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skybox.html
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<!-- vim: sw=2 ts=2 expandtab smartindent ft=javascript
-->
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<title>WebGL Demo</title>
<style> document, body { margin: 0px; padding: 0px; overflow: hidden; } </style>
</head>
<body>
<canvas id="glcanvas"></canvas>
<script>
function mat4_create() {
let out = new Float32Array(16);
out[0] = 1;
out[5] = 1;
out[10] = 1;
out[15] = 1;
return out;
}
function mat4_transpose(out, a) {
/* If we are transposing ourselves we can skip a few steps but have to cache some values */
if (out === a) {
let a01 = a[1], a02 = a[2], a03 = a[3];
let a12 = a[6], a13 = a[7];
let a23 = a[11];
out[1] = a[4];
out[2] = a[8];
out[3] = a[12];
out[4] = a01;
out[6] = a[9];
out[7] = a[13];
out[8] = a02;
out[9] = a12;
out[11] = a[14];
out[12] = a03;
out[13] = a13;
out[14] = a23;
} else {
out[0] = a[0];
out[1] = a[4];
out[2] = a[8];
out[3] = a[12];
out[4] = a[1];
out[5] = a[5];
out[6] = a[9];
out[7] = a[13];
out[8] = a[2];
out[9] = a[6];
out[10] = a[10];
out[11] = a[14];
out[12] = a[3];
out[13] = a[7];
out[14] = a[11];
out[15] = a[15];
}
return out;
}
function mat4_invert(out, a) {
let a00 = a[0],
a01 = a[1],
a02 = a[2],
a03 = a[3];
let a10 = a[4],
a11 = a[5],
a12 = a[6],
a13 = a[7];
let a20 = a[8],
a21 = a[9],
a22 = a[10],
a23 = a[11];
let a30 = a[12],
a31 = a[13],
a32 = a[14],
a33 = a[15];
let b00 = a00 * a11 - a01 * a10;
let b01 = a00 * a12 - a02 * a10;
let b02 = a00 * a13 - a03 * a10;
let b03 = a01 * a12 - a02 * a11;
let b04 = a01 * a13 - a03 * a11;
let b05 = a02 * a13 - a03 * a12;
let b06 = a20 * a31 - a21 * a30;
let b07 = a20 * a32 - a22 * a30;
let b08 = a20 * a33 - a23 * a30;
let b09 = a21 * a32 - a22 * a31;
let b10 = a21 * a33 - a23 * a31;
let b11 = a22 * a33 - a23 * a32;
/* Calculate the determinant */
let det =
b00 * b11 - b01 * b10 + b02 * b09 + b03 * b08 - b04 * b07 + b05 * b06;
if (!det) {
return null;
}
det = 1.0 / det;
out[0] = (a11 * b11 - a12 * b10 + a13 * b09) * det;
out[1] = (a02 * b10 - a01 * b11 - a03 * b09) * det;
out[2] = (a31 * b05 - a32 * b04 + a33 * b03) * det;
out[3] = (a22 * b04 - a21 * b05 - a23 * b03) * det;
out[4] = (a12 * b08 - a10 * b11 - a13 * b07) * det;
out[5] = (a00 * b11 - a02 * b08 + a03 * b07) * det;
out[6] = (a32 * b02 - a30 * b05 - a33 * b01) * det;
out[7] = (a20 * b05 - a22 * b02 + a23 * b01) * det;
out[8] = (a10 * b10 - a11 * b08 + a13 * b06) * det;
out[9] = (a01 * b08 - a00 * b10 - a03 * b06) * det;
out[10] = (a30 * b04 - a31 * b02 + a33 * b00) * det;
out[11] = (a21 * b02 - a20 * b04 - a23 * b00) * det;
out[12] = (a11 * b07 - a10 * b09 - a12 * b06) * det;
out[13] = (a00 * b09 - a01 * b07 + a02 * b06) * det;
out[14] = (a31 * b01 - a30 * b03 - a32 * b00) * det;
