Le rendu de micro-reflets, utile pour simuler l'apparence de matériaux pailletés, de métal brossé ou de plastique rayé, est un défi théorique et technique en informatique graphique. Il implique l'utilisation de fonctions de distribution de réflectance bidirectionnelles surfaciques (P-BRDFs) hautes fréquences et qui varient spatialement. Dans cette thèse, nous proposons deux nouvelles P-BRDFs basées sur des cartes de normales presque parfaitement spéculaires. La première empêche toute création d'énergie grâce à une normalisation dépendante de l'empreinte du rayon, contrairement à la méthode précédente [YHMR16]. Cette normalisation est possible grâce à une nouvelle représentation d'une carte de normales en une mixture de NDFs de Beckmann décentrées et non-alignées sur les axes. La deuxième méthode améliore la première et empêche, pour la première fois, toute création et perte d'énergie, en simulant du multi-rebonds dans la micro-géométrie du matériau. Elle permet donc un rendu sans artefacts de surfaces opaques possédant des micro-reflets. De plus, nous donnons un algorithme d'échantillonnage optimal, utilisant la visibilité des normales. L'idée clé de cette méthode est la définition d'une V-cavité en chaque point de la surface. Pour simuler le multi-rebonds à l'intérieur, nous compensons l'énergie perdue par une modélisation simple rebond, en la réintégrant à l'aide d'une BRDF de compensation d'énergie. Nos méthodes ont le même ordre de grandeur que la méthode précédente en matière de temps de rendu et d'empreinte mémoire. / Glint rendering, useful for simulating the appearance of glittery materials, brushed metal or scratched plastic, is a theoretical and technical challenge in computer graphics. It involves the use of spatially varying patch bidirectional reflectance distribution functions (P-BRDFs) with high frequencies. In this thesis we propose two new P-BRDFs based on specular normal maps. Unlike the previous method [YHMR16], our first BRDF prevents any creation of energy through footprint-dependent normalisation. This normalisation is possible thanks to a new representation of the normal map based on a mixture of non-centered and non-axis aligned Beckmann NDFs. The second method improves the first one and prevents, for the first time, any creation and loss of energy, by simulating multiple scattering in the microgeometry. It enables artifact-free rendering of opaque and sparkling surfaces. In addition, we provide an optimal sampling algorithm using the visibility information of the normals. The key idea of this method is the definition of a V-cavity for each point of the surface. To simulate multiple scattering inside it, we compensate for the energy lost by a single scattering model, by reintegrating lost energy with an energy compensation BRDF. The rendering time and memory footprint of our methods are in the same order of magnitude than previous methods.

Procedural textures and image textures are commonplace in graphics today, finding uses in such places as animated movies and video games. Unlike image texture maps, procedural textures typically suffer from minification aliasing. I present a method that, given a procedural texture on a surface, automatically creates an anti-aliased version of the procedural texture. The new procedural texture maintains the original textures details, but reduces minification aliasing artifacts. This new algorithm creates an image pyramid similar to MIP-Maps to represent the texture. Whereas a MIP-Map stores per-texel color, however, my texture hierarchy stores weighted sums of reflectance functions, allowing a wider-range of effects to be anti-aliased. The stored reflectance functions are automatically selected based on an analysis of the different functions found over the surface. When the texture is viewed at close range, the original texture is used, but as the texture footprint grows, the algorithm gradually replaces the textures result with an anti-aliased one. This results in faster development time for writing procedural textures as well as higher visual fidelity and faster rendering. With the optional addition of authoring guidelines, the analysis phase can be sped up by as much as two orders of magnitude. Furthermore, I developed a method for handling pre-filtered integration of reflectance functions to anti-alias specular highlights. The normal-centric BRDF (NBRDF) allows for fast evaluation over a range of normals appearing on the surface of an object. The NBRDF is easy to implement on the GPU for real-time results and can be combined with procedural reduction maps for real-time procedural texture minification anti-aliasing.