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apple2shader
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apple2shader/screenEmu.js

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"use strict";
const screenEmu = (function () {
// From AppleIIVideo.cpp
const HORIZ_START = 16;
const HORIZ_BLANK = (9 + HORIZ_START) // 25;
const HORIZ_DISPLAY = 40;
const HORIZ_TOTAL = (HORIZ_BLANK + HORIZ_DISPLAY) // 65;
const CELL_WIDTH = 14;
const CELL_HEIGHT = 8;
const VERT_NTSC_START = 38;
const VERT_PAL_START = 48;
const VERT_DISPLAY = 192;
const BLOCK_WIDTH = HORIZ_DISPLAY; // 40
const BLOCK_HEIGHT = (VERT_DISPLAY / CELL_HEIGHT); // 24
// From CanvasInterface.h
const NTSC_FSC = 315/88 * 1e6; // 3579545 = 3.5 Mhz: Color Subcarrier
const NTSC_4FSC = 4 * NTSC_FSC; // 14318180 = 14.3 Mhz
const NTSC_HTOTAL = (63+5/9) * 1e-6;
const NTSC_HLENGTH = (52+8/9) * 1e-6;
const NTSC_HHALF = (35+2/3) * 1e-6;
const NTSC_HSTART = NTSC_HHALF - NTSC_HLENGTH/2;
const NTSC_HEND = NTSC_HHALF + NTSC_HLENGTH/2;
const NTSC_VTOTAL = 262;
const NTSC_VLENGTH = 240;
const NTSC_VSTART = 19;
const NTSC_VEND = NTSC_VSTART + NTSC_VLENGTH;
const PAL_FSC = 4433618.75; // Color subcarrier
const PAL_4FSC = 4 * PAL_FSC;
const PAL_HTOTAL = 64e-6;
const PAL_HLENGTH = 52e-6;
const PAL_HHALF = (37+10/27) * 1e-6;
const PAL_HSTART = PAL_HHALF - PAL_HLENGTH / 2;
const PAL_HEND = PAL_HHALF + PAL_HLENGTH / 2;
const PAL_VTOTAL = 312;
const PAL_VLENGTH = 288;
const PAL_VSTART = 21;
const PAL_VEND = PAL_VSTART + PAL_VLENGTH;
// From OpenGLCanvas.cpp
const NTSC_I_CUTOFF = 1300000;
const NTSC_Q_CUTOFF = 600000;
const NTSC_IQ_DELTA = NTSC_I_CUTOFF - NTSC_Q_CUTOFF;
// From AppleIIVideo::updateTiming
const ntscClockFrequency = NTSC_4FSC * HORIZ_TOTAL / 912;
const ntscVisibleRect = [[ntscClockFrequency * NTSC_HSTART, NTSC_VSTART],
[ntscClockFrequency * NTSC_HLENGTH, NTSC_VLENGTH]];
const ntscDisplayRect = [[HORIZ_START, VERT_NTSC_START],
[HORIZ_DISPLAY, VERT_DISPLAY]];
const ntscVertTotal = NTSC_VTOTAL;
const palClockFrequency = 14250450.0 * HORIZ_TOTAL / 912;
const palVisibleRect = [[palClockFrequency * PAL_HSTART, PAL_VSTART],
[palClockFrequency * PAL_HLENGTH, PAL_VLENGTH]];
const palDisplayRect = [[HORIZ_START, VERT_PAL_START],
[HORIZ_DISPLAY, VERT_DISPLAY]];
const palVertTotal = PAL_VTOTAL;
const VERTEX_SHADER =`
// an attribute will receive data from a buffer
attribute vec4 a_position;
attribute vec2 a_texCoord;
varying vec2 v_texCoord;
// all shaders have a main function
void main() {
// gl_Position is a special variable a vertex shader
// is responsible for setting
gl_Position = a_position;
v_texCoord = a_texCoord;
}
`;
const COMPOSITE_SHADER = `
precision mediump float;
varying vec2 v_texCoord;
uniform sampler2D texture;
uniform vec2 textureSize;
uniform float subcarrier;
uniform sampler2D phaseInfo;
uniform vec3 c0, c1, c2, c3, c4, c5, c6, c7, c8;
uniform mat3 decoderMatrix;
uniform vec3 decoderOffset;
float PI = 3.14159265358979323846264;
vec3 pixel(in vec2 q)
{
vec3 c = texture2D(texture, q).rgb;
vec2 p = texture2D(phaseInfo, vec2(0, q.y)).rg;
float phase = 2.0 * PI * (subcarrier * textureSize.x * q.x + p.x);
return c * vec3(1.0, sin(phase), (1.0 - 2.0 * p.y) * cos(phase));
}
vec3 pixels(vec2 q, float i)
{
return pixel(vec2(q.x + i, q.y)) + pixel(vec2(q.x - i, q.y));
}
void main(void)
{
vec2 q = v_texCoord;
vec3 c = pixel(q) * c0;
c += pixels(q, 1.0 / textureSize.x) * c1;
c += pixels(q, 2.0 / textureSize.x) * c2;
c += pixels(q, 3.0 / textureSize.x) * c3;
c += pixels(q, 4.0 / textureSize.x) * c4;
c += pixels(q, 5.0 / textureSize.x) * c5;
c += pixels(q, 6.0 / textureSize.x) * c6;
c += pixels(q, 7.0 / textureSize.x) * c7;
c += pixels(q, 8.0 / textureSize.x) * c8;
gl_FragColor = vec4(decoderMatrix * c + decoderOffset, 1.0);
}
`;
const DISPLAY_SHADER = `
precision mediump float;
varying vec2 v_texCoord;
uniform sampler2D texture;
uniform vec2 textureSize;
uniform float barrel;
uniform vec2 barrelSize;
