Bezier曲面纹理合成模拟三维真实感鱼体
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摘要
随着图形学的发展以及3D动画的兴起，生物现象的真实模拟逐渐成为计算机图形学领域研究的热点。各种生物现象(如树皮、羽毛、毛发、毛皮等)结构复杂、特征各异，必须单独研究。国内外研究人员对大多数生物体体表都具有的鳞片状结构(或类似鳞片状结构)的模拟也开展了一些研究。在此基础上，对鱼体的真实感模拟进行研究，具有理论和实际意义。
首先，鉴于曲面建模的快速性、灵活性特点，采用应用广泛的双三次Bezier曲面建模鱼体。将整个鱼体分为若干部分，通过调整Bezier曲面的控制点对各部分独立建模，减少整体建模的难度。根据鱼体的对称特性，通过左侧鱼体建模数据可得到右侧鱼体建模数据，实现鱼体的快速准确建模。
其次，根据鱼鳞和鱼鳍的特点，分别设计其纹理合成单元。为消除纹理合成中易出现的接缝现象，对纹理合成单元进行无缝处理，实现其上、下、左、右无缝自拼接。在此基础上，利用Bezier曲面的u、v参数将鱼体Bezier曲面划分为四边形网格，并用u、v参数的跨度值和方向约束鱼体纹理合成中尺度和方向的变化，实现快速鱼体纹理合成。
再次，为真实地表现鱼体表面几何细节和光泽，制作鱼鳞和鱼鳍纹理合成单元的法线图，使用法线贴图技术渲染鱼体。为模拟鱼体体表的色斑，设计鱼身第二层网格和色斑纹理合成单元，并设置随机函数，通过对随机函数的控制实现色斑形状和分布的随机动态显示。
最后，在Windows平台上，使用VC++语言、专业三维图形API OpenGL以及可编程图形硬件语言Cg，实现鱼体的真实感模拟系统，对提出的方法进行实验验证。实验结果表明，本文方法能够逼真地模拟真实鱼体，展现其微小几何细节和丰富的色泽、色斑等体表特征。
The simulation of biological phenomena is an important research aspect in ComputerGraphics. With the development of Computer Graphics and the rise of3D animation, therealistic simulation of biological phenomena has been becoming a hot spot. A variety ofbiological phenomena (such as bark, feathers, hair, fur and so on) have complex structuresand different characteristics, so the research on them must be done separately. Theresearchers in China and abroad have made some research on scales-like structures whichare common surface characteristics to many species of animals. On this base, the realisticsimulation of the fish has theoretical and practical significance.
Firstly, considering the rapidity and flexibility of Surface Modeling and the great dealapplication of bicubic Bezier surfaces, this paper use bicubic Bezier surfaces to model thefish.In order to reduce the difficulty of modeling, we divide the fish into several parts, andmodel them individually by adjusting the control points of Bezier surfaces. According tothe symmetry of the fish, we use the Modeling data of the left side of the fish to get that ofthe right side of the fish, finishing the rapid and exact modeling of the whole fish.
Secondly, according to the features of the fish scale and the fish fin, we designtexture synthesis units for them separately. In order to eliminate the seam phenomena intexture synthesis, we made seamless processing for them. Using the parameters u and v,we subdivide the Bezier surfaces of the fish into regular quadrilateral meshes, and use thedirection and the interval value of u and v to control that of the fish texture on the meshes,implementing the fish texture synthesis rapidly.
Thirdly, in order to really display the geometry details and the gloss of the fish, wemake the normal maps of the scales texture unit and the fin texture unit, and render thefish by applying the Normal Mapping. We also design the second mesh on the fish bodyand the color spot texture unit to simulate the color spot on the fish body. By controllingrandom function, the shape and distribution of the color spot on the fish body can bedisplayed dynamically in real time.
Finally, by using VC++, OpenGL and Cg on Windows platform, we design a realisticfish simulation system to validate the effectiveness of the methods proposed. Experimental results show that our methods can realistically simulate the real fish, displaying the smallgeometry details and the rich color, gloss and color spot.
