guimbretière)

16. Education Outside In (Geometry Center, University of Minnesota)

17. Current Technologies

18. Impact of Computers Moore’s Law Power of a CPU doubles every 18 months / 2 years Moore’s Law Power of a CPU doubles every 18 months / 2 years

19. Impact of Video Games (Nvidia) Number of transistors on GPU doubles each 6 months. Three times Moore’s LawThree times Moore’s Law –Good article on Jen-Hsun Huang, Nvidia CEO: http://www.wired.com/wired/archive/10.07/Nvidia_pr.html Number of transistors on GPU doubles each 6 months. Three times Moore’s LawThree times Moore’s Law –Good article on Jen-Hsun Huang, Nvidia CEO: http://www.wired.com/wired/archive/10.07/Nvidia_pr.html $7 Billion Man $5.6 Billion Man Worldwide revenues Retro flashback??? Lee Majors Col. Steve Austin

20. Impact of Video Games But… Video game sales is roughly same as Hollywood box officeVideo game sales is roughly same as Hollywood box office Americans bought $3.2 billion in VCRs and DVDs in 2002Americans bought $3.2 billion in VCRs and DVDs in 2002 Total revenues to movie studios is 5 times total video game revenuesTotal revenues to movie studios is 5 times total video game revenuesBut… Video game sales is roughly same as Hollywood box officeVideo game sales is roughly same as Hollywood box office Americans bought $3.2 billion in VCRs and DVDs in 2002Americans bought $3.2 billion in VCRs and DVDs in 2002 Total revenues to movie studios is 5 times total video game revenuesTotal revenues to movie studios is 5 times total video game revenues

21. Future of Consoles 33 million PS2s (in 2002)33 million PS2s (in 2002) 3.9 million Xboxes (in 2002)3.9 million Xboxes (in 2002) –MSFT still losing lots of $$ per console Predicted 200 million PDA/Cell game players in 2005Predicted 200 million PDA/Cell game players in 2005 33 million PS2s (in 2002)33 million PS2s (in 2002) 3.9 million Xboxes (in 2002)3.9 million Xboxes (in 2002) –MSFT still losing lots of $$ per console Predicted 200 million PDA/Cell game players in 2005Predicted 200 million PDA/Cell game players in 2005

22. Display technologies Cathode Ray Tubes (CRTs) Most common display device todayMost common display device today Evacuated glass bottleEvacuated glass bottle Extremely high voltageExtremely high voltage Cathode Ray Tubes (CRTs) Most common display device todayMost common display device today Evacuated glass bottleEvacuated glass bottle Extremely high voltageExtremely high voltage

23. CRT details Heating element (filament)Heating element (filament) Electrons pulled towards anode focusing cylinderElectrons pulled towards anode focusing cylinder Vertical and horizontal deflection platesVertical and horizontal deflection plates Beam strikes phosphor coating on front of tubeBeam strikes phosphor coating on front of tube Heating element (filament)Heating element (filament) Electrons pulled towards anode focusing cylinderElectrons pulled towards anode focusing cylinder Vertical and horizontal deflection platesVertical and horizontal deflection plates Beam strikes phosphor coating on front of tubeBeam strikes phosphor coating on front of tube

24. Electron Gun Contains a filament that, when heated, emits a stream of electrons Electrons are focused with an electromagnet into a sharp beam and directed to a specific point of the face of the picture tube The front surface of the picture tube is coated with small phospher dots When the beam hits a phospher dot it glows with a brightness proportional to the strength of the beam and how long it is hit Contains a filament that, when heated, emits a stream of electrons Electrons are focused with an electromagnet into a sharp beam and directed to a specific point of the face of the picture tube The front surface of the picture tube is coated with small phospher dots When the beam hits a phospher dot it glows with a brightness proportional to the strength of the beam and how long it is hit

25. CRT characteristics What’s the largest (diagonal) CRT you’ve seen? Why is that the largest?Why is that the largest? –Evacuated tube == massive glass –Symmetrical electron paths (corners vs. center) How might one measure CRT capabilities? Size of tubeSize of tube Brightness of phosphers vs. darkness of tubeBrightness of phosphers vs. darkness of tube Speed of electron gunSpeed of electron gun Width of electron beamWidth of electron beam Pixels?Pixels? What’s the largest (diagonal) CRT you’ve seen? Why is that the largest?Why is that the largest? –Evacuated tube == massive glass –Symmetrical electron paths (corners vs. center) How might one measure CRT capabilities? Size of tubeSize of tube Brightness of phosphers vs. darkness of tubeBrightness of phosphers vs. darkness of tube Speed of electron gunSpeed of electron gun Width of electron beamWidth of electron beam Pixels?Pixels?

