Lập trình đồ họa trong C (phần 11) potx

... objects and texture patterns. Reducing Object-Intersection Calculations Raysurface intersection calculations can account for as much as 95 percent of the processing time in a ray tracer. ... vectors in the viewing and specular-reflection direc- tions, we can calculate the value of cos4 with the dot product V R. Assuming the specular-reflection coefficient is a constant, we can .....

Ngày tải lên: 07/07/2014, 05:20

... by scan con- verting the basic geometric-structure specifications into pixel patterns. Typically, graphics programming packages provide functions to describe a scene in terms of these basic ... other conic sections, quadric surfaces, spline curves and surfaces, polygon color areas, and character strings. We begin our discussion of picture-generation procedures by examining device-level ....

Ngày tải lên: 07/07/2014, 05:20

... Identifying a concave polygon by calculating cross products of successive pairsof edge vectors. some cross products is positive while others have a negative z component, we have a concave polygon. ... Area Clipping (polygons) Curve Clipping Text Clipp~ng Line and polygon clipping routines are standard components of graphics pack- ages, but many packages accommodate curved o...

Ngày tải lên: 07/07/2014, 05:20

... physicdly bnscd by specifying the forCec acting on the objects to be animated. For complex scenes, we can separate the frames into individual components or objects called cels celluloid ... we can expect to obtain a set of well-matched colors. Rahdomly selected hues can be expected to produce harsh and clashing color combinations. Another consideration in the selection of color...

Ngày tải lên: 07/07/2014, 05:20

... general curve contour, then fitting.the selected points with a polynomial. One way to accomplish the curve fitting is to construct a cubic polynomial curve section between each pair of specified ... tint n, wcPt2 pts) Draw a connected sequence of n-1 line segments, specified in pts . pCircle (wcPt2 center, float r) Draw a circle of radius r at center. ppillarea (int n, wcPt2 pts)...

Ngày tải lên: 07/07/2014, 05:20

... With the direct storage scheme, when- ever a particular color code is specified in an application program, the corre- sponding binary value is placed in the frame buffer for each-component pixel ... fill color with the two back- ground colors to obtain the new pixel color. With three background colors and one foreground color, or with two background and two foreground colors, we nccd a...

Ngày tải lên: 07/07/2014, 05:20

... lines arc then processed through the intersection calculations, which must solve simultaneous circle-line equations Splitting Concave Polygons We can identify a concave polygon by calculating ... Identifying a concave polygon by calculating cross products of successive pairsof edge vectors. some cross products is positive while others have a negative z component, we have a co...

Ngày tải lên: 07/07/2014, 05:20

... noecho) ; I /* set buttons to choice device. event mode */ 1 setChoiceMode (1, 6. event, noechol ; do ( awaitEvent (60, vs, deviceclass, devicecode): if (deviceclass == choice) ... electronic circuit schematics, are commonly put together using com- puter-aided design methods. Graphical methods are used also for representing economic, financial, organizational, scientific,...

Ngày tải lên: 07/07/2014, 05:20

... objects according to the lighting conditions in the scene and according to assigned sur- face characteristics. Lighhng speclhcations include the intensity and positions of light sources ... Some atmospheric effects can change the perceived color of an object, and we can model these effects with depth cueing. Visible Line and Surface Identification We can also clarify depth ... three...

Ngày tải lên: 07/07/2014, 05:20

... described in the following section, searches the octants and suboctants of a unit cube to locate the regions occupied by the two objects that are to be combined. 10-16 OCTREES Hierarchical ... quadtree nodes accordingly. If each quadrant in the original space has a Invemd Circle L . Original Circb Figum 10-104 Inversion of a circle with respect to another circle. tran...

Ngày tải lên: 07/07/2014, 05:20