Nadat we op Tweakers.net het nieuws van deel 2 hebben overgeslagen, kunnen we nu melden dat ze op FiringSquad deel 3 hebben staan van hoe videokaarten werken. In dit derde deel wordt verteld over PCI en AGP gevolgd door een flink stuk over 3D-kaarten. De quote is geplukt uit een stukje over 3D-rendering:
There are four basic steps to render a 3D image:
Transform: The CPU reads the 3D data, then interprets and generates the vertices and lines that are used to make up the model and manipulates them in 3D space.
Lighting: A few different types of 3D lighting are used, the most common of which is "vertex lighting". In this scheme, each vertex is given a light value, which is applied to the model by the processor, giving the model the illusion of being struck by an outside light source. The second, and only recently use method is called "Lightmapping", by which a pre-rendered bitmap image is laid upon the rendered output to create the illusion of light and shadow by darkening different areas of the map/model. Lightmapping is not true lighting at all since it's a pre-drawn image, and it handled during the rendering stage.
Triangle Setup and Clipping: Once the transform and lighting is done, the information is compiled, and the polygons are drawn into the frame buffer. Clipping is a mathematical process in which the system attempts to determine where polygons will not be seen and does not render them. The system still has to perform T&L functions for non-visible polygons however, because it needs to know where they are in case they're eventually seen.
Clipping is also a term used to describe a condition where two polygons visibly intersect each other, such as part of a weapon protruding through the characters arm.
Rendering: The final stage consists of converting the now compiled 3D image into scan line data for output to your monitor. Textures are applied to the images, filtering and any perspective corrections are done at this point. Finally the image is output to the screen, and then the entire process is repeated for each successive frame.
Tnx Venator voor de link!