26. Display technologies: CRTs Vector Displays Anybody remember Battlezone? Tempest?Anybody remember Battlezone? Tempest? Vector Displays Anybody remember Battlezone? Tempest?Anybody remember Battlezone? Tempest?

27. Display Technologies: CRTs Vector Displays Early computer displays: basically an oscilloscopeEarly computer displays: basically an oscilloscope Control X,Y with vertical/horizontal plate voltageControl X,Y with vertical/horizontal plate voltage Often used intensity as ZOften used intensity as Z Name two disadvantages Just does wireframe Just does wireframe Complex scenes cause visible flicker Complex scenes cause visible flicker Vector Displays Early computer displays: basically an oscilloscopeEarly computer displays: basically an oscilloscope Control X,Y with vertical/horizontal plate voltageControl X,Y with vertical/horizontal plate voltage Often used intensity as ZOften used intensity as Z Name two disadvantages Just does wireframe Just does wireframe Complex scenes cause visible flicker Complex scenes cause visible flicker

28. Display Technologies: CRTs Raster Displays Raster: A rectangular array of points or dotsRaster: A rectangular array of points or dots Pixel: One dot or picture element of the rasterPixel: One dot or picture element of the raster Scan line: A row of pixelsScan line: A row of pixels Raster Displays Raster: A rectangular array of points or dotsRaster: A rectangular array of points or dots Pixel: One dot or picture element of the rasterPixel: One dot or picture element of the raster Scan line: A row of pixelsScan line: A row of pixels

29. Display technologies: CRTs Raster Displays Black and white television: an oscilloscope with a fixed scan pattern: left to right, top to bottomBlack and white television: an oscilloscope with a fixed scan pattern: left to right, top to bottom –As beam sweeps across entire face of CRT, beam intensity changes to reflect brightness Analog signal vs. digital displayAnalog signal vs. digital display Raster Displays Black and white television: an oscilloscope with a fixed scan pattern: left to right, top to bottomBlack and white television: an oscilloscope with a fixed scan pattern: left to right, top to bottom –As beam sweeps across entire face of CRT, beam intensity changes to reflect brightness Analog signal vs. digital displayAnalog signal vs. digital display

30. Display technologies: CRT Can a computer display work like a black and white TV? Must synchronizeMust synchronize –Your program makes decisions about the intensity signal at the pace of the CPU… –The screen is “painted” at the pace of the electron gun scanning the raster Solution: special memory to buffer image with scan-out synchronous to the raster. We call this the framebuffer.Solution: special memory to buffer image with scan-out synchronous to the raster. We call this the framebuffer. Digital description to analog signal to digital displayDigital description to analog signal to digital display Can a computer display work like a black and white TV? Must synchronizeMust synchronize –Your program makes decisions about the intensity signal at the pace of the CPU… –The screen is “painted” at the pace of the electron gun scanning the raster Solution: special memory to buffer image with scan-out synchronous to the raster. We call this the framebuffer.Solution: special memory to buffer image with scan-out synchronous to the raster. We call this the framebuffer. Digital description to analog signal to digital displayDigital description to analog signal to digital display

31. Display Technologies: CRTs Phosphers Flourescence: Light emitted while the phospher is being struck by electronsFlourescence: Light emitted while the phospher is being struck by electrons Phospherescence: Light emitted once the electron beam is removedPhospherescence: Light emitted once the electron beam is removed Persistence: The time from the removal of the excitation to the moment when phospherescence has decayed to 10% of the initial light outputPersistence: The time from the removal of the excitation to the moment when phospherescence has decayed to 10% of the initial light outputPhosphers Flourescence: Light emitted while the phospher is being struck by electronsFlourescence: Light emitted while the phospher is being struck by electrons Phospherescence: Light emitted once the electron beam is removedPhospherescence: Light emitted once the electron beam is removed Persistence: The time from the removal of the excitation to the moment when phospherescence has decayed to 10% of the initial light outputPersistence: The time from the removal of the excitation to the moment when phospherescence has decayed to 10% of the initial light output

32. Display Technologies: CRTs Refresh Frame must be “refreshed” to draw new imagesFrame must be “refreshed” to draw new images As new pixels are struck by electron beam, others are decayingAs new pixels are struck by electron beam, others are decaying Electron beam must hit all pixels frequently to eliminate flickerElectron beam must hit all pixels frequently to eliminate flicker Critical fusion frequencyCritical fusion frequency –Typically 60 times/sec –Varies with intensity, individuals, phospher persistence, lighting... Refresh Frame must be “refreshed” to draw new imagesFrame must be “refreshed” to draw new images As new pixels are struck by electron beam, others are decayingAs new pixels are struck by electron beam, others are decaying Electron beam must hit all pixels frequently to eliminate flickerElectron beam must hit all pixels frequently to eliminate flicker Critical fusion frequencyCritical fusion frequency –Typically 60 times/sec –Varies with intensity, individuals, phospher persistence, lighting...