首先，鉴于曲面建模的快速性、灵活性特点，采用应用广泛的双三次Bezier曲面建模鱼体。将整个鱼体分为若干部分，通过调整Bezier曲面的控制点对各部分独立建模，减少整体建模的难度。根据鱼体的对称特性，通过左侧鱼体建模数据可得到右侧鱼体建模数据，实现鱼体的快速准确建模。
其次，根据鱼鳞和鱼鳍的特点，分别设计其纹理合成单元。为消除纹理合成中易出现的接缝现象，对纹理合成单元进行无缝处理，实现其上、下、左、右无缝自拼接。在此基础上，利用Bezier曲面的u、v参数将鱼体Bezier曲面划分为四边形网格，并用u、v参数的跨度值和方向约束鱼体纹理合成中尺度和方向的变化，实现快速鱼体纹理合成。
再次，为真实地表现鱼体表面几何细节和光泽，制作鱼鳞和鱼鳍纹理合成单元的法线图，使用法线贴图技术渲染鱼体。为模拟鱼体体表的色斑，设计鱼身第二层网格和色斑纹理合成单元，并设置随机函数，通过对随机函数的控制实现色斑形状和分布的随机动态显示。
最后，在Windows平台上，使用VC++语言、专业三维图形API OpenGL以及可编程图形硬件语言Cg，实现鱼体的真实感模拟系统，对提出的方法进行实验验证。实验结果表明，本文方法能够逼真地模拟真实鱼体，展现其微小几何细节和丰富的色泽、色斑等体表特征。
The simulation of biological phenomena is an important research aspect in ComputerGraphics. With the development of Computer Graphics and the rise of3D animation, therealistic simulation of biological phenomena has been becoming a hot spot. A variety ofbiological phenomena (such as bark, feathers, hair, fur and so on) have complex structuresand different characteristics, so the research on them must be done separately. Theresearchers in China and abroad have made some research on scales-like structures whichare common surface characteristics to many species of animals. On this base, the realisticsimulation of the fish has theoretical and practical significance.
Firstly, considering the rapidity and flexibility of Surface Modeling and the great dealapplication of bicubic Bezier surfaces, this paper use bicubic Bezier surfaces to model thefish.In order to reduce the difficulty of modeling, we divide the fish into several parts, andmodel them individually by adjusting the control points of Bezier surfaces. According tothe symmetry of the fish, we use the Modeling data of the left side of the fish to get that ofthe right side of the fish, finishing the rapid and exact modeling of the whole fish.
Secondly, according to the features of the fish scale and the fish fin, we designtexture synthesis units for them separately. In order to eliminate the seam phenomena intexture synthesis, we made seamless processing for them. Using the parameters u and v,we subdivide the Bezier surfaces of the fish into regular quadrilateral meshes, and use thedirection and the interval value of u and v to control that of the fish texture on the meshes,implementing the fish texture synthesis rapidly.
Thirdly, in order to really display the geometry details and the gloss of the fish, wemake the normal maps of the scales texture unit and the fin texture unit, and render thefish by applying the Normal Mapping. We also design the second mesh on the fish bodyand the color spot texture unit to simulate the color spot on the fish body. By controllingrandom function, the shape and distribution of the color spot on the fish body can bedisplayed dynamically in real time.
Finally, by using VC++, OpenGL and Cg on Windows platform, we design a realisticfish simulation system to validate the effectiveness of the methods proposed. Experimental results show that our methods can realistically simulate the real fish, displaying the smallgeometry details and the rich color, gloss and color spot.
引文
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[9]聂俊岚,王艳芬.块纹理合成中纹理块尺寸自适应算法[J].计算机辅助设计与图形学学报,2008,20(10):1353-1357.
[10]张军,朱为,黄伟强.一种新的结构自适应纹理合成算法[J].小型微型计算机系统,2011,32(2):351-355.
[11] Wei L Y, Levoy M. Texture Synthesis over Arbitrary Manifold Surfaces[C]. Proceedings of TheAcm Siggraph Conference on Computer Graphics. New York: ACM Press,2001:355-360.
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[13] Ying L, Hertzmann, Biermann H, et al. Texture and Shape Synthesis on Surfaces[C]. Proceedingsof the12th Eurographics Workshop on Rendering Techniques. New York: ACM Press,2001:301-312.
[14] Zhang J, Zhou K, Velho L, et al. Synthesis of Progressively-Variant Textures on ArbitrarySurfaces[J]. ACM Transactions on Graphics,2003,22(3):295-302.
[15] Praun E, Finkelstein A, Hoppe H. Lapped Textures[C]. Proceedings of ACM SIGGRAPH2000.New York: ACM Press,2000:465-470.