uniform float scanlineLevel;
uniform sampler2D shadowMask;
uniform vec2 shadowMaskSize;
uniform float shadowMaskLevel;
uniform float centerLighting;
uniform sampler2D persistence;
uniform vec2 persistenceSize;
uniform vec2 persistenceOrigin;
uniform float persistenceLevel;
uniform float luminanceGain;
float PI = 3.14159265358979323846264;
void main(void)
{
vec2 qc = (v_texCoord - vec2(0.5, 0.5)) * barrelSize;
vec2 qb = barrel * qc * dot(qc, qc);
vec2 q = v_texCoord + qb;
vec3 c = texture2D(texture, q).rgb;
float scanline = sin(PI * textureSize.y * q.y);
c *= mix(1.0, scanline * scanline, scanlineLevel);
vec3 mask = texture2D(shadowMask, (v_texCoord + qb) * shadowMaskSize).rgb;
c *= mix(vec3(1.0, 1.0, 1.0), mask, shadowMaskLevel);
vec2 lighting = qc * centerLighting;
c *= exp(-dot(lighting, lighting));
c *= luminanceGain;
vec2 qp = v_texCoord * persistenceSize + persistenceOrigin;
c = max(c, texture2D(persistence, qp).rgb * persistenceLevel - 0.5 / 256.0);
gl_FragColor = vec4(c, 1.0);
}
`;
const RGB_SHADER = `
precision mediump float;
varying vec2 v_texCoord;
uniform sampler2D texture;
uniform vec2 textureSize;
uniform vec3 c0, c1, c2, c3, c4, c5, c6, c7, c8;
uniform mat3 decoderMatrix;
uniform vec3 decoderOffset;
vec3 pixel(vec2 q)
{
return texture2D(texture, q).rgb;
}
vec3 pixels(in vec2 q, in float i)
{
return pixel(vec2(q.x + i, q.y)) + pixel(vec2(q.x - i, q.y));
}
void main(void)
{
vec2 q = v_texCoord;
vec3 c = pixel(q) * c0;
c += pixels(q, 1.0 / textureSize.x) * c1;
c += pixels(q, 2.0 / textureSize.x) * c2;
c += pixels(q, 3.0 / textureSize.x) * c3;
c += pixels(q, 4.0 / textureSize.x) * c4;
c += pixels(q, 5.0 / textureSize.x) * c5;
c += pixels(q, 6.0 / textureSize.x) * c6;
c += pixels(q, 7.0 / textureSize.x) * c7;
c += pixels(q, 8.0 / textureSize.x) * c8;
gl_FragColor = vec4(decoderMatrix * c + decoderOffset, 1.0);
}
`;
function buildTiming(clockFrequency, displayRect, visibleRect, vertTotal, fsc) {
const vertStart = displayRect[0][1];
// Total number of CPU cycles per frame: 17030 for NTSC.
const frameCycleNum = HORIZ_TOTAL * vertTotal;
// first displayed column.
const horizStart = Math.floor(displayRect[0][0]);
// imageSize is [14 * visible rect width in cells, visible lines]
const imageSize = [Math.floor(CELL_WIDTH * visibleRect[1][0]),
Math.floor(visibleRect[1][1])];
// imageLeft is # of pixels from first visible point to first displayed point.
const imageLeft = Math.floor((horizStart-visibleRect[0][0]) * CELL_WIDTH);
const colorBurst = [2 * Math.PI * (-33/360 + (imageLeft % 4) / 4)];
const cycleNum = frameCycleNum + 16;
// First pixel that OpenEmulator draws when painting normally.
const topLeft = [imageLeft, vertStart - visibleRect[0][1]];
// First pixel that OpenEmulator draws when painting 80-column mode.
const topLeft80Col = [imageLeft - CELL_WIDTH/2, vertStart - visibleRect[0][1]];
return {
fsc: fsc,
clockFrequency: clockFrequency,
displayRect: displayRect,
visibleRect: visibleRect,
vertStart: vertStart,
vertTotal: vertTotal,
frameCycleNum: frameCycleNum,
horizStart: horizStart,
imageSize: imageSize,
imageLeft: imageLeft,
colorBurst: colorBurst,
cycleNum: cycleNum,
topLeft: topLeft,
topLeft80Col: topLeft80Col,
};
}
const Point = class {
constructor(x, y) {
this.x = x;
this.y = y;
}
}
const Size = class {
constructor(width, height) {
this.width = width;
this.height = height;
}
copy() {
return new Size(this.width, this.height);
}
}
const Rect = class {
constructor(x, y, width, height) {
this.origin = new Point(x, y);
this.size = new Size(width, height);
}
get x() {
return this.origin.x;
}
get y() {
return this.origin.y;
}
get width() {
return this.size.width;
}
get height() {
return this.size.height;
}
get l() {
return this.origin.x;
}
get r() {
return this.origin.x + this.size.width;
}
get t() {
return this.origin.y;
}
get b() {
return this.origin.y + this.size.height;
}
}
const Vector = class {
constructor(n) {
this.data = new Float32Array(n);
}
// Normalize the vector.
