PPT-Lecture 13: OpenGL Shading Language (GLSL)

COMP 175 Computer Graphics April 18 2018 Last week we discussed the many of the new tricks in Graphics require lowlevel access to the Graphics pipeline For example using textures which is a pain in regular OpenGL. Graphics with OpenGL/GLUT What is OpenGL? • OpenGL ( Open G raphics L ibrary) • A software interface to graphics hardware • a standard specification defining a cross - language, c . Basis for real-time rendering and GPU architecture. 劉哲宇. ,. Liou. . Jhe. -Yu. Motivation . for learning graphics . fundamentals. Q: I’m . an architect. I do hardware, not . algorithms. Can’t . Graphics Programming. Katia Oleinik: koleinik@bu.edu. Graphics Programming. OpenGL. Low-level API. cross-language . cross-platform . 2D, 3D computer graphics. GLUT - The OpenGL Utility Toolkit. simple, easy and small. CSE 291 . [Fall. . 2015]. , Lecture . 4. Brief Intro to Programmable . Shaders. . http://. www.cs.ucsd.edu. /~. ravir. OpenGL Rendering Pipeline. Geometry . Primitive . Operations. Pixel. Operations. M. . Ramanathan. STTP CAD 2011. Introduction to OpenGL. What Is OpenGL?. Graphics rendering API. high-quality color images composed of geometric and image primitives. window system independent. operating system independent. Non-photorealistic Rendering. a longtime goal of graphics research has been to render a scene that is indistinguishable from a photograph of the scene. non-photorealistic rendering, or stylized depiction, is inspired by artistic styles. 2 Fases. Data van CPU overbrengen naar GPU. Mesh data, Render State, Blend State.... GPU rendert scene. Programeerbare shaders verwerken input. Scene wordt naar de Frame Buffer geschreven. Rendering. By . jared. brock. Overview. Project Description. What I must implement. What I would like to implement. Technique: . Cel. -Shading. What is . cel. -shading?. Requirements for . Cel. -shading. Generate Lighting Map. Converting virtual objects to pixel colors. . . Frame . Buffer: a buffer of memory to store the colors of the screen, one memory cell per pixel. . http://www.webopedia.com/TERM/F/frame_buffer.html. http://en.wikipedia.org/wiki/Framebuffer. It is . NOT. a . programming language. .. It . is a Graphics Rendering . API. . consisting of a . set of . functions . with . a well . defined interface.. Whenever . we say that a program is OpenGL-based or OpenGL applications, we mean that it is written in some programming language (such as C/C or Java) that makes calls to one or more of OpenGL libraries. Department of Geography and Planning. University at Albany. What is a GPU?. A GPU is a . graphics processing unit. Modern GPUs are composed of multiple processors. Each of these processors can perform operations similar to those of CPUs. Shader. ?. Small program, domain-specific language. Originally to compute surface appearance and . shading. “. Shader. ” is now used for any GPU computation. History. Shade Trees [Cook 1984]. Expressions for displacement, surface, light, atmosphere. Ed Angel. University of New Mexico. Dave . Shreiner. ARM, Inc. Evolution of the OpenGL Pipeline. A Prototype Application in OpenGL. OpenGL Shading Language (GLSL). Vertex Shaders. Fragment Shaders. Examples. CSE 3541. Prof. Roger Crawfis. More Complex Lighting. Diffuse and Specular shading can get quite complex. . Phong. and . Gouraud. shading models are more ad-hoc.. Other models take into account microfacets and sub-surface scattering..