由于没有考虑物体表面位置的影响,基本的环境映射技术在反射计算中存在一定的几何偏差,而且无法实现视差效果。本文通过引入位置修正对该技术进行了改进。首先,利用距离图来保存环境表面位置信息;然后,分两种情况利用距离图对环境贴图的查询矢量进行修正,以减小反射计算的几何偏差;最后,通过分层渲染的方法处理包含多个环境物体的场景。实验结果表明,位置修正的引入提高了环境映射光照计算的准确性;并且能获得因物体互相遮挡而产生的视差效果。

The reflection education of the environment mapping technique is geometrically biased and cannot obtain parallax effects because the object’s surface position is unknown. We improved the technique by introducing position rectification. First, the environment’s position information is stored in a distance map; then the query vector of the environment map is rectified in two conditions using the distance map to reduce the geometrical bias in the calculation of the reflection.A layered rendering method is given to manipulate scenes that contain multiple objects.Our results show the introduction of the position rectification boosts the accuracy of environment mapping in reflection calculation and can obtain the parallax effect caused by the occlusions of objects.