normalize() {
const vec = this.data;
let sum = 0;
for (const item of vec) {
sum += item;
}
const gain = 1/sum;
for (const i in vec) {
vec[i] *= gain;
}
return this;
}
// Multiply this Vector by another, or by a number.
mul(other) {
const w = new Vector(0);
if ((typeof other != "number") && (this.data.length != other.data.length)) {
return w;
}
w.data = new Float32Array(this.data);
for (let i = 0; i < w.data.length; i++) {
if (typeof other == "number") {
w.data[i] *= other;
} else {
w.data[i] *= other.data[i];
}
}
return w;
}
realIDFT() {
const size = this.data.length;
const w = new Vector(size);
for (let i = 0; i < size; i++) {
const omega = 2 * Math.PI * i / size;
for (let j = 0; j < size; j++) {
w.data[i] += this.data[j] * Math.cos(j * omega);
}
}
for (let i = 0; i < size; i++) {
w.data[i] /= size;
}
return w;
}
resize(n) {
const newData = new Float32Array(n);
for (let i=0; i < Math.min(newData.length, this.data.length); i++) {
newData[i] = this.data[i];
}
this.data = newData;
return this;
}
// Chebyshev Window
//
// Based on ideas at:
// http://www.dsprelated.com/showarticle/42.php
//
static chebyshevWindow(n, sidelobeDb) {
const m = n - 1;
let w = new Vector(m);
const alpha = Math.cosh(Math.acosh(Math.pow(10, sidelobeDb / 20)) / m);
for (let i = 0; i < m; i++) {
const a = Math.abs(alpha * Math.cos(Math.PI * i / m));
if (a > 1)
w.data[i] = Math.pow(-1, i) * Math.cosh(m * Math.acosh(a));
else
w.data[i] = Math.pow(-1, i) * Math.cos(m * Math.acos(a));
}
w = w.realIDFT();
w.resize(n);
w.data[0] /= 2;
w.data[n-1] = w.data[0];
const max = w.data.reduce((prev, cur) => Math.max(prev, Math.abs(cur)));
for (const i in w.data) {
w.data[i] /= max;
}
return w;
}
// Lanczos Window
static lanczosWindow(n, fc) {
let v = new Vector(n);
fc = Math.min(fc, 0.5);
const halfN = Math.floor(n / 2);
for (let i = 0; i < n; i++) {
const x = 2 * Math.PI * fc * (i - halfN);
v.data[i] = (x == 0.0) ? 1.0 : Math.sin(x) / x;
}
return v;
}
};
const Matrix3 = class {
constructor(c00, c01, c02,
c10, c11, c12,
c20, c21, c22) {
this.data = new Float32Array([c00, c01, c02, c10, c11, c12, c20, c21, c22]);
}
at(i, j) {
return this.data[3 * i + j];
}
mul(val) {
const m = new Matrix3(0,0,0,0,0,0,0,0,0);
if (typeof val == "number") {
m.data = this.data.map(x => x * val);
} else {
for (let i = 0; i < 3; i++) {
for (let j = 0; j < 3; j++) {
for (let k = 0; k < 3; k++) {
m.data[i * 3 + j] += val.data[i * 3 + k] * this.data[k * 3 + j];
}
}
}
}
return m;
}
}
// https://codereview.stackexchange.com/a/128619
const loadImage = path =>
new Promise((resolve, reject) => {
const img = new Image();
img.onload = () => resolve(img);
img.onerror = () => reject(`error loading '${path}'`);
img.src = path;
});
// Given an image that's 560x192, render it into the larger space
// required for NTSC or PAL.
// image: a 560x192 image, from the same domain (hence readable).
// details: NTSC_DETAILS, or PAL_DETAILS
// returns: a canvas
const screenData = (image, details) => {
if ((image.naturalWidth != 560) || (image.naturalHeight != 192)) {
throw new Error('screenData expects an image 560x192;' +
` got ${image.naturalWidth}x${image.naturalHeight}`);
}
const canvas = document.createElement('canvas');
const context = canvas.getContext('2d');
const width = details.imageSize[0];
const height = details.imageSize[1];
canvas.width = width;
canvas.height = height;
context.fillStyle = 'rgba(0,0,0,1)';
context.fillRect(0, 0, width, height);
context.drawImage(image, details.topLeft80Col[0], details.topLeft80Col[1]);
const imageData = context.getImageData(0, 0, width, height);
return [canvas, imageData];
};
// Given an ImageData (RGBA), convert to luminance by taking the max
// of (R,G,B) for each pixel. Return a Uint8Array.
