![]() Sfxdef name, baseaddr, length, period, channel Each is a sfxdef line giving a pointer to the sound effect's data, the length in steps, how much to slow it down, and which channel to play it on. Sound effects are defined in pently_sfx_table in musicseq.s. A sound effect will never interrupt another sound effect that has more frames remaining. If there is already a sound effect playing on the first square wave channel, another sound effect played at the same time will automatically be moved to the second, but a sound effect for the triangle or noise channel will not be moved. If you need higher pitches and are satisfied with them being slightly out of tune, you can modify this program to extend it up another octave (through about 75 semitones) and use it to produce a new period file.Īt any moment, the mixer chooses to play either the music or the sound effect based on whatever is louder on each channel. ![]() The pitch table ntscPeriods.s is generated by mktables.py, a program written in Python. These frequencies apply to NTSC playback: The player automatically compensates for different APU speeds based on bit 0 of the tvSystem variable (0: NTSC NES or Dendy famiclone 1: PAL NES).īecause of the NES's limited precision for wave period values, note frequencies become less precise at high pitches. The following values are valid for the square wave channels the triangle wave channel always plays one octave lower. Pently expresses pitch in terms of a built-in table of wave periods in equal temperament (12edo). In NSF, the NSF shell stores the TV system in tvSystem. The file paldetect.s can be included in an NES program call getTVSystem and store the result into tvSystem before the first call to pently_start_music. Pently includes a subroutine that will automatically detect the TV system by measuring the frame length. export a 1-byte RAM variable called tvSystem. For pently_dalsegno_callback, carry is clear at the end of a track or set if looping. They can be useful for synchronizing animations to music. ![]() These are called before each row is processed and when a dalSegno or fine is processed, respectively. export two callback functions: pently_row_callback and pently_dalsegno_callback. If Pently is assembled with the command line switch -DPENTLY_USE_ROW_CALLBACK=1, your code must provide and. include "pentlyseq.inc" to use the macros described below. The file musicseq.s contains the sound effects, instruments, songs, and patterns that you define it should. If using getCurBeatFraction, additionally include math.s and bpmmath.s. Your makefile will need to assemble pentlysound.s, pentlymusic.s, musicseq.s and ntscPeriods.s, and link them into your program. getCurBeatFraction Reads the fraction of the current beat. Make sure your NMI handler finishes within 1500 or so cycles (not taking the whole NMI or waiting for sprite 0) while calling this, or the result in A will be wrong. Returns 0 in A for NTSC systems, 1 for PAL NES, or 2 for Dendy-style PAL famiclones. getTVSystem Waits for two NMIs, counting the time between them. pently_play_note Plays note A (see pitch table) on channel X (0, 4, 8, 12, or 16) with instrument Y from pently_instruments. Calling pently_resume_music without having first called pently_start_music or after a fine results in undefined behavior. pently_resume_music Resumes the playing song. pently_stop_music Stops the song, allowing sound effects to continue. pently_start_music Starts to a song, element A from the songTable. pently_update Updates the sound channels. ![]() Watch out: this trashes RAM $0000 through $0004, so be careful to save this data if you are calling this method from game logic. pently_start_sound Plays a sound effect, element A from the psg_sound_table. Call this at the start of a program or as a "panic button" before entering a long stretch of code where you don't call pently_update. Pently_init Initializes all sound channels. The following methods, declared in the assembly language include file pently.inc, make up the public API: It also reminds one of Greek πέντε (pénte) meaning "five", as it supports five tracks (pulse 1, pulse 2, triangle, drums, and attack injection) mapped onto the NES audio circuit's four tone generator channels. The name comes from Polish pętla meaning a loop. It has seen use in NES games dating back to 2009, including Concentration Room, Thwaite, Zap Ruder, the menu of Action 53, Double Action Blaster Guys, RHDE: Furniture Fight, and Sliding Blaster. Pently is a music and sound effect player code library for use in games for the Nintendo Entertainment System written in assembly language with ca65. This document describes Pently, the audio engine used in Pin Eight NES games since 2009. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |