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OpenGL Shading Language

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OpenGL Shading Language ( GLSL ) is a high-level shading language with a syntax based on the C programming language . It was created by the OpenGL ARB (OpenGL Architecture Review Board) to give developers more direct control of the graphics pipeline without having to use ARB assembly language or hardware-specific languages.

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41-446: With advances in graphics cards, new features have been added to allow for increased flexibility in the rendering pipeline at the vertex and fragment level. Programmability at this level is achieved with the use of fragment and vertex shaders . Originally, this functionality was achieved by writing shaders in ARB assembly language – a complex and unintuitive task. The OpenGL ARB created

82-839: A browser war with Netscape. On the JavaScript front, Microsoft created its own interpreter called JScript . Microsoft first released JScript in 1996, alongside initial support for CSS and extensions to HTML . Each of these implementations was noticeably different from their counterparts in Netscape Navigator . These differences made it difficult for developers to make their websites work well in both browsers, leading to widespread use of "best viewed in Netscape" and "best viewed in Internet Explorer" logos for several years. Brendan Eich later said of this period: "It's still kind of

123-535: A graphical user interface , Mosaic , was released in 1993. Accessible to non-technical people, it played a prominent role in the rapid growth of the early World Wide Web . The lead developers of Mosaic then founded the Netscape corporation, which released a more polished browser, Netscape Navigator , in 1994. This quickly became the most-used. During these formative years of the Web, web pages could only be static, lacking

164-519: A sidekick language. It's considered slow or annoying. People do pop-ups or those scrolling messages in the old status bar at the bottom of your old browser ." In November 1996, Netscape submitted JavaScript to Ecma International , as the starting point for a standard specification that all browser vendors could conform to. This led to the official release of the first ECMAScript language specification in June 1997. The standards process continued for

205-532: A Navigator beta in September 1995, the name was changed to JavaScript for the official release in December. The choice of the JavaScript name has caused confusion, implying that it is directly related to Java. At the time, the dot-com boom had begun and Java was a popular new language, so Eich considered the JavaScript name a marketing ploy by Netscape. Microsoft debuted Internet Explorer in 1995, leading to

246-418: A database query to return information. The notable standalone runtimes are Node.js , Deno , and Bun . The following features are common to all conforming ECMAScript implementations unless explicitly specified otherwise. JavaScript supports much of the structured programming syntax from C (e.g., if statements, while loops, switch statements, do while loops, etc.). One partial exception

287-436: A few years, with the release of ECMAScript 2 in June 1998 and ECMAScript 3 in December 1999. Work on ECMAScript 4 began in 2000. However, the effort to fully standardize the language was undermined by Microsoft gaining an increasingly dominant position in the browser market. By the early 2000s, Internet Explorer 's market share reached 95%. This meant that JScript became the de facto standard for client-side scripting on

328-452: A stand-alone JavaScript runtime system. As of 2018, Node had been used by millions of developers, and npm had the most modules of any package manager in the world. The ECMAScript draft specification is currently maintained openly on GitHub , and editions are produced via regular annual snapshots. Potential revisions to the language are vetted through a comprehensive proposal process. Now, instead of edition numbers, developers check

369-592: A variety of apps . The most popular runtime system for non-browser usage is Node.js . JavaScript is a high-level , often just-in-time compiled language that conforms to the ECMAScript standard. It has dynamic typing , prototype-based object-orientation , and first-class functions . It is multi-paradigm , supporting event-driven , functional , and imperative programming styles . It has application programming interfaces (APIs) for working with text, dates, regular expressions , standard data structures , and

410-827: A variety of other software systems, both for server-side website deployments and non-browser applications . Initial attempts at promoting server-side JavaScript usage were Netscape Enterprise Server and Microsoft 's Internet Information Services , but they were small niches. Server-side usage eventually started to grow in the late 2000s, with the creation of Node.js and other approaches . Electron , Cordova , React Native , and other application frameworks have been used to create many applications with behavior implemented in JavaScript. Other non-browser applications include Adobe Acrobat support for scripting PDF documents and GNOME Shell extensions written in JavaScript. JavaScript has been used in some embedded systems , usually by leveraging Node.js. A JavaScript engine