const luminanceData = (imageData) => {
const width = imageData.width;
const height = imageData.height;
const data = imageData.data;
const size = width * height;
const ary = new Uint8Array(size);
for (let i = 0; i < size; i++) {
ary[i] = Math.max(data[i*4], data[i*4+1], data[i*4+2]);
}
return ary;
};
const TEXTURE_NAMES = [
"SHADOWMASK_TRIAD",
"SHADOWMASK_INLINE",
"SHADOWMASK_APERTURE",
"SHADOWMASK_LCD",
"SHADOWMASK_BAYER",
"IMAGE_PHASEINFO",
"IMAGE_IN",
"IMAGE_DECODED",
"IMAGE_PERSISTENCE",
];
const BUFFER_NAMES = [
"POSITION",
"TEXCOORD",
];
const SHADER_NAMES = [
"COMPOSITE",
"DISPLAY",
"RGB",
];
const resizeCanvas = (canvas) => {
// Lookup the size the browser is displaying the canvas.
const displayWidth = canvas.clientWidth;
const displayHeight = canvas.clientHeight;
// Check if the canvas is not the same size.
if (canvas.width != displayWidth ||
canvas.height != displayHeight) {
canvas.width = displayWidth;
canvas.height = displayHeight;
}
};
// Code from:
// https://webglfundamentals.org/webgl/lessons/webgl-fundamentals.html
const createShader = (gl, name, type, source) => {
const shader = gl.createShader(type);
gl.shaderSource(shader, source);
gl.compileShader(shader);
const success = gl.getShaderParameter(shader, gl.COMPILE_STATUS);
if (success) {
return shader;
}
const log = gl.getShaderInfoLog(shader);
gl.deleteShader(shader);
throw new Error(`unable to compile shader ${name}: \n${log}`);
};
// Code from:
// https://webglfundamentals.org/webgl/lessons/webgl-fundamentals.html
const createProgram = (gl, name, ...shaders) => {
const program = gl.createProgram();
for (let shader of shaders) {
gl.attachShader(program, shader);
}
gl.linkProgram(program);
const success = gl.getProgramParameter(program, gl.LINK_STATUS);
if (success) {
return program;
}
const log = gl.getProgramInfoLog(program);
gl.deleteProgram(program);
throw new Error(`unable to compile program ${name}: \n${log}`);
};
const TextureInfo = class {
constructor(width, height, glTexture) {
this.width = width;
this.height = height;
this.glTexture = glTexture;
}
get size() {
return new Size(this.width, this.height);
}
};
const DisplayConfiguration = class {
constructor() {
this.videoDecoder = "CANVAS_YUV";
this.videoBrightness = 0;
this.videoContrast = 1;
this.videoSaturation = 1;
this.videoHue = 0;
this.videoCenter = [0,0];
this.videoSize = [1,1];
this.videoBandwidth = 6000000; // 14318180;
this.videoLumaBandwidth = 2000000; // 600000;
this.videoChromaBandwidth = 600000; // 2000000;
this.videoWhiteOnly = false;
this.displayResolution = [640, 480];
this.displayPixelDensity = 72;
this.displayBarrel = 0.05; // 0;
this.displayScanlineLevel = 0.05; // 0;
this.displayShadowMaskLevel = 0.05; // 0;
this.displayShadowMaskDotPitch = 0.5; // 1;
this.displayShadowMask = "SHADOWMASK_TRIAD";
this.displayPersistence = 0;
this.displayCenterLighting = 1;
this.displayLuminanceGain = 1;
}
};
// Corresponds to OEImage. Contains the data on an NTSC/PAL/whatever
// image. The `data` field is an ImageData object with the actual
// image data.
