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bfirsh · Mar 31, 2024 · 893c5a5 · 893c5a5
1 parent 148326b
commit 893c5a5
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Showing 3 changed files with 27 additions and 25 deletions.
diff --git a/example/nes-embed.js b/example/nes-embed.js
@@ -2,6 +2,7 @@ var SCREEN_WIDTH = 256;
 var SCREEN_HEIGHT = 240;
 var FRAMEBUFFER_SIZE = SCREEN_WIDTH*SCREEN_HEIGHT;
 
+var nes;
 var canvas_ctx, image;
 var framebuffer_u8, framebuffer_u32;
 
@@ -12,17 +13,6 @@ var audio_samples_L = new Float32Array(SAMPLE_COUNT);
 var audio_samples_R = new Float32Array(SAMPLE_COUNT);
 var audio_write_cursor = 0, audio_read_cursor = 0;
 
-var nes = new jsnes.NES({
-	onFrame: function(framebuffer_24){
-		for(var i = 0; i < FRAMEBUFFER_SIZE; i++) framebuffer_u32[i] = 0xFF000000 | framebuffer_24[i];
-	},
-	onAudioSample: function(l, r){
-		audio_samples_L[audio_write_cursor] = l;
-		audio_samples_R[audio_write_cursor] = r;
-		audio_write_cursor = (audio_write_cursor + 1) & SAMPLE_MASK;
-	},
-});
-
 function onAnimationFrame(){
 	window.requestAnimationFrame(onAnimationFrame);
 
@@ -76,6 +66,22 @@ function keyboard(callback, event){
 }
 
 function nes_init(canvas_id){
+	var audio_ctx = new window.AudioContext({
+		latencyHint: "interactive",
+	});
+
+	nes = new jsnes.NES({
+		onFrame: function(framebuffer_24){
+			for(var i = 0; i < FRAMEBUFFER_SIZE; i++) framebuffer_u32[i] = 0xFF000000 | framebuffer_24[i];
+		},
+		onAudioSample: function(l, r){
+			audio_samples_L[audio_write_cursor] = l;
+			audio_samples_R[audio_write_cursor] = r;
+			audio_write_cursor = (audio_write_cursor + 1) & SAMPLE_MASK;
+		},
+		sampleRate: audio_ctx.sampleRate,
+	});
+
 	var canvas = document.getElementById(canvas_id);
 	canvas_ctx = canvas.getContext("2d");
 	image = canvas_ctx.getImageData(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
@@ -89,13 +95,12 @@ function nes_init(canvas_id){
 	framebuffer_u32 = new Uint32Array(buffer);
 
 	// Setup audio.
-	var audio_ctx = new window.AudioContext({
-		latencyHint: "interactive",
-		sampleRate: 48000,
-	});
 	var script_processor = audio_ctx.createScriptProcessor(AUDIO_BUFFERING, 0, 2);
 	script_processor.onaudioprocess = audio_callback;
 	script_processor.connect(audio_ctx.destination);
+
+	document.addEventListener('keydown', (event) => {keyboard(nes.buttonDown, event)});
+	document.addEventListener('keyup', (event) => {keyboard(nes.buttonUp, event)});
 }
 
 function nes_boot(rom_data){
@@ -152,6 +157,3 @@ function nes_volume(value){
 	  nes.papu.setMasterVolume(value);
   }
 }
-
-document.addEventListener('keydown', (event) => {keyboard(nes.buttonDown, event)});
-document.addEventListener('keyup', (event) => {keyboard(nes.buttonUp, event)});
diff --git a/src/nes.js b/src/nes.js
@@ -12,6 +12,7 @@ var NES = function (opts) {
     onBatteryRamWrite: function () {},
 
     emulateSound: true,
+    sampleRate: 48000,
   };
   if (typeof opts !== "undefined") {
     var key;
@@ -159,7 +160,7 @@ NES.prototype = {
 
   getFPS: function () {
     var now = +new Date();
-    var fps = null;
+    var fps = 0;
     if (this.lastFpsTime) {
       fps = this.fpsFrameCount / ((now - this.lastFpsTime) / 1000);
     }

diff --git a/src/papu.js b/src/papu.js
@@ -2,8 +2,7 @@ var utils = require("./utils");
 
 var CPU_FREQ_NTSC = 1789772.5; //1789772.72727272d;
 // var CPU_FREQ_PAL = 1773447.4;
-var APU_TO_CPU_CYCLE_NTSC = 14915;
-// var APU_TO_CPU_CYCLE_PAL = 16627;
+var APU_TO_CPU_CYCLE = 14915;
 
 var PAPU = function (nes) {
   this.nes = nes;
@@ -60,7 +59,7 @@ var PAPU = function (nes) {
   this.dcValue = 0;
 
   // Master volume:
-  this.masterVolume = 256;
+  this.masterVolume = 0;
 
   // Stereo positioning:
   this.stereoPosLSquare1 = null;
@@ -103,12 +102,12 @@ var PAPU = function (nes) {
 
 PAPU.prototype = {
   reset: function () {
-
+    this.sampleRate = this.nes.opts.sampleRate;
     this.sampleTimerMax = Math.floor(
       (1024.0 * CPU_FREQ_NTSC) / this.sampleRate
     );
 
-    this.frameTime = APU_TO_CPU_CYCLE_NTSC;
+    this.frameTime = APU_TO_CPU_CYCLE;
 
     this.sampleTimer = 0;
 
@@ -382,7 +381,7 @@ PAPU.prototype = {
     // Clock frame counter at double CPU speed:
     this.masterFrameCounter += nCycles << 1;
     if (this.masterFrameCounter >= this.frameTime) {
-      // 240Hz tick (NTSC):
+      // 240Hz tick:
       this.masterFrameCounter -= this.frameTime;
       this.frameCounterTick();
     }