Research And Implementation Of Military Terrain Simulation System Based On OpenGL

The modern information technology and computer technology's rapid development promotes the transformation of the military terrain study pattern. the basic unit of our army still uses simple sand table, but the speed of manufacture is slow, the transportation is inconvenient, and the performance scope is limited. It meets with difficulty the modern battlefield informationization. Developing simple practical convenient three dimensional terrain simulation software satisfies the need of the general basic unit, which is still an important topic for our army informationization construction. This article bases on the basic unit innate condition, takes the paper military map as the data source, uses the processing method of the map scanning digitization, gathers the elevation data, establishes digital elevation model (DEM),completes the terrain visualization with OpenGL, has constructed a military terrain simulation system.The article has absorbed massive advanced theory achievements of the computer graphics and the geographic information system. This article has studied on the key elaboration on some difficult part of the military terrain simulation system's technology. the article outlines the map digitization processing technology, and introduces the acquisition and the model method of digital elevation model(DEM) data in detail. It analyzes the simulation system requirements. we takes Visual C++ and the OpenGL as tool, has developed the army battlefield simulation system, realizes roaming in the three dimensional terrain, and satisfies the military application the primary need. The prime task and the research results include:(1)The paper has analyzed the principle and the programme of OpenGL, includes the OpenGL characteristic, the major function ,and the work flow of the three dimensional graph exaggerating with OpenGL. The paper introduces simply the program development kit VC++ 6.0 and summarizes the process of the programming about OpenGL and MFC and the overall frame of application procedure.(2)The paper has conducted the research to the three dimensional terrain's visualization, the plan of the three dimensional terrain scene with OpenGL, must choose the reasonable establishment to the related parameter value.it must establishe the illumination model,which include the establishment of photo source, the selection of illumination model, the establishment of object material quality, thus forms the geometry illumination model. The illumination model can reflect the surface fluctuation condition intuitively, but cannot reappear the surface real appearance. In the foundation of production geometric model ,the paper uses the texture mapping to realize the third dimension process with emphasis, strengthens the ground third dimension effect.(3)The paper has taken the comparison to many kinds of toprographical data gathering methods, has selected the best mode of the map scanning digitization, and takes as the military terrain simulation system's data acquisition way. The paper has taken the comparison to model type, and selects the regular square grid model. the data quantity of DEM is huge, it must be simplified to guarantee the scene real-time roaming. In the imagery processing ,the separate wavelet analysis has the high scale of compression, the rapidly-simplified speed, the maintaining the signal the characteristic invariable after the transformation, and so on a series of merits. For a lot of the topographical data or the high resolution terrain that must realize the multi-resolution situation, we take advance of the good performance of the wavelet transformation's filter which decomposes to the graph, carries on the simplification and the compression to the topographical data. the low frequency ingredient of DEM data after the wavelet transformation may regard as the simplified DEM data. Through the multiple system wavelet's decomposition, we can simplifies the DEM data continuously, may construct the multi-resolution topographical model with ease.(4)The paper has studied roaming function realization. OpenGL has provided the demonstration tabulation and the double buffer mechanism to realize the three dimensional landscape real-time dynamic to provide the powerful guarantee. In the scene roaming control technology, we designed two kinds of roaming way to satisfy the different observation request. one is control-like free roaming (keyboard and mouse's hand control) and the other is preinstall way automated roaming. Through modeling parameter's dynamic revision, we simulates the scene browsing effect of the viewpoint in each direction and the position, and has designed the complete scene real-time roaming plan.(5)Based on the above theories and the findings, we take the Windows XP system and Visual C++ 6.0 as platforms, uses the three dimensional graph exaggeration tool OpenGL to realize the development, describes the military terrain visualization system's design process. We establishes the military terrain system program to realize the process, which includes the system overall portal frame construction, the system structure analysis, various part of functional design and the mainly realizing method, the process and so on, and has completed the army military terrain simulation system. This system can accept the standard DEM data and may simplify the terrain data, also has realized the third dimension three dimensional terrain visualization. it can increase sky background, provides the regular square grid model, the illumination model, the texture model and so on different pattern terrain cut to demonstrate. It might increase the terrain feature, demonstrate the profitable target, realizes two ways roaming, also provides the dynamic guidance. In the interactive aspect, the system has realized the spatial point geographic coordinate and the elevation information inquiry, and may inquire the detailed information to the profitable target. In addition, the system provides foreign output function of the scene animation record and the picture bitmap preservation.In brief, in the foundation of the domestic and foreign research results, we already applied the above each method in the development of the software system. the army military terrain simulation system obtained, and the final outcome has achieved development request. This article adopts the paper map to transform the digital map, and through the digital map to establish DEM. the method might be promoted in the geographic information system and the military simulation domain.In the end, we have made a conclusion of the above research work, pointed out the places needed improvements, and put forward the expectation of future works.