How Graphics cards Works?

To make a 3-D image, the graphics card first creates a wire frame out of straight
lines. Then, it rasterizes the image (fills in the remaining pixels). It also
adds lighting, texture and color.

3D projection
Any method of mapping 3D points to a 2D plane. As
most current methods for displaying graphical data are based on planar 2D
media.

Graphics pipeline (Rendering pipeline)

Refers to the sequence of steps used to create a 2D
raster representation of a 3D scene

Stages of the graphics pipeline:

  • 3D geometric primitives

    First, the scene is created out of geometric primitives.
    Traditionally this is done using triangles

  • Modeling and transformation

    Transform from the local coordinate system to the 3d world coordinate system.

  • Camera transformation

    Transform the 3d world coordinate system into the 3d camera coordinate system,
    with the camera as the origin.

  • Lighting

    Illuminate according to lighting and reflectance. If a model of teapot is a
    brilliant white color, but in a totally black room, then the camera sees it as
    black. In this step the effect of lighting and reflections are calculated.

  • Projection transformation

    Transform the 3d world coordinates into the 2d view of the camera, for instance
    the object the camera is centered on would be in the center of the 2d view of
    the camera.

    In the case of a Perspective projection, objects which are
    distant from the camera are made smaller.

    In an orthographic projection, objects retain their original size
    regardless of distance from the camera.

  • Clipping

    Geometric primitives that now fall completely outside of the viewing frustum
    will not be visible and are discarded at this stage.

  • Scan conversion or rasterization

    Rasterization is the process by which the 2D image space representation
    of the scene is converted into raster format and the correct resulting pixel
    values are determined. From now on, operations will be carried out on each
    single pixel. This stage is rather complex, involving multiple steps often
    referred as a group under the name of pixel pipeline.

  • Texturing,fragment shading

    At this stage of the pipeline individual fragments (or
    pre-pixels) are assigned a color based on values interpolated from the vertices
    during rasterization, from a texture in memory, or from a shader program.

     
    Another term you should be familiar with:
    Double
    buffering
    uses a memory buffer to address the
    flicker problems associated with multiple paint operations. When double
    buffering is enabled, all paint operations are first rendered to a memory
    buffer instead of the drawing surface on the screen. After all paint operations
    are completed, the memory buffer is copied directly to the drawing surface
    associated with it. Because only one graphics operation is performed on the
    screen, the image flickering associated with complex painting operations is
    eliminated.

Leave a Reply

Your email address will not be published. Required fields are marked *