const ImageInfo = class {
constructor(sampleRate, blackLevel, whiteLevel, subCarrier, colorBurst,
phaseAlternation, data) {
if (typeof data != "object") {
throw new Error(`want typeof data == 'object'; got '${typeof data}'`);
}
if (!(data instanceof ImageData)) {
throw new Error(`want data instanceof ImageData; got '${data.constructor.name}'`);
}
this.sampleRate = sampleRate;
this.blackLevel = blackLevel;
this.whiteLevel = whiteLevel;
this.subCarrier = subCarrier;
this.colorBurst = colorBurst;
this.phaseAlternation = phaseAlternation;
this.data = data;
}
get width() {
return this.data.width;
}
get height() {
return this.data.height;
}
get size() {
return new Size(this.data.width, this.data.height);
}
};
const ScreenView = class {
constructor(canvas) {
const gl = canvas.getContext("webgl");
const float_texture_ext = gl.getExtension('OES_texture_float');
if (float_texture_ext == null) {
throw new Error("WebGL extension 'OES_texture_float' unavailable");
}
this.canvas = canvas;
this.gl = gl;
this.textures = {};
this.shaders = {};
this.buffers = {};
this.image = null;
this.display = null;
this.imageSampleRate = null;
this.imageBlackLevel = null;
this.imageWhiteLevel = null;
this.imageSubcarrier = null;
this.viewportSize = new Size(0, 0);
this.configurationChanged = true;
this.imageChanged = true;
this.shaderEnabled = true;
}
get image() {
return this._image
}
set image(image) {
this._image = image;
this.imageChanged = true;
}
set displayConfiguration(displayConfiguration) {
this.display = displayConfiguration;
this.configurationChanged = true;
}
async initOpenGL() {
const gl = this.gl;
gl.enable(gl.BLEND);
gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA);
this.textures = {};
for (let name of TEXTURE_NAMES) {
this.textures[name] = new TextureInfo(0, 0, gl.createTexture());
}
for (let name of BUFFER_NAMES) {
this.buffers[name] = gl.createBuffer();
}
await this.loadTextures();
gl.pixelStorei(gl.PACK_ALIGNMENT, 1);
gl.pixelStorei(gl.UNPACK_ALIGNMENT, 1);
this.loadShaders();
}
freeOpenGL() {
const gl = this.gl;
for (let name of TEXTURE_NAMES) {
gl.deleteTexture(this.textures[name].glTexture);
}
for (let name of BUFFER_NAMES) {
gl.deleteBuffer(this.buffers[name]);
}
this.deleteShaders();
}
loadTextures() {
return Promise.all([
this.loadTexture("textures/Shadow Mask Triad.png", true, "SHADOWMASK_TRIAD"),
this.loadTexture("textures/Shadow Mask Inline.png", true, "SHADOWMASK_INLINE"),
this.loadTexture("textures/Shadow Mask Aperture.png", true, "SHADOWMASK_APERTURE"),
this.loadTexture("textures/Shadow Mask LCD.png", true, "SHADOWMASK_LCD"),
this.loadTexture("textures/Shadow Mask Bayer.png", true, "SHADOWMASK_BAYER"),
]);
}
async loadTexture(path, isMipMap, name) {
const gl = this.gl;
const texInfo = this.textures[name];
const image = await loadImage(path);
gl.bindTexture(gl.TEXTURE_2D, texInfo.glTexture);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA,
gl.RGBA, gl.UNSIGNED_BYTE, image);
if (isMipMap) {
gl.generateMipmap(gl.TEXTURE_2D);
}
texInfo.width = image.naturalWidth;
texInfo.height = image.naturalHeight;
}
loadShaders() {
this.loadShader("COMPOSITE", COMPOSITE_SHADER);
this.loadShader("DISPLAY", DISPLAY_SHADER);
this.loadShader("RGB", RGB_SHADER);
}
loadShader(name, source) {
const glVertexShader = createShader(this.gl, name, this.gl.VERTEX_SHADER, VERTEX_SHADER);
const glFragmentShader = createShader(this.gl, name, this.gl.FRAGMENT_SHADER, source);
const glProgram = createProgram(this.gl, name, glVertexShader, glFragmentShader);
this.gl.deleteShader(glVertexShader);
this.gl.deleteShader(glFragmentShader);
this.shaders[name] = glProgram;
}
deleteShaders() {
for (let name of SHADER_NAMES) {
if (this.shaders[name]) {
this.gl.deleteProgram(this.shaders[name]);
this.shaders[name] = false;
}
}
}
vsync() {
const gl = this.gl;
resizeCanvas(this.canvas);
const canvasWidth = this.canvas.width;
const canvasHeight = this.canvas.height;
// if viewport size has changed:
if ((this.viewportSize.width != canvasWidth)
|| (this.viewportSize.height != this.canvasHeight)) {
this.viewportSize = new Size(canvasWidth, canvasHeight);
gl.viewport(0, 0, canvasWidth, canvasHeight);
this.configurationChanged = true;
}
if (this.imageChanged) {
this.uploadImage();
}
if (this.configurationChanged) {
this.configureShaders();
}
if (this.imageChanged || this.configurationChanged) {
this.renderImage();
}
if (this.imageChanged || this.configurationChanged ||
this.image.displayPersistence != 0) {
