自由曲面的透视纹理映射研究

从纹理映射的基本方法出发,分析传统多边形纹理映射存在的不足,提出了自由曲面的透视变换纹理映射.首先介绍透视变换和透视纹理映射原理,并简要分析其在自由曲面纹理映射中的应用.由于多边形纹理映射的精度问题及自由曲面表达的多样性,因此在自由曲面纹理映射中,选择双三次 Bezier面片逼近自由曲面.然后详细介绍了透视纹理映射的算法步骤:先得到纹理空间参数与对象空间坐标之间的对应关系,通过计算对象空间坐标与屏幕空间之间关系,确定纹理空间与屏幕空间的对应关系.最后提出了纹理走样的处理方法.该方法不仅可以应用于自由曲面纹理映射,还可有效地应用到多面体、自由形体表面的纹理映射.

Research on the perspective texture mapping of free-form surface

Based on texture mapping, a perspective texture mapping is proposed in this paper. First, the principle of perspective transformation and its application in the texture mapping of free-form surface are presented. During the perspective texture mapping, the precision of approximation of bicubic patches is better than that of polyhedrons, so bicubic Bezier patches are used to approximate free-form surface. Then, the arithmetic of the perspective texture mapping is introduced: through getting the corresponding relationship between the texture space and the object space, and the corresponding relationship between the object space and the screen space, we get the corresponding relationship between the texture space and the screen space. Finally the aliasing is discussed. This method can also be effectively used for polyhedron and free-form body.