一个新的线光源照明模型

A NEW SHADING MODEL FOR LINEAR LIGHT SOURCE

摘要: 提出了一个有效的线光源照明模型。该模型同时考虑了线光源在被照射表面引起的漫反射分量和镜面反射分量。通过将线光源看作一个具有无限细小宽度的有向长方形光源，我们得到了一个计算漫反射分量的简洁公式。而镜面反射分量被表示成一个Phong镜面模型为积分核的积分，高斯积分技术则用来求解该积分。考虑到镜面反射分量的求解比较复杂，我们通过一个简单的测试算法来快速决定当前被照射点是否位于高光区域内。最后，结合shaft体技术，给出了一个有效的线光源阴影生成算法。结果表明，该模型绘制的图形具有很强的真实感效果。

Abstract: A new shading model for linear light source is presented.It accounts for both diffuse reflection and specular reflection of the illuminated surface.By regarding a linear light source as a directional rectangular light source with infinitesimal width,a simple formula is derived for calculating the diffuse reflection component.The specular reflection component is represented by an integration taking Phong's specular model as the kernel and evaluated by a linear approximation.Finally,an efficient shadow detection algorithm for linear light source is proposed.The images rendered with the shading model are very photorealistic.