60 lines
1.8 KiB
V
60 lines
1.8 KiB
V
// vtest build: !openbsd
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import gg
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import sokol.audio
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struct AppState {
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mut:
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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 = unsafe { nil } // used for drawing
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}
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fn my_audio_stream_callback(mut soundbuffer &f32, num_frames int, num_channels int, mut acontext AppState) {
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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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// "Techno" by Gabriel Miceli
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y := (t * (((t / 10 | 0) ^ ((t / 10 | 0) - 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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a := f32(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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acontext.frame_0 += num_frames
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}
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fn graphics_frame(mut state AppState) {
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ws := gg.window_size()
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center_y := f32(ws.height / 2)
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state.gg.begin()
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for x in 0 .. 1024 {
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vx := ws.width * f32(x) / 1024.0
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vy := center_y * 3.0 / 4.0 * (state.frames[2 * x] + state.frames[2 * x + 1])
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color := gg.Color{f(state, x), f(state, x + 300), f(state, x + 700), 255}
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state.gg.draw_line(vx, center_y, vx, center_y + vy, color)
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}
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state.gg.end()
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}
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fn f(state &AppState, idx int) u8 {
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return u8(127 + state.frames[(int(state.gg.frame) + idx) & 2047] * 128)
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}
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fn main() {
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println('Based on the ByteBeat formula from: https://www.youtube.com/watch?v=V4GfkFbDojc \n "Techno" by Gabriel Miceli')
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mut state := &AppState{}
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audio.setup(stream_userdata_cb: my_audio_stream_callback, user_data: state)
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defer { audio.shutdown() }
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state.gg = gg.new_context(
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bg_color: gg.Color{50, 50, 50, 255}
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width: 800
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height: 600
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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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}
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