this.drawDisplayCanvas();
}
}
uploadImage() {
const gl = this.gl;
const image = this.image;
this.resizeTexture("IMAGE_IN", image.width, image.height);
const texInfoImage = this.textures["IMAGE_IN"];
gl.bindTexture(gl.TEXTURE_2D, texInfoImage.glTexture);
const format = gl.LUMINANCE;
const type = gl.UNSIGNED_BYTE;
const luminance = luminanceData(image.data);
gl.texSubImage2D(gl.TEXTURE_2D, 0,
0, 0, // xoffset, yoffset
image.data.width,
image.data.height,
format, type, luminance);
// Update configuration
if ((image.sampleRate != this.imageSampleRate) ||
(image.blackLevel != this.imageBlackLevel) ||
(image.whiteLevel != this.imageWhiteLevel) ||
(image.subCarrier != this.imageSubcarrier))
{
this.imageSampleRate = image.sampleRate;
this.imageBlackLevel = image.blackLevel;
this.imageWhiteLevel = image.whiteLevel;
this.imageSubcarrier = image.subCarrier;
this.configurationChanged = true;
}
// Upload phase info
const texHeight = 2**Math.ceil(Math.log2(image.height));
const colorBurst = image.colorBurst
const phaseAlternation = image.phaseAlternation;
const phaseInfo = new Float32Array(3 * texHeight);
for (let x = 0; x < image.height; x++) {
const c = colorBurst[x % colorBurst.length] / 2 / Math.PI;
phaseInfo[3 * x + 0] = c - Math.floor(c);
phaseInfo[3 * x + 1] = phaseAlternation[x % phaseAlternation.length];
}
const texInfoPhase = this.textures["IMAGE_PHASEINFO"];
gl.bindTexture(gl.TEXTURE_2D, texInfoPhase.glTexture);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGB, 1, texHeight, 0,
gl.RGB, gl.FLOAT, phaseInfo);
}
getRenderShader() {
switch (this.display.videoDecoder) {
case "CANVAS_RGB":
case "CANVAS_MONOCHROME":
return [this.shaders["RGB"], "RGB"];
case "CANVAS_YUV":
case "CANVAS_YIQ":
case "CANVAS_CXA2025AS":
return [this.shaders["COMPOSITE"], "COMPOSITE"];
}
return [null, null];
}
configureShaders() {
const gl = this.gl;
const [renderShader, renderShaderName] = this.getRenderShader();
const displayShader = this.shaders["DISPLAY"];
if (!renderShader || !displayShader)
return;
const isCompositeDecoder = (renderShaderName == "COMPOSITE");
// Render shader
gl.useProgram(renderShader);
// Subcarrier
if (isCompositeDecoder) {
gl.uniform1f(gl.getUniformLocation(renderShader, "subcarrier"),
this.imageSubcarrier / this.imageSampleRate);
}
// Filters
const w = Vector.chebyshevWindow(17, 50).normalize();
let wy, wu, wv;
const bandwidth = this.display.videoBandwidth / this.imageSampleRate;
if (isCompositeDecoder) {
let yBandwidth = this.display.videoLumaBandwidth / this.imageSampleRate;
let uBandwidth = this.display.videoChromaBandwidth / this.imageSampleRate;
let vBandwidth = uBandwidth;
if (this.display.videoDecoder == "CANVAS_YIQ")
uBandwidth = uBandwidth + NTSC_IQ_DELTA / this.imageSampleRate;
// Switch to video bandwidth when no subcarrier
if ((this.imageSubcarrier == 0.0) || this.display.videoWhiteOnly)
{
yBandwidth = bandwidth;
uBandwidth = bandwidth;
vBandwidth = bandwidth;
}
wy = w.mul(Vector.lanczosWindow(17, yBandwidth));
wy = wy.normalize();
wu = w.mul(Vector.lanczosWindow(17, uBandwidth));
wu = wu.normalize().mul(2);
wv = w.mul(Vector.lanczosWindow(17, vBandwidth));
wv = wv.normalize().mul(2);
} else {
wy = w.mul(Vector.lanczosWindow(17, bandwidth));
wu = wv = wy = wy.normalize();
}
gl.uniform3f(gl.getUniformLocation(renderShader, "c0"),
wy.data[8], wu.data[8], wv.data[8]);
gl.uniform3f(gl.getUniformLocation(renderShader, "c1"),
wy.data[7], wu.data[7], wv.data[7]);
gl.uniform3f(gl.getUniformLocation(renderShader, "c2"),
wy.data[6], wu.data[6], wv.data[6]);
gl.uniform3f(gl.getUniformLocation(renderShader, "c3"),
wy.data[5], wu.data[5], wv.data[5]);
gl.uniform3f(gl.getUniformLocation(renderShader, "c4"),
wy.data[4], wu.data[4], wv.data[4]);
gl.uniform3f(gl.getUniformLocation(renderShader, "c5"),
wy.data[3], wu.data[3], wv.data[3]);
gl.uniform3f(gl.getUniformLocation(renderShader, "c6"),
wy.data[2], wu.data[2], wv.data[2]);
gl.uniform3f(gl.getUniformLocation(renderShader, "c7"),
wy.data[1], wu.data[1], wv.data[1]);
gl.uniform3f(gl.getUniformLocation(renderShader, "c8"),
wy.data[0], wu.data[0], wv.data[0]);
// Decoder matrix
let decoderMatrix = new Matrix3(1, 0, 0,
0, 1, 0,
0, 0, 1);
// Encode
if (!isCompositeDecoder) {
// Y'PbPr encoding matrix
decoderMatrix = new Matrix3(0.299, -0.168736, 0.5,
0.587, -0.331264, -0.418688,
0.114, 0.5, -0.081312).mul(decoderMatrix);
}
// Set hue
if (this.display.videoDecoder == "CANVAS_MONOCHROME")
decoderMatrix = new Matrix3(1, 0.5, 0,
0, 0, 0,
