General assistant technique for generating shadow through shadow map

Abstract

The invention discloses a general assistant technique for generating a shadow through a shadow map. The technique comprises the following steps: carrying out precomputation on a contour template to obtain a contour sampling point lookup table; drawing a scene in a light source space and forming a linear shadow map with a shadow map algorithm based on uniform point sampling being combined; drawing a scene in a vision field space, transferring pixels to the light source space and classifying the pixels into contour pixels and non-contour pixels; for the non-contour pixels, using linear interpolation to calculate depths of shielding objects and comparing the depth values to obtain a shadow result; and for the contour pixels, reading contour sampling points in the pre-constructed contour sampling point lookup table through local similarity relation, and obtaining a shadow result according to the position relation of the pixel coordinates and the contour sampling points. According to the general assistant technique for generating the shadow through the shadow map, on the basis of the conventional shadow map algorithm, less extra performance overhead is used, and shadow generation quality or algorithm performance of the algorithm is improved.

Description

technical field [0001] The invention relates to the field of computer graphics shadow drawing, in particular to an auxiliary technology for generating shadows from a general shadow map. Background technique [0002] Shadows are one of the important elements of the real world and an integral part of photorealistic rendering of composite images. It carries important information such as the position of the light source in the scene and the direction of light transmission. Although shadow drawing algorithms have been a classic problem in computer graphics, the problem of how to efficiently and robustly generate shadows has not been fully resolved. The two mainstream algorithms for drawing shadows are the shadow map algorithm and the shadow volume algorithm, which represent two hard shadow generation ideas based on images and geometry. Among them, the biggest feature of the shadow map algorithm is that it is simple and efficient, and the performance of the algorithm is basicall...

AI Technical Summary

Problems solved by technology

Among them, warping / fitting (Lloyd D B, Govindaraju N K, Quammen C, et al. Logarithmic perspective shadowmaps[J]. ACM Transactions on Graphics, 2008, 27(4): Article No.106) and z-segmentation (Lloyd D B, Although efficient Higher, but they can only make the aliasing evenly distributed in the scene, the processing effect of aliasing is still heavily dependent on the size of the resolution, and the warping / fitting method cannot handle projection aliasing

Adaptive segmentation (Fernando R, Fernandez S, Bala K, et al. Adaptive shadow maps [C]. Proceedings of the 28th annual conference on Computer graphics and interactive techniques (SIGGRAPH'01). New York: ACM Press, 2001: 387- 390) and aliasing elimination (Aila T, Laine S. Alias-free shadow maps [C]. Proceedings of the Fifteenth Eurographics conference On Rendering Techniques. Aire-la-Ville: Eurographics Association Press, 2004: 161-166) and other algorithms can theoretically Completely avoid the aliasing problem of the shadow map, but the algorithm efficiency is low, and it does not directly play a big role in real-time applications

On the other hand, compared with the original shadow map algorithm, which only needs to store a single-channel depth map, methods such as z-segmentation, adaptive segmentation, and aliasing removal require more additional shadow map storage space.

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