From 5e2b4bbbc602344ff43e4499cc80c866a2b934c2 Mon Sep 17 00:00:00 2001
From: zenith391 <39484230+zenith391@users.noreply.github.com>
Date: Thu, 21 Dec 2023 22:41:35 +0100
Subject: [PATCH] wasm: fix audio

---
 examples/media-player.zig      | 10 +++++++---
 src/audio.zig                  |  2 +-
 src/backends/macos/backend.zig |  2 +-
 src/backends/wasm/backend.zig  |  6 +++---
 src/backends/wasm/capy.js      | 18 ++++++++++--------
 5 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/examples/media-player.zig b/examples/media-player.zig
index 61200713..d4ac4374 100644
--- a/examples/media-player.zig
+++ b/examples/media-player.zig
@@ -14,9 +14,13 @@ fn sine(generator: *const capy.audio.AudioGenerator, time: u64, n_frames: u32) v
     var i: u32 = 0;
     const frequency = pitch.get();
 
+    const seconds_per_frame = 1.0 / 44100.0;
+
+    const time_seconds: f64 = @as(f64, @floatFromInt(time)) / 44100.0;
+
     while (i < n_frames) : (i += 1) {
-        const inner_time = @as(f32, @floatFromInt((time + i) % 44100)) / 44100 * frequency * 2 * std.math.pi;
-        const value = @sin(inner_time);
+        const inner_time = (time_seconds + @as(f64, @floatFromInt(i)) * seconds_per_frame) * 2 * std.math.pi * frequency;
+        const value: f32 = @floatCast(@sin(inner_time));
         left[i] = value;
         right[i] = value;
     }
@@ -36,7 +40,7 @@ pub fn main() !void {
         capy.alignment(.{}, capy.column(.{}, .{
             rotatingDisc(), // TODO
             capy.label(.{ .text = "Audio Name", .alignment = .Center }),
-            capy.slider(.{ .min = 20, .max = 2000, .step = 1 })
+            capy.slider(.{ .min = 40, .max = 2000, .step = 1 })
                 .bind("value", &pitch),
         })),
     );
diff --git a/src/audio.zig b/src/audio.zig
index c55b5f62..7c300710 100644
--- a/src/audio.zig
+++ b/src/audio.zig
@@ -83,7 +83,7 @@ pub fn backendUpdate() void {
     generatorsMutex.lock();
     defer generatorsMutex.unlock();
     for (generators.items) |generator| {
-        generator.onWriteRequested(44100);
+        generator.onWriteRequested(4410);
     }
 }
 
diff --git a/src/backends/macos/backend.zig b/src/backends/macos/backend.zig
index 36a03669..1ce5e7d3 100644
--- a/src/backends/macos/backend.zig
+++ b/src/backends/macos/backend.zig
@@ -13,7 +13,7 @@ const MouseButton = shared.MouseButton;
 // pub const PeerType = *opaque {};
 pub const PeerType = objc.id;
 
-const atomicValue = if (@hasDecl(std.atomic,"Value")) std.atomic.Value else std.atomic.Atomic; // support zig 0.11 as well as current master
+const atomicValue = if (@hasDecl(std.atomic, "Value")) std.atomic.Value else std.atomic.Atomic; // support zig 0.11 as well as current master
 var activeWindows = atomicValue(usize).init(0);
 var hasInit: bool = false;
 
diff --git a/src/backends/wasm/backend.zig b/src/backends/wasm/backend.zig
index 70353e43..bc59653c 100644
--- a/src/backends/wasm/backend.zig
+++ b/src/backends/wasm/backend.zig
@@ -566,11 +566,11 @@ pub const AudioGenerator = struct {
         const channels = 2;
         const channelDatas = try allocator.alloc([]f32, channels);
         for (channelDatas) |*buffer| {
-            buffer.* = try allocator.alloc(f32, 44100); // 1 second of buffer
+            buffer.* = try allocator.alloc(f32, 4410); // 0.1 seconds of buffer
             @memset(buffer.*, 0);
         }
         return AudioGenerator{
-            .source = js.createSource(sampleRate, 500.0),
+            .source = js.createSource(sampleRate, 0.1),
             .buffers = channelDatas,
         };
     }
@@ -583,7 +583,7 @@ pub const AudioGenerator = struct {
         js.audioCopyToChannel(
             self.source,
             self.buffers[channel].ptr,
-            self.buffers[channel].len,
+            self.buffers[channel].len * @sizeOf(f32),
             channel,
         );
     }
diff --git a/src/backends/wasm/capy.js b/src/backends/wasm/capy.js
index 6aab46b5..01197963 100644
--- a/src/backends/wasm/capy.js
+++ b/src/backends/wasm/capy.js
@@ -478,7 +478,7 @@ let env = {
 				source: source,
 				frameCount: frameCount,
 				nextUpdate: audioContext.currentTime,
-				soundBuffer: new SoundBuffer(audioContext, 44100, 6, false),
+				soundBuffer: new SoundBuffer(audioContext, 44100, 6, true),
 			};
 			return audioSources.push(audioSource) - 1;
 		},
@@ -585,22 +585,24 @@ async function loadExtras() {
 		}
 		drawCommands = [];
 
+		requestAnimationFrame(update);
+	}
+	//setInterval(update, 32);
+	requestAnimationFrame(update);
+
+	function audioUpdate() {
 		// Audio
 		const latency = 0.1; // The latency we want, in seconds.
-		if (audioContext.currentTime > lastAudioUpdateTime - latency) {
+		if (audioContext.currentTime > lastAudioUpdateTime + latency) {
 			// Trigger an event so the audio buffer is refilled
 			pushEvent({
 				type: 6,
 				args: [],
 			});
-			lastAudioUpdateTime += latency;
+			lastAudioUpdateTime = audioContext.currentTime - 0.01;
 		}
-		
-		
-		requestAnimationFrame(update);
 	}
-	//setInterval(update, 32);
-	requestAnimationFrame(update);
+	setInterval(audioUpdate, 50);
 
 	window.onresize = function() {
 		pushEvent({ type: 0, target: rootElementId });