[16] Magda S, Kriegman D J. Fast Texture Synthesis on Arbitrary Meshes[C]. Proceedings of ACMSIGGRAPH2003Sketches&Applications. San Diego: ACM Press,2003:82-89.
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[18]吴福理,石教英.基于三角块的曲面纹理合成[J].计算机辅助设计与图形学学报,2005,17(2):236-241.
[19]薛峰,张佑生,江巨浪,等.基于纹理延伸和三角块拼接的快速曲面纹理合成[J].计算机辅助设计与图形学学报,2007,19(2):221-225.
[20]江巨浪,张佑生,薛峰,等.运用局部纹理映射加速曲面纹理合成[J].计算机辅助设计与图形学学报,2008,20(11):1507-1513.
[21]王元龙,张荣国,冯军华,等.三角网格曲面纹理合成技术研究[J].工程图形学学报,2011,1(1):104-110.
[22] Fu C W, Leung M K. Texture Tiling on Arbitrary Topological Surfaces using Wang Tiles[C].Proceedings of Eurographics Symposium on Rendering. NewYork: ACM Press,2005:99104.
[23]薛峰,陆华锋,成诚,等.基于Triangle_Tiles的三维曲面实时纹理合成[J].系统仿真学报,2009,21(22):7168-7171.
[24]严志程,陈为.基于二维纹理样本的方向场引导的体纹理合成[J].计算机辅助设计与图形学学报,2008,20(9):1104-1109.
[25] Pietroni N, Cignoni P, Otaduy M, et al. Solid-Texture Synthesis: A Survey[J]. IEEE ComputerGraphics and Applicatioin,2010,30(4):74-89.
[26]江巨浪,薛峰,郑江云,等.一种基于样图的体纹理快速生成算法[J].计算机辅助设计与图形学学报,2011,23(8):1311-1318.
[27] Lengyel J E, Praun E, Finkelstein A, et al. Real-Time Fur over Arbitrary Surfaces[C]. Proceedingsof the2001Symposium on Interactive3D Graphics. New York: ACM Press,2001:227-232.
[28] Chen Y Y, Xu Y Q, Guo B N, et al. Modeling and Rendering of Realistic Feathers[J]. ACMTransactions on Graphics,2002,21(3):630-636.
[29] Franco C G, Walter M. Modeling and Rendering of Individual Feathers[C]. Proceedings of15thBrazilian Symposium on Computer Graphics and Image Processing. Fortaleza-CE, Brazil: ACMPress,2002:293-299.
[30] Streit L, Heidrich W. A Biologically-Parameterized Feather Model[J]. Computer Graphics Forum,2002,21(3):565-573.
[31] Baranoski G V G, Krishnaswamy A. Light Interaction with Human Skin:From Believable Imagesto Predictable Models[C]. ACM SIGGRAPH ASIA2008courses. Singapore: ACM Press,2008:1-80.
[32] Wang L, Yu Y Z, Zhou K, et al. Exampled-Based Hair Geometry Synthesis[J]. ACM Transactionson Graphics,2009,28(3):561-569.
[33] Zhou K, Huang X, Tong Y Y, et al. Mesh Quilting For Geometric Texture Synthesis[J]. ACMTransactions on Graphics,2006,25(3):690-697.
[34]韩建伟,王青,周昆,等.基于WangTiles的几何纹理合成[J]. Journal of Software,2009,20(12):3254-3264.
[35] Andersen V, Desbrun M, Baerentzen J A, et al. Height and Tilt Geometric Texture[C]. Proceedingsof the5th International Symposium on Advances in Visual Computing. Las Vegas, NV, USA:Springer-Verlag Berlin, Heidelberg,2009:656-667.
[36] Landreneau E, Schaefer S. Scales and Scale-like Structures[J]. Computer Graphics Forum,2010,29(1):1653-1660.
[37]朱心雄.自由曲线曲面造型技术[M].北京:科学出版社,2000:66-85.
[38] Wei L Y, Lefebvre S, Kwatra V, et al. State of the Art in Example-based Texture Synthesis[C].Eurographics'09State of the Art Reports. Munich, Germany: Eurographics,2009:1-25.
[39] Zhang E, Mischaikow K, Turk G. Vector Field Design on Surfaces[J]. ACM Transactions onGraphics,2006,25(4):1294–1326.
[40] Fisher M, Schroder P, Desbrun M, et al. Design of Tangent Vector Fields[J]. ACM Transactioinson Graphics,2007,26(3):56.
