History of Technology in Games Where We've Been… … Today

Total Page:16

File Type:pdf, Size:1020Kb

History of Technology in Games Where We've Been… … Today Where We’ve Been… History of Technology in Games ! Processing ! Storage 3D Graphics ! Graphics ! CRT CMPUT 250 ! Vector Graphics Fall 2007 ! Raster Graphics ! Bitmaps Tuesday, October 9 ! Resolution, Colour Depth, Frame Rate ! Early Arcade Games Raster Wins CMPUT 250: Fall 2007 Lecture #10: History 3 … Today ! 2D Graphics ! 3D Graphics ! Camera ! Sprites ! Meshes ! Layers ! Triangles ! Collision Detection ! Models ! Specialization and Generalization ! Culling ! Volume Partitioning ! History of Home Consoles ! Advances in 3D ! Shading and Texturing ! Special Effects CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 3D Graphics Types of Rendering ! This is a very complex subject ! Non Real-Time (e.g., raytracing) ! Video screens are 2D; World is 3D ! Trace paths of beams of light in the world and compute ! Produce a 2D image of a 3D world their colour when they hit the camera’s field of view ! Virtually build our 3D world ! Slow (minutes or hours for one frame) but high quality ! Point a virtual camera at it ! Used in movies like Pixar’s Toy Story, etc. ! How do we describe the objects in the world? ! Sometimes used to pre-render scenes in games Scene ! These images can also be used as a background ! What does our camera do? ! Real-Time Rendering ! Draw image in real-time (quickly enough to animate) ! Lower quality but world can change with player actions CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 The Camera The Camera: Frustum ! A camera is a view of the world ! Volume visible to camera: view frustum ! Occupies a position in 3D space (x,y,z) and points in a direction ! Viewing angle (horizontal and vertical) ! Real cameras also have: ! Focal length ! Lens Distortion ! Focus ! Depth of Field © George Otto, Penn State University CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 The Camera: Styles The Camera: Styles ! Fixed cameras ! Free cameras ! Chase camera (3rd person, follows behind) ! Finite position and direction (Myst, 7th Guest) ! Free-look (1st person, looks wherever you point) ! Fixed position (Myst 3) ! Look-spring (1st or 3rd camera can be moved but ! Fixed direction (some RTS, isometric view) automatically returns to its default when released) ! Rear-view (look behind you) ! Fixed path (rail-shooters like Virtua Cop) ! Droppable (move and then leave it there) ! Fixed path with free direction (rail-shooters like ! Switching from 1st to 3rd or vice versa Panzer Dragoon) CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 The Camera: Friend or Foe? Simple “3D” Tricks ! Obstructions in 3rd person view ! Scaling: making 2D sprites bigger or smaller to simulate moving toward or away ! Where does the chase camera go when you ! Boot Hill (Midway, 1977) back into a wall? ! Isometric view: 2D artistic style showing ! Camera won’t allow the angle you want perspective from a fixed angle ! Camera too slow ! Zaxxon (Sega, 1982) ! These aren’t really rendering ! Camera too erratic or has jerky transitions ! We want a world with real 3D objects (i.e., they occupy ! Camera too automatic or too manual some volume of space… not just an area of the screen) CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 The Scene Polygons ! Need to represent things in the world ! Polygons are 2D objects described by three ! Irrelevant what they look like inside or more points connected by line segments. ! Let’s make “hollow” objects ! They are closed (all line segments ! Here’s the plan: connected) and line segments do not cross ! Objects defined by surfaces (or meshes) each other. ! Surfaces built out of polygons ! A point used to describe a polygon is called ! Polygons built out of triangles a vertex (plural: vertices). ! Triangles defined by their vertices CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 Example of Polygons Examples of Non-Polygons Not closed Not line segments Line segments cross CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 Triangles Coordinates ! Simplest polygon ! Two dimensional points can be described using 2D coordinates or vertices ! Nice mathematical properties ! Each coordinate is two numbers (x and y), referring to ! Can divide up more complex polygons into horizontal and vertical position triangles (tessellation) ! For our surfaces, we must use 3D coordinates (x, y, z) referring to horizontal, vertical, and depth ! Our polygons (triangles) will be described by 3D coordinates CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 