Modified cosine-quadratic reflectance model

In the article, a new light reflectance model is proposed. The model is based on the modified cosine-quadratic bidirectional reflectance distribution function. The concept of bidirectional reflectance distribution function is analyzed. The disadvantages of existing physically accurate and empirical bidirectional reflectance distribution functions, including classical cosine-quadratic function, are discussed. The necessity of new empirical distributive functions development is justified. The comparison of double integrals of hemispherical reflectivity of reference Blinn function and classical cosine-quadratic function is provided. Based on the comparison, the new expression of cosine-quadratic distributive function calculation is obtained. The proposed expression makes it possible to significantly increase the accuracy of glare epicentre reproduction and is intended for use in highly productive three-dimensional rendering systems