adapt simple embedding example
(bring your own smb.nes)
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.gitignore
vendored
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.gitignore
vendored
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.direnv
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smb.nes
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18
index.html
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index.html
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<!DOCTYPE html>
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<title>Embedding Example</title>
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<script type="text/javascript" src="jsnes/dist/jsnes.js"></script>
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<script type="text/javascript" src="nes-embed.js"></script>
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</head>
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<body>
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<div style="margin: auto; max-height: 75vh; aspect-ratio: 4 / 3;">
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<canvas id="nes-canvas" width="256" height="240" style="width: 100%; max-height: 75vh; image-rendering: pixelated; aspect-ratio: 4 / 3;"/>
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</div>
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<button onclick="nes_load_url('nes-canvas', 'smb.nes')">Start!</button>
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<p>DPad: Arrow keys<br/>B button: Z, A button: X, Select: Tab / C, Start: Return / V</p>
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</body>
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</html>
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132
nes-embed.js
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132
nes-embed.js
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var SCREEN_WIDTH = 256;
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var SCREEN_HEIGHT = 240;
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var FRAMEBUFFER_SIZE = SCREEN_WIDTH*SCREEN_HEIGHT;
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var canvas_ctx, image;
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var framebuffer_u8, framebuffer_u32;
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var AUDIO_BUFFERING = 512;
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var SAMPLE_COUNT = 4*1024;
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var SAMPLE_MASK = SAMPLE_COUNT - 1;
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var audio_samples_L = new Float32Array(SAMPLE_COUNT);
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var audio_samples_R = new Float32Array(SAMPLE_COUNT);
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var audio_write_cursor = 0, audio_read_cursor = 0;
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var nes = new jsnes.NES({
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onFrame: function(framebuffer_24){
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for(var i = 0; i < FRAMEBUFFER_SIZE; i++) framebuffer_u32[i] = 0xFF000000 | framebuffer_24[i];
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},
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onAudioSample: function(l, r){
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audio_samples_L[audio_write_cursor] = l;
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audio_samples_R[audio_write_cursor] = r;
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audio_write_cursor = (audio_write_cursor + 1) & SAMPLE_MASK;
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},
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});
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function onAnimationFrame(){
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window.requestAnimationFrame(onAnimationFrame);
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image.data.set(framebuffer_u8);
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canvas_ctx.putImageData(image, 0, 0);
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}
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function audio_remain(){
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return (audio_write_cursor - audio_read_cursor) & SAMPLE_MASK;
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}
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function audio_callback(event){
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var dst = event.outputBuffer;
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var len = dst.length;
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// Attempt to avoid buffer underruns.
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if(audio_remain() < AUDIO_BUFFERING) nes.frame();
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var dst_l = dst.getChannelData(0);
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var dst_r = dst.getChannelData(1);
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for(var i = 0; i < len; i++){
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var src_idx = (audio_read_cursor + i) & SAMPLE_MASK;
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dst_l[i] = audio_samples_L[src_idx];
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dst_r[i] = audio_samples_R[src_idx];
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}
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audio_read_cursor = (audio_read_cursor + len) & SAMPLE_MASK;
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}
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const KEY_MAPPINGS = [{
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"ArrowUp": "BUTTON_UP",
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"ArrowDown": "BUTTON_DOWN",
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"ArrowLeft": "BUTTON_LEFT",
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"ArrowRight": "BUTTON_RIGHT",
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"KeyZ": "BUTTON_B",
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"KeyX": "BUTTON_A",
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"KeyC": "BUTTON_SELECT",
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"KeyV": "BUTTON_START",
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"Enter": "BUTTON_START",
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"Tab": "BUTTON_SELECT"
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}]
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function keyboard(callback, event){
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var player = 1;
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for (const mapping of KEY_MAPPINGS) {
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const button = mapping[event.code];
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if (button) {
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callback(player, jsnes.Controller[button]);
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event.preventDefault();
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}
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player ++;
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}
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}
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function nes_init(canvas_id){
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var canvas = document.getElementById(canvas_id);
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canvas_ctx = canvas.getContext("2d");
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image = canvas_ctx.getImageData(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
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canvas_ctx.fillStyle = "black";
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canvas_ctx.fillRect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
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// Allocate framebuffer array.
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var buffer = new ArrayBuffer(image.data.length);
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framebuffer_u8 = new Uint8ClampedArray(buffer);
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framebuffer_u32 = new Uint32Array(buffer);
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// Setup audio.
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var audio_ctx = new window.AudioContext();
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var script_processor = audio_ctx.createScriptProcessor(AUDIO_BUFFERING, 0, 2);
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script_processor.onaudioprocess = audio_callback;
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script_processor.connect(audio_ctx.destination);
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}
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function nes_boot(rom_data){
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nes.loadROM(rom_data);
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window.requestAnimationFrame(onAnimationFrame);
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}
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function nes_load_data(canvas_id, rom_data){
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nes_init(canvas_id);
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nes_boot(rom_data);
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}
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function nes_load_url(canvas_id, path){
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nes_init(canvas_id);
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var req = new XMLHttpRequest();
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req.open("GET", path);
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req.overrideMimeType("text/plain; charset=x-user-defined");
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req.onerror = () => console.log(`Error loading ${path}: ${req.statusText}`);
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req.onload = function() {
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if (this.status === 200) {
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nes_boot(this.responseText);
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} else if (this.status === 0) {
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// Aborted, so ignore error
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} else {
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req.onerror();
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}
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};
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req.send();
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}
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document.addEventListener('keydown', (event) => {keyboard(nes.buttonDown, event)});
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document.addEventListener('keyup', (event) => {keyboard(nes.buttonUp, event)});
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