451-520: A white paper in which he coined the term Ajax and described a set of technologies, of which JavaScript was the backbone, to create web applications where data can be loaded in the background, avoiding the need for full page reloads. This sparked a renaissance period of JavaScript, spearheaded by open-source libraries and the communities that formed around them. Many new libraries were created, including jQuery , Prototype , Dojo Toolkit , and MooTools . Google debuted its Chrome browser in 2008, with

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492-524: Is scoping : originally JavaScript only had function scoping with var ; block scoping was added in ECMAScript 2015 with the keywords let and const . Like C, JavaScript makes a distinction between expressions and statements . One syntactic difference from C is automatic semicolon insertion , which allow semicolons (which terminate statements) to be omitted. JavaScript is weakly typed , which means certain types are implicitly cast depending on

533-518: Is a software component that executes JavaScript code . The first JavaScript engines were mere interpreters , but all relevant modern engines use just-in-time compilation for improved performance. JavaScript engines are typically developed by web browser vendors, and every major browser has one. In a browser, the JavaScript engine runs in concert with the rendering engine via the Document Object Model and Web IDL bindings. However,

574-437: Is an accepted version of this page JavaScript ( / ˈ dʒ ɑː v ə s k r ɪ p t / ), often abbreviated as JS , is a programming language and core technology of the Web , alongside HTML and CSS . 99% of websites use JavaScript on the client side for webpage behavior. Web browsers have a dedicated JavaScript engine that executes the client code . These engines are also utilized in some servers and

615-487: Is by far the most-used. Other notable ones include Angular , Bootstrap , Lodash , Modernizr , React , Underscore , and Vue . Multiple options can be used in conjunction, such as jQuery and Bootstrap. However, the term "Vanilla JS" was coined for websites not using any libraries or frameworks at all, instead relying entirely on standard JavaScript functionality. The use of JavaScript has expanded beyond its web browser roots. JavaScript engines are now embedded in

656-543: Is the dominant client-side scripting language of the Web, with 99% of all websites using it for this purpose. Scripts are embedded in or included from HTML documents and interact with the DOM . All major web browsers have a built-in JavaScript engine that executes the code on the user's device. Over 80% of websites use a third-party JavaScript library or web framework as part of their client-side scripting. jQuery

697-450: The Document Object Model (DOM). The ECMAScript standard does not include any input/output (I/O), such as networking , storage , or graphics facilities. In practice, the web browser or other runtime system provides JavaScript APIs for I/O. Although Java and JavaScript are similar in name, syntax , and respective standard libraries , the two languages are distinct and differ greatly in design. The first popular web browser with

738-511: The Firefox browser. Firefox was well received by many, taking significant market share from Internet Explorer. In 2005, Mozilla joined ECMA International, and work started on the ECMAScript for XML (E4X) standard. This led to Mozilla working jointly with Macromedia (later acquired by Adobe Systems ), who were implementing E4X in their ActionScript 3 language, which was based on an ECMAScript 4 draft. The goal became standardizing ActionScript 3 as

779-500: The V8 JavaScript engine that was faster than its competition. The key innovation was just-in-time compilation (JIT), so other browser vendors needed to overhaul their engines for JIT. In July 2008, these disparate parties came together for a conference in Oslo . This led to the eventual agreement in early 2009 to combine all relevant work and drive the language forward. The result was

820-511: The ECMAScript 5 standard, released in December 2009. Ambitious work on the language continued for several years, culminating in an extensive collection of additions and refinements being formalized with the publication of ECMAScript 6 in 2015. The creation of Node.js in 2009 by Ryan Dahl sparked a significant increase in the usage of JavaScript outside of web browsers. Node combines the V8 engine, an event loop , and I/O APIs , thereby providing

861-461: The OpenGL API, which is available on many different platforms (e.g., Linux , macOS , Windows ). There are language bindings for C , C++ , C# , JavaScript , Delphi , Java , and many more. GLSL shaders themselves are simply a set of strings that are passed to the hardware vendor's driver for compilation from within an application using the OpenGL API's entry points. Shaders can be created on