out[15] = (a20 * b03 - a21 * b01 + a22 * b00) * det;
return out;
}
const _scratch = mat4_create();
function mat4_from_zyx_rotation(out, x, y, z) {
mat4_from_z_rotation(out, z);
mat4_from_y_rotation(_scratch, y);
mat4_mul(out, out, _scratch);
mat4_from_x_rotation(_scratch, x);
mat4_mul(out, out, _scratch);
return out;
}
function mat4_from_x_rotation(out, rad) {
let s = Math.sin(rad);
let c = Math.cos(rad);
/* Perform axis-specific matrix multiplication */
out[0] = 1;
out[1] = 0;
out[2] = 0;
out[3] = 0;
out[4] = 0;
out[5] = c;
out[6] = s;
out[7] = 0;
out[8] = 0;
out[9] = -s;
out[10] = c;
out[11] = 0;
out[12] = 0;
out[13] = 0;
out[14] = 0;
out[15] = 1;
return out;
}
function mat4_from_y_rotation(out, rad) {
let s = Math.sin(rad);
let c = Math.cos(rad);
/* Perform axis-specific matrix multiplication */
out[0] = c;
out[1] = 0;
out[2] = -s;
out[3] = 0;
out[4] = 0;
out[5] = 1;
out[6] = 0;
out[7] = 0;
out[8] = s;
out[9] = 0;
out[10] = c;
out[11] = 0;
out[12] = 0;
out[13] = 0;
out[14] = 0;
out[15] = 1;
return out;
}
function mat4_from_z_rotation(out, rad) {
let s = Math.sin(rad);
let c = Math.cos(rad);
/* Perform axis-specific matrix multiplication */
out[0] = c;
out[1] = s;
out[2] = 0;
out[3] = 0;
out[4] = -s;
out[5] = c;
out[6] = 0;
out[7] = 0;
out[8] = 0;
out[9] = 0;
out[10] = 1;
out[11] = 0;
out[12] = 0;
out[13] = 0;
out[14] = 0;
out[15] = 1;
return out;
}
function mat4_from_translation(out, v) {
out[0] = 1;
out[1] = 0;
out[2] = 0;
out[3] = 0;
out[4] = 0;
out[5] = 1;
out[6] = 0;
out[7] = 0;
out[8] = 0;
out[9] = 0;
out[10] = 1;
out[11] = 0;
out[12] = v[0];
out[13] = v[1];
out[14] = v[2];
out[15] = 1;
return out;
}
function mat4_from_scaling(out, v) {
out[0] = v[0];
out[1] = 0;
out[2] = 0;
out[3] = 0;
out[4] = 0;
out[5] = v[1];
out[6] = 0;
out[7] = 0;
out[8] = 0;
out[9] = 0;
out[10] = v[2];
out[11] = 0;
out[12] = 0;
out[13] = 0;
out[14] = 0;
out[15] = 1;
return out;
}
function mat4_mul(out, a, b) {
let a00 = a[0], a01 = a[1], a02 = a[2], a03 = a[3];
let a10 = a[4], a11 = a[5], a12 = a[6], a13 = a[7];
let a20 = a[8], a21 = a[9], a22 = a[10], a23 = a[11];
let a30 = a[12], a31 = a[13], a32 = a[14], a33 = a[15];
/* Cache only the current line of the second matrix */
let b0 = b[0],
b1 = b[1],
b2 = b[2],
b3 = b[3];
out[0] = b0 * a00 + b1 * a10 + b2 * a20 + b3 * a30;
out[1] = b0 * a01 + b1 * a11 + b2 * a21 + b3 * a31;
out[2] = b0 * a02 + b1 * a12 + b2 * a22 + b3 * a32;
out[3] = b0 * a03 + b1 * a13 + b2 * a23 + b3 * a33;
b0 = b[4];
b1 = b[5];
b2 = b[6];
b3 = b[7];
out[4] = b0 * a00 + b1 * a10 + b2 * a20 + b3 * a30;
out[5] = b0 * a01 + b1 * a11 + b2 * a21 + b3 * a31;
out[6] = b0 * a02 + b1 * a12 + b2 * a22 + b3 * a32;
out[7] = b0 * a03 + b1 * a13 + b2 * a23 + b3 * a33;
b0 = b[8];
b1 = b[9];
b2 = b[10];
b3 = b[11];
