Publicación: High-Perfomance Algorithms for Real-Time GPGPU Volumetric Cloud Rendering from an Enhanced Physical-Math Abstraction Approach
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2019
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Atribución-NoComercial-SinDerivadas 4.0 Internacional
info:eu-repo/semantics/openAccess
info:eu-repo/semantics/openAccess
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Universidad Nacional de Educación a Distancia (España). Escuela Internacional de Doctorado. Programa de Doctorado en Ingeniería de Sistemas y Control
Resumen
La tendencia actual en aplicaciones que requieren paisajes sintéticos, tales como simuladores de vuelo, videojuegos y software educativo, es implementar escenarios realistas con una fluida experiencia interactiva. La interacción en tiempo real requiere un equipamiento hardware muy potente para recrear el paisaje detallista en tiempo de ejecución. Una de las características que más contribuye al realismo es un cielo nuboso con una iluminación verosímil y con la posibilidad de acercarse, girar y atravesar las nubes. Desde el surgimiento de los gráficos por computador a comienzos de los años ochenta, ingenieros, físicos y matemáticos como James Blinn, James Kajiya y Geoffrey Gardner han conseguido recrear el efecto de las nubes de forma analítica con bajo y alto detalle. Los mod- elos de bajo detalle funcionaban en tiempo-real en estaciones de trabajo con poca resolución utilizando geometría básica; mientras que los modelos de alto detalle requerían un elevado número de horas de cálculo en aquella época. Actualmente, los ingenieros precisan la segunda opción en tiempo-real. Para alcanzar este requisito se precisan tarjetas gráficas multinúcleo masivas que se usan en la industria de la animación pero es una solución cara. El objetivo de esta investigación es conseguir una calidad de nubes parecida usando tarjetas gráficas al alcance de cualquier usuario. La investigación utiliza una aproximación ontogenética para la creación de las nubes usando un alto nivel de descripción para evitar los pesados cálculos de los modelos físico-matemáticos. A partir de la citada aproximación ontogenética, el primer problema que aborda la tesis es la representación estática de las masas gaseosas y las formas de la nube. La contribución clave de esta parte es usar técnicas modernas de muestreo de ruido junto con primitivas adaptadas a las formas Gaussianas o de geometría fractal basada en lenguajes formales. La utilización de esta novedosa técnica para representar la naturaleza asimétrica de los cúmulos y el efecto de la dispersión de la luz con baja carga de cálculo ha sido crucial para alcanzar un nivel de calidad similar al de otros métodos con gran carga de computación. El segundo problema que se aborda es el comportamiento dinámico de las masas nubosas cuando están afectadas por la presión y las corrientes de advección. La innovadora utilización del hardware gráfico para la simulación de fluidos junto con un algoritmo de animación sim- plificado permite mejorar el realismo de la deformación y la traslación de la nube. Como conclusión, esta tesis demuestra, a partir de pruebas empíricas y de calidad de imagen, que es posible realizar una generación de nubes de alta calidad en tiempo-real en tarjetas gráficas convencionales con un óptimo balance entre realismo y rendimiento. Por otro lado, la implementación realizada proporciona una plataforma reutilizable para la industria de los gráficos por ordenador.
The current trend in computer graphics applications requiring landscape rendering, such as flight simulators, computer games and educational software, is implementing realistic outdoor scenarios with a smooth interactive experience. Achieving real-time performance requires powerful hardware to render the details of the landscapes in execution time. One of the features that contributes most to realism is a cloudy sky with credible lighting and the possibility of approaching, moving around and traversing the clouds. Since the upcoming of computer graphics in the early eighties, engineers, physicists and mathematicians like James Blinn, James Kajiya and Geoffrey Gardner have tried to recreate clouds analytically with both low and high rendering detail. The low-detail models were ren- dered in real-time in low-resolution work-stations with straightforward geometry; whereas the highly detailed ones required considerable rendering hours in those ages due to the physically oriented models with all meteorological equations. Nowadays, engineers demand the second type in real-time. Achieving this feat with those models requires massive multi-core graphics hardware that is used in the animation industry but it is expensive. The goal of the present research is achieving a similar cloud quality with high performance using consumer-level hardware. The research follows the ontogenetic approach that performs cloud rendering using a high-level description to avoid the heavy calculations of physical- mathematical models. In the implementation of the ontogenetic method, the first problem that this thesis resolves is the static rendering of the gaseous mass and the cloud shapes. The key contribution of this part is using modern techniques of noise sampling along with Gaussian-optimized primitives or randomized fractal clouds described in a formal language. The use of these novel techniques to reproduce the irregular nature of cumuliform clouds and the effect of light-scattering with low computing cost was crucial to achieve a quality level similar to other high-computing methods. The second problem that this thesis deals with is the dynamic behaviour of cloud masses when they are affected by pressure and wind advection. A novel utilization of multi-core hardware for the simulation of the atmospheric fluid together with simplified algorithms of animation improve the realism in cloud deformation and translation. In summary, this thesis demonstrates, from empiric and image quality benchmarks, that it is possible to accomplish real-time cloud rendering without expensive hardware elements and with an optimum balance between realism and performance. Besides, the actual implementation provides a reusable framework for the graphics industry.
The current trend in computer graphics applications requiring landscape rendering, such as flight simulators, computer games and educational software, is implementing realistic outdoor scenarios with a smooth interactive experience. Achieving real-time performance requires powerful hardware to render the details of the landscapes in execution time. One of the features that contributes most to realism is a cloudy sky with credible lighting and the possibility of approaching, moving around and traversing the clouds. Since the upcoming of computer graphics in the early eighties, engineers, physicists and mathematicians like James Blinn, James Kajiya and Geoffrey Gardner have tried to recreate clouds analytically with both low and high rendering detail. The low-detail models were ren- dered in real-time in low-resolution work-stations with straightforward geometry; whereas the highly detailed ones required considerable rendering hours in those ages due to the physically oriented models with all meteorological equations. Nowadays, engineers demand the second type in real-time. Achieving this feat with those models requires massive multi-core graphics hardware that is used in the animation industry but it is expensive. The goal of the present research is achieving a similar cloud quality with high performance using consumer-level hardware. The research follows the ontogenetic approach that performs cloud rendering using a high-level description to avoid the heavy calculations of physical- mathematical models. In the implementation of the ontogenetic method, the first problem that this thesis resolves is the static rendering of the gaseous mass and the cloud shapes. The key contribution of this part is using modern techniques of noise sampling along with Gaussian-optimized primitives or randomized fractal clouds described in a formal language. The use of these novel techniques to reproduce the irregular nature of cumuliform clouds and the effect of light-scattering with low computing cost was crucial to achieve a quality level similar to other high-computing methods. The second problem that this thesis deals with is the dynamic behaviour of cloud masses when they are affected by pressure and wind advection. A novel utilization of multi-core hardware for the simulation of the atmospheric fluid together with simplified algorithms of animation improve the realism in cloud deformation and translation. In summary, this thesis demonstrates, from empiric and image quality benchmarks, that it is possible to accomplish real-time cloud rendering without expensive hardware elements and with an optimum balance between realism and performance. Besides, the actual implementation provides a reusable framework for the graphics industry.
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Facultades y escuelas::E.T.S. de Ingeniería Informática
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Programa de doctorado en ingeniería de sistemas y control