503 research outputs found

    Mobile graphics: SIGGRAPH Asia 2017 course

    Get PDF
    Peer ReviewedPostprint (published version

    Towards a filmic look and feel in real time computer graphics

    Get PDF
    Film footage has a distinct look and feel that audience can instantly recognize, making its replication desirable for computer generated graphics. This thesis presents methods capable of replicating significant portions of the film look and feel while being able to fit within the constraints imposed by real-time computer generated graphics on consumer hardware

    Real-time Realistic Rain Rendering

    Get PDF
    Artistic outdoor filming and rendering need to choose specific weather conditions in order to properly trigger the audience reaction; for instance, rain, one of the most common conditions, is usually employed to transmit a sense of unrest. Synthetic methods to recreate weather are an important avenue to simplify and cheapen filming, but simulations are a challenging problem due to the variety of different phenomena that need to be computed. Rain alone involves raindrops, splashes on the ground, fog, clouds, lightnings, etc. We propose a new rain rendering algorithm that uses and extends present state of the art approaches in this field. The scope of our method is to achieve real-time renders of rain streaks and splashes on the ground, while considering complex illumination effects and allowing an artistic direction for the drops placement. Our algorithm takes as input an artist-defined rain distribution and density, and then creates particles in the scene following these indications. No restrictions are imposed on the dimensions of the rain area, thus direct rendering approaches could rapidly overwhelm current computational capabilities with huge particle amounts. To solve this situation, we propose techniques that, in rendering time, adaptively sample the particles generated in order to only select the ones in the regions that really need to be simulated and rendered. Particle simulation is executed entirely in the graphics hardware. The algorithm proceeds by placing the particles in their updated coordinates. It then checks whether a particle is falling as a rain streak, it has reached the ground and it is a splash or, finally, if it should be discarded because it has entered a solid object of the scene. Different rendering techniques are used for each case. Complex illumination parameters are computed for rain streaks to select textures matching them. These textures are generated in a preprocess step and realistically simulate light when interacting with the optical properties of the water drops

    Efficient From-Point Visibility for Global Illumination in Virtual Scenes with Participating Media

    Get PDF
    Sichtbarkeitsbestimmung ist einer der fundamentalen Bausteine fotorealistischer Bildsynthese. Da die Berechnung der Sichtbarkeit allerdings äußerst kostspielig zu berechnen ist, wird nahezu die gesamte Berechnungszeit darauf verwendet. In dieser Arbeit stellen wir neue Methoden zur Speicherung, Berechnung und Approximation von Sichtbarkeit in Szenen mit streuenden Medien vor, die die Berechnung erheblich beschleunigen, dabei trotzdem qualitativ hochwertige und artefaktfreie Ergebnisse liefern

    Efficient multi-bounce lightmap creation using GPU forward mapping

    Get PDF
    Computer graphics can nowadays produce images in realtime that are hard to distinguish from photos of a real scene. One of the most important aspects to achieve this is the interaction of light with materials in the virtual scene. The lighting computation can be separated in two different parts. The first part is concerned with the direct illumination that is applied to all surfaces lit by a light source; algorithms related to this have been greatly improved over the last decades and together with the improvements of the graphics hardware can now produce realistic effects. The second aspect is about the indirect illumination which describes the multiple reflections of light from each surface. In reality, light that hits a surface is never fully absorbed, but instead reflected back into the scene. And even this reflected light is then reflected again and again until its energy is depleted. These multiple reflections make indirect illumination very computationally expensive. The first problem regarding indirect illumination is therefore, how it can be simplified to compute it faster. Another question concerning indirect illumination is, where to compute it. It can either be computed in the fixed image that is created when rendering the scene or it can be stored in a light map. The drawback of the first approach is, that the results need to be recomputed for every frame in which the camera changed. The second approach, on the other hand, is already used for a long time. Once a static scene has been set up, the lighting situation is computed regardless of the time it takes and the result is then stored into a light map. This is a texture atlas for the scene in which each surface point in the virtual scene has exactly one surface point in the 2D texture atlas. When displaying the scene with this approach, the indirect illumination does not need to be recomputed, but is simply sampled from the light map. The main contribution of this thesis is the development of a technique that computes the indirect illumination solution for a scene at interactive rates and stores the result into a light atlas for visualizing it. To achieve this, we overcome two main obstacles. First, we need to be able to quickly project data from any given camera configuration into the parts of the texture that are currently used for visualizing the 3D scene. Since our approach for computing and storing indirect illumination requires a huge amount of these projections, it needs to be as fast as possible. Therefore, we introduce a technique that does this projection entirely on the graphics card with a single draw call. Second, the reflections of light into the scene need to be computed quickly. Therefore, we separate the computation into two steps, one that quickly approximates the spreading of the light into the scene and a second one that computes the visually smooth final result using the aforementioned projection technique. The final technique computes the indirect illumination at interactive rates even for big scenes. It is furthermore very flexible to let the user choose between high quality results or fast computations. This allows the method to be used for quickly editing the lighting situation with high speed previews and then computing the final result in perfect quality at still interactive rates. The technique introduced for projecting data into the texture atlas is in itself highly flexible and also allows for fast painting onto objects and projecting data onto it, considering all perspective distortions and self-occlusions

    Acquisition of Surface Light Fields from Videos

    Get PDF
    La tesi presenta un nuovo approccio per la stima di Surface Light Field di oggetti reali, a partire da sequenze video acquisite in condizioni di illuminazione fisse e non controllate. Il metodo proposto si basa sulla separazione delle due componenti principali dell'apparenza superficiale dell'oggetto: la componente diffusiva, modellata come colore RGB, e la componente speculare, approssimata mediante un modello parametrico funzione della posizione dell'osservatore. L'apparenza superficiale ricostruita permette una visualizzazione fotorealistica e in real-time dell'oggetto al variare della posizione dell'osservatore, consentendo una navigazione 3D interattiva
    • …
    corecore