76 lines
2.6 KiB
Zig
76 lines
2.6 KiB
Zig
const std = @import("std");
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const soundio = @import("soundio");
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const c = soundio.c;
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const SoundIo = soundio.SoundIo;
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const OutStream = soundio.OutStream;
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var seconds_offset: f32 = 0;
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fn write_callback(
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maybe_outstream: ?[*]c.SoundIoOutStream,
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frame_count_min: c_int,
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frame_count_max: c_int,
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) callconv(.C) void {
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_ = frame_count_min;
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const outstream = OutStream{ .handle = @ptrCast(*c.SoundIoOutStream, maybe_outstream) };
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const layout = outstream.layout();
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const float_sample_rate = outstream.sampleRate();
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const seconds_per_frame = 1.0 / @intToFloat(f32, float_sample_rate);
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var frames_left = frame_count_max;
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while (frames_left > 0) {
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var frame_count = frames_left;
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var areas: [*]c.SoundIoChannelArea = undefined;
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outstream.beginWrite(
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@ptrCast([*]?[*]c.SoundIoChannelArea, &areas),
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&frame_count,
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) catch |err| std.debug.panic("write failed: {s}", .{@errorName(err)});
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if (frame_count == 0) break;
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const pitch = 440.0;
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const radians_per_second = pitch * 2.0 * std.math.pi;
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var frame: c_int = 0;
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while (frame < frame_count) : (frame += 1) {
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const sample = std.math.sin((seconds_offset + @intToFloat(f32, frame) *
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seconds_per_frame) * radians_per_second);
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{
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var channel: usize = 0;
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while (channel < @intCast(usize, layout.channelCount())) : (channel += 1) {
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const channel_ptr = areas[channel].ptr;
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const sample_ptr = &channel_ptr[@intCast(usize, areas[channel].step * frame)];
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@ptrCast(*f32, @alignCast(@alignOf(f32), sample_ptr)).* = sample;
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}
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}
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}
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seconds_offset += seconds_per_frame * @intToFloat(f32, frame_count);
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outstream.endWrite() catch |err| std.debug.panic("end write failed: {s}", .{@errorName(err)});
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frames_left -= frame_count;
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}
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}
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pub fn main() !void {
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const sio = try SoundIo.init();
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defer sio.deinit();
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try sio.connect();
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sio.flushEvents();
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const default_output_index = sio.defaultOutputDeviceIndex() orelse return error.NoOutputDeviceFound;
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const device = sio.getOutputDevice(default_output_index) orelse return error.OutOfMemory;
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defer device.unref();
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std.debug.print("Output device: {s}\n", .{device.name()});
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const outstream = try device.createOutStream();
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defer outstream.deinit();
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outstream.setFormat(.float32LE);
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outstream.setWriteCallback(write_callback);
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try outstream.open();
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try outstream.start();
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while (true) sio.waitEvents();
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}
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