基于OpenGL的VxWorks系统反走样技术研究与应用

发布时间：2018-08-21 07:16

【摘要】：在现有的嵌入式图形系统中,图形显示占据着越来越重要的地位。特别是在一些特殊的嵌入式图形系统中,如飞机座舱显示画面,飞机在飞行中的姿态比较复杂,为了能够实时反映飞机姿态,所以要求飞机座舱内的图形显示器的图形画面能够动态、实时、平滑和清晰的进行显示。显示画面的质量与字符发生器的硬件结构和图形生成算法有关。由于机载液晶显示器在显示旋转的字符、刻度线时会因为光栅显示器的分辨率限制从而存在图形的锯齿状的走样现象,严重的走样现象将影响飞行员对飞机姿态的判断,从而造成飞行隐患甚至飞行事故。根据国内外座舱显示技术、OpenGL技术的发展及图形反走样算法的现状,本文选择VxWorks嵌入式操作系统作为硬件的操作系统,应用图形反走样算法设计出满足座舱显示系统的图形画面。本文所取得成果包括以下几个方面：通过对多种反走样方法进行研究和比较,在原有的Bresenham直线生成算法上进行改进,采用多像素绘制直线,有效的避免了原有Bresenham直线生成算法的出现的锯齿现象。在基于VC++平台上编制使用反走样算法图形绘制程序,对反走样算法使用前后程序生成的图形进行比较,使用反走样算法生成的图形基本解决了原有图形绘制过程中明显的图形走样问题,图形中的锯齿现象明显减弱,同时验证了改进的Bresenham直线反走样算法和字符反走样算法的可行性和有效性。为了验证改进的Bresenham直线反走样算法和字符反走样算法在硬件系统的可移植性,本文选择通用的MPC8245评估板作为字符图形发生器的硬件系统,结合嵌入式操作系统VxWorks完成了反走样算法在PowerPC硬件平台上的仿真测试和算法移植,使用OpenGL标准图形库绘制图形,图形显示效果良好。
[Abstract]:Graphic display plays a more and more important role in the embedded graphics system. Especially in some special embedded graphics systems, such as aircraft cockpit display screen, the attitude of aircraft in flight is more complex, in order to reflect the attitude of aircraft in real time, Therefore, the graphics display in aircraft cockpit can be dynamic, real-time, smooth and clear display. The quality of the display screen is related to the hardware structure of the character generator and the graphics generation algorithm. Because airborne LCD displays rotated characters and the scale line is limited by the resolution of the grating display, there is a zigzag aliasing phenomenon of the graphics. The serious aliasing phenomenon will affect the pilots' judgment of the aircraft attitude. Thus causes the flight hidden danger and even the flight accident. According to the development of cockpit display technology and the current situation of graphic anti-aliasing algorithm at home and abroad, this paper chooses VxWorks embedded operating system as the hardware operating system, and designs a graphic picture to satisfy the cockpit display system by using the graphic anti-aliasing algorithm. The results obtained in this paper include the following aspects: through the research and comparison of various anti-aliasing methods, the original Bresenham line generation algorithm is improved, and the lines are drawn with multi-pixels. It effectively avoids the sawtooth phenomenon of the original Bresenham line generation algorithm. Based on VC platform, the graphics drawing program using anti-aliasing algorithm is compiled, and the graphics generated by the anti-aliasing algorithm before and after the use of the anti-aliasing algorithm are compared. The figure generated by the anti-aliasing algorithm basically solves the obvious problem of figure aliasing in the original drawing process, and the sawtooth phenomenon in the graph is obviously weakened. At the same time, the feasibility and effectiveness of the improved Bresenham line aliasing algorithm and character antialiasing algorithm are verified. In order to verify the portability of the improved Bresenham linear anti-aliasing algorithm and the character anti-aliasing algorithm in the hardware system, this paper chooses the universal MPC8245 evaluation board as the hardware system of the character graph generator. The simulation test and algorithm transplantation of anti-aliasing algorithm on PowerPC hardware platform are completed with the embedded operating system VxWorks. The graphics are drawn by using OpenGL standard graphics library, and the graphic display effect is good.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP391.41;TP368.1

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