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sysaudio: various fixes to WebAudio backend

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Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
This commit is contained in:
Stephen Gutekanst 2022-08-28 15:59:01 -07:00 • committed by Stephen Gutekanst
parent 2e61125601
commit a18938a84f
1 changed files with 39 additions and 15 deletions
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54
libs/sysaudio/src/webaudio.zig
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@ -6,9 +6,9 @@ const js = @import("sysjs");
const Audio = @This();
pub const DataCallback = if (@import("builtin").zig_backend == .stage1)
fn (device: *Device, user_data: ?*anyopaque, sample: *f32) void
fn (device: *Device, user_data: ?*anyopaque, buffer: []u8) void
else
*const fn (device: *Device, user_data: ?*anyopaque, sample: *f32) void;
*const fn (device: *Device, user_data: ?*anyopaque, buffer: []u8) void;
pub const Device = struct {
context: js.Object,
@ -19,13 +19,13 @@ pub const Device = struct {
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))));
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", &.{});
_ = device.context.call("suspend", &.{});
}
pub fn start(device: Device) void {
@ -66,7 +66,7 @@ pub fn waitEvents(_: Audio) void {}
const default_channel_count = 2;
const default_sample_rate = 48000;
const default_buffer_size = 512;
const default_buffer_size = 1024; // 21.33ms
pub fn requestDevice(audio: Audio, config: DeviceDescriptor) Error!Device {
// NOTE: WebAudio only supports F32 audio format, so config.format is unused
@ -90,8 +90,14 @@ pub fn requestDevice(audio: Audio, config: DeviceDescriptor) Error!Device {
context.set("node", node.toValue());
{
const audio_process_event = js.createFunction(audioProcessEvent, &.{context.toValue()});
defer audio_process_event.deinit();
// TODO(sysaudio): this capture leaks for now, we need a better way to pass captures via sysjs
// that passes by value I think.
const captures = std.heap.page_allocator.alloc(js.Value, 1) catch unreachable;
captures[0] = context.toValue();
const audio_process_event = js.createFunction(audioProcessEvent, captures);
// TODO(sysaudio): this leaks, we need a good place to clean this up.
// defer audio_process_event.deinit();
node.set("onaudioprocess", audio_process_event.toValue());
}
@ -108,27 +114,45 @@ 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);
defer audio_event.deinit();
const output_buffer = audio_event.get("outputBuffer").view(.object);
defer output_buffer.deinit();
const buffer_length = default_buffer_size * @sizeOf(f32);
var buffer: [buffer_length]u8 = undefined;
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 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 source = js.constructType("Uint8Array", &.{js.createNumber(buffer_length)});
defer source.deinit();
cb(&dev, ud, buffer[0..]);
source.copyBytes(buffer[0..]);
const float_source = js.constructType("Float32Array", &.{
source.get("buffer"),
source.get("byteOffset"),
js.createNumber(source.get("byteLength").view(.num) / 4),
});
defer float_source.deinit();
js.global().set("source", source.toValue());
js.global().set("float_source", float_source.toValue());
js.global().set("output_buffer", output_buffer.toValue());
// TODO: investigate if using copyToChannel would be better?
//_ = output_buffer.call("copyToChannel", &.{ float_source.toValue(), js.createNumber(@intToFloat(f64, channel)) });
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));
}
_ = output_data.call("set", &.{float_source.toValue()});
}
}