Meshes Multiple Meshes ! A collection of triangles for a single ! Figures can be composed of multiple “object” is called a mesh meshes. The pieces (meshes) can separate. ! In the end, a mesh is just a big list of vertex coordinates CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 Normal Vectors How to Draw a Scene ! World is built out of many, many triangles ! Recall our objects are hollow and we only ! Place the camera in the world care about the “outside” ! We can calculate what a triangle looks like from the camera’s position ! Which side is the outside? ! But some triangles obscure others (?) ! Normal vectors point out from a triangle’s ! One idea: visible side ! sort triangles by how far away they are ! draw them from furthest to closest ! closer triangles will be drawn over top of further triangles CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 Problem Culling ! Too many triangles ! Reduce the number of triangles we need to draw ! Limited number can be drawn per frame ! Culling is the process of eliminating triangles ! Essentially the same problem we had in vector from the list of those we need to draw. graphics and sprite graphics ! Can obviously ignore ! Always need to consider scene complexity ! triangles behind the camera ! Many factors to complexity ! triangles out of the forward field of view up-down and ! Number of potentially visible triangles right-left ! Effects in rendering those triangles ! triangles beyond the camera’s range ! How can we draw complex worlds? ! all this is called frustrum culling ! only consider triangles inside the camera’s frustrum CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 The Camera: Frustum Clipping ! Volume visible to camera: frustum ! Only considering triangles inside the frustum now ! Triangle may only be partially inside ! Cut off part of triangle that is outside ! This process is called clipping © George Otto, Penn State University CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 Still have problems… Philosophical Question ! With complex worlds, even computing what triangles are inside the frustum may be too slow! Ever wonder why you can’t just ! Camera’s max depth may cover most of the world blow any and every wall up? ! Need a fast way of deciding what triangles might be visible before we cull ! Let’s break the world up into manageable spaces CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 Static vs. Dynamic Objects Volume Partitioning ! Static Objects, e.g., walls, statues, trees ! Use static objects to divide up (partition) ! Precompute (calculate ahead of time) and store the world into separate spaces (volumes) information about the visibility of its triangles ! Use the information to speed up rendering ! Rooms are a natural way to do this ! If most of the world is static… life is good ! We can manually specify the division when ! … but boring we design the levels ! Static objects can still help ! There are more automatic methods, but we start with a portal system. CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 Portals Portals ! Divide world into regions connected by portals A A B C ! Camera is limited to triangles in the same B region as it (or adjoining regions) D C ! Allow portals to be open or closed to keep D the number of regions small CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 Automated Volume Partitioning ! Automated methods split the world’s volume up into pieces using geometry. ! Examples include ! Binary space partitioning ! Quadtrees ! Octrees ! Many games use a mixture of manual and automatic methods CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 Early 3D Early 3D: 2.5D ! Made possible by volume partitioning ! One “floor”: possibly variable height ! 2D graphics (sprites) in a 3D environment ! No rooms above rooms (except by trickery) ! The Games ! History ! Ultima Underworld (Looking Glass, 1992) ! Ultima Underworld allowed a complex environment ! Wolfenstein 3D (id Software, 1992) (angled walls, inclined surfaces) but was slow ! Doom (id Software, 1993) ! Wolfenstein 3D made simplifying assumptions (e.g. all- ! Heretic (Raven Software, 1994) right angles, all floors the same level) and was fast ! Marathon (Bungie, 1994) ! Doom relaxed restrictions (some angled walls, some ! System Shock (Looking Glass, 1994) variable height floors) while keeping the speed ! Duke Nukem 3D (3D Realms, 1996) ! Heretic allowed angling viewpoint up and down CMPUT 250: Fall 2007 Lecture #10: History 3 CMPUT 250: Fall 2007 Lecture #10: History 3 Early 3D: Beyond 2.5D System Shock (Looking Glass, 1994) ! More History: !