33. Display Technologies: CRTs Raster Displays Interlaced ScanningInterlaced Scanning Assume can only scan 30 times / secondAssume can only scan 30 times / second To reduce flicker, divide frame into two “fields” of odd and even linesTo reduce flicker, divide frame into two “fields” of odd and even lines Raster Displays Interlaced ScanningInterlaced Scanning Assume can only scan 30 times / secondAssume can only scan 30 times / second To reduce flicker, divide frame into two “fields” of odd and even linesTo reduce flicker, divide frame into two “fields” of odd and even lines 1/30 Sec 1/60 Sec Field 1 Field 2 Frame

34. Display Technologies: CRTs CRT timing Scanning (left to right, top to bottom)Scanning (left to right, top to bottom) –Vertical Sync Pulse: Signals the start of the next field –Vertical Retrace: Time needed to get from the bottom of the current field to the top of the next field –Horizontal Sync Pulse: Signals the start of the new scan line –Horizontal Retrace: The time needed to get from the end of the current scan line to the start of the next scan line CRT timing Scanning (left to right, top to bottom)Scanning (left to right, top to bottom) –Vertical Sync Pulse: Signals the start of the next field –Vertical Retrace: Time needed to get from the bottom of the current field to the top of the next field –Horizontal Sync Pulse: Signals the start of the new scan line –Horizontal Retrace: The time needed to get from the end of the current scan line to the start of the next scan line

35. What is a pixel? Wood chips Chrome spheres Trash Wood chips Chrome spheres Trash Daniel Rozin – NYU: (movies) http://fargo.itp.tsoa.nyu.edu/~danny/art.html

36. Display Technology: Color CRTs Color CRTs are much more complicated Requires manufacturing very precise geometryRequires manufacturing very precise geometry Uses a pattern of color phosphors on the screen:Uses a pattern of color phosphors on the screen: Why red, green, and blue phosphors?Why red, green, and blue phosphors? Color CRTs are much more complicated Requires manufacturing very precise geometryRequires manufacturing very precise geometry Uses a pattern of color phosphors on the screen:Uses a pattern of color phosphors on the screen: Why red, green, and blue phosphors?Why red, green, and blue phosphors? Delta electron gun arrangementIn-line electron gun arrangement

38. Delta electron gun arrangement

39. Display Technology: Color CRTs Color CRTs have Three electron gunsThree electron guns A metal shadow mask to differentiate the beamsA metal shadow mask to differentiate the beams Color CRTs have Three electron gunsThree electron guns A metal shadow mask to differentiate the beamsA metal shadow mask to differentiate the beams

40. Display Technology: Raster Raster CRT pros: Allows solids, not just wireframesAllows solids, not just wireframes Leverages low-cost CRT technology (i.e., TVs)Leverages low-cost CRT technology (i.e., TVs) Bright! Display emits lightBright! Display emits lightCons: Requires screen-size memory arrayRequires screen-size memory array Discreet sampling (pixels)Discreet sampling (pixels) Practical limit on size (call it 40 inches)Practical limit on size (call it 40 inches) BulkyBulky Finicky (convergence, warp, etc)Finicky (convergence, warp, etc) Raster CRT pros: Allows solids, not just wireframesAllows solids, not just wireframes Leverages low-cost CRT technology (i.e., TVs)Leverages low-cost CRT technology (i.e., TVs) Bright! Display emits lightBright! Display emits lightCons: Requires screen-size memory arrayRequires screen-size memory array Discreet sampling (pixels)Discreet sampling (pixels) Practical limit on size (call it 40 inches)Practical limit on size (call it 40 inches) BulkyBulky Finicky (convergence, warp, etc)Finicky (convergence, warp, etc)