out[8] = b0 * a00 + b1 * a10 + b2 * a20 + b3 * a30;
out[9] = b0 * a01 + b1 * a11 + b2 * a21 + b3 * a31;
out[10] = b0 * a02 + b1 * a12 + b2 * a22 + b3 * a32;
out[11] = b0 * a03 + b1 * a13 + b2 * a23 + b3 * a33;
b0 = b[12];
b1 = b[13];
b2 = b[14];
b3 = b[15];
out[12] = b0 * a00 + b1 * a10 + b2 * a20 + b3 * a30;
out[13] = b0 * a01 + b1 * a11 + b2 * a21 + b3 * a31;
out[14] = b0 * a02 + b1 * a12 + b2 * a22 + b3 * a32;
out[15] = b0 * a03 + b1 * a13 + b2 * a23 + b3 * a33;
return out;
}
const VEC3_UP = [0, 0, 1];
function mat4_target_to(out, eye, target, up=VEC3_UP) {
let eyex = eye[0], eyey = eye[1], eyez = eye[2],
upx = up[0], upy = up[1], upz = up[2];
let z0 = eyex - target[0],
z1 = eyey - target[1],
z2 = eyez - target[2];
let len = z0 * z0 + z1 * z1 + z2 * z2;
if (len > 0) {
len = 1 / Math.sqrt(len);
z0 *= len;
z1 *= len;
z2 *= len;
}
let x0 = upy * z2 - upz * z1,
x1 = upz * z0 - upx * z2,
x2 = upx * z1 - upy * z0;
len = x0 * x0 + x1 * x1 + x2 * x2;
if (len > 0) {
len = 1 / Math.sqrt(len);
x0 *= len;
x1 *= len;
x2 *= len;
}
out[0] = x0;
out[1] = x1;
out[2] = x2;
out[3] = 0;
out[4] = z1 * x2 - z2 * x1;
out[5] = z2 * x0 - z0 * x2;
out[6] = z0 * x1 - z1 * x0;
out[7] = 0;
out[8] = z0;
out[9] = z1;
out[10] = z2;
out[11] = 0;
out[12] = eyex;
out[13] = eyey;
out[14] = eyez;
out[15] = 1;
return out;
}
function mat4_transform_vec4(out, a, m) {
let x = a[0], y = a[1], z = a[2], w = a[3];
out[0] = m[0] * x + m[4] * y + m[8] * z + m[12] * w;
out[1] = m[1] * x + m[5] * y + m[9] * z + m[13] * w;
out[2] = m[2] * x + m[6] * y + m[10] * z + m[14] * w;
out[3] = m[3] * x + m[7] * y + m[11] * z + m[15] * w;
return out;
}
function mat4_perspective(out, fovy, aspect, near, far) {
let f = 1.0 / Math.tan(fovy / 2),
nf;
out[0] = f / aspect;
out[1] = 0;
out[2] = 0;
out[3] = 0;
out[4] = 0;
out[5] = f;
out[6] = 0;
out[7] = 0;
out[8] = 0;
out[9] = 0;
out[11] = -1;
out[12] = 0;
out[13] = 0;
out[15] = 0;
if (far != null && far !== Infinity) {
nf = 1 / (near - far);
out[10] = (far + near) * nf;
out[14] = 2 * far * near * nf;
} else {
out[10] = -1;
out[14] = -2 * near;
}
return out;
}
function mat4_ortho(out, left, right, bottom, top, near, far) {
let lr = 1 / (left - right);
let bt = 1 / (bottom - top);
let nf = 1 / (near - far);
out[0] = -2 * lr;
out[1] = 0;
out[2] = 0;
out[3] = 0;
out[4] = 0;
out[5] = -2 * bt;
out[6] = 0;
out[7] = 0;
out[8] = 0;
out[9] = 0;
out[10] = 2 * nf;
out[11] = 0;
out[12] = (left + right) * lr;
out[13] = (top + bottom) * bt;
out[14] = (far + near) * nf;
out[15] = 1;
return out;
}
let cubeRotation = 0.0;
let deltaTime = 0;
window.onload = () => {
const canvas = document.querySelector("#glcanvas");
const gl = canvas.getContext("webgl2");
if (gl === null) {
alert(
"Unable to initialize WebGL. Your browser or machine may not support it."