Recommended publications
  • Steam Early Access
    STEAM EARLY ACCESS ONLINE GAME MANUAL www.nefariousdimensions.com PLEASE CAREFULLY READ THE OPERATIONS MANUAL COMPLETELY BEFORE USING YOUR HARDWARE SYSTEM, DISC OR ACCESSORY. THIS MANUAL CONTAINS IMPORTANT HEALTH AND SAFETY INFORMATION. IMPORTANT SAFETY INFORMATION: READ THE FOLLOWING WARNINGS BEFORE YOU OR YOUR CHILD PLAY VIDEO GAMES. • Some people (about 1 in 4000) may have seizures or blackouts triggered by light flashes or patterns, and this may occur while they are watching TV or playing video games, even if they have never had a seizure before. •Anyone who has had a seizure, loss of awareness, or other symptom linked to an epileptic condition should consult a doctor before playing a video game. • Parents should watch their children play video games. Stop playing and consult a doctor if you or your child has any of the following symptoms: Convulsions Eye or muscle twitching Altered vision Loss of awareness Involuntary movements Disorientation • To reduce the likelihood of a seizure when playing video games: 1. Sit or stand as far from the screen as possible. 2. Play video games on the smallest available television screen. 3. Do not play if you are tired or need sleep. 4. Play in a well-lit room. 5. Take a 10 to 15 minute break every hour. Playing video games can make your muscles, joints, skin or eyes hurt. Follow these instructions to avoid problems such as tendinitis, carpal tunnel syndrome, skin irritation or eyestrain: •Avoid excessive play. Parents should monitor their children for appropriate play. • Take a 10 to 15 minute break every hour, even if you don’t think you need it.
    [Show full text]
  • Fundamentals of Real-Time Camera Design
    Fundamentals of Real-Time Camera Design Mark Haigh-Hutchinson Senior Software Engineer Retro Studios Inc. [email protected] www.realtimecameras.com 1. Introduction Camera design influences every aspect of interactive game applications. As the main avenue through which the player interacts with the game, the quality of the camera system and its effectiveness at presenting the game world to the player has a major influence on player satisfaction and enjoyment of the game. A poorly implemented camera system will cripple the game design and no amount of excellence in graphical presentation or game play mechanics will overcome it. A brief perusal of game reviews will certainly confirm this. On the other hand, a well designed camera system - one that presents the game in an unobtrusive and easy to understand manner - will elevate a good design to a great one. In light of this, it is somewhat surprising that there is so little information available to the designers and implementers of game camera systems. Fundamentals of Real Time Camera Design is aimed at expanding the knowledge of designers and programmers with regards to this crucial yet often overlooked topic. While there is common ground between traditional cinematography techniques and game camera systems (especially, of course, with respect to non-interactive cinematic sequences), the interactive nature of games and their requirements of dynamically changing game play demands different approaches and solutions. Interactive applications lag behind traditional film in that the underlying principles of real time camera design are still in their formative process. However, enough information is now available to establish a set of ground rules that will apply regardless of the game genre or presentation style.
