复杂环境光源下虚实融合光照实时计算

Real-time Illumination Computing Algorithm Mixing of Virtual and Actual Reality under Complex Environment Lighting

在互动电子游戏、增强现实等对实时计算要求很高的交互式图形应用中,大量使用复杂环境光源对虚拟物体进行照明,使其和真实场景的光照一致,虚实融合。提出了用Cook Torrance光照模型进行虚实场景的光照计算;利用球面调和基函数的方法,实时地计算高动态范围环境映射光照系数,得到高动态范围环境映射的二次多项式表达形式,在着色器计算该式得到漫反射分量;通过环境映射技术对镜面反射进行模拟,全部光照计算在GPU中完成。实验结果表明,该方法在动态变化的复杂环境光源下,完成对虚拟物体光照实时计算,绘制速度每秒30帧以上,绘制结果具有较强的真实感。

In the interactive graphics applications such as games and augmented reality which require high demanding real time performance, the adoption of complex environment lighting has been increasing to illuminate the synthetic objects naturally in the dynamic scenes and make them merge consistently, we propose the Cook Torrance illumination model to accomplish the illumination computing. Our method analyze spherical harmonics to determine the lighting coefficients of high dynamic range environment map in real time and use them to obtain a quadratic polynomial form of high dynamic range environment map. Then calculate the expression in the shader to obtain the diffuse component of the illumination model. And the specular component of it is approximated via the technology of environment maps. Finally all of them are computed in GPU. The experimental results show our algorithm renders the synthetic objects at rates of over 30 FPS under dynamic complex environment lighting and achieves photo-realistic visual effect.