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