In
computer graphics
Computer graphics deals with generating images and art with the aid of computers. Computer graphics is a core technology in digital photography, film, video games, digital art, cell phone and computer displays, and many specialized applications. ...
, the render output unit or raster operations pipeline (ROP) is a hardware component in modern
graphics processing unit
A graphics processing unit (GPU) is a specialized electronic circuit designed for digital image processing and to accelerate computer graphics, being present either as a discrete video card or embedded on motherboards, mobile phones, personal ...
s (GPUs) and one of the final steps in the
rendering process of modern
graphics cards
A graphics card (also called a video card, display card, graphics accelerator, graphics adapter, VGA card/VGA, video adapter, display adapter, or colloquially GPU) is a computer expansion card that generates a feed of graphics output to a displa ...
. The
pixel pipelines take
pixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, p ...
(each pixel is a dimensionless point) and
texel
Texel (; Texels dialect: ) is a municipality and an island with a population of 13,643 in North Holland, Netherlands. It is the largest and most populated island of the West Frisian Islands in the Wadden Sea. The island is situated north of Den ...
information and process it, via specific
matrix
Matrix (: matrices or matrixes) or MATRIX may refer to:
Science and mathematics
* Matrix (mathematics), a rectangular array of numbers, symbols or expressions
* Matrix (logic), part of a formula in prenex normal form
* Matrix (biology), the m ...
and
vector operations, into a final pixel or depth value; this process is called
rasterization
In computer graphics, rasterisation (British English) or rasterization (American English) is the task of taking an image described in a vector graphics format (shapes) and converting it into a raster image (a series of pixels, dots or lines, whic ...
. Thus, ROPs control
antialiasing, when more than one sample is merged into one pixel. The ROPs perform the transactions between the relevant
buffer
Buffer may refer to:
Science
* Buffer gas, an inert or nonflammable gas
* Buffer solution, a solution used to prevent changes in pH
* Lysis buffer, in cell biology
* Metal ion buffer
* Mineral redox buffer, in geology
Technology and engineeri ...
s in the
local memory – this includes writing or reading values, as well as blending them together.
Dedicated antialiasing hardware used to perform hardware-based antialiasing methods like
MSAA is contained in ROPs.
All data rendered has to travel through the ROP in order to be written to the
framebuffer
A framebuffer (frame buffer, or sometimes framestore) is a portion of random-access memory (RAM) containing a bitmap that drives a video display. It is a memory buffer containing data representing all the pixels in a complete video frame. Mode ...
, from there it can be transmitted to the display.
Therefore, the ROP is where the GPU's output is assembled into a
bitmap
In computing, a bitmap (also called raster) graphic is an image formed from rows of different colored pixels. A GIF is an example of a graphics image file that uses a bitmap.
As a noun, the term "bitmap" is very often used to refer to a partic ...
ped image ready for display.
Historically the number of ROPs,
texture mapping units (TMUs), and
shader
In computer graphics, a shader is a computer program that calculates the appropriate levels of light, darkness, and color during the rendering of a 3D scene—a process known as '' shading''. Shaders have evolved to perform a variety of s ...
processing units/
stream processors have been equal. However, from 2004, several
GPUs have decoupled these areas to allow optimum transistor allocation for application workload and available memory performance. As the trend continues, it is expected that graphics processors will continue to decouple the various parts of their architectures to enhance their adaptability to future graphics applications. This design also allows chip makers to build a modular line-up, where the top-end GPUs are essentially using the same logic as the low-end products.
The terminology for ROPs can vary between manufacturers. For instance, while NVIDIA refers to them as ROPs, AMD uses the term "Render Backend" (RB).
See also
*
Graphics pipeline
The computer graphics pipeline, also known as the rendering pipeline, or graphics pipeline, is a framework within computer graphics that outlines the necessary procedures for transforming a three-dimensional (3D) scene into a two-dimensional (2 ...
*
Rendering (computer graphics)
Rendering is the process of generating a physically-based rendering, photorealistic or Non-photorealistic rendering, non-photorealistic image from input data such as 3D models. The word "rendering" (in one of its senses) originally meant the ...
*
Execution unit
In computer engineering, an execution unit (E-unit or EU) is a part of a processing unit that performs the operations and calculations forwarded from the instruction unit. It may have its own internal control sequence unit (not to be confused w ...
*
Bit blit
Bit blit (also written BITBLT, BIT BLT, BitBLT, Bit BLT, Bit Blt etc., which stands for ''bit block transfer'') is a data operation commonly used in computer graphics in which several bitmaps are combined into one using a ''boolean function''.
Th ...
References
3D rendering
Graphics hardware
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