Difference between revisions of "SoundData:setSample"

(Improved example that chooses better values and explains choices, and uses frequency. thanks to zorg for help.)
(Example: Play a sine wave: play something that sounds closer to music)
Line 25: Line 25:
 
Nothing.
 
Nothing.
  
== Example: Play a sine wave ==
+
== Example: Generate notes with a sine wave ==
  
 
<source lang="lua">
 
<source lang="lua">
local tau          = math.pi * 2
+
local tau          =   math.pi * 2
local samplerate  = 44100 -- Hz
+
local samplerate  =         44100 -- Hz
local bits        =     16 -- 8 bits would yield very low quality sound
+
local bits        =           16 -- 8 bits results in very low quality sound
local channels    =     2 -- löve only supports mono or stereo
+
local channels    =             2 -- löve only supports mono or stereo
local buffercount  =     2 -- probably better to use fewer buffers
+
local buffercount  =             2 -- probably better to use fewer buffers
local qsource      = love.audio.newQueueableSource(samplerate, bits, channels, buffercount)
+
local qsource      = love.audio.newQueueableSource(samplerate, bits, channels, buffercount)
local samplepoints =     64 -- how many numbers does one buffer hold
+
local samplepoints = samplerate/10 -- how many numbers does one buffer hold
local buffer      = love.sound.newSoundData(samplepoints, samplerate, bits, channels)
+
local buffer      = love.sound.newSoundData(samplepoints, samplerate, bits, channels)
local phase        =   0.0
+
local phase        =           0.0
local frequency    = 220.00 -- Hz
+
local frequency    =       220.00 -- Hz
local amplitude    =   0.5 -- 50%
+
local amplitude    =           0.5 -- 50%
  
  
Line 58: Line 58:
 
function love.keypressed(key)
 
function love.keypressed(key)
 
     if key == 'k' then
 
     if key == 'k' then
         frequency = frequency * 2^(1/2)
+
         frequency = frequency * 2^(1/12)
 
     elseif key == 'j' then
 
     elseif key == 'j' then
         frequency = frequency * 2^(-1/2)
+
         frequency = frequency * 2^(-1/12)
 
     end
 
     end
 
end
 
end
 
</source>
 
</source>
 
 
 
  
 
== See Also ==
 
== See Also ==

Revision as of 22:19, 24 November 2021

Sets the value of the sample-point at the specified position. For stereo SoundData objects, the data from the left and right channels are interleaved in that order.

Function

Synopsis

SoundData:setSample( i, sample )

Arguments

number i
An integer value specifying the position of the sample (starting at 0).
number sample
The normalized samplepoint (range -1.0 to 1.0).

Returns

Nothing.

Function

Available since LÖVE 11.0
This variant is not supported in earlier versions.

Sets the value of a sample using an explicit sample index instead of interleaving them in the sample position parameter.

Synopsis

SoundData:setSample( i, channel, sample )

Arguments

number i
An integer value specifying the position of the sample (starting at 0).
number channel
The index of the channel to set within the given sample.
number sample
The normalized samplepoint (range -1.0 to 1.0).

Returns

Nothing.

Example: Generate notes with a sine wave

local tau          =   math.pi * 2
local samplerate   =         44100 -- Hz
local bits         =            16 -- 8 bits results in very low quality sound
local channels     =             2 -- löve only supports mono or stereo
local buffercount  =             2 -- probably better to use fewer buffers
local qsource      = love.audio.newQueueableSource(samplerate, bits, channels, buffercount)
local samplepoints = samplerate/10 -- how many numbers does one buffer hold
local buffer       = love.sound.newSoundData(samplepoints, samplerate, bits, channels)
local phase        =           0.0
local frequency    =        220.00 -- Hz
local amplitude    =           0.5 -- 50%


local function synth()
    phase = phase + (tau * frequency / samplerate)
    return math.sin(phase) * amplitude
end

function love.update(dt)
    while qsource:getFreeBufferCount() > 0 do
        for i = 0, samplepoints - 1 do
            buffer:setSample(i, synth())
        end
        qsource:queue(buffer)
        qsource:play()
    end
end

function love.keypressed(key)
    if key == 'k' then
        frequency = frequency * 2^(1/12)
    elseif key == 'j' then
        frequency = frequency * 2^(-1/12)
    end
end

See Also


Other Languages