);
return;
}
let texture_starfield = gl.createTexture();
{
const texture_starfield_size = 1 << 12;
const blur_factor = 0.00085;
const image_brightness = 0.2;
const geo_vbuf_pos = gl.createBuffer();
const geo_vbuf_uv = gl.createBuffer();
const geo_ibuf = gl.createBuffer();
let shaders;
/* compile shaders */
{
const vs_geo = `
attribute vec3 a_pos;
attribute vec2 a_uv;
varying vec2 v_uv;
void main() {
gl_Position = vec4(a_pos.xyz, 1);
v_uv = a_uv;
}`;
const fs_geo = `
precision mediump float;
uniform sampler2D u_texture;
uniform float u_brightness;
varying vec2 v_uv;
void main() {
gl_FragColor = texture2D(u_texture, v_uv) * u_brightness;
}`;
const vs_fullscreen_blur = `#version 300 es
precision mediump float;
out vec2 v_texcoord;
void main(void) {
float x = float((gl_VertexID & 1) << 2);
float y = float((gl_VertexID & 2) << 1);
v_texcoord.x = x * 0.5;
v_texcoord.y = y * 0.5;
gl_Position = vec4(x - 1.0, y - 1.0, 1, 1);
}
`;
const fs_fullscreen_blur = `#version 300 es
precision mediump float;
uniform sampler2D u_texture;
uniform vec2 u_direction;
in vec2 v_texcoord;
out vec4 frag_color;
void main(void) {
vec2 one_pixel = u_direction*(vec2(1) / vec2(textureSize(u_texture, 0)));
frag_color = texture(u_texture, v_texcoord) * 0.2270270270;
frag_color += texture(u_texture, v_texcoord + one_pixel ) * 0.1945945946;
frag_color += texture(u_texture, v_texcoord - one_pixel ) * 0.1945945946;
frag_color += texture(u_texture, v_texcoord + one_pixel*2.0) * 0.1216216216;
frag_color += texture(u_texture, v_texcoord - one_pixel*2.0) * 0.1216216216;
frag_color += texture(u_texture, v_texcoord + one_pixel*3.0) * 0.0540540541;
frag_color += texture(u_texture, v_texcoord - one_pixel*3.0) * 0.0540540541;
frag_color += texture(u_texture, v_texcoord + one_pixel*4.0) * 0.0162162162;
frag_color += texture(u_texture, v_texcoord - one_pixel*4.0) * 0.0162162162;
}
`;
function createProgram(gl, vertexSource, fragmentSource) {
function createShader(gl, type, source) {
const shader = gl.createShader(type);
gl.shaderSource(shader, source);
gl.compileShader(shader);
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
throw new Error(gl.getShaderInfoLog(shader));
}
return shader;
}
const program = gl.createProgram();
const vertexShader = createShader(gl, gl.VERTEX_SHADER, vertexSource);
const fragmentShader = createShader(gl, gl.FRAGMENT_SHADER, fragmentSource);
gl.attachShader(program, vertexShader);
gl.attachShader(program, fragmentShader);
gl.linkProgram(program);
if (!gl.getProgramParameter(program, gl.LINK_STATUS)) {
throw new Error(gl.getProgramInfoLog(program));
}
const wrapper = {program};
const numAttributes = gl.getProgramParameter(program, gl.ACTIVE_ATTRIBUTES);
for (let i = 0; i < numAttributes; i++) {
const attribute = gl.getActiveAttrib(program, i);
