Generating Procedural Textures in Shader

Práce se zabývá problematikou generování procedurálních textur a jejich použití v OpenGL. Jsou zde popsány teoretické základy OpenGL a shaderů. Jádrem je rozebrání principů metod generování procedurálních textur pomocí různých algoritmů a šumů, zvláště pak Perlinův šum. Příklady shaderů procedurálních textur jsou demonstrovány v aplikaci, napsané v C++, aplikované na modelu areálu Božetěchova FIT VUT Brno.This work deals with procedural texture generation using programmable graphics pipeline in OpenGL. It describes basics of OpenGL operation and programmable shading. The main contribution is the analysis of methods used for generating procedural textures using various algorithms and noise functions, with focus on Perlin noise. The examples of procedural texture shaders are demonstrated by a C++ application, displaying 3D model of Božetěchova building.

Real-time soft shadows using a single light sample

We present a real-time rendering algorithm that generates soft shadows of dynamic scenes using a single light sample. As a depth-map algorithm it can handle arbitrary shadowed surfaces. The shadow-casting surfaces, however, should satisfy a few geometric properties to prevent artifacts. Our algorithm is based on a bivariate attenuation function, whose result modulates the intensity of a light causing shadows. The first argument specifies the distance of the occluding point to the shadowed point; the second argument measures how deep the shadowed point is inside the shadow. The attenuation function can be implemented using dependent texture accesses; the complete implementation of the algorithm can be accelerated by today's graphics hardware. We outline the implementation, and discuss details of artifact prevention and filtering

Automated Extraction of Flow Features

Computational Fluid Dynamics (CFD) simulations are routinely performed as part of the design process of most fluid handling devices. In order to efficiently and effectively use the results of a CFD simulation, visualization tools are often used. These tools are used in all stages of the CFD simulation including pre-processing, interim-processing, and post-processing, to interpret the results. Each of these stages requires visualization tools that allow one to examine the geometry of the device, as well as the partial or final results of the simulation. An engineer will typically generate a series of contour and vector plots to better understand the physics of how the fluid is interacting with the physical device. Of particular interest are detecting features such as shocks, re-circulation zones, and vortices (which will highlight areas of stress and loss). As the demand for CFD analyses continues to increase the need for automated feature extraction capabilities has become vital. In the past, feature extraction and identification were interesting concepts, but not required in understanding the physics of a steady flow field. This is because the results of the more traditional tools like; isc-surface, cuts and streamlines, were more interactive and easily abstracted so they could be represented to the investigator. These tools worked and properly conveyed the collected information at the expense of a great deal of interaction. For unsteady flow-fields, the investigator does not have the luxury of spending time scanning only one "snapshot" of the simulation. Automated assistance is required in pointing out areas of potential interest contained within the flow. This must not require a heavy compute burden (the visualization should not significantly slow down the solution procedure for co-processing environments). Methods must be developed to abstract the feature of interest and display it in a manner that physically makes sense

Capturing improved TLS data of Maulbronn Monastery andintegration of the mesh into the existing UNITY visualization

