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sysaudio: webaudio: Implement audio playback using data_callback

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Supports passing user context as well as provides the current device.
This commit is contained in:
iddev5 2022-07-17 18:04:44 +05:30 • committed by Stephen Gutekanst
parent c22e54bcd7
commit d12ba02c38
1 changed files with 37 additions and 3 deletions
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40
sysaudio/src/webaudio.zig
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@ -5,6 +5,8 @@ const js = @import("sysjs");
const Audio = @This();
pub const DataCallback = fn (device: *Device, user_data: ?*anyopaque, sample: *f32) void;
pub const Device = struct {
context: js.Object,
@ -12,6 +14,13 @@ pub const Device = struct {
device.context.deinit();
}
pub fn setCallback(device: Device, callback: DataCallback, user_data: ?*anyopaque) void {
device.context.set("device", js.createNumber(@intToFloat(f64, @ptrToInt(&device))));
device.context.set("callback", js.createNumber(@intToFloat(f64, @ptrToInt(&callback))));
if (user_data) |ud|
device.context.set("user_data", js.createNumber(@intToFloat(f64, @ptrToInt(ud))));
}
pub fn pause(device: Device) void {
device.context.call("suspend", &.{});
}
@ -78,7 +87,7 @@ pub fn requestDevice(audio: Audio, config: DeviceDescriptor) Error!Device {
context.set("node", node.toValue());
{
const audio_process_event = js.createFunction(audioProcessEvent);
const audio_process_event = js.createFunction(audioProcessEvent, &.{context.toValue()});
defer audio_process_event.deinit();
node.set("onaudioprocess", audio_process_event.toValue());
}
@ -92,9 +101,34 @@ pub fn requestDevice(audio: Audio, config: DeviceDescriptor) Error!Device {
return Device{ .context = context };
}
fn audioProcessEvent(args: js.Object, _: usize) js.Value {
fn audioProcessEvent(args: js.Object, _: usize, captures: []js.Value) js.Value {
const device_context = captures[0].view(.object);
const audio_event = args.getIndex(0).view(.object);
_ = audio_event;
const output_buffer = audio_event.get("outputBuffer").view(.object);
const callback = device_context.get("callback");
if (!callback.is(.undef)) {
// Do not deinit, we are not making a new device, just creating a view to the current one.
var dev = Device{ .context = device_context };
const cb = @intToPtr(*DataCallback, @floatToInt(usize, callback.view(.num)));
const user_data = device_context.get("user_data");
const ud = if (user_data.is(.undef)) null else @intToPtr(*anyopaque, @floatToInt(usize, user_data.view(.num)));
var channel: usize = 0;
while (channel < @floatToInt(usize, output_buffer.get("numberOfChannels").view(.num))) : (channel += 1) {
const output_data = output_buffer.call("getChannelData", &.{js.createNumber(@intToFloat(f64, channel))}).view(.object);
defer output_data.deinit();
var sample: usize = 0;
while (sample < @floatToInt(usize, output_buffer.get("length").view(.num))) : (sample += 1) {
var ret_sample: f32 = undefined;
cb.*(&dev, ud, &ret_sample);
output_data.setIndex(sample, js.createNumber(ret_sample));
}
}
}
return js.createUndefined();
}