Cathode Ray Tubes

1. Cathode Ray Tubes Aspect ration refers to the number of horizontal pixels to vertical pixels in a display. Traditional displays used a 4:3 aspect ratio. Most new widescreen monitors use either a 16:10 or 16:9 aspect ratio. The 16:9 is the ratio typically used for HDTVs. Resolution is the number of pixels that can be displayed on the screen. All LCD screens can display only a single given resolution referred to as the native resolution. This is the physical number of horizontal and vertical pixels that make up the LCD matrix of the display. The highest resolution I have found is QSXGA which is 2560 x 2048 with an aspect ratio of 5:4

2. Refresh Rates Refresh Rate is the number of times a display's image is repainted or refreshed per second. In a CRT, the refresh rate is limited by the monitor's horizontal scan rate and the resolution, since higher resolution means more scan lines. In an LCD the normal definition of refresh rate does not apply to the an LCD monitor. This is because LCDs employ a separate backlight to illuminate the image being portrayed by the LCD's liquid crystal shutters. The shutters themselves do not have a "refresh rate" as such as they always stay at whatever opacity they were last instructed to. However nearly all LCD backlights, which commonly operate at ~200Hz) have a separate figure known as flicker, which describes how many times a second the backlight pulses on and off.

3. LCD’s • Solids molecules always maintain their orientation and stay in the same position with respect to one another. • liquids can change their orientation and move anywhere in the liquid. • Some substances that can exist like a liquid and sort of like a solid. When they are in this state, their molecules tend to maintain their orientation, like the molecules in a solid, but also move around to different positions, like the molecules in a liquid. • This means that liquid crystals are neither a solid nor a liquid. • It only takes a little more heat to turn that same liquid crystal into a real liquid. Hence liquid crystals are very sensitive to temperature and why a laptop computer display may act strangely in cold weather or during a hot day at the beach.

4. Video Connections Older CRT monitors required the signal information in analogue form. However, computers are digital, so the computer and video adapter need to convert digital data into analogue format using a video card or graphics card. • VGA stands for Video Graphic Interface. Since 1987, a VGA connection was the standard method to connect a computer to a monitor. VGA originally supported 640 x 480 resolution. • Super VGA - VGA evolved into Super VGA. Super VGA can display resolutions up to 1024 x 768 pixels. Super VGA, or SVGA, can also display more colours at high resolution than VGA. SVGA is the standard connection between computers and monitors.

5. Connectors • DVI Digital video interface (DVI) is used to connect to digital displays and is appropriate for HD video. DVI carries analogue data as well as digital data. There are four types of DVI connections, DVI-DL (Dual Link) DVI-A (Analogue), DVI-D (Digital), DVI-I (Analogue and Digital). DVI is used for LCD, plasma and projection displays. •  HDMI High-Definition Multimedia Interface carries both digital audio and digital video in an uncompressed high quality format. HDMI is used for LCD, Plasma, and Projection displays. HDMI cables support 1080p, or true high definition video. One of the most notable differences between HDMI and DVI-D is that HDMI can support audio whereas DVI-D is strictly a video format and cannot transmit any kind of audio.

6. Graphics Cards Graphics processing unit (GPU) - is designed specifically to perform floating-point calculations, which are fundamental to 3D graphics rendering. The main attributes of the GPU are the core clock frequency, which typically ranges from 250 MHz to 4 GHz and the number of pipelines Video BIOS - governs the video card's operations and provides the instructions that allow the computer and software to interact with the card. Video memory - the memory capacity of most modern video cards ranges from 128 MB to 4 GB, though very few cards actually go over 1 GB. Since video memory needs to be accessed by the GPU and the display circuitry, it often uses special high-speed or multi-port memory, such as VRAM, WRAM, SGRAM, etc. Recently manufacturers have moved towards GDDR3, GDDR4, GDDR5, and even GDDR6. The effective memory clock rate in modern cards is generally between 400 MHz and 3.8 GHz.

7. Graphics Cards Dedicated graphics cards • The most powerful class of GPU’s typically interface with the motherboard by means of an expansion slot such as PCI Express (PCIe). • Technologies such as SLI by NVIDIA and CrossFire by ATI allow multiple GPU’s to be used to draw a single image, increasing the processing power available for graphics. Integrated graphics solutions • These utilise a portion of a computer's system RAM rather than dedicated graphics memory. Computers with integrated graphics account for 90% of all PC shipments. • They are cheaper than dedicated graphics solutions, but are less capable. Integrated solutions are often considered unfit to play 3D games or run graphically intensive programs. • However, today's integrated solutions are more than capable of handling 2D graphics or low stress 3D graphics. However, most integrated graphics still struggle with high-end video games.

