Elearning: Welcome. Matej Novotný | Graphical systems, visualization, multimedia. I'm an assistant professor at Comenius University, Bratislava. My professional interests are information visualization, visual computing, user interfaces, visual communication. And I also enjoy teaching. Research Similarity brushing Interactive data exploration of relations through multi-dimensional data brushing and visualization. Teaching Graphical Systems, Visualization and Multimedia Introduction to computer graphics.
Web Graphics Fundamentals of graphic design and web-related media. Specular reflection. Diagram of specular reflection Reflections on still water are an example of specular reflection. in the figure), and that the incident, normal, and reflected directions are coplanar. This behavior was first discovered through careful observation and measurement by Hero of Alexandria (AD c. 10–70).[1] Explanation[edit] The law of reflection arises from diffraction of a plane wave with small wavelength on a flat boundary: when the boundary size is much larger than the wavelength then electrons of the boundary are seen oscillating exactly in phase only from one direction – the specular direction.
If a mirror becomes very small compared to the wavelength, the law of reflection no longer holds and the behavior of light is more complicated. The reflectivity of a surface is the ratio of reflected power to incident power. The image in a flat mirror has these features: Direction of reflection[edit] from the surface to the light source and the surface normal direction the specularly reflected direction. Diffuse reflection. A surface built from a non-absorbing powder such as plaster, or from fibers such as paper, or from a polycrystalline material such as white marble, reflects light diffusely with great efficiency.
Many common materials exhibit a mixture of specular and diffuse reflection. The visibility of objects, excluding light-emitting ones, is primarily caused by diffuse reflection of light: it is diffusely-scattered light that forms the image of the object in the observer's eye. Figure 1 – General mechanism of diffuse reflection by a solid surface (refraction phenomena not represented) Figure 2 – Diffuse reflection from an irregular surface Mechanism[edit] Diffuse reflection from solids is generally not due to surface roughness. The most general mechanism by which a surface gives diffuse reflection does not involve exactly the surface: most of the light is contributed by scattering centers beneath the surface,[2][3] as illustrated in Figure 1 at right. Specular vs. diffuse reflection[edit] Mip-Mapping in Direct3D - DirectX and XNA. Introduction For those of you who don't know, mip-mapping is a form of anti-aliasing that is used in many 3D rendering engines.
It prevents the well-known interference pattern that occurs on detailed textures, known as the 'moiré pattern'. This happens because when the texture is far enough away, there are more texels (texture pixels) then there are pixels to be rendered on the screen. This means that some texels get skipped over, and visual information is lost. The ugly 'bitty' look near the top is the moiré pattern in action. In a properly anti-aliased rendering, what would happen is all of the texels that land within a single pixel on the screen would be weighted, summed and a final average value is placed on the screen. The idea of mip-mapping is simple: if what you are drawing is really big then use a big texture, and if it's small, use a small texture.
Same scene rendered using mip-mapping. Mip-Map Factory Say you have a detailed texture of size 128 x 128. The Rendering Pipeline. Mipmap. Basic Use[edit] Mipmaps are used for: Speeding up rendering times. (Smaller textures equate to less memory usage.)Improving the quality. Rendering large textures where only small subsets of points are used can easily produce moiré patterns.Reducing stress on GPU. Origin[edit] Mipmapping was invented by Lance Williams in 1983 and is described in his paper Pyramidal parametrics.[1] From the abstract: "This paper advances a 'pyramidal parametric' prefiltering and sampling geometry which minimizes aliasing effects and assures continuity within and between target images.
" How it works[edit] An example of mipmap image storage: the principal image on the left is accompanied by filtered copies of reduced size. If the texture has a basic size of 256 by 256 pixels, then the associated mipmap set may contain a series of 8 images, each one-fourth the total area of the previous one: 128×128 pixels, 64×64, 32×32, 16×16, 8×8, 4×4, 2×2, 1×1 (a single pixel). The original RGB image Anisotropic filtering[edit] Phong reflection model. The Phong reflection model (also called Phong illumination or Phong lighting) is an empirical model of the local illumination of points on a surface. In 3D computer graphics, it is sometimes ambiguously referred to as Phong shading, in particular if the model is used in combination with the interpolation method of the same name and in the context of pixel shaders or other places where a lighting calculation can be referred to as “shading”.
History[edit] The Phong reflection model was developed by Bui Tuong Phong at the University of Utah, who published it in his 1973 Ph.D. dissertation.[1][2] It was published in conjunction with a method for interpolating the calculation for each individual pixel that is rasterized from a polygonal surface model; the interpolation technique is known as Phong shading, even when it is used with a reflection model other than Phong's. Description[edit] Phong reflection is an empirical model of local illumination. For each light source in the scene, components. 1-AIN-160 Diskrétna matematika (2) Novinky Výučba tento semester O kurze Tu nájdete informačný list predmetu. Cieľ predmetu Prednáška poskytne študentom matematické základy nevyhnutné pre štúdium informatiky. Stručná osnova predmetu Základy teórie množín. Binárne relácie. Relácie na množine. Zobrazenia (funkcie). Mohutnosti množín. Úvod do teórie formálnych jazykov.
Literatúra Grimaldi, R. Doplňujúca literatúra Bukovský, L.: Množiny a všeličo okolo nich, Alfa, Bratislava 1985. Podmieňujúce predmety 1-AIN-120 Diskrétna matematika (1) Nadväzujúce predmety 1-AIN-410 Matematika (3) Výučba. Free Pascal a Lazarus.