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import gg
import gx
import sokol.audio
const credits = 'Based on the ByteBeat formula from: https://www.youtube.com/watch?v=V4GfkFbDojc \n "Techno" by Gabriel Miceli'
struct AppState {
mut:
gframe int // the current graphical frame
frame_0 int // offset of the current audio frames, relative to the start of the music
frames [2048]f32 // a copy of the last rendered audio frames
gg &gg.Context // used for drawing
}
fn my_audio_stream_callback(buffer &f32, num_frames int, num_channels int, mut acontext AppState) {
mut soundbuffer := unsafe { buffer }
for frame := 0; frame < num_frames; frame++ {
t := int(f32(acontext.frame_0 + frame) * 0.245)
// "Techno" by Gabriel Miceli
y := (t * (((t / 10 | 0) ^ ((t / 10 | 0) - 1280)) % 11) / 2 & 127) +
(t * (((t / 640 | 0) ^ ((t / 640 | 0) - 2)) % 13) / 2 & 127)
for ch := 0; ch < num_channels; ch++ {
idx := frame * num_channels + ch
unsafe {
a := f32(byte(y) - 127) / 255.0
soundbuffer[idx] = a
acontext.frames[idx & 2047] = a
}
}
}
acontext.frame_0 += num_frames
}
fn main() {
println(credits)
mut state := &AppState{
gg: 0
}
audio.setup(
stream_userdata_cb: my_audio_stream_callback
user_data: state
)
state.gg = gg.new_context(
bg_color: gx.rgb(50, 50, 50)
width: 1024
height: 400
create_window: true
window_title: 'ByteBeat Music'
frame_fn: graphics_frame
user_data: state
)
state.gg.run()
audio.shutdown()
}
fn graphics_frame(mut state AppState) {
state.gframe++
state.gg.begin()
state.draw()
state.gg.end()
}
[inline]
fn (mut state AppState) bsample(idx int) byte {
return byte(127 + state.frames[(state.gframe + idx) & 2047] * 128)
}
fn (mut state AppState) draw() {
// first, reset and setup ortho projection
for x in 0 .. 1024 {
mut y := 100 * (state.frames[2 * x] + state.frames[2 * x + 1])
state.gg.draw_line(x, 200, x, 200 + y, gx.rgba(state.bsample(x), state.bsample(x + 300),
state.bsample(x + 700), 255))
}
}
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