Point-based rendering methods have proven to be effective for the display of large point cloud surface models. For a realistic visualization of the models, transparency and shadows are essential features. We propose a method for point cloud rendering with transparency and shadows at interactive rates. Our approach does not require any global or local surface reconstruction method, but operates directly on the point cloud. All passes are executed in image space and no pre-computation steps are required. The underlying technique for our approach is a depth peeling method for point cloud surface representations. Having detected a sorted sequence of surface layers, they can be blended front to back with given opacity values to obtain renderings with transparency. These computation steps achieve interactive frame rates. For renderings with shadows, we determine a point cloud shadow texture that stores for each point of a point cloud whether it is lit by a given light source. The extraction of the layer of lit points is obtained using the depth peeling technique, again. For the shadow texture computation, we also apply a Monte-Carlo integration method to approximate light from an area light source, leading to soft shadows. Shadow computations for point light sources are executed at interactive frame rates. Shadow computations for area light sources are performed at interactive or near-interactive frame rates depending on the approximation quality.

Le but de la thèse est d’analyser l’importance idéologique et religieuse des expéditions égyptiennes au pays de Pount, particulièrement sous la XVIIIe dynastie. La 1ère partie (chapitres 1-4) présente en détail les sources relatives aux expéditions pountites et des produits en rapportés. Bien que la prééminence soit réservée aux sources de la XVIIIe dynastie, les documents datant d’autres périodes ont été aussi inclus dans les analyses. La 2e partie (chapitres 5-8) constitue une synthèse des conclusions formulées en résultat des analyses faites dans la 1ère partie. De cette façon, l’auteur examine les divers toponymes relatifs au pays de Pount (chapitre 5), le problème de la localisation exacte de Pount (chapitre 6), le caractère des expéditions pountites en comparaison aux autres types des missions étrangères égyptiennes (chapitre 7) aussi bien que les divers liens entre le pays de Pount et la religion et l’idéologie du pouvoir en Égypte (chapitre 8). L’auteur conclut que Pount jouait un rôle crucial dans l’idéologie du pouvoir égyptienne étant particulièrement associé au dieu solaire aussi bien qu’à la déesse Hathor. Les produits pountites étaient extrêmement importants tant pour le culte funéraire royal et privé que pour le culte divin rendu dans les temples. C’est pourquoi l’organisation d’une expédition pountite était un devoir du roi qui, selon les croyances égyptiennes, obéissait à un ordre direct du dieu solaire. En plus, aux diverses époques on peut percevoir une volonté de rétablir les contacts avec Pount afin de restaurer l’ordre naturel après une période de la crise, ce qui est particulièrement visible sous le règne d’Hatchepsout de la XVIIIe dynastie. / The aim of the dissertation is to analyse the religious and ideological significance of the ancient Egyptian Punt expeditions, particularly in the 18th dynasty. In the first part (chapters 1-4) the sources concerning the ancient Egyptian Punt expeditions as well as the products imported to Egypt in their result were discussed in detail. Although the pre-eminence is given to the 18th dynasty sources, documents from other periods were also included in the analysis. The second part (chapters 5-8) constitutes a synthesis of the conclusions drawn in result of the analysis of the sources of the first part. Therefore, the author discusses various toponyms related to the land of Punt (chapter 5), the problem of Punt’s exact location (chapter 6), the character of the Punt expeditions in comparison with other foreign missions (chapter 7) as well as various links between the land of Punt and Egyptian religion and ideology of kingship (chapter 8). The author concludes that the land of Punt played an important role in the Egyptian ideology of kingship being especially associated with the sun-god as well as with the goddess Hathor. Puntite products were crucial for both royal and private funerary cult as well as for the divine cult carried out in the temples. This is why the organisation of a Punt expedition was a duty of the Egyptian king, who, according to Egyptian beliefs, was obeying a direct order of the sun-god. Moreover, in various periods we may observe a wish to re-establish the contacts with Punt in order to restore the natural order of things after a period of crisis, which is especially visible in the reign of Hatshepsut of the 18th dynasty.

Point-based rendering methods have proven to be effective for the display of large point cloud surface models. For a realistic visualization of the models, transparency and shadows are essential features. We propose a method for point cloud rendering with transparency and shadows at interactive rates. Our approach does not require any global or local surface reconstruction method, but operates directly on the point cloud. All passes are executed in image space and no pre-computation steps are required. The underlying technique for our approach is a depth peeling method for point cloud surface representations. Having detected a sorted sequence of surface layers, they can be blended front to back with given opacity values to obtain renderings with transparency. These computation steps achieve interactive frame rates. For renderings with shadows, we determine a point cloud shadow texture that stores for each point of a point cloud whether it is lit by a given light source. The extraction of the layer of lit points is obtained using the depth peeling technique, again. For the shadow texture computation, we also apply a Monte-Carlo integration method to approximate light from an area light source, leading to soft shadows. Shadow computations for point light sources are executed at interactive frame rates. Shadow computations for area light sources are performed at interactive or near-interactive frame rates depending on the approximation quality.