Basics of Graphics Pipeline (Extra)
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foreword
I saw this answer in Baidu Zhizhi, and the description of 24-bit true color is represented by 24-bit binary. Where does this theoretical knowledge come from? Suddenly remembered that the display principle of the raster scan display explained this problem well.
1. The definition and development of computer graphics hardware
Pioneering phase 50's - 60's
1950's CRT-like viewer cathode ray tube as graphics display for Whirlwind 1
1958 Roller plotters and flatbed plotters (permanent output devices)
Late 50's Light pen as input device Signs Interactive Birth of graphics technology
Rapid development stage Early 1960s-late 1960s
Large companies carried out research on graphics disciplines
60s Random scan display (refresh 30 times per second)
Sutherland, father of graphics,
cost reduction stage Late 1960s-early 70s
Storage tube display (reduced Graphics hardware cost)
In the early 1970s, a batch of portable and general-purpose products appeared.
The development stage was from the early 1970s to the early 1980s.
Raster scan displays
appeared. A variety of input devices
GKS, PHIGS international standards were established.
Promotion stage In the mid-1980s-mid-1990s,
graphics workstations appeared Apello Sun, HP Widely used in graphics applications
since the 1990s
Two, raster scan display
Let's go straight to raster scan displays.
Display principle: The trajectory of the electron beam is fixed. That is, the screen is scanned from left to right and top to bottom to generate a raster. That is to add a constant scanning frequency signal to the x, y deflection system, which are called line scanning and frame scanning respectively. Its advantage is that it is readable and can control brightness and color (3 bits - 1 bit). The storage method is bitmap.
Logic block diagram of black and white raster display
Frame buffer is a continuous computer memory, for black and white monochrome display each pixel requires one bit of memory (1024*1024 -> 10th power of 2) a bit plane
buffer can only store black and white graphic
frames The cache is an array device, and the raster display is an analog device, so it also needs a digital analog device. The
structure diagram of the black and white grayscale raster display with N-bit
buffer requires enough bit planes and frame buffers to reflect the color and gray of the graphics in the raster graphics display. degree level. A frame buffer with N-bit grayscale and the brightness of each pixel on the display is controlled by the contents of each pixel location in the N-bit plane.
The binary number in the memory is translated into gray scale, ranging from 0 to the N-1 power of 2.
A simple color frame buffer memory map
is a logical map of the color raster display, for red, blue, and green Primary Colors has a three-plane framebuffer and three electron guns.
A color framebuffer memory with 24 bit planes
Each color gun passes through the framebuffer bit planes to increase the gray scale of the color category. As shown above, each primary color electron gun has an 8-bit frame buffer and an 8-bit digital-to-analog converter. Each primary color can have 256 gray levels. The combination of the three primary colors will be the 3rd power of the 8th power of 2 = 2 to the 24th power.
Summarize
For example: The above is what I will talk about today.