wrapper[attribute.name] = gl.getAttribLocation(program, attribute.name);
}
const numUniforms = gl.getProgramParameter(program, gl.ACTIVE_UNIFORMS);
for (let i = 0; i < numUniforms; i++) {
const uniform = gl.getActiveUniform(program, i);
wrapper[uniform.name] = gl.getUniformLocation(program, uniform.name);
}
return wrapper;
}
shaders = {
fullscreenBlur: createProgram(gl, vs_fullscreen_blur, fs_fullscreen_blur),
geo: createProgram(gl, vs_geo, fs_geo)
}
}
let atlas = gl.createTexture();
const ATLAS_SIZE = 2; /* in emoji */
const EMOJI_SIZE = 300;
{
const canvas = document.createElement("canvas");
canvas.width = canvas.height = ATLAS_SIZE * EMOJI_SIZE;
const ctx = canvas.getContext("2d");
{
const atlas = ['⭐️', '💫', '✨', '🪐'];
const PAD = EMOJI_SIZE*0.05;
ctx.font = (EMOJI_SIZE - PAD*2) + 'px sans-serif';
let i = 0;
for (const char of atlas) {
const x = ( i % ATLAS_SIZE ) * EMOJI_SIZE;
const y = (Math.floor(i / ATLAS_SIZE)) * EMOJI_SIZE;
ctx.fillText(
char,
x + PAD,
y + EMOJI_SIZE - PAD*2
);
i++;
}
}
gl.bindTexture(gl.TEXTURE_2D, atlas);
gl.texImage2D(
/* target */ gl.TEXTURE_2D,
/* level */ 0,
/* internalformat */ gl.RGBA,
/* width */ canvas.width,
/* height */ canvas.height,
/* border, */ 0,
/* format, */ gl.RGBA,
/* type, */ gl.UNSIGNED_BYTE,
/* data */ canvas
);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
}
let render_targets = [
{ tex: null, fb: null },
{ tex: null, fb: null },
];
gl.viewport(
0,
0,
texture_starfield_size,
texture_starfield_size
);
/* create scene-sized render-target for post-processing fx (like shadows) */
for (const target of render_targets) {
target.tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, target.tex);
// define size and format of level 0
gl.texImage2D(
gl.TEXTURE_2D,
/* level, */ 0,
/* internalFormat, */ gl.RGBA,
/* width, */ texture_starfield_size,
/* height, */ texture_starfield_size,
/* border, */ 0,
/* format, */ gl.RGBA,
/* type, */ gl.UNSIGNED_BYTE,
/* data */ null
);
// set the filtering so we don't need mips
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
target.fb = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, target.fb);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, target.tex, 0);
}
const geo = {
idx: [],
pos: [],
uv : [],
};
{
function drawBox(x, y, size, atlas_index) {
/* generate UVs from atlas_index */
{
const u = ( atlas_index % ATLAS_SIZE );
const v = (Math.floor(atlas_index / ATLAS_SIZE));
geo.uv.push(
(u+1)/ATLAS_SIZE, (v+1)/ATLAS_SIZE,
(u+0)/ATLAS_SIZE, (v+1)/ATLAS_SIZE,
(u+0)/ATLAS_SIZE, (v+0)/ATLAS_SIZE,
(u+1)/ATLAS_SIZE, (v+0)/ATLAS_SIZE,
);
}
/* generate position + index */
{
const vbuf_i = geo.pos.length / 3;
geo.pos.push(x+size, y-size, 0.1);
geo.pos.push(x-size, y-size, 0.1);
geo.pos.push(x-size, y+size, 0.1);