8. Sprites and Blit’s • A Sprite is an independent graphic object controlled by its own bit plane (area of memory). Commonly used in video games, sprites move freely across the screen, passing by, through and colliding with each other. Programming sprites is easier than programming an object to move around on the same plane as other objects. • A Bit Blit - (which stands for Bit-Block (Image) Transfer but is pronounced Bit Blit) is an operation in which several bitmaps are combined.

9. The two pictures below are that of a sprite (a pug) and its mask. The mask is a monochrome bitmap that has black areas where we want the sprite to be transparent. The sprite, on the other hand, must be white in these areas. What we want is to be able to see the background through these areas. The trick is to first blit the background, then blit the mask using logical OR, and then blit the sprite over it using logical AND.

10. Stream Processing • A stream is simply a set of records that require similar computation. Streams provide data parallelism. • It can be visualised as a processor with many small cores, each dedicated to one small data set as in SIMD processing. Such applications can use multiple computational units, such as the floating point units • Given a set of data (a stream), a series of operations are applied to each element in the stream. • Uniform streaming, where one operation is applied to all elements in the stream . These operations are usually pipelined, and local on-chip memory is reused to minimise external memory bandwidth.

11. Definitions • Modelling describes the process of forming the shape of an object. The two most common sources of 3D models are those originated on the computer by an artist or engineer using some kind of 3D modelling tool, and those scanned into a computer from real-world objects. • Layout and animation - before objects are rendered, they must be placed (laid out) within a scene. This is what defines the spatial relationships between objects in a scene including location and size. • Animation refers to the temporal description of an object, i.e., how it moves and deforms over time. • Rendering - is the process of generating an image from a model, by means of computer programs. It includes geometry, viewpoint, texture, lighting, and shading information. • Shader - is a set of software instructions, which is used primarily to calculate rendering effects on graphics hardware with a high degree of flexibility.

12. Shaders and TMU’s • Vertex shaders deform or transform 3D elements. • Pixel shaders can change pixel colors e.g. a light source in a 3D scene in which some colors appear brighter when the object is lit, while others create shadows. • Used in games. e.g. a shader could make the pixels surrounding a 3D sword appear to glow. • Fill rate. The fill rate is generally referred to as the rate at which a graphics processor can draw pixels. • Texture Mapping Units – TMUs work in conjunction with pixel and vertex shader units. TheTMU applies texture operations to pixels. The number of texture units in a graphics processor is used when comparing two different cards for texturing performance.

13. Definitions • Alpha-blending - a technique used when computer graphics are laid on top of each other and one or more of the objects contain a transparent, or semi-transparent, portion. • It ensures that the pixels of the graphic which are underneath a transparent area are visible through it and that their colour or brightness is adjusted according to the degree of transparency of the upper object.

14. Rendering • 3D Rendering - is the process of producing an image based on three-dimensional data stored within a computer. • All objects in a 3D scene are made up of triangles.

15. Rendering • Any type of image can be seen at every angle, including aerial shots. Details such as shadows, dust, and textures can be added and rendered to make illustrations look more lifelike. The rendering could add the simulation of realistic lighting, shadows, atmosphere, colour, texture, and optical effects such as the refraction of light or motion-blur seen on moving objects - or the rendering might not be realistic at all, and could be designed to appear as a painting or abstract image.

16. Storyboard: a Story Artist's Rendition of the Scene

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19. LCD’s The combination of four facts make LCD’s possible: • Light can be polarised. • Liquid crystals can transmit and change polarised light. • The structure of liquid crystals can be changed by electric current. • There are transparent substances that can conduct electricity.

20. Graphics Cards Hybrid solutions • This newer class of GPU’s competes with integrated graphics in the low-end desktop and notebook markets. They are more expensive than integrated graphics, but much less expensive than dedicated graphics cards. • These also share memory with the system, but have a smaller dedicated amount of it than discrete graphics cards do, to make up for the high latency of the system RAM. Technologies within PCI Express can make this possible.

21. ORing a black mask pixel (all zero bits) with a background pixel will give back the background pixel. ORing a white mask pixel (all one bits) with a background will give a white pixel. So after blitting the mask, we'll have a white ghost in the shape of our sprite floating over the background. ANDing a white sprite pixel (all ones) with a background pixel will give back the background pixel. ANDing a non-white sprite pixel with the white (all ones) background (the ghost from previous step) will give the sprite pixel. We'll end up with the sprite superimposed on the background.