Real-time transparent object GPU (graphic processing unit) parallel generating method based on three-dimensional point cloud

Abstract

The invention discloses a real-time transparent object GPU (graphic processing unit) parallel generating method based on three-dimensional point cloud, which comprises steps of: (1) generating a background map of a nontransparent object; (2) generating geometric buffer of a transparent object, generating all three-dimensional points by a sphere generating way, utilizing hardware depth detection to acquire depth of an approximate plane, and simultaneously saving material information of the transparent object; (3) smoothing the depth, using the depth information in the geometric buffer to perform smooth filtering to the depth to acquire a smooth surface; (4) calculating thickness of the transparent object, generating all three-dimensional points, and utilizing hardware Alpha to mix and calculate the thickness of the transparent object; and (5) coloring the transparent object, using the depth and the material information to perform illumination computation to the transparent object, utilizing the thickness to calculate refraction and reflection properties of the transparent object, and utilizing the background map to finish coloring. The method avoids the surface rebuilding step in the traditional method, and can meet the requirement of real-time generation of a million-level transparent object based on point cloud.

Description

technical field [0001] The invention is a GPU parallel technology for directly generating transparent objects from three-dimensional point clouds obtained by numerical simulation or collection by using a method of smoothing and filtering depth images, and is used for generating transparent objects in realistic virtual reality environments. Background technique [0002] In the process of modeling transparent objects, the point cloud representation of the object is often obtained by acquisition or simulation. For example, the spatial position of a large number of discrete points on the surface of the real object can be directly obtained through a 3D scanner. In addition, the simulation of interactive fluids, as the main generation method of transparent objects, often uses Smoothed Particle Hydrodynamics (SPH for short). Document 1-Gingold RA, Monaghan JJ (1977) Smoothed particle hydrodynamics—theory and application to non-spherical stars. Mon Not R Astron Soc181:375389 first p...

AI Technical Summary

Problems solved by technology

Using the above method needs to construct the entire scalar field for each frame and then track the surface to finally generate objects. The calculation scale is large and the memory access overhead is large, which is difficult to meet the requirements of real-time applications. Literature 4-Müller, M., SCHIRM, S., AND DUTHALER, S.2007. Screen space meshes. In SCA'07: Proceedings of the 2007ACM SIG-GRAPH / Eurographics symposium on Computer animation, Eurographics Association, Aire-la-Ville, Switzerland, Switzerland, 915. Proposed in the eye coordinate system A method of generating the boundary of a 3D point cloud as a grid, which only constructs the visible surface of a transparent object, first calculates the depth of each pixel in the screen space, then smooths the obtained depth map and then constructs a polygonal mesh from the depth map, However, the depth map constructed by this method cannot be directly mapped to the GPU, and the process of constructing the grid is also a complex calculation process.

For methods that require resampling to obtain a scalar field and then track the surface, the resampling process itself is difficult to guarantee the details of the original signal, which will lead to further loss of the details of the original object in the subsequent surface tracking process, and the process of reconstructing the surface There are often problems of large amount of calculation and multiple storage times, and it is difficult to adapt to the application of real-time or interactive level programs; although the method of constructing a grid in the eye coordinate system does not need to construct an intermediate scalar field, it is directly constructed from the point cloud The speed of the grid slows down as the number of points increases, and it is also difficult to generate transparent objects in real time for large-scale point clouds

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