geo.pos.push(x+size, y+size, 0.1);
geo.idx.push(
vbuf_i + 0,
vbuf_i + 1,
vbuf_i + 2,
vbuf_i + 2,
vbuf_i + 3,
vbuf_i + 0
);
}
}
for (let x = -1; x <= 1; x += 0.1) {
for (let y = -1; y <= 1; y += 0.1) {
drawBox(
x + (0.5 - Math.random())*0.1,
y + (0.5 - Math.random())*0.1,
0.0015 + Math.random()*0.0035,
~~(Math.random()*4)
);
}
}
}
{
/* clear framebuffers */
{
const BRIGHTNESS = 0.9;
{
gl.bindFramebuffer(gl.FRAMEBUFFER, render_targets[1].fb);
/* clear all */
gl.clearColor(0.0, 0.0, 0.0, 1.0 - BRIGHTNESS);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
}
/* bind first rendertarget in blur swapchain */
{
gl.bindFramebuffer(gl.FRAMEBUFFER, render_targets[0].fb);
/* clear all */
gl.clearColor(0.0, 0.0, 0.0, 1.0 - BRIGHTNESS);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
}
}
/* basic setup */
{
/* set up premultiplied alpha */
gl.blendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA);
gl.enable(gl.BLEND);
/* enable depth */
gl.enable(gl.DEPTH_TEST);
gl.depthFunc(gl.LEQUAL);
}
/* geo pass */
function geoPass() {
gl.useProgram(shaders.geo.program);
gl.enableVertexAttribArray(shaders.geo.a_pos);
gl.enableVertexAttribArray(shaders.geo.a_uv);
/* upload/bind atlas */
{
gl.activeTexture(gl.TEXTURE1);
gl.bindTexture(gl.TEXTURE_2D, atlas);
gl.uniform1i(shaders.geo.u_texture, 1);
}
gl.uniform1f(shaders.geo.u_brightness, image_brightness);
/* upload/bind geometry */
{
gl.bindBuffer(gl.ARRAY_BUFFER, geo_vbuf_pos);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(geo.pos), gl.STATIC_DRAW);
gl.vertexAttribPointer(shaders.geo.a_pos, 3, gl.FLOAT, false, 0, 0);
gl.bindBuffer(gl.ARRAY_BUFFER, geo_vbuf_uv);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(geo.uv), gl.STATIC_DRAW);
gl.vertexAttribPointer(shaders.geo.a_uv, 2, gl.FLOAT, false, 0, 0);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, geo_ibuf);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array(geo.idx), gl.STATIC_DRAW);
}
gl.drawElements(gl.TRIANGLES, geo.idx.length, gl.UNSIGNED_SHORT, 0);
}
geoPass();
/* blur passes! */
{
const blur_size = texture_starfield_size * blur_factor;
const passes = [
[render_targets[1].fb, render_targets[0].tex, [0*blur_size, 8*blur_size]],
[render_targets[0].fb, render_targets[1].tex, [7*blur_size, 0*blur_size]],
[render_targets[1].fb, render_targets[0].tex, [0*blur_size, 6*blur_size]],
[render_targets[0].fb, render_targets[1].tex, [5*blur_size, 0*blur_size]],
[render_targets[1].fb, render_targets[0].tex, [0*blur_size, 4*blur_size]],
[render_targets[0].fb, render_targets[1].tex, [3*blur_size, 0*blur_size]],
[render_targets[1].fb, render_targets[0].tex, [0*blur_size, 2*blur_size]],
[render_targets[0].fb, render_targets[1].tex, [1*blur_size, 0*blur_size]]
];
for (const [dst_fb, src_tex, dir] of passes) {