    [Show full text]
  • The Trackball Controller: Improving the Analog Stick
    The Trackball Controller: Improving the Analog Stick Daniel Natapov I. Scott MacKenzie Department of Computer Science and Engineering York University, Toronto, Canada {dnatapov, mack}@cse.yorku.ca ABSTRACT number of inputs was sufficient. Despite many future additions Two groups of participants (novice and advanced) completed a and improvements, the D-Pad persists on all standard controllers study comparing a prototype game controller to a standard game for all consoles introduced after the NES. controller for point-select tasks. The prototype game controller Shortcomings of the D-Pad became apparent with the introduction replaces the right analog stick of a standard game controller (used of 3D games. The Sony PlayStation and the Sega Saturn, for pointing and camera control) with a trackball. We used Fitts’ introduced in 1995, supported 3D environments and third-person law as per ISO 9241-9 to evaluate the pointing performance of perspectives. The controllers for those consoles, which used D- both controllers. In the novice group, the trackball controller’s Pads, were not well suited for 3D, since navigation was difficult. throughput was 2.69 bps – 60.1% higher than the 1.68 bps The main issue was that game characters could only move in eight observed for the standard controller. In the advanced group the directions using the D-Pad. To overcome this, some games, such trackball controller’s throughput was 3.19 bps – 58.7% higher than the 2.01 bps observed for the standard controller. Although as Resident Evil, used the forward and back directions of the D- the trackball controller performed better in terms of throughput, Pad to move the character, and the left and right directions for pointer path was more direct with the standard controller.
    [Show full text]
  • First Person Shooter the Subjective Cyberspace
    i i i i i i i i i i i i i i i i i i i i Herlander Elias First Person Shooter The Subjective Cyberspace LabCom Books 2009 i i i i i i i i CREDITS Publishing House: LabCom Books Covilhã, Portugal, 2009 www.livroslabcom.ubi.pt Communication Studies Series Director: António Fidalgo Cover Design: Herlander Elias (Layout) Translation: Pedro Guilherme, Catherine Hshin & Herlander Elias Desktop Publishing: Marco Oliveira Legal Deposit number: 294384/09 ISBN: 978-989-654-019-7 Title: First Person Shooter: The Subjective Cyberspace Copyright c Herlander Elias, Author, 2009 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Herlander Elias. c Videogame Image Credits: From the videogame Mirror’s Edge TM (2008) developed by Swedish DICE, an EA (Electronic Arts) studio, for PlayStation 3TM. Used with permission. All rights reserved to DICE and EA. Thanks to Jenny Huldschiner at DICE, Sweden. i i i i i i i i Dedicated to... Júlio Semião Elias, My father iii i i i i i i i i ACKNOWLEDGEMENTS Marisa Alexandra Elias, Júlio Semião Elias, Rui Aguadeiro, David Gorjão Silva, António Fernando Cascais, Mónica Miranda, Gisela Gonçalves, Erik Davis, Miltos Manetas, Palle Torsson, Tobias Bernstrup, Marc Laidlaw, Fer- nando Poeiras, Mário Caeiro, Orlando Salvador, Sónia Alves, Catarina Ruivo, Catarina Campino, Jorge Martins Rosa, Óscar Mealha, Anabela Gradim, Paulo Faustino, Paulo Ferreira, Amélia Sousa, Paulo Serra, António Fidalgo, José A.
    [Show full text]
  • First-Person Shooter Controls on Touchscreen Devices: a Heuristic Evaluation of Three Games on the Ipod Touch
    First-Person Shooter Controls on Touchscreen Devices: a Heuristic Evaluation of Three Games on the iPod Touch Tuomas Hynninen University of Tampere Department of Computer Sciences Interactive Technology M.Sc. thesis Thesis supervisor: Roope Raisamo November 2012 University of Tampere Department of Computer Sciences Interactive Technology Tuomas Hynninen: First-Person Shooter Controls on Touchscreen Devices: a Heuristic Evaluation of Three Games on the iPod Touch M.Sc. thesis, 64 pages, 4 index pages November 2012 Today's touchscreen devices have a large amount of computing power which enables them to run high performance software, such as first-person shooter games rendered in 3D. Devices such as the iPod Touch that were originally built for music and other media consumption also provide a wide variety of features. For example, the iPod Touch can be used to surf the Internet, play quality video and audio and run complex video games. This thesis concentrates on first-person shooters games on the iPod Touch and provides a detailed breakdown of how developers have used the device's touch interface in their games. Related research, especially regarding first-person shooters and touch input, is explored and discussed. Completely new heuristics were developed in order to analyze the properties and effectiveness of the controls. In total, three iPod Touch games and nine control modes were evaluated. The results showed that the effectiveness of the controls was lacking. Target acquisition and tracking proved to be especially problematic. The results followed conclusions and observations made in related research. Suggestions for future work include investigating touchscreen hardware improvements and exploring different FPS game designs for mobile platforms.
