The first video adapters were the simplest signal converters. Several decades have passed, and the video adapter, having acquired a huge number of different functions, has evolved into a high-performance device.
It is necessary
A modern video card and a working computer
Instructions
Step 1
The principle of operation of the video adapter is easy to understand by tracing the history of this device. The invention of monitors made life much easier for personal computer users. But for the monitor and the system unit to work together, a device was needed that converts data from the computer's memory into a video signal for the display. The graphics card (video card, video adapter) became such a device. The first video adapters did not perform any calculations, and the color of each pixel in the frame was calculated by the central processor.
Step 2
However, the requirements for realism, clarity and color of the image grew, which created an increased load on the central processor. The solution to the problem of unloading the processor was the invention of graphics accelerators - a new type of video cards that could provide certain graphics functions at the hardware level. That is, they could calculate the color of pixels when the cursor is displayed, when moving windows or filling the selected area of the image. Thus, the video adapter was already responsible for the process of creating the image. In the 90s of the last century, a new problem appeared related to the acceleration of 3D game engines. To address this issue, 3D accelerators were invented. These devices functioned only in conjunction with a video adapter. When launching three-dimensional applications, 3D-accelerators performed calculations of 3D image models and converted them into two-dimensional ones. The calculation data was sent to the video adapter, which "completed" the frame with the interface and transmitted it to the display. In the recent past, video adapters and 3D accelerators were combined into one device. Actually, this is today's video adapter.
Step 3
It is convenient to illustrate how the video adapter works using the example of building a frame of a three-dimensional application. In computer modeling, any 3D object has many triangles - faces, or "polygons". Various models of shrubs, buildings, weapons and moving creatures are just artfully conjugated faces with stretched textures on them. When calculating the image, the central processor transmits the coordinates of the points - the vertices of the graphic object and the texture - to the memory of the video card. The texture will cover the wireframe of the calculated 3D model. The rest is behind the video adapter.
Step 4
A 3D model is just a monotonic collection of uniformly colored faces. The process of shaping the wireframe of vertices and textures into the resulting frame image is called the graphics pipeline. First, the vertices go to the vertex processor, which deals with their rotation, translation, scaling and determining the color of each vertex taking into account lighting (Transforming & Lighting). Then comes projection - converting the coordinates of the 3D environment into a two-dimensional coordinate system of the display. Next comes the rasterization. This is a lot of operations with image pixels. Invisible surfaces, such as the backs of image objects, are removed. For each point of the frame, its virtual distance from the display plane is calculated and the corresponding filling is carried out. At this stage, texture selection and anti-aliasing are performed.
Step 5
Modern video adapters are electronic devices with tremendous computing performance. In this regard, there are many ideas for alternative use of video adapters in medicine and meteorological forecasting.