gl.bindFramebuffer(gl.FRAMEBUFFER, dst_fb);
gl.useProgram(shaders.fullscreenBlur.program);
gl.uniform2fv(shaders.fullscreenBlur.u_direction, dir);
/* bind tex */
{
gl.activeTexture(gl.TEXTURE0);
gl.bindTexture(gl.TEXTURE_2D, src_tex);
gl.uniform1i(shaders.fullscreenBlur.u_texture, 0);
}
gl.drawArrays(gl.TRIANGLE_FAN, 0, 3);
}
}
geoPass();
}
gl.deleteFramebuffer(render_targets[0].fb);
texture_starfield = render_targets[0].tex;
gl.deleteFramebuffer(render_targets[1].fb);
gl.deleteTexture(render_targets[1].tex);
gl.deleteTexture(atlas);
gl.viewport(
0,
0,
canvas.width,
canvas.height
);
gl.deleteBuffer(geo_vbuf_pos);
gl.deleteBuffer(geo_vbuf_uv );
gl.deleteBuffer(geo_ibuf );
}
(window.onresize = () => {
gl.viewport(
0,
0,
canvas.width = window.innerWidth*window.devicePixelRatio,
canvas.height = window.innerHeight*window.devicePixelRatio
);
canvas.style.width = window.innerWidth + 'px';
canvas.style.height = window.innerHeight + 'px';
})();
const vsSource = `
attribute vec4 a_vpos;
attribute vec2 a_uv;
uniform mat4 u_mvp;
varying lowp vec2 v_uv;
void main(void) {
gl_Position = u_mvp * a_vpos;
v_uv = a_uv;
}
`;
const fsSource = `
varying lowp vec2 v_uv;
uniform sampler2D u_texture;
void main(void) {
gl_FragColor = texture2D(u_texture, v_uv);
}
`;
let shaderProgram;
{
let vsShader, fsShader;
{
vsShader = gl.createShader(gl.VERTEX_SHADER);
fsShader = gl.createShader(gl.FRAGMENT_SHADER);
/* compile shaders in parallel
* https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/WebGL_best_practices#compile_shaders_and_link_programs_in_parallel
* https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/WebGL_best_practices#dont_check_shader_compile_status_unless_linking_fails
*
* improvement:
* https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/WebGL_best_practices#prefer_khr_parallel_shader_compile
*/
gl.shaderSource(fsShader, fsSource);
gl.shaderSource(vsShader, vsSource);
gl.compileShader(fsShader);
gl.compileShader(vsShader);
}
shaderProgram = gl.createProgram();
gl.attachShader(shaderProgram, vsShader);
gl.attachShader(shaderProgram, fsShader);
gl.linkProgram(shaderProgram);
if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
console.error(`Link failed: ${gl.getProgramInfoLog(shaderProgram)}`);
console.error(`vs info-log: ${gl.getShaderInfoLog(vsShader)}`);
console.error(`fs info-log: ${gl.getShaderInfoLog(fsShader)}`);
return;
}
}
const programInfo = {
program: shaderProgram,
a_vpos: gl.getAttribLocation(shaderProgram, "a_vpos"),
a_uv: gl.getAttribLocation(shaderProgram, "a_uv"),
u_mvp: gl.getUniformLocation(shaderProgram, "u_mvp"),
u_texture: gl.getUniformLocation(shaderProgram, "u_texture"),
};
const buffers = {
pos: gl.createBuffer(),
col: gl.createBuffer(),
idx: gl.createBuffer(),
};
/* fill buffers */
