OpenAL (Open Audio Library) è una libreria per la riproduzione e la manipolazione di effetti sonori sviluppata seguendo lo stile della più conosciuta libreria grafica OpenGL.
Si tratta di un software multipiattaforma grazie a una interfaccia di programmazione indipendente dall'hardware ed è disponibile su sistemi operativi Linux, Windows, MacOS, FreeBSD, BeOS e OS/2.
Sviluppata dalla Creative Labs e dalla Loki Entertainment AL è stata pensata per essere utilizzata nel mondo della riproduzione audio 2D - 3D, ciò significa che si rivela un ottima scelta per applicazioni quali videogiochi 3D e software di simulazione in genere.
La somiglianza ad OpenGL oltre che nel nome si rivela nella filosofia di progettazione e nella sua implementazione, risulta quindi notevolmente semplice includere codice AL all'interno di applicazioni GL già sviluppate.
Dato che AL si è dimostrata un ottimo prodotto la maggior parte delle nuove applicazioni 3D Linux ne fanno uso mentre in Windows sta cominciando a farsi strada ponendosi come seria alternativa a DirectSound, la libreria audio delle DirectX.
OpenAL può vantare tra i propri "clienti" alcune giochi di notevole caratura come Unreal Tournament 2003 della Epic Games e Soldier Of Fortune 2 della Raven Software.
Compito primario di OpenAL è quello di fornire al programmatore una serie di API per posizionare fonti audio in un mondo tridimensionale tenendo in considerazione i parametri che potrebbero influenzarla quali:
- Distance-based attenuation distanza dell'ascoltatore
- Position-based panning posizione dell'ascoltatore
- Doppler effects effetto Doppler
- Sound radiation dispersione del suono attraverso un campo acustico
- Sound reverb riverbero del suono (ancora in fase di implementazione)
Sono presenti anche funzioni di utilità per il caricamento di file .WAV e .mp3 oltre che alla possibilità di accedere alle estensioni della Creative EAX (Environmental Audio Extension).
Altre informazioni sono disponibili sul sito ufficilale www.openal.org.
Al momento nonostante una buona comunità di sviluppatori OpenAL è ancora in uno stadio primitivo ma, come dimostrano la scelta adoperata da Epic Games e dalla Raven Software, ha un grande potenziale e buone probabilità di diventare un punto di riferimento nel campo audio così come OpenGL lo è in quello della grafica.
scuole in America
In the USA the ages for compulsory education vary from state to state.
?In most states combulsorv education starts when children are 5 and continues until they are 16-18 depending on the state. Today a growing number of states are requiring compulsory education until the age of 18.?Compulsory education is divided into two levels: elementary school?and high school.?The first vear of elementarv school is called Kindergarten and here pupils do various activities, learn the alphabet and how to play with other children. After Kindergarten there are five or six years of schooling called grades. In elementary schools pupils are taught basic subjects like English (spelling, vocabulary and grammar), Arithmetic and Physical Education.?High school generally consists of six years of schooling and goes from the 7th grade up to the final 12th grade. When pupils complete the 12th grade, they receive a High School Diploma, since there is no final examination as in many other countries. Students take a large variety of subjects without special emphasis in any particular subject. The subjects that are required in nearly all US high schools are English, Mathematics, Science, Social Sciences and Physical Education. Students can also choose from among a list of other subjects called 'electives' like Computer Studies, Art, Music, Foreign Languages and Driving, just to mention a few. Credits are given for each course and more credits are given for the more difficult courses.?Post-secondary education in the USA is known as college or university and commonly consists of four years of study at an institution of higher learning. There are about 4,400 colleges and universities in the country.?Schools differ in their reputation; generally, the most prestigious schools are private, rather than public. In the USA there are a number of very famous and prestigious universities like Harvard, Yale, Princeton and so on. They are usually very expensive so students try and get scholarships otherwise they ask for student loans and look for part-time jobs to support themselves.
In American education students are evaluated by marks or grades from A, the best, to F, the worst. Each year is also called grade so it is easy to calculate which grade a student is in from their age: for example, at 12 they are in grade 6, at 16 they are in grade 10 and so on. In high school, students in their first vear are called freshmen, in their second vear sophomores, in their third year juniors, and in their last year seniors.
The school day starts at around 8 a.m. in the morning and finishes at around 3.30 p.m. There is no school on Saturdays. Students do not have to wear uniforms except in some private schools but there is a strict dress code nonetheless. No very short skirts or very low necklines are allowed and neither is piercing or tattoos. Lunch is served in the school cafeteria or alternatively students bring their own lunch from home.
In US schools there are many extra-curricular activities like team sports, drama groups, Bible-study groups and societies ranging from the Chess Club to the Society Against Drunken Driving (SADD). Team sports play an important part in American education. They contribute to transmit values like teamwork, self-discipline, sportsmanship and also social and racial integration.
Illuminismo
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