41. CRTs – A Review CRT technology hasn’t changed much in 50 yearsCRT technology hasn’t changed much in 50 years Early television technologyEarly television technology –high resolution –requires synchronization between video signal and electron beam vertical sync pulse Early computer displaysEarly computer displays –avoided synchronization using ‘vector’ algorithm –flicker and refresh were problematic CRT technology hasn’t changed much in 50 yearsCRT technology hasn’t changed much in 50 years Early television technologyEarly television technology –high resolution –requires synchronization between video signal and electron beam vertical sync pulse Early computer displaysEarly computer displays –avoided synchronization using ‘vector’ algorithm –flicker and refresh were problematic

42. CRTs – A Review Raster Displays (early 70s)Raster Displays (early 70s) –like television, scan all pixels in regular pattern –use frame buffer (video RAM) to eliminate sync problems RAMRAM –¼ MB (256 KB) cost $2 million in 1971 –Do some math… - 1280 x 1024 screen resolution = 1,310,720 pixels - Monochrome color (binary) requires 160 KB - High resolution color requires 5.2 MB Raster Displays (early 70s)Raster Displays (early 70s) –like television, scan all pixels in regular pattern –use frame buffer (video RAM) to eliminate sync problems RAMRAM –¼ MB (256 KB) cost $2 million in 1971 –Do some math… - 1280 x 1024 screen resolution = 1,310,720 pixels - Monochrome color (binary) requires 160 KB - High resolution color requires 5.2 MB

43. Movie Theaters U.S. film projectors play film at 24 fps Projectors have a shutter to block light during frame advanceProjectors have a shutter to block light during frame advance To reduce flicker, shutter opens twice for each frame – resulting in 48 fps flashingTo reduce flicker, shutter opens twice for each frame – resulting in 48 fps flashing 48 fps is perceptually acceptable48 fps is perceptually acceptable European film projectors play film at 25 fps American films are played ‘as is’ in Europe, resulting in everything moving 4% fasterAmerican films are played ‘as is’ in Europe, resulting in everything moving 4% faster Faster movements and increased audio pitch are considered perceptually acceptableFaster movements and increased audio pitch are considered perceptually acceptable U.S. film projectors play film at 24 fps Projectors have a shutter to block light during frame advanceProjectors have a shutter to block light during frame advance To reduce flicker, shutter opens twice for each frame – resulting in 48 fps flashingTo reduce flicker, shutter opens twice for each frame – resulting in 48 fps flashing 48 fps is perceptually acceptable48 fps is perceptually acceptable European film projectors play film at 25 fps American films are played ‘as is’ in Europe, resulting in everything moving 4% fasterAmerican films are played ‘as is’ in Europe, resulting in everything moving 4% faster Faster movements and increased audio pitch are considered perceptually acceptableFaster movements and increased audio pitch are considered perceptually acceptable

44. Viewing Movies at Home Film to DVD transfer Problem: 24 film fps must be converted toProblem: 24 film fps must be converted to –NTSC U.S. television interlaced 29.97 fps 768x494 –PAL Europe television 25 fps 752x582 Use 3:2 Pulldown First frame of movie is broken into first three fields (odd, even, odd)First frame of movie is broken into first three fields (odd, even, odd) Next frame of movie is broken into next two fields (even, odd)Next frame of movie is broken into next two fields (even, odd) Next frame of movie is broken into next three fields (even, odd, even)…Next frame of movie is broken into next three fields (even, odd, even)… Film to DVD transfer Problem: 24 film fps must be converted toProblem: 24 film fps must be converted to –NTSC U.S. television interlaced 29.97 fps 768x494 –PAL Europe television 25 fps 752x582 Use 3:2 Pulldown First frame of movie is broken into first three fields (odd, even, odd)First frame of movie is broken into first three fields (odd, even, odd) Next frame of movie is broken into next two fields (even, odd)Next frame of movie is broken into next two fields (even, odd) Next frame of movie is broken into next three fields (even, odd, even)…Next frame of movie is broken into next three fields (even, odd, even)…

46. Display Technology: LCDs Liquid Crystal Displays (LCDs) LCDs: organic molecules, naturally in crystalline state, that liquefy when excited by heat or E fieldLCDs: organic molecules, naturally in crystalline state, that liquefy when excited by heat or E field Crystalline state twists polarized light 90º.Crystalline state twists polarized light 90º. Liquid Crystal Displays (LCDs) LCDs: organic molecules, naturally in crystalline state, that liquefy when excited by heat or E fieldLCDs: organic molecules, naturally in crystalline state, that liquefy when excited by heat or E field Crystalline state twists polarized light 90º.Crystalline state twists polarized light 90º.