[41] Ray N, Vallet B, Li W C, et al. N-Symmetry Direction Field Design[J]. ACM Transactions onGraphics,2008,27(2):1-13.
[42] Lefebvre S, Hoppe H. Appearance-Space Texture Synthesis[J]. ACM Transactions on Graphic,2006,25(3):541-548.
[43] Soler C, Cani M P, Angelidis A. Hierarchical pattern mapping[J]. ACM Transactions on Graphics,2002,21(3):673–680.
[44]李治国,郭立.基于OpenGL的曲面造型[J].计算机仿真,2008,25(4):206-209.
[45]网易科技报道.光与影，法线贴图技术的物理学基础[EB/OL].(2004-05-14)[2011-10-10]. http://tech.163.com/04/0514/11/0MBEOMH00009157B.html.
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[2] Wei L Y, Levoy M. Fast Texture Synthesis Using Tree-structured Vector Quantization[C].Proceedings of the27th Annual Conference on Computer Graphics and Interactive Techniques.New York: ACM Press,2000:479-488.
[3] Efros A A,Freeman W T. Image quilting for texture synthesis and transfer[C]. Proceedings of the28th Annual Conference on Computer Graphics and Interactive Techniques. New York: ACMPress,2001:341-346.
[4] Kwatra V, Essa I, Turk G, et al. Graphcut Textures: Image and Video Synthesis Using GraphCuts[J]. ACM Transactions on Graphic,2003,22(3):277-286.
[5] Cohen M F, Shade J, Hiller S, et al. Wang Tiles for Image and Texture Generation[J]. ACMTransactions on Graphic,2003,33(3):287-294.
[6] Wei L Y. Tile-Based Texture Mapping on Graphics Hardware[C]. ACM SIGGRAPH2004Sketches. New York: ACM Press,2004:55-63.
[7] Ng T Y, Wen C H, Tan T S, et al. Generating an w-tile Set for Texture Synthesis[C]. ComputerGraphics International2005. New York: ACM Press,2005:177-184.
[8]孙岩,汤颖,鲍虎军.基于结构的纹理合成[J].小型微型计算机系统,2006,27(10):1939-1942.
[9]聂俊岚,王艳芬.块纹理合成中纹理块尺寸自适应算法[J].计算机辅助设计与图形学学报,2008,20(10):1353-1357.
[10]张军,朱为,黄伟强.一种新的结构自适应纹理合成算法[J].小型微型计算机系统,2011,32(2):351-355.
[11] Wei L Y, Levoy M. Texture Synthesis over Arbitrary Manifold Surfaces[C]. Proceedings of TheAcm Siggraph Conference on Computer Graphics. New York: ACM Press,2001:355-360.
[12] Turk G. Texture Synthesis on Surfaces[C]. Proceedings of the28th Annual Conference onComputer Graphics and Interactive Techniques. New York: ACM Press,2001:347-354.
[13] Ying L, Hertzmann, Biermann H, et al. Texture and Shape Synthesis on Surfaces[C]. Proceedingsof the12th Eurographics Workshop on Rendering Techniques. New York: ACM Press,2001:301-312.
[14] Zhang J, Zhou K, Velho L, et al. Synthesis of Progressively-Variant Textures on ArbitrarySurfaces[J]. ACM Transactions on Graphics,2003,22(3):295-302.
[15] Praun E, Finkelstein A, Hoppe H. Lapped Textures[C]. Proceedings of ACM SIGGRAPH2000.New York: ACM Press,2000:465-470.
[16] Magda S, Kriegman D J. Fast Texture Synthesis on Arbitrary Meshes[C]. Proceedings of ACMSIGGRAPH2003Sketches&Applications. San Diego: ACM Press,2003:82-89.
[17]汤颖,孙汉秋,张宏鑫,等.用户控制的纹理合成[J].计算机辅助设计与图形学学报,2004,16(10):1412-1418.
[18]吴福理,石教英.基于三角块的曲面纹理合成[J].计算机辅助设计与图形学学报,2005,17(2):236-241.
[19]薛峰,张佑生,江巨浪,等.基于纹理延伸和三角块拼接的快速曲面纹理合成[J].计算机辅助设计与图形学学报,2007,19(2):221-225.
[20]江巨浪,张佑生,薛峰,等.运用局部纹理映射加速曲面纹理合成[J].计算机辅助设计与图形学学报,2008,20(11):1507-1513.