0, 0, 0).mul(decoderMatrix);
// Disable color decoding when no subcarrier
if (isCompositeDecoder)
{
if ((this.imageSubcarrier == 0.0) || this.display.videoWhiteOnly) {
decoderMatrix = new Matrix3(1, 0, 0,
0, 0, 0,
0, 0, 0).mul(decoderMatrix);
}
}
// Saturation
decoderMatrix = new Matrix3(1, 0, 0,
0, this.display.videoSaturation, 0,
0, 0, this.display.videoSaturation).mul(decoderMatrix);
// Hue
const hue = 2 * Math.PI * this.display.videoHue;
decoderMatrix = new Matrix3(1, 0, 0,
0, Math.cos(hue), -Math.sin(hue),
0, Math.sin(hue), Math.cos(hue)).mul(decoderMatrix);
// Decode
switch (this.display.videoDecoder) {
case "CANVAS_RGB":
case "CANVAS_MONOCHROME":
// Y'PbPr decoder matrix
decoderMatrix = new Matrix3(1, 1, 1,
0, -0.344136, 1.772,
1.402, -0.714136, 0).mul(decoderMatrix);
break;
case "CANVAS_YUV":
case "CANVAS_YIQ":
// Y'UV decoder matrix
decoderMatrix = new Matrix3(1, 1, 1,
0, -0.394642, 2.032062,
1.139883, -0.580622, 0).mul(decoderMatrix);
break;
case "CANVAS_CXA2025AS":
// Exchange I and Q
decoderMatrix = new Matrix3(1, 0, 0,
0, 0, 1,
0, 1, 0).mul(decoderMatrix);
// Rotate 33 degrees
hue = -Math.PI * 33 / 180;
decoderMatrix = new Matrix3(1, 0, 0,
0, Math.cos(hue), -Math.sin(hue),
0, Math.sin(hue), Math.cos(hue)).mul(decoderMatrix);
// CXA2025AS decoder matrix
decoderMatrix = new Matrix3(1, 1, 1,
1.630, -0.378, -1.089,
0.317, -0.466, 1.677).mul(decoderMatrix);
break;
default:
throw new Error(`unknown videoDecoder: ${this.display.videoDecoder}`);
}
// Brightness
const brightness = this.display.videoBrightness - this.imageBlackLevel;
let decoderOffset;
if (isCompositeDecoder)
decoderOffset = decoderMatrix.mul(new Matrix3(brightness, 0, 0,
0, 0, 0,
0, 0, 0));
else
decoderOffset = decoderMatrix.mul(new Matrix3(brightness, 0, 0,
brightness, 0, 0,
brightness, 0, 0));
gl.uniform3f(gl.getUniformLocation(renderShader, "decoderOffset"),
decoderOffset.at(0, 0),
decoderOffset.at(0, 1),
decoderOffset.at(0, 2));
// Contrast
let contrast = this.display.videoContrast;
const videoLevel = (this.imageWhiteLevel - this.imageBlackLevel);
if (videoLevel > 0)
contrast /= videoLevel;
else
contrast = 0;
if (contrast < 0)
contrast = 0;
decoderMatrix = decoderMatrix.mul(contrast);
gl.uniformMatrix3fv(gl.getUniformLocation(renderShader, "decoderMatrix"),
false, decoderMatrix.data);
// Display shader
gl.useProgram(displayShader);
// Barrel
gl.uniform1f(gl.getUniformLocation(displayShader, "barrel"),
this.display.displayBarrel);
// Shadow mask
gl.uniform1i(gl.getUniformLocation(displayShader, "shadowMask"), 1);
gl.uniform1f(gl.getUniformLocation(displayShader, "shadowMaskLevel"),
this.display.displayShadowMaskLevel);
// Persistence
const frameRate = 60;
gl.uniform1f(gl.getUniformLocation(displayShader, "persistenceLevel"),
this.display.displayPersistence /
(1.0 / frameRate + this.display.displayPersistence));
if (this.display.displayPersistence == 0)
this.resizeTexture("IMAGE_PERSISTENCE", 0, 0);
// Center lighting
let centerLighting = this.display.displayCenterLighting;
if (Math.abs(centerLighting) < 0.001)
centerLighting = 0.001;
gl.uniform1f(gl.getUniformLocation(displayShader, "centerLighting"),
1.0 / centerLighting - 1);
// Luminance gain
gl.uniform1f(gl.getUniformLocation(displayShader, "luminanceGain"),
this.display.displayLuminanceGain);
}
renderImage() {
const gl = this.gl;
const [renderShader, renderShaderName] = this.getRenderShader();
if (!renderShader || !this.shaderEnabled)
return;
const isCompositeDecoder = (renderShaderName == "COMPOSITE");
gl.useProgram(renderShader);
const texSize = this.textures["IMAGE_IN"].size;
this.resizeTexture("IMAGE_DECODED", texSize.width, texSize.height);
gl.uniform1i(gl.getUniformLocation(renderShader, "texture"), 0);
gl.uniform2f(gl.getUniformLocation(renderShader, "textureSize"),
texSize.width, texSize.height);
if (isCompositeDecoder)
{
gl.uniform1i(gl.getUniformLocation(renderShader, "phaseInfo"), 1);
gl.activeTexture(gl.TEXTURE1);
gl.bindTexture(gl.TEXTURE_2D, this.textures["IMAGE_PHASEINFO"].glTexture);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.activeTexture(gl.TEXTURE0);
}
// Render to the back buffer, to avoid using FBOs
// (support for vanilla OpenGL 2.0 cards)
// I think webgl is rendering to the back buffer anyway, until
// we stop executing javascript statements and give control
// back, at which point it flips. So we might not need
// this. Although truly, I'm not certain what it's doing. If we
// *do* end up needing it, we'll have to go full webgl2.