47. Display Technology: LCDs Liquid Crystal Displays (LCDs) LCDs: organic molecules, naturally in crystalline state, that liquefy when excited by heat or E fieldLCDs: organic molecules, naturally in crystalline state, that liquefy when excited by heat or E field Crystalline state twists polarized light 90ºCrystalline state twists polarized light 90º Liquid Crystal Displays (LCDs) LCDs: organic molecules, naturally in crystalline state, that liquefy when excited by heat or E fieldLCDs: organic molecules, naturally in crystalline state, that liquefy when excited by heat or E field Crystalline state twists polarized light 90ºCrystalline state twists polarized light 90º

48. Display Technology: LCDs Transmissive & reflective LCDs: LCDs act as light valves, not light emitters, and thus rely on an external light source.LCDs act as light valves, not light emitters, and thus rely on an external light source. Laptop screenLaptop screen –backlit –transmissive display Palm Pilot/Game BoyPalm Pilot/Game Boy –reflective display Transmissive & reflective LCDs: LCDs act as light valves, not light emitters, and thus rely on an external light source.LCDs act as light valves, not light emitters, and thus rely on an external light source. Laptop screenLaptop screen –backlit –transmissive display Palm Pilot/Game BoyPalm Pilot/Game Boy –reflective display

49. Display Technology: Plasma Plasma display panels Similar in principle to fluorescent light tubesSimilar in principle to fluorescent light tubes Small gas-filled capsules are excited by electric field, emits UV lightSmall gas-filled capsules are excited by electric field, emits UV light UV excites phosphorUV excites phosphor Phosphor relaxes, emits some other colorPhosphor relaxes, emits some other color Plasma display panels Similar in principle to fluorescent light tubesSimilar in principle to fluorescent light tubes Small gas-filled capsules are excited by electric field, emits UV lightSmall gas-filled capsules are excited by electric field, emits UV light UV excites phosphorUV excites phosphor Phosphor relaxes, emits some other colorPhosphor relaxes, emits some other color

50. Display Technology Plasma Display Panel Pros Large viewing angleLarge viewing angle Good for large-format displaysGood for large-format displays Fairly brightFairly brightCons ExpensiveExpensive Large pixels (~1 mm versus ~0.2 mm)Large pixels (~1 mm versus ~0.2 mm) Phosphors gradually depletePhosphors gradually deplete Less bright than CRTs, using more powerLess bright than CRTs, using more power Plasma Display Panel Pros Large viewing angleLarge viewing angle Good for large-format displaysGood for large-format displays Fairly brightFairly brightCons ExpensiveExpensive Large pixels (~1 mm versus ~0.2 mm)Large pixels (~1 mm versus ~0.2 mm) Phosphors gradually depletePhosphors gradually deplete Less bright than CRTs, using more powerLess bright than CRTs, using more power

51. Display Technology: DMD / DLP Digital Micromirror Devices (projectors) or Digital Light Processing Microelectromechanical (MEM) devices, fabricated with VLSI techniquesMicroelectromechanical (MEM) devices, fabricated with VLSI techniques Digital Micromirror Devices (projectors) or Digital Light Processing Microelectromechanical (MEM) devices, fabricated with VLSI techniquesMicroelectromechanical (MEM) devices, fabricated with VLSI techniques

52. Display Technology: DMD / DLP DMDs are truly digital pixels Vary grey levels by modulating pulse length Color: multiple chips, or color-wheel Great resolution Very bright Flicker problems DMDs are truly digital pixels Vary grey levels by modulating pulse length Color: multiple chips, or color-wheel Great resolution Very bright Flicker problems

53. Display Technologies: Organic LED Arrays Organic Light-Emitting Diode (OLED) Arrays The display of the future? Many think so.The display of the future? Many think so. OLEDs function like regular semiconductor LEDsOLEDs function like regular semiconductor LEDs But they emit lightBut they emit light –Thin-film deposition of organic, light-emitting molecules through vapor sublimation in a vacuum. –Dope emissive layers with fluorescent molecules to create color. Organic Light-Emitting Diode (OLED) Arrays The display of the future? Many think so.The display of the future? Many think so. OLEDs function like regular semiconductor LEDsOLEDs function like regular semiconductor LEDs But they emit lightBut they emit light –Thin-film deposition of organic, light-emitting molecules through vapor sublimation in a vacuum. –Dope emissive layers with fluorescent molecules to create color. http://www.kodak.com/global/en/professional/products/specialProducts/OEL/creating.jhtml

