Pixel shaders, also known as fragment shaders, compute color and other attributes of each fragment. Pixel shaders range from always outputting the same color, to applying a lighting value, to doing bump mapping, shadows, specular highlights, translucency and other phenomena.
Pixel shaders, also known as fragment shaders, compute color and other attributes of each fragment. Pixel shaders range from always outputting the same color, to applying a lighting value, to doing bump mapping, shadows, specular highlights, translucency and other phenomena.
They can alter the depth of the fragment (for Z-buffering), or output more than one color if multiple render targets are active.
In 3D graphics, a pixel shader alone cannot produce very complex effects, because it operates only on a single fragment, without knowledge of a scene's geometry. However, pixel shaders do have knowledge of the screen coordinate being drawn, and can sample the screen and nearby pixels if the contents of the entire screen are passed as a texture to the shader. This technique can enable a wide variety of two-dimensional postprocessing effects, such as blur, or edge detection/enhancement for cartoon/cel shaders.
Pixel shaders may also be applied in intermediate stages to any two-dimensional images in the pipeline, whereas vertex shaders always require a 3D model. For instance, a pixel shader is the only kind of shader that can act as a postprocessor or filter for a video stream after it has been rasterized.