{
gl.bindBuffer(gl.ARRAY_BUFFER, buffers.pos);
gl.bufferData(
gl.ARRAY_BUFFER,
new Float32Array([
1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1,
-1, 1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1,
1, 1, -1, 1, 1, 1, 1, -1, 1, 1, -1, -1,
-1, 1, -1, 1, 1, -1, 1, -1, -1, -1, -1, -1,
1, -1, -1, 1, -1, 1, -1, -1, 1, -1, -1, -1,
-1, 1, 1, -1, 1, -1, -1, -1, -1, -1, -1, 1
]),
gl.STATIC_DRAW
);
gl.bindBuffer(gl.ARRAY_BUFFER, buffers.col);
gl.bufferData(
gl.ARRAY_BUFFER,
new Float32Array([
0, 0, 1, 0, 1, 1, 0, 1,
0, 0, 1, 0, 1, 1, 0, 1,
0, 0, 1, 0, 1, 1, 0, 1,
0, 0, 1, 0, 1, 1, 0, 1,
0, 0, 1, 0, 1, 1, 0, 1,
0, 0, 1, 0, 1, 1, 0, 1
]),
gl.STATIC_DRAW
);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, buffers.idx);
gl.bufferData(
gl.ELEMENT_ARRAY_BUFFER,
new Uint16Array([
0, 1, 2, 0, 2, 3, /* front */
4, 5, 6, 4, 6, 7, /* back */
8, 9, 10, 8, 10, 11, /* top */
12, 13, 14, 12, 14, 15, /* bottom */
16, 17, 18, 16, 18, 19, /* right */
20, 21, 22, 20, 22, 23, /* left */
]),
gl.STATIC_DRAW
);
}
let then = 0;
requestAnimationFrame(function render(now) {
requestAnimationFrame(render);
now *= 0.001;
deltaTime = now - then;
then = now;
cubeRotation += deltaTime*0.05;
const SKYBOX_SIZE = 100_000;
const FIELD_OF_VIEW = 75 / 180 * Math.PI;
const u_mvp = mat4_perspective(
mat4_create(),
FIELD_OF_VIEW, /* fieldOfView */
gl.canvas.clientWidth / gl.canvas.clientHeight, /* aspect */
0.1, /* zNear */
SKYBOX_SIZE, /* zFar */
);
mat4_mul(
u_mvp,
u_mvp,
mat4_from_zyx_rotation(mat4_create(), cubeRotation, cubeRotation*0.7, cubeRotation*0.3)
);
mat4_mul(
u_mvp,
u_mvp,
mat4_from_scaling(mat4_create(), [SKYBOX_SIZE*0.5, SKYBOX_SIZE*0.5, SKYBOX_SIZE*0.5])
);
/* draw */
{
gl.useProgram(programInfo.program);
gl.clearColor(0.0, 0.0, 0.0, 1.0);
gl.clearDepth(1.0);
gl.enable(gl.DEPTH_TEST);
gl.depthFunc(gl.LEQUAL);
/* upload/bind atlas */
{
gl.activeTexture(gl.TEXTURE0);
gl.bindTexture(gl.TEXTURE_2D, texture_starfield);
gl.uniform1i(programInfo.u_texture, 0);
}
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
{
gl.bindBuffer(gl.ARRAY_BUFFER, buffers.pos);
gl.vertexAttribPointer(
programInfo.a_vpos,
3, /* numComponents, */
gl.FLOAT, /* type, */
false, /* normalize, */
0, /* stride, */
0 /* offset */
);
gl.enableVertexAttribArray(programInfo.a_vpos);
}
{
gl.bindBuffer(gl.ARRAY_BUFFER, buffers.col);
gl.vertexAttribPointer(
programInfo.a_uv,
2, /* numComponents, */
gl.FLOAT, /* type, */
false, /* normalize, */
0, /* stride, */
0, /* offset */
);
gl.enableVertexAttribArray(programInfo.a_uv);
}
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, buffers.idx);
gl.uniformMatrix4fv(
programInfo.u_mvp,
false,
u_mvp
);
gl.drawElements(
gl.TRIANGLES,
36, /* vertexCount */
gl.UNSIGNED_SHORT, /* type */
0 /* offset */
);
}
})
}
</script>