54. Display Technologies: Organic LED Arrays OLED pros: TransparentTransparent FlexibleFlexible Light-emitting, and quite bright (daylight visible)Light-emitting, and quite bright (daylight visible) Large viewing angleLarge viewing angle Fast (< 1 microsecond off-on-off)Fast (< 1 microsecond off-on-off) Can be made large or smallCan be made large or small Available for cell phones and car stereosAvailable for cell phones and car stereos OLED pros: TransparentTransparent FlexibleFlexible Light-emitting, and quite bright (daylight visible)Light-emitting, and quite bright (daylight visible) Large viewing angleLarge viewing angle Fast (< 1 microsecond off-on-off)Fast (< 1 microsecond off-on-off) Can be made large or smallCan be made large or small Available for cell phones and car stereosAvailable for cell phones and car stereos

55. Display Technologies: Organic LED Arrays OLED cons: Not very robust, display lifetime a key issueNot very robust, display lifetime a key issue Currently only passive matrix displaysCurrently only passive matrix displays –Passive matrix: Pixels are illuminated in scanline order, but the lack of phospherescence causes flicker –Active matrix: A polysilicate layer provides thin film transistors at each pixel, allowing direct pixel access and constant illum. OLED cons: Not very robust, display lifetime a key issueNot very robust, display lifetime a key issue Currently only passive matrix displaysCurrently only passive matrix displays –Passive matrix: Pixels are illuminated in scanline order, but the lack of phospherescence causes flicker –Active matrix: A polysilicate layer provides thin film transistors at each pixel, allowing direct pixel access and constant illum.

56. Additional Displays Display Walls (Princeton)

57. Additional Displays StereoStereo

58. Video Controllers Graphics Hardware Frame buffer is anywhere in system memoryFrame buffer is anywhere in system memory Graphics Hardware Frame buffer is anywhere in system memoryFrame buffer is anywhere in system memory System Bus CPUVideo Controller System Memory Monitor Frame buffer Cartesian Coordinates

59. Video Controllers Graphics Hardware Permanent place for frame bufferPermanent place for frame buffer Direct connection to video controllerDirect connection to video controller Graphics Hardware Permanent place for frame bufferPermanent place for frame buffer Direct connection to video controllerDirect connection to video controller System Bus CPUVideo Controller System Memory Monitor Frame buffer Cartesian Coordinates Frame Buffer

60. Video Controllers The need for synchronization System Bus CPUVideo Controller System Memory Monitor Frame Buffer synchronized

61. Video Controllers The need for synchronization Double bufferingDouble buffering The need for synchronization Double bufferingDouble buffering System Bus CPUVideo Controller System Memory Monitor Double Buffer synchronized previouscurrent

62. Raster Graphics Systems Display Processor Display Processor System Memory System Memory CPU Frame Buffer Frame Buffer Monitor Video Controller Video Controller System Bus I/O Devices Figure 2.29 from Hearn and Baker

63. Frame Buffer Figure 1.2 from Foley et al.

64. Frame Buffer Refresh Figure 1.3 from FvDFH Refresh rate is usually 30-75Hz

65. DAC Direct Color Framebuffer Store the actual intensities of R, G, and B individually in the framebuffer 24 bits per pixel = 8 bits red, 8 bits green, 8 bits blue 16 bits per pixel = ? bits red, ? bits green, ? bits blue Store the actual intensities of R, G, and B individually in the framebuffer 24 bits per pixel = 8 bits red, 8 bits green, 8 bits blue 16 bits per pixel = ? bits red, ? bits green, ? bits blue

66. Color Lookup Framebuffer Store indices (usually 8 bits) in framebuffer Display controller looks up the R,G,B values before triggering the electron guns Store indices (usually 8 bits) in framebuffer Display controller looks up the R,G,B values before triggering the electron guns Frame Buffer DAC Pixel color = 14 Color Lookup Table 0 1024 14 R G B

67. A Graphics System

68. Today’s Interfaces What is spatial dimensionality of computer screen?What is spatial dimensionality of computer screen? What is dimensionality of mouse input?What is dimensionality of mouse input? How many degrees of freedom (DOFs) define the position of your hand in space?How many degrees of freedom (DOFs) define the position of your hand in space? Space ballSpace ball What is spatial dimensionality of computer screen?What is spatial dimensionality of computer screen? What is dimensionality of mouse input?What is dimensionality of mouse input? How many degrees of freedom (DOFs) define the position of your hand in space?How many degrees of freedom (DOFs) define the position of your hand in space? Space ballSpace ball