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902-465: The OpenGL API. It is only with OpenGL versions 3.3 and above that the GLSL and OpenGL major and minor version numbers match. These versions for GLSL and OpenGL are related in the following table: OpenGL ES and WebGL use OpenGL ES Shading Language (abbreviated: GLSL ES or ESSL ). The two languages are related but not directly compatible. They can be interconverted through SPIRV-Cross . GLSL contains

943-690: The OpenGL Shading Language to provide a more intuitive method for programming the graphics processing unit while maintaining the open standards advantage that has driven OpenGL throughout its history. Originally introduced as an extension to OpenGL 1.4, GLSL was formally included into the OpenGL 2.0 core in 2004 by the OpenGL ARB. It was the first major revision to OpenGL since the creation of OpenGL 1.0 in 1992. Some benefits of using GLSL are: GLSL versions have evolved alongside specific versions of

984-470: The United States. The trademark was originally issued to Sun Microsystems on 6 May 1997, and was transferred to Oracle when they acquired Sun in 2009. A letter was circulated in September 2024, spearheaded by Ryan Dahl , calling on Oracle to free the JavaScript trademark . Brendan Eich the original creator of JavaScript, was among the over 14,000 signatories who supported the initiative. JavaScript

1025-405: The Web. Microsoft initially participated in the standards process and implemented some proposals in its JScript language, but eventually it stopped collaborating on ECMA work. Thus ECMAScript 4 was mothballed. During the period of Internet Explorer dominance in the early 2000s, client-side scripting was stagnant. This started to change in 2004, when the successor of Netscape, Mozilla , released

1066-426: The ability to import scripts. JavaScript is a single- threaded language. The runtime processes messages from a queue one at a time, and it calls a function associated with each new message, creating a call stack frame with the function's arguments and local variables . The call stack shrinks and grows based on the function's needs. When the call stack is empty upon function completion, JavaScript proceeds to

1107-519: The capability for dynamic behavior after the page was loaded in the browser. There was a desire in the flourishing web development scene to remove this limitation, so in 1995, Netscape decided to add a programming language to Navigator. They pursued two routes to achieve this: collaborating with Sun Microsystems to embed the Java language, while also hiring Brendan Eich to embed the Scheme language. The goal

1148-448: The extensions: GLSL shaders can also be used with Vulkan , and are a common way of using shaders in Vulkan. GLSL shaders are precompiled before use, or at runtime, into a binary bytecode format called SPIR-V , usually using offline compiler. Vertex (computer graphics) A vertex (plural vertices ) in computer graphics is a data structure that describes certain attributes, like

1189-456: The fly from within an application, or read-in as text files, but must be sent to the driver in the form of a string. The set of APIs used to compile, link, and pass parameters to GLSL programs are specified in three OpenGL extensions, and became part of core OpenGL as of OpenGL Version 2.0. The API was expanded with geometry shaders in OpenGL 3.2, tessellation shaders in OpenGL 4.0 and compute shaders in OpenGL 4.3. These OpenGL APIs are found in

1230-905: The hardware level. Many of these functions are similar to those in the math library of the C programming language while others are specific to graphics programming. Most of the built-in functions and operators, can operate both on scalars and vectors (up to 4 elements), for one or both operands. Common built-in functions that are provided and are commonly used for graphics purposes are: mix , smoothstep , normalize , inversesqrt , clamp , length , distance , dot , cross , reflect , refract and vector min and max . Other functions like abs , sin , pow , etc, are provided but they can also all operate on vector quantities, i.e. pow(vec3(1.5, 2.0, 2.5), abs(vec3(0.1, -0.2, 0.3))) . GLSL supports function overloading (for both built-in functions and operators, and user-defined functions), so there might be multiple function definitions with

