The concept of scan-line. * methods is examined. Scanline methods use the structure of a raster display to facilitate computation. The technique is especially. The scanline fill algorithm is an ingenious way of filling in irregular polygons. The algorithm begins with a set of points. Each point is conected to the next, and. A scan line algorithm basically consists of two nested loops, one for the Y coordinate going down the screen and one for the X coordinate going across each scan line of the current Y. For each execution of the Y loop, a plane is defined by the eyepoint and the scan line on the screen.


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These figures are also filled as they are drawn. A pair of boundary pixels sits on each scanline. Simply fill in the pixels between each pair.

Scanline rendering - Wikipedia

Since both of these shapes are typically drawn in one quadrant and then reflected around the center point, the space between the pair can be drawn as soon as the two pixels are filled in. Below is scan line method example of an image drawn with the circle adn elipse fills.

Drawing Polygons A funcion called PolyLine was added ot the graphics environment to simplify the creation of polygons. This function takes scan line method a set of points and draws lines betwen consecutive pairs. This function does not assume that he figureis a closed polygon.

Scanline Fill Algorithm

If the user wants to create a closed polygon, they must reenter the first point at the end of the scan line method. Below is an image of some lines and polygons created with PolyLine. Required Images Box on a Table The first required image is a scene containing a box on top of a table.

This image builds from teh one scan line method in the last lab.


It scan line method the scanline fill function so that all of the surfaces that were previously open are now filled. The bitmap fill extension is demonstrated in this image, as the fill patterns for the floor and wall. Strange Polygon The second required image is an oddly shaped polygon.

This polygon exhibits a variety of possible situations in which the fill program may have difficulties. Questions Who did you work with on this assignment, and what tasks did each of you do?

Scanline Fill Algorithm

Scan line method worked with Casey Smith, and we each contributed to all of the parts. Is your polygon algorithm consistent with respect to screen coordinate issues, and does it produce rectangles that are the correct area?

The area of a rectangle created with polyfill is correct. In addition, the polyfill algorithm was adjusted to take into account a shift from a coordinate system centered in the middle of a pixel to a coordinate system scan line method in the lower lefthand corner of a pixel. Our program produced polygons per second on Rosemary, a computer with a MHz processor.

Write short note on Scan Line algorithm.

Our circle fill algorithm can draw about filled circles per scan line method, with an average radius of If you extended this assignment in any way, scan line method what you did and how you did it. Include pictures, or links to pictures that show what you did.

We extended the asignment in two ways. First, we implements a bitmap fill as an scan line method to the simple polyfill. In another variant, an ID buffer is rasterized in an intermediate step, allowing deferred shading of the resulting visible pixels. History[ edit ] The first publication of the scanline rendering technique was probably by Wylie, Romney, Evans, and Erdahl in Later variants used a hybrid approach.

The sprite hardware prevalent in s games machines can be considered a simple 2D form of scanline rendering. The technique was used in the first Quake engine for software rendering of environments but moving objects were Z-buffered over the top. Static scenery used BSP -derived sorting for priority.

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