[EN] This Master Thesis consists in improving the existing 3D visualization of the Maulbronn monastery, because there are areas with excess brightness that is produced by the windows. To achieve this purpose, the old scans that were part of an existing FARO SCENE project have been analysed. After analysing the scans, those areas that had to be repeated to improve texture were detected. Additionally, tests have been done to find out which parameters are best suited to improve the quality of the HDR images. Afterwards, different scans have been taken with the best parameters. This data has been processed and recorded with the data from the previous scans, resulting in the creation of a mesh for each zone, along with the position file and HDR images. Geomagic Qualify has also been used to improve mesh geometry. Then the images have been edited in Photoshop to represent a better texture for the mesh, as well as masks have been created not to apply those areas of the images that do not have good quality. In order to reproject the images on the mesh, the Agisoft Metashape program has been used, resulting in a tiled model. Once the tiled model is obtained, only the last level has been used to incorporate the new meshes into UNITY. Finally, the texture and some parts related to walkability have been improved through the use of several scripts. This project is divided into three parts. The first is the theoretical part, where the basic concepts of 3D visualization and data processing are explained. The different types of software that have been used are also explained. The second part is the explanation of the practical part, in what it consists and in what steps it is divided. Finally, in the last part of the document are the results, conclusions, future lines of the project and references.[ES] Este proyecto consiste en mejorar la visualización 3D existente del monasterio de Maulbronn, porque hay áreas con exceso de brillo que producen las ventanas. Para lograr este propósito, se analizaron los antiguos escaneos que formaban parte de un proyecto FARO SCENE existente. Después de analizar los escaneos, se detectaron aquellas áreas que tuvieron que repetirse para mejorar la textura. Además, se han realizado pruebas para descubrir qué parámetros son los más adecuados para mejorar la calidad de las imágenes HDR. Posteriormente, se han realizado diferentes escaneos con los mejores parámetros. Estos datos se procesaron y registraron con los datos de los escaneos anteriores, lo que resultó en la creación de una malla para cada zona, junto con el archivo de posición y las imágenes HDR. Geomagic Qualify también se ha utilizado para mejorar la geometría de la malla. Luego, las imágenes se han editado en Photoshop para representar una mejor textura para la malla, así como se han creado máscaras para no aplicar aquellas áreas de las imágenes que no tienen buena calidad. Para reproyectar las imágenes en la malla, se ha utilizado el programa Agisoft Metashape, lo que da como resultado un modelo en mosaico. Una vez que se obtiene el modelo de mosaico, solo se ha utilizado el último nivel para incorporar las nuevas mallas a UNITY. Finalmente, la textura y algunas partes relacionadas con la capacidad de caminar se han mejorado mediante el uso de varios scripts. Este proyecto se divide en tres partes. La primera es la parte teórica, donde se explican los conceptos básicos de visualización 3D y procesamiento de datos. También se explican los diferentes tipos de software que se han utilizado. La segunda parte es la explicación de la parte práctica, en qué consiste y en qué pasos se divide. Finalmente, en la última parte del documento están los resultados, conclusiones, líneas futuras del proyecto y referencias.Arcón Navarro, R. (2020). Capturing improved TLS data of Maulbronn Monastery andintegration of the mesh into the existing UNITY visualization. http://hdl.handle.net/10251/139512TFG

Generating haptic texture using solid noise

Texture enhances haptic interaction by providing unique, distinguishable, and versatile surfaces. In computer haptics, texture can render environments more realistic and provide useful information. In this paper, an algorithm is proposed for virtual texture simulation by using solid noise, where only a few parameters need to be altered to generate a range of realistic and diverse textures by reproducing different frequencies similar to that of real vibrational signals in a virtual environment. The proposed method can capture the textural effect in a haptic simulation while retaining a simple overall geometry and stable update rate. This method also allows the user to change the texture at runtime and can be easily incorporated into any existing code and used in any traditional haptic device without affecting overall haptic-rendering performance. Moreover, the solid noise texture is independent of object geometry and can be applied to any shape without additional computations. We conducted a human-subject study to evaluate the recognition accuracy for each generated haptic texture as well as its realism and correspondence to real texture. The results indicated the high performance of the method and its ability to generate haptic textures with a very high recognition rate that were highly realistic. 2021 The AuthorsThis paper was jointly supported by Qatar University M-QJRC-2020-7. The findings achieved herein are solely the responsibility of the authors. The Open Access funding is provided by the Qatar National Library .Scopu

Design and Motion Media for Modern Theatre

This report describes the work completed for three plays: Dogfight, Next to Normal, and Three Sisters

Rendu de pierres précieuses en temps réel

National audienceLe but de ce stage a été de trouver une méthode rapide pour génèrer des images de pierres précieuses en temps réel à partir d'un modèle géométrique et de paramètres physiques. La motivatione st de pouvoir évaluer l'aspect visuel d'une pierre sous n'importe quel point de vue, de modifier les paramètres physiques et de géométrie. Le tout avec un retour visuel instantanné