// glReadBuffer(GL_BACK);
const imageSize = this.image.size;
for (let y = 0; y < this.image.height; y += this.viewportSize.height) {
for (let x = 0; x < this.image.width; x += this.viewportSize.width) {
// Calculate rects
const clipSize = this.viewportSize.copy();
if ((x + clipSize.width) > imageSize.width)
clipSize.width = imageSize.width - x;
if ((y + clipSize.height) > imageSize.height)
clipSize.height = imageSize.height - y;
const textureRect = new Rect(x / texSize.width,
y / texSize.height,
clipSize.width / texSize.width,
clipSize.height / texSize.height);
const canvasRect = new Rect(-1,
-1,
2 * clipSize.width / this.viewportSize.width,
2 * clipSize.height / this.viewportSize.height);
// Render
gl.bindTexture(gl.TEXTURE_2D, this.textures["IMAGE_IN"].glTexture);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
// What is this, some ancient fixed pipeline nonsense? No way.
// glLoadIdentity();
const positionLocation = gl.getAttribLocation(renderShader, "a_position");
const texcoordLocation = gl.getAttribLocation(renderShader, "a_texCoord");
const positionBuffer = this.buffers["POSITION"];
gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
const p_x1 = canvasRect.l;
const p_x2 = canvasRect.r;
const p_y1 = canvasRect.t;
const p_y2 = canvasRect.b;
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
p_x1, p_y1,
p_x2, p_y1,
p_x1, p_y2,
p_x1, p_y2,
p_x2, p_y1,
p_x2, p_y2,
]), gl.STATIC_DRAW);
const texcoordBuffer = this.buffers["TEXCOORD"];
gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);
const t_x1 = textureRect.l;
const t_x2 = textureRect.r;
const t_y1 = textureRect.t;
const t_y2 = textureRect.b;
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
t_x1, t_y1,
t_x2, t_y1,
t_x1, t_y2,
t_x1, t_y2,
t_x2, t_y1,
t_x2, t_y2,
]), gl.STATIC_DRAW);
gl.clearColor(0, 0, 0, 0);
gl.clear(gl.COLOR_BUFFER_BIT);
gl.enableVertexAttribArray(positionLocation);
gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
gl.vertexAttribPointer(positionLocation, 2, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(texcoordLocation);
gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);
gl.vertexAttribPointer(texcoordLocation, 2, gl.FLOAT, false, 0, 0);
gl.drawArrays(gl.TRIANGLES, 0, 6);
}
}
// TODO(zellyn): implement
}
// TODO(zellyn): implement
drawDisplayCanvas() {
}
// Resize the texture with the given name to the next
// highest power of two width and height. Wouldn't be
// necessary with webgl2.
resizeTexture(name, width, height) {
const gl = this.gl;
const texInfo = this.textures[name];
if (!texInfo) {
throw new Error(`Cannot find texture named ${name}`);
}
if (width < 4) width = 4;
if (height < 4) height = 4;
width = 2**Math.ceil(Math.log2(width));
height = 2**Math.ceil(Math.log2(height));
if (texInfo.width != width || texInfo.height != height) {
texInfo.width = width;
texInfo.height = height;
gl.bindTexture(gl.TEXTURE_2D, texInfo.glTexture);
const dummy = new Uint8Array(width * height);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.LUMINANCE, width, height, 0,
gl.LUMINANCE, gl.UNSIGNED_BYTE, dummy);
}
}
}
return {
C: {
HORIZ_START: HORIZ_START,
HORIZ_BLANK: HORIZ_BLANK,
HORIZ_DISPLAY: HORIZ_DISPLAY,
HORIZ_TOTAL: HORIZ_TOTAL,
CELL_WIDTH: CELL_WIDTH,
CELL_HEIGHT: CELL_HEIGHT,
VERT_NTSC_START: VERT_NTSC_START,
VERT_PAL_START: VERT_PAL_START,
VERT_DISPLAY: VERT_DISPLAY,
BLOCK_WIDTH: BLOCK_WIDTH,
BLOCK_HEIGHT: BLOCK_HEIGHT,
NTSC_I_CUTOFF: NTSC_I_CUTOFF,
NTSC_Q_CUTOFF: NTSC_Q_CUTOFF,
NTSC_IQ_DELTA: NTSC_IQ_DELTA,
NTSC_DETAILS: buildTiming(ntscClockFrequency, ntscDisplayRect,
ntscVisibleRect, ntscVertTotal, NTSC_FSC),
PAL_DETAILS: buildTiming(palClockFrequency, palDisplayRect,
palVisibleRect, palVertTotal, PAL_FSC),
},
loadImage: loadImage,
screenData: screenData,
resizeCanvas: resizeCanvas,
createShader: createShader,
createProgram: createProgram,
// Classes.
ScreenView: ScreenView,
DisplayConfiguration: DisplayConfiguration,
ImageInfo: ImageInfo,
Vector: Vector,
};
})();
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