High-Level Shader Language Research Articles

Boundary SPH for Robust Particle–Mesh Interaction in Three Dimensions

This paper introduces an algorithm to tackle the boundary condition (BC) problem, which has long persisted in the numerical and computational treatment of smoothed particle hydrodynamics (SPH). Central to the BC problem is a need for an effective method to reconcile a numerical representation of particles with 2D or 3D geometry. We describe and evaluate an algorithmic solution—boundary SPH (BSPH)—drawn from a novel twist on the mesh-based boundary method, allowing SPH particles to interact (directly and implicitly) with either convex or concave 3D meshes. The method draws inspiration from existing works in graphics, particularly discrete signed distance fields, to determine whether particles are intersecting or submerged with mesh triangles. We evaluate the efficacy of BSPH through application to several simulation environments of varying mesh complexity, showing practical real-time implementation in Unity3D and its high-level shader language (HLSL), which we test in the parallelization of particle operations. To examine robustness, we portray slip and no-slip conditions in simulation, and we separately evaluate convex and concave meshes. To demonstrate empirical utility, we show pressure gradients as measured in simulated still water tank implementations of hydrodynamics. Our results identify that BSPH, despite producing irregular pressure values among particles close to the boundary manifolds of the meshes, successfully prevents particles from intersecting or submerging into the boundary manifold. Average FPS calculations for each simulation scenario show that the mesh boundary method can still be used effectively with simple simulation scenarios. We additionally point the reader to future works that could investigate the effect of simulation parameters and scene complexity on simulation performance, resolve abnormal pressure values along the mesh boundary, and test the method’s robustness on a wider variety of simulation environments.

Инженерный расчет разноглубинного рыболовного трала

This paper presents a method for calculating the power and geometric properties of a midwater fishing trawl, which is a complicated engineering structure made up of tied flexible (threads, ropes, flap) and rigid (rigging, trawl boards) elements. A computational model, the functional relations for internal forces and geometric characteristics of the trawl, and a calculation procedure based on the finite element method are proposed. The computational algorithm is implemented on a graphics processing unit of a personal computer with the use of DirectCompute, Shader Model 5, and high-level shader language. The performance and resource intensity of the algorithm applied in the computer-aided design system for industrial fishing gear are assessed in terms of the number of trawl nodes and computing equipment. A comparative analysis of the calculated and experimentally obtained characteristics of the trawl physical model is presented. According to the results, the computational error in geometric characteristics and internal forces is less than 3 and 5%, respectively.

Modeling of soft tissue thermal damage based on GPU acceleration

Hyperthermia treatments require precise control of thermal energy to form the coagulation zones which sufficiently cover the tumor without affecting surrounding healthy tissues. This has led modeling of soft tissue thermal damage to become important in hyperthermia treatments to completely eradicate tumors without inducing tissue damage to surrounding healthy tissues. This paper presents a methodology based on GPU acceleration for modeling and analysis of bio-heat conduction and associated thermal-induced tissue damage for prediction of soft tissue damage in thermal ablation, which is a typical hyperthermia therapy. The proposed methodology combines the Arrhenius Burn integration with Pennes’ bio-heat transfer for prediction of temperature field and thermal damage in soft tissues. The problem domain is spatially discretized on 3-D linear tetrahedral meshes by the Galerkin finite element method and temporally discretized by the explicit forward finite difference method. To address the expensive computation load involved in the finite element method, GPU acceleration is implemented using the High-Level Shader Language and achieved via a sequential execution of compute shaders in the GPU rendering pipeline. Simulations on a cube-shape specimen and comparison analysis with standalone CPU execution were conducted, demonstrating the proposed GPU-accelerated finite element method can effectively predict the temperature distribution and associated thermal damage in real time. Results show that the peak temperature is achieved at the heat source point and the variation of temperature is mainly dominated in its direct neighbourhood. It is also found that by the continuous application of point-source heat energy, the tissue at the heat source point is quickly necrotized in a matter of seconds, while the entire neighbouring tissues are fully necrotized in several minutes. Further, the proposed GPU acceleration significantly improves the computational performance for soft tissue thermal damage prediction, leading to a maximum reduction of 55.3 times in computation time comparing to standalone CPU execution.

GPU-ACCELERATED FINITE ELEMENT MODELING OF BIO-HEAT CONDUCTION FOR SIMULATION OF THERMAL ABLATION

Efficient simulation of heating processes in thermal ablation is of great importance for surgical simulation of thermal ablation procedures. This paper presents a Graphics Processing Unit (GPU) assisted finite element methodology for modeling and analysis of bio-heat transfer processes in the treatment of thermal ablation. The proposed methodology employs finite element method for discretization of the bio-heat equation, and the finite element modeling is implemented using the High-Level Shader Language of the Microsoft Direct3D 11. Simulations and comparison analyses are conducted, demonstrating computational performance improvement of up to 55.3 times using the proposed methodology.

Prediction of aerial-image motion blurs due to the flying vehicle dynamics and camera characteristics in a virtual environment

This study presents comprehensive studies on practical means to predict aerial-image motion blurs due to the flying vehicle dynamics, including flying altitude; cruising speed; and angular velocities and finally installed camera characteristics; such as, frame rate and image size. The resulting predictions of blur values are in-turn used to generate blurry images to be fed as input data for later use in a de-blurring-in-the-loop of a Mono-simultaneous localization and mapping system. The whole process is coordinated by means of an integrated aerial virtual environment. The integrated aerial virtual environment consists of a three-dimensional graphical engine which could communicate with a full six-degrees of freedom aircraft dynamic simulator to precisely generate trajectories of the flying vehicle. Any accumulated real-time image taken by the camera installed on the aircraft during its mission considers the relevant vehicle states for necessary adjustments. We practically exploit C++, High-Level Shader Language, as well as JSBSim to expand the components of the package. Extensive case- studies show that the developed approach is quite effective in controlled environments.

Research on Key Factors in Shader Programming of Dynamic Water Surface

Research on real time dynamic water surface is a hotspot in the study of virtual reality with very broad application prospect. With the rapid development of calculating ability of GPU (Graphics Processing Unit) and the development of HLSL (High-Level Shader Language), the tasks such as vertex shader ,pixel shader, calculation of normal vector, dynamic texture mapping and calculation of water reflections and refractions can be done by GPU. In our research we studied the key factors affecting the effect of dynamic water surface and indicated that the writer presents some opinions which can generate more accurate reflections and refractions of water through adjusting light intensity and colorimchy by lighting and perturbing 2D texture mapping with normal mapping. A shader program in Virtools has been written and applied in virtual reality project. In the actual operation the effect is real and the rendering speed has greatly increased.

A game loop architecture for the GPU used as a math coprocessor in real-time applications

This article concerns the use of a graphics processor unit (GPU) as a math co-processor in real-time applications in special games and physics simulations. To validate this approach, we present a new game loop architecture that employs GPUs for general-purpose computations (GPGPUs). A critical issue here is the process distribution between the CPU and the GPU. The architecture consists of a model for distribution, and our implementation offers many advantages in comparison to other approaches without the GPGPU stage. This architecture can be used either by a general-purpose language such as the Compute Unified Device Architecture (CUDA), or shader languages such as the High-Level Shader Language (HLSL) and the OpenGL Shading Language (GLSL). Although the architecture proposed here aims at supporting mathematics and physics on the GPU, it is possible to adapt any kind of generic computation. This article discusses the model implementation in an open-source game engine and presents the results of using this platform.