60.Em Computação Gráfica, a técnica mipmap objetiva reduzir o custo computacional e o efeito de serrilhado
(aliasing) durante a rasterização de superfícies com mapeamento de textura. Isso é feito com base em um
pré-processamento, por textura, que resulta em um acréscimo no consumo de memória.
Assinale a alternativa que apresenta, corretamente, de quanto é esse acréscimo em relação à textura
original.
a) 025%
b) 033%
c) 050%
d) 075%
e) 100%
gabarito B
http://en.wikipedia.org/wiki/Subpixel_rendering
Non-striped variants of the RBG-GBR alternated layout[edit]
Variants of the previous layout have been proposed by Clairvoyante/Nouvoyance (and demonstrated by Samsung) as members of the PenTile matrix family of layouts specifically designed for subpixel rendering efficiency.
For example, taking advantage of the doubled visible horizontal resolution, one could double the vertical resolution to make the definition more isotropic. However this would reduce the aperture of pixels, producing lower contrasts. A better alternative uses the fact that the blue subpixels are those that contribute the least to the visible intensity, so that they are less precisely located by the eye. Blue subpixels are then rendered just as a diamond in the center of a pixel square, and the rest of the pixel surface is split in four parts as a checker board of red and green subpixels with smaller sizes. Rendering images with this variant can use the same technique as before, except that now there's a near-isotropic geometry that supports both the horizontal and the vertical with the same geometric properties, making the layout ideal for displaying the same image details when the LCD panel can be rotated.
The doubled vertical and horizontal visual resolution allows to reduce the subpixel density of about 33%, in order to increase their aperture also of about 33%, with the same separation distance between subpixels (for their electronic interconnection), And also to reduce the power dissipation of about 50% with a white/black contrast increased of about 50% and still a visual-pixel resolution enhanced by about 33% (i.e. about 125 dpi instead of 96 dpi), but with only half the total number of subpixels for the same displayed surface.
Checkered RG-BW layout[edit]
Another variant, called the RGBW Quad, uses a checkerboard with 4 subpixels per pixel, adding a white subpixel, or more specifically, replacing one of the green subpixels of Bayer filter Pattern with a white subpixel, to increase the contrast and reduce the energy needed to illuminate white pixels (because colour filters in classic RGB striped panels absorb more than 65% of the total white light used to illuminate the panel). As each subpixel is a square instead of a thin rectangle, this also increases the aperture with the same average subpixel density, and same pixel density along both axis. As the horizontal density is reduced and the vertical density remains identical (for the same square pixel density), it becomes possible to increase the pixel density of about 33%, while maintaining the contrast comparable to classic RGB or BGR panels, taking profit of the more efficient use of light and lowered absorption levels by the colour filters.