    [Show full text]
  • Graphics, Genres, and Design the Early Days Hardware Vs. Software
    ! Themes Graphics, Genres, and Design ! hardware vs. software ! specialization vs. generalization ! state vs. dynamics CMPUT 299 ! cost of state and dynamics Fall 2005 ! storage: ram vs. rom ! graphics Finnegan Southey XBox Live GamerTag: Alea CMPUT 299 - Fall 2005 Graphics, Genres, and Design The Early Days Hardware vs. Software ! The very earliest video games (pre-1975) ! Later games (1975 to present) were built were custom built machines. using new-fangled microprocessors ! Designed/built by engineers (like a TV). ! General-purpose hardware that runs software. Tennis for Two ! No need to engineer from scratch for every (Brookhaven Labs,1958) game. Gunfight (Taito, 1975) CMPUT 299 - Fall 2005 Graphics, Genres, and Design Pong (Atari, 1972) CMPUT 299 - Fall 2005 Graphics, Genres, and Design Development of Early Games Development of Early Games ! Programs written by one individual. ! Games were simple. ! Graphics, sound, controls, rules, AI… ! The machines were still quite simple ! Very limited storage …all by one person. ! no “pictures” or recorded music ! Limited speed ! focus on moving small things around on the screen ! Only so much one could do ! more people would be a waste of effort CMPUT 299 - Fall 2005 Graphics, Genres, and Design CMPUT 299 - Fall 2005 Graphics, Genres, and Design State vs. Dynamics State ! Fundamental distinction in computing (and ! positions of all game entities many other things) ! walls ! State ! resources: health, magic points, money, fuel, etc. ! All information that describes the game at a given ! points:
    [Show full text]
  • Fights in Tight Spaces 70
    Widen your vision with a GB3461WQSU Red Eagle with FreeSync Premium Unleash your full gaming potential and enjoy superb image quality with this 144Hz IPS panel offering 1ms MPRT and 3440x1440 resolution. 3440 x 1440 Find your match at gmaster.iiyama.com Burnout revenge ‘m suddenly aware that burnout is a very to have 10,000 games you want to make, neatly real problem. I’m a highly motivated person: organised in a queue in your brain, each waiting for I taught myself to code and make games, its turn. But I can’t. I can’t do any of them. They’ve all I such was my passion for the medium, and I’ve been patiently waiting their turn for decades, and I’m never struggled with my mental health before. letting them down as they rot in a queue. But this? This is different. This is new. I’ve never felt DAN MARSHALL So here I sit, paralysed by the idea that whatever like this before, and it’s weird and worrying. I start making right now is going to dominate the next Dan set up Size Here’s the problem: in the final nine months of two to three years of my life. I need to be sure it’s Five Games back in development on Lair of the Clockwork God, I worked 2006 before selling something I’m going to relish, and something that I’m hard. I didn’t crunch, per se, I worked regular hours indie games online going to enjoy making and playtesting.