1271-492: The new ECMAScript 4. To this end, Adobe Systems released the Tamarin implementation as an open source project. However, Tamarin and ActionScript 3 were too different from established client-side scripting, and without cooperation from Microsoft , ECMAScript 4 never reached fruition. Meanwhile, very important developments were occurring in open-source communities not affiliated with ECMA work. In 2005, Jesse James Garrett released

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1312-414: The next message in the queue. This is called the event loop , described as "run to completion" because each message is fully processed before the next message is considered. However, the language's concurrency model describes the event loop as non-blocking : program I/O is performed using events and callback functions . This means, for example, that JavaScript can process a mouse click while waiting for

1353-516: The object correctly. Most attributes of a vertex represent vectors in the space to be rendered . These vectors are typically 1 ( x ), 2 ( x, y ), or 3 ( x, y, z ) dimensional and can include a fourth homogeneous coordinate ( w ). These values are given meaning by a material description. In real-time rendering these properties are used by a vertex shader or vertex pipeline . Such attributes can include: For how vertices are processed on 3D graphics cards, see shader . JavaScript This

1394-409: The operation used. Values are cast to strings like the following: Values are cast to numbers by casting to strings and then casting the strings to numbers. These processes can be modified by defining toString and valueOf functions on the prototype for string and number casting respectively. JavaScript has received criticism for the way it implements these conversions as the complexity of

1435-460: The position of a point in 2D or 3D space , or multiple points on a surface . 3D models are most often represented as triangulated polyhedra forming a triangle mesh . Non-triangular surfaces can be converted to an array of triangles through tessellation . Attributes from the vertices are typically interpolated across mesh surfaces. The vertices of triangles are associated not only with spatial position but also with other values used to render

1476-437: The rules can be mistaken for inconsistency. For example, when adding a number to a string, the number will be cast to a string before performing concatenation, but when subtracting a number from a string, the string is cast to a number before performing subtraction. Often also mentioned is {} + [] resulting in 0 (number). This is misleading: the {} is interpreted as an empty code block instead of an empty object, and

1517-1052: The same name, having different number of parameters or parameter types. Each of them can have own independent return type. GLSL defines a subset of the C preprocessor (CPP), combined with its own special directives for specifying versions and OpenGL extensions. The parts removed from CPP are those relating to file names such as #include and __FILE__ . The GL_ARB_shading_language_include extension (implemented for example in Nvidia drivers on Windows and Linux, and all Mesa 20.0.0 drivers on Linux, FreeBSD and Android) implements ability to use #include in source code, allowing easier sharing of code and definitions between many shaders without extra manual pre-processing. Similar extension GL_GOOGLE_include_directive and GL_GOOGLE_cpp_style_line_directive exist for using GLSL with Vulkan, and are supported in reference SPIR-V compiler ( glslang aka glslangValidator). GLSL shaders are not stand-alone applications; they require an application that utilizes

1558-454: The same operators as the operators in C and C++ , with the exception of pointers . Bitwise operators were added in version 1.30. Similar to the C programming language , GLSL supports loops and branching, for instance: if-else, for, switch, etc. Recursion is forbidden and checked for during compilation. User-defined functions are supported and built-in functions are provided. The graphics card manufacturer may optimize built-in functions at

1599-436: The status of upcoming features individually. The current JavaScript ecosystem has many libraries and frameworks , established programming practices, and substantial usage of JavaScript outside of web browsers. Plus, with the rise of single-page applications and other JavaScript-heavy websites, several transpilers have been created to aid the development process. "JavaScript" is a trademark of Oracle Corporation in

1640-502: The use of JavaScript engines is not limited to browsers; for example, the V8 engine is a core component of the Node.js runtime system . A JavaScript engine must be embedded within a runtime system (such as a web browser or a standalone system) to enable scripts to interact with the broader environment. The runtime system includes the necessary APIs for input/output operations, such as networking , storage , and graphics , and provides

1681-399: Was a "language for the masses", "to help nonprogrammers create dynamic, interactive Web sites ". Netscape management soon decided that the best option was for Eich to devise a new language, with syntax similar to Java and less like Scheme or other extant scripting languages . Although the new language and its interpreter implementation were called LiveScript when first shipped as part of

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