Drawing 3D Function Graph Based On OpenGL

Scientific visualization (the Scientific Computing of the Visualization in, brief name VISC) is produced in the end of 80's in 20 centuries, appearing at the beginning in the United States of science foundation(NSF) in the nation sponsor, the twice small scaled special subject seminar that convened up on February in October,1986 and 1987 . after this two seminar , the final report titled"the Scientific Computing of the Visualization"was published, and pointed out to apply image, picture technique and compute in science, which produced an new research fields, this was science visualization , the academics assigns name also comes from the topic of this reports.The seminar gives the definitions, spead over area and in the near future and long-term study direction concerning science visualization , symbolizing science visualization turn conducts and actions a formal birth of academics subject.As a newly arising academics subject,Science visualization has been established much more developments since its founding.Because it contacts closely to apply physically, each nations as to it's all studied to throw in a great deal of manpower material resources with application, this make the development had good foundation, up to now, it has been the important research point of calculator science from its creation.From a computing perspective, VISC is part of a greater field called visualization. This involves research in computer graphics, image processing, high performance computing, and other areas. The same tools that are used for SciVis may be applied to animation, or multimedia presentation, for example.Scientific visualization combines the data with graphics to use the graphics and image to show the data intuitively. With the help of the technology of computer graphics and computer image Proeessing,both the intermediate data and the final result of scientific calculation Can be shown directly and handled mutually.Therefore,in this way,some abstract rules and theories would be much easier to understand,a lot of lengthy and uninteresting data become vivid and attarctive.At the same time,it will enrich visual technology in computer field,and Promote the development of relevant subject.The common techniques in 3D visualization design involving OpenGL,VRML,Direct3D and JAVA3D, these techniques have different characteristics each other, Currently, the three-dimensional graphics is widely used in many fields. OpenGL is undoubtedly the one of the best three-dimensional graphics standard. It has the function of GL and it is open for multifold hardware flats and multifold operating systems. It has great performance。because the cross-platform characteristic of OpenGL, many people make use of OpenGL to write 3D application procedure, the OpenGL function is very strong, put together with 3D moldel software can realize a good 3D design. Actually,OpenGL is an interface betten graphic and hardware. It includes more than 120 graphic functions, the developer can build up 2D model and 3D realtime nteraction by using these functions, The OpenGL powerful graphics functions doesn't requere the developer write the data of 3D object model to a fixed data format, so the developer can not only use own data directly ,but also can make use of the data source of other different formats.This kind of flexibility extremely saved the developer's time,and raising the performance of software development.This thesis made researches on scientific visualization arithmetic based on OpenGL,and built a good foundation for relative work in many fields. First, the history, domestic and international development present condition and future development trend of science visiualization was introduced,Firstly,it introduced the background of the development of scientific visualization both domestic and abroad,including the state of the development and the significance of the study as well as the basic theory of three-dimensional visualization,also it expatiated on the OpenGL programming technology and environment ,and created the 3D-graphics classes in Delphi programming language,thus made it more convenient to use OpenGL under a Delphi programming environment. The main content and the research results of this thesis are as following.Firstly,Using computer to generate realistic images has always been one of the most important subjects in the field of computer graphics.Its major job is to use computer graphics display equipments to simulate,as accurately as possible,those scenes we observe in realities by using planar images with spatial sense.In more specific terms,it is to simulate the effects of being illuminated by various kinds of illuminants.Along with the development of the theories of computer graphics,great accomplishments have been achieved in this field.We have made considerable progress in the technology of surface facade,illumination modeling,visibility,and texture mapping,etc.And now we are able to generate better and more realistic images.the thesis analyzes the particular property of 3D function's hidden-surface determination and compares some traditional hidden-surface determination algorithms,such as scan-line,z-buffer,horizon line and list priority algorithm. Especially ,emphasis on the improved peak value scan line algorithm, the thesis also explains how to adopt the algorithm to utilize fast hidden-surface determination.Secondly, Illumination processing is the key problem while producing realistic images,People has proposed some availability model on shading rendering processing.by combining illumination model and shading processing techenology,we can get strongly realistic 3D functions.this thesis analyzes the properties of ambient light,and introduced how to realize the advanced rendering from single point light source to multiple point light source, the thesis also makes the detail analysis and comparison of polygon, Gouraud and Phong shading models'rendering result. conduct the research and practice to the light settlement technology in graphics. The color of all sorts of material can be gained through the apply of light function, and gain the light effect similar to nature.Thirdly, integrating the techniques of hidden-surface determination and shading model, and using the OOP programming language DELPHI,A drawing 3D function graph software based on OpenGL is developed.