A vertex is a collection of data per 3D coordinate. We will briefly explain each part of the pipeline in a simplified way to give you a good overview of how the pipeline operates.Īs input to the graphics pipeline we pass in a list of three 3D coordinates that should form a triangle in an array here called Vertex Data this vertex data is a collection of vertices. Note that the blue sections represent sections where we can inject our own shaders.Īs you can see, the graphics pipeline contains a large number of sections that each handle one specific part of converting your vertex data to a fully rendered pixel. Shaders are written in the OpenGL Shading Language ( GLSL) and we'll delve more into that in the next chapter.īelow you'll find an abstract representation of all the stages of the graphics pipeline. This gives us much more fine-grained control over specific parts of the pipeline and because they run on the GPU, they can also save us valuable CPU time. Some of these shaders are configurable by the developer which allows us to write our own shaders to replace the existing default shaders. The processing cores run small programs on the GPU for each step of the pipeline. Because of their parallel nature, graphics cards of today have thousands of small processing cores to quickly process your data within the graphics pipeline. All of these steps are highly specialized (they have one specific function) and can easily be executed in parallel. The graphics pipeline can be divided into several steps where each step requires the output of the previous step as its input. The graphics pipeline takes as input a set of 3D coordinates and transforms these to colored 2D pixels on your screen. In this chapter we'll briefly discuss the graphics pipeline and how we can use it to our advantage to create fancy pixels. The graphics pipeline can be divided into two large parts: the first transforms your 3D coordinates into 2D coordinates and the second part transforms the 2D coordinates into actual colored pixels. The process of transforming 3D coordinates to 2D pixels is managed by the graphics pipeline of OpenGL. In OpenGL everything is in 3D space, but the screen or window is a 2D array of pixels so a large part of OpenGL's work is about transforming all 3D coordinates to 2D pixels that fit on your screen. Moreover, the dimensions of the radiation field and the correct alignment of the tertiary circular collimator can be also documented.Hello Triangle Getting-started/Hello-Triangle The mean displacement in AP, Lat, and Vert coordinates respectively, over 84 patients, between the coordinates calculated by the computerized procedure employing fiducial markers and the coordinates calculated by using the rulers was 0.3 +/- 0.4 mm.įrom the results obtained with the two methods we can conclude that rulers method can be used as a fast indirect control of the position of the radiation isocenter. Prior to irradiation, the coordinates of the intersection of the beams axes, which is in a known spatial relationship with the isocenter, are read directly on portal x-ray films and their coincidence with the coordinates set during patient positioning, is checked. The center of the beam is identified by a cylindrical localizer, fixed to the plate of the supplemental collimator, with a 2 x 50 mm tungsten rod coincident with the beam axis and is projected onto the x-ray portal verification films. The accuracy is compared to that of accepted computerized procedures employing fiducial markers. A simple method that verifies the coincidence of the isocenter with the center of the target volume in radiosurgery treatment conditions is described.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |