Add sample, sample_left, sample_right to FeMedia and FeMusic

[oomek]

• Add a 1kHz low-pass filter to attenuate aliasing caused by hight frequencies during visualisation

Example layout and assets:

fe.layout.width = 640
fe.layout.height = 480
fe.layout.preserve_aspect_ratio = true

local snap = fe.add_artwork( "snap", 0, 0, 640, 480 )

local lst = fe.add_listbox( 256, 0, 128, 480 )
lst.rows = 15;
lst.charsize = 10;
lst.bg_alpha = 255

local s11 = fe.add_image( "spkr1a.png", 120, 240, 200, 200 )
s11.anchor = Anchor.Centre
local s12 = fe.add_image( "spkr2.png", 120, 240, 200, 200 )
s12.anchor = Anchor.Centre
local s13 = fe.add_image( "spkr3.png", 120, 240, 200, 200 )
s13.anchor = Anchor.Centre

local s21 = fe.add_image( "spkr1b.png", 520, 240, 200, 200 )
s21.anchor = Anchor.Centre
local s22 = fe.add_image( "spkr2.png", 520, 240, 200, 200 )
s22.anchor = Anchor.Centre
local s23 = fe.add_image( "spkr3.png", 520, 240, 200, 200 )
s23.anchor = Anchor.Centre

local su1 = fe.add_surface( 0, 0, 256, 480, fe.monitors[0].width/3, fe.monitors[0].height )
su1.repeat = true
su1.clear = false
su1.blend_mode = BlendMode.Screen

local su2 = fe.add_surface( 384, 0, 256, 480, fe.monitors[0].width/3, fe.monitors[0].height )
su2.repeat = true
su2.clear = false
su2.blend_mode = BlendMode.Screen

local clr1 = su1.add_rectangle( 256, 0, 1, 960 )
clr1.set_rgb( 0, 0, 0 )
local dot1 = su1.add_rectangle( 256, 480 + 360 + 64, 1, 1 )
dot1.set_rgb( 255, 100, 255 )

local clr2 = su2.add_rectangle( 256, 0, 1, 960 )
clr2.set_rgb( 0, 0, 0 )
local dot2 = su2.add_rectangle( 256, 480 + 360, 1, 1 )
dot2.set_rgb( 100, 255, 100 )

fe.add_ticks_callback( "on_tick" )
function on_tick ( ttime )
{
    // Speakers
    s11.width = s11.height = fabs( snap.sample_left ) * 20 + 200
    s12.width = s12.height = fabs( snap.sample_left ) * 40 + 200

    s21.width = s21.height = snap.sample * 10 + 200
    s22.width = s22.height = snap.sample * 20 + 200

    // Graphs
    su1.subimg_x = ( su1.subimg_x + 1 ) % su1.subimg_width
    dot1.height = fabs( snap.sample ) * -256
    dot1.x = ( su1.subimg_width + su1.subimg_x - 1 ) % su1.subimg_width
    clr1.x = ( su1.subimg_width + su1.subimg_x - 1 ) % su1.subimg_width

    su2.subimg_x = ( su2.subimg_x + 1 ) % su2.subimg_width
    dot2.height = ( snap.sample ) * 128
    dot2.x = ( su2.subimg_width + su1.subimg_x - 1 ) % su1.subimg_width
    clr2.x = ( su2.subimg_width + su1.subimg_x - 1 ) % su1.subimg_width
}