    [Show full text]
  • FIRST-PERSON SHOOTER in Unity
    presents Build Your Own FIRST-PERSON SHOOTER in Unity Learn Unity • Create enemies • Design levels • Make Zombie Panic 01_WF_Unity FPS Guide_Cover V3_LA_RL_LA_PK.indd 1 09/01/2020 13:42 Find hundreds more books and magazines in the TARTED S STORE wfmag.cc/store Robots, musical instruments, smart displays and more Create AMAZING projects with this programmable controller MAGAZINE FROM THE MAKERS OF Editorial Editor Ryan Lambie Email [email protected] Features Editor Ian Dransfield Email [email protected] Book Production Editor Phil King Sub-Editors You too can David Higgs, Vel Ilic, Nicola King Design make a shooter criticalmedia.co.uk Head of Design an one person make a first-person shooter? The size, scope, Lee Allen and sheer detail of a typical triple-A game – the Call of Dutys, Designer Battlefields and Halos of this world – might leave you thinking Harriet Knight C that the answer’s a resounding no. But beneath all the polish and modes, the basic elements that underpin the shooter Contributors genre haven’t changed all that much since Doom and Quake defined it way Stuart Fraser, Patrick Gordon, Steve Lee, back in the 1990s. Andrew Palmer, Ryan Shah, Mark Vanstone In fact, with a bit of help and guidance, even a relative newcomer can put together a simple shooter with most of the trappings you’d expect: a level Publishing to navigate around, keys that unlock doors and, most importantly, hordes of Publishing Director enemies to blast. Russell Barnes That’s where this guide comes in “Follow our guide Email [email protected] – it’ll take you step by step through Director of Communications the process of making your very through to the end Liz Upton own first-person shooter.
    [Show full text]
  • Supporting Spectators in Online Multiplayer Games
    Supporting Spectators in Online Multiplayer Games Ashwin R. Bharambe∗ Venkata N. Padmanabhan Srinivasan Seshan Carnegie Mellon University Microsoft Research Carnegie Mellon University ABSTRACT ease with which the views can be generated. Taken together, We examine network support for spectators in online multi- these characteristics of spectating enable a rich and flexible set player games. We consider how the associated challenges are of strategies for bandwidth optimization, ranging from adjust- different from those in traditional audio/video streaming. Specif- ing the frequency of updates to adjusting the field of view. ically, we consider two problems: spectating (distributing the In addition, spectators need not be passive viewers like a TV gaming stream reliably to spectators, who may outnumber the audience. They can actively “cheer” the players, just as in a players by several orders of magnitude) and cheering (deliver- real game or sporting event. While such cheering can take dif- ing the spectators’ audio cheers to the players as well as to other ferent forms, audio is perhaps the most natural form, and is the spectators). We point out the many unique challenges and op- focus of our discussion here. At first glance, cheering might portunities for optimization that arise in this context in terms of appear to be no different from “conference” mode (as opposed resilience, bandwidth adaptation, and dynamically varying user to “lecture” mode) in the A/V context. However, cheering dif- interest. We outline a solution based on overlay networking fers in a few key ways. First, there is typically no floor control. and quantify some of our design arguments with a preliminary Multiple members of the audience are typically speaking at the evaluation of Quake III, a popular first-person shooting game.
    [Show full text]
  • The Evolution of FPS Games Controllers: How Use Progressively Shaped Their Present Design
    The evolution of FPS games controllers: how use progressively shaped their present design Kostas GKIKAS† Dimitris NATHANAEL† Nicolas MARMARAS‡ [email protected] [email protected] [email protected] †University of the Aegean – Department of product and systems design engineering ‡National Technical University of Athens – ErgoU Ermoupolis, GR-84100, Greece Abstract First Person Shooter (FPS) is a genre of computer games with immense success over the last decade. The genre has evolved rapidly thanks to technological advances in 3D graphics and Artificial Intelligence to high levels of realism. However, its hardware interface has received, or so it seems, little attention; most expert players finding a conventional keyboard and mouse configuration as the best choice. In this paper we take a close look at the evolution of FPS controller configuration. We try to show that this historically evolved control configuration, although not optimum in any analytical sense, blends in an original way diverse and often conflicting ergonomic requirements. We conclude by suggesting that the sustainability of the keyboard-mouse as the FPS controller of choice is mainly due to its inherent plasticity. This plasticity has facilitated not only the continuous streamlining of the controller configuration per-se but has also significantly influenced the genre’s evolution as a whole. Keywords: FPS games, controllers, mapping, task-artefact cycle 1. Introduction The aim of human-computer interface design in general is to achieve high levels of usability. Usability is defined in ISO 9241-11 as “the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use” [ISO (1998)].
    [Show full text]