Journal of Geo-information Science >
Research on Smooth Transition of Color Rendering for 3D Terrain
Received date: 2014-03-25
Revised date: 2014-05-12
Online published: 2015-01-05
Terrain rendering using gradient color is a common way to express spatial distribution and change of topography or other geological factors. Observation and analysis of geological information in the three-dimensional interactive analysis system require users to change the visual angle and distance of the sight according to the observation location and the extent of the analysis area. When the observation distance is very close, an obvious stratification phenomenon will appear when using a color ribbon of selected colors to render terrain, which is unable to express perfectly the smooth transition effect of terrain color rendering. For operation requirements and to overcome existed problems of terrain gradient color rendering in the three dimensional geological interactive system, this paper analyzes characteristics of two color models: RGB and HSL. Combined with the color smooth transition principle of OpenGL, double-color gradient rendering for terrain is realized through interpolating linearly every color component in the RGB color space respectively. And multi-color gradient rendering is achieved for terrain through interpolating hue linearly and fixing saturation and lightness in the color space HSL. In addition, lighting calculation is proposed to be added to enhance the three-dimensional effect of color gradient shaded terrain. At last, a piece of terrain is selected to test the above methods. The rendered effects of the terrain using the double-color gradient interpolation, the multi-color gradient interpolation and a color ramp with 30 colors are compared with each other. Experimental results show that these methods can provide better compatibility with smooth shading algorithms of the OpenGL library, keep smooth gradual transition between colors in a threedimensional interactive environment when observing the terrain from any distance, and achieve smoother color gradient rendering for the terrain.
Key words: color model; terrain visualization; color gradient; lighting computation
HAN Litao, FAN Kenan . Research on Smooth Transition of Color Rendering for 3D Terrain[J]. Journal of Geo-information Science, 2015 , 17(1) : 31 -36 . DOI: 10.3724/SP.J.1047.2014.00031
[1] 郭礼珍,李霖,张园玉.基于视觉表象的彩色晕渲地图色彩设计[J].武汉大学学报(信息科学版),2004,29(6):492- 495.
[2] 张志华,侯恩科,马露.基于OpenGL的三维模型渲染方法研究[J].中国矿业,2011,20(2):114-117.
[3] 陈望婷,朱庆.地形三维可视化中的彩色地貌晕渲图多模式色彩设计[J].测绘信息与工程,2006,31(6):47-49.
[4] 赵尚民,程维明,周成虎,等.计算机环境下地貌晕渲图制作的探讨[J].地球信息科学学报,2009,11(6):795-800.
[5] 何宗宜,刘祥,魏秀琴.基于DEM的彩色地貌晕渲的制作[J].测绘科学,2006,31(6):137-142.
[6] 甘昱,庞小平,李雪梅.大比例尺彩色地貌晕渲图的生成技术[J].测绘通报,2005(11):58-62.
[7] 江文萍,毋河海,杜清运,等.大型彩色地貌晕渲的自动生成技术研究[J].武汉大学学报(信息科学版),2004,29(6): 496-499.
[8] 郭明武,吴凡,黄宇,等.工程化数字地貌自动晕渲系统的设计与实现[J].测绘通报,2006(10):16-19.
[9] 陈张建,陈张建,陈锁忠,茅晶晶.基于等值线分布区域树的分层设色图自动生成研究[J].地理与地理信息科学, 2007,23(3):47-50.
[10] 魏金桃,方强飞,齐永刚.三维海底晕渲图绘制方法探究[J].海洋测绘,2013,33(1):60-62
[11] 吴玉清.地图制图中地貌晕渲实现技术的研究[D].北京: 中国测绘科学研究院,2010.
[12] 余建伟,朱海红,姜文亮,等.基于熵的彩色晕渲图设色方案辅助设计[J].武汉大学学报(信息科学版),2008,33(3): 302-305
[13] 姜文亮,李霖,应申.计算机地貌晕渲效果增强方法研究[J].武汉大学学报(信息科学版),2007,32(12):1116-1118.
[14] Zhou Z K, Wang J, Zhao H C. Efficient data-parallel algorithm for elevation color generation in terrain rendering[J]. Applied Mechanics and Materials, 2012,155-156:37- 41.
[15] Livny Y, Sokolovsky N, Grinshpoun T, et al. A GPU persistent grid mapping for terrain rendering[J]. Visual Computer, 2008,24:139-153.
[16] Milicich S D, Bardsley C, Bignall G, et al. 3-D interpretative modeling applied to the geology of the kawerau geothermal system[J]. Geothermics, 2014,51:344-350.
[17] 李宋,吴文权,詹咏.颜色渐变的方法研究[J].上海理工大学学报,2004,26(3):224-228.
[18] 范克楠.大规模海底地形可视化关键技术研究[D].青岛: 山东科技大学,2013.
[19] 孙家广.计算机图形学(第三版)[M].北京:清华大学出版社,2001:510-521.
[20] Dave S, 李军,徐波,等译.OpenGL 编程指南[M].北京:机械工业出版社,2010:114-122.
[21] 韩李涛,孔巧丽,戴洪磊,等.基于OpenGL 的规则格网地形法线计算优化研究[J]. 测绘科学,2012,37(5): 17-19.
/
〈 | 〉 |