[21]王元龙,张荣国,冯军华,等.三角网格曲面纹理合成技术研究[J].工程图形学学报,2011,1(1):104-110.
[22] Fu C W, Leung M K. Texture Tiling on Arbitrary Topological Surfaces using Wang Tiles[C].Proceedings of Eurographics Symposium on Rendering. NewYork: ACM Press,2005:99104.
[23]薛峰,陆华锋,成诚,等.基于Triangle_Tiles的三维曲面实时纹理合成[J].系统仿真学报,2009,21(22):7168-7171.
[24]严志程,陈为.基于二维纹理样本的方向场引导的体纹理合成[J].计算机辅助设计与图形学学报,2008,20(9):1104-1109.
[25] Pietroni N, Cignoni P, Otaduy M, et al. Solid-Texture Synthesis: A Survey[J]. IEEE ComputerGraphics and Applicatioin,2010,30(4):74-89.
[26]江巨浪,薛峰,郑江云,等.一种基于样图的体纹理快速生成算法[J].计算机辅助设计与图形学学报,2011,23(8):1311-1318.
[27] Lengyel J E, Praun E, Finkelstein A, et al. Real-Time Fur over Arbitrary Surfaces[C]. Proceedingsof the2001Symposium on Interactive3D Graphics. New York: ACM Press,2001:227-232.
[28] Chen Y Y, Xu Y Q, Guo B N, et al. Modeling and Rendering of Realistic Feathers[J]. ACMTransactions on Graphics,2002,21(3):630-636.
[29] Franco C G, Walter M. Modeling and Rendering of Individual Feathers[C]. Proceedings of15thBrazilian Symposium on Computer Graphics and Image Processing. Fortaleza-CE, Brazil: ACMPress,2002:293-299.
[30] Streit L, Heidrich W. A Biologically-Parameterized Feather Model[J]. Computer Graphics Forum,2002,21(3):565-573.
[31] Baranoski G V G, Krishnaswamy A. Light Interaction with Human Skin:From Believable Imagesto Predictable Models[C]. ACM SIGGRAPH ASIA2008courses. Singapore: ACM Press,2008:1-80.
[32] Wang L, Yu Y Z, Zhou K, et al. Exampled-Based Hair Geometry Synthesis[J]. ACM Transactionson Graphics,2009,28(3):561-569.
[33] Zhou K, Huang X, Tong Y Y, et al. Mesh Quilting For Geometric Texture Synthesis[J]. ACMTransactions on Graphics,2006,25(3):690-697.
[34]韩建伟,王青,周昆,等.基于WangTiles的几何纹理合成[J]. Journal of Software,2009,20(12):3254-3264.
[35] Andersen V, Desbrun M, Baerentzen J A, et al. Height and Tilt Geometric Texture[C]. Proceedingsof the5th International Symposium on Advances in Visual Computing. Las Vegas, NV, USA:Springer-Verlag Berlin, Heidelberg,2009:656-667.
[36] Landreneau E, Schaefer S. Scales and Scale-like Structures[J]. Computer Graphics Forum,2010,29(1):1653-1660.
[37]朱心雄.自由曲线曲面造型技术[M].北京:科学出版社,2000:66-85.
[38] Wei L Y, Lefebvre S, Kwatra V, et al. State of the Art in Example-based Texture Synthesis[C].Eurographics'09State of the Art Reports. Munich, Germany: Eurographics,2009:1-25.
[39] Zhang E, Mischaikow K, Turk G. Vector Field Design on Surfaces[J]. ACM Transactions onGraphics,2006,25(4):1294–1326.
[40] Fisher M, Schroder P, Desbrun M, et al. Design of Tangent Vector Fields[J]. ACM Transactioinson Graphics,2007,26(3):56.
[41] Ray N, Vallet B, Li W C, et al. N-Symmetry Direction Field Design[J]. ACM Transactions onGraphics,2008,27(2):1-13.
[42] Lefebvre S, Hoppe H. Appearance-Space Texture Synthesis[J]. ACM Transactions on Graphic,2006,25(3):541-548.
[43] Soler C, Cani M P, Angelidis A. Hierarchical pattern mapping[J]. ACM Transactions on Graphics,2002,21(3):673–680.
[44]李治国,郭立.基于OpenGL的曲面造型[J].计算机仿真,2008,25(4):206-209.
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