Note: This is a summary from a Tessellation chapter found in this amazing book Graphic Shaders This book has a very good chapter on Tessellation OpenGL 4.0 Shading Language Cookbook If you are interested in learning more about tessellation, I would recommend these book: Graphics Shaders: Theory and Practice (A bit expensive, but worth every penny) The TES is responsible for determining the position of each vertex of the primitives that are produced by the TPG. i.e., it defines how the primitives should be generated by the TPG and what algorithm to use. The TCS is responsible for setting up the TPG. The TPG produces the primitives based on a set of standard tessellation algorithms.
Tessellation geometry generator#
The tessellation shader is composed of two stages: The Tessellation Control Shader (TCS) and the Tessellation Evaluation Shader (TES).īetween the TCS and the TES there is an additional operation called the Tessellation Primitive Generator (TPG).
So where is the Tessellation Shader in the Graphics Pipeline? The Tessellation shader follows the Vertex Shader and comes before the Geometry Shader. A tessellation of a flat surface is the tiling of a plane using one or more geometric shapes. Geometry Shaders can give you a new different geometry topology. For example, you get more lines from a segment, or more triangles from a triangle patch.
Tessellation Shaders can create new geometry, but the new geometry is of the same sort as what you started with. However, There is a big difference between the two. Both Tessellation and Geometry shaders are capable of creating new geometry from existing geometry. You may have also heard about Geometry Shaders. With Tessellation Shaders, you can add geometric details dynamically.
Tessellation geometry software#
For example, if you want to add more geometric detail to your model, you would usually add detail through your modeling software such as Blender. Overall, Tessellation Shaders increase the quality of your final image, but it can do this dynamically. Tessellation Shaders sole purpose is to interpolate geometry to create additional geometry that can perform adaptive subdivision based on criteria such as size or curvatures. The new OpenGL 4.0 supports Tessellation Shaders. Hunt using an irregular pentagon (shown on the right).Tessellation is a process that divides a surface into a smoother mesh of triangles. Another spiral tiling was published 1985 by Michael D. The first such pattern was discovered by Heinz Voderberg in 1936 and used a concave 11-sided polygon (shown on the left). Lu, a physicist at Harvard, metal quasicrystals have "unusually high thermal and electrical resistivities due to the aperiodicity" of their atomic arrangements.Īnother set of interesting aperiodic tessellations is spirals. The geometries within five-fold symmetrical aperiodic tessellations have become important to the field of crystallography, which since the 1980s has given rise to the study of quasicrystals. According to ArchNet, an online architectural library, the exterior surfaces "are covered entirely with a brick pattern of interlacing pentagons." An early example is Gunbad-i Qabud, an 1197 tomb tower in Maragha, Iran. The patterns were used in works of art and architecture at least 500 years before they were discovered in the West. Medieval Islamic architecture is particularly rich in aperiodic tessellation. These tessellations do not have repeating patterns. Notice how each gecko is touching six others. The following "gecko" tessellation, inspired by similar Escher designs, is based on a hexagonal grid. By their very nature, they are more interested in the way the gate is opened than in the garden that lies behind it." In doing so, they have opened the gate leading to an extensive domain, but they have not entered this domain themselves.
This further inspired Escher, who began exploring deeply intricate interlocking tessellations of animals, people and plants.Īccording to Escher, "Crystallographers have … ascertained which and how many ways there are of dividing a plane in a regular manner. His brother directed him to a 1924 scientific paper by George Pólya that illustrated the 17 ways a pattern can be categorized by its various symmetries. According to James Case, a book reviewer for the Society for Industrial and Applied Mathematics (SIAM), in 1937, Escher shared with his brother sketches from his fascination with 11 th- and 12 th-century Islamic artwork of the Iberian Peninsula. The most famous practitioner of this is 20 th-century artist M.C. Escher & modified monohedral tessellationsĪ unique art form is enabled by modifying monohedral tessellations. A dual of a regular tessellation is formed by taking the center of each shape as a vertex and joining the centers of adjacent shapes.
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