基于逆向光线跟踪与图像绘制的运动水面反射场景绘制

Rendering of Moving Water Reflection Based on Backward Ray Tracing and Image Based Rendering

提出了一种结合图像绘制和逆向光线跟踪的绘制算法来生成水面反射场景。首先,采用逆向光线跟踪方法获得视点所见水面反射场景点;然后在反射光线与场景相交点求解时,采用场景图像平面搜索,并将搜索到的图像平面象素点反向投影到观察坐标系求取光线与场景物体相交点以获取反射物颜色;最后按照Fresnel公式计算获得视点所见的水面上某点的颜色,通过对整个图像平面进行遍历,获得水面反射场景。使用该方法绘制的水面反射场景能够物理真实地模拟水面反射效果。对于波动水面附近或漂浮于水面上物体的反射场景,该方法较其它方法能够更好地获得物理真实的绘制结果。

A water reflection algorithm was presented based on image based rendering(IBR)and backward ray tracing.At first,backward ray tracing method was used to find the reflection point set of water surface which can be seen by eye.Then the scene image plane research was used to find out the cross point of reflected light ray and the scene objects and the cross point in the image plane was projected inversely to the view coordination system to find the color of reflected things.Finally,the point color which can be seen by eye was calculated by Fresnel equation.The algorithm can physically simulate the water reflection effect especially when there are things nearby or floating on the moving water.