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<!doctype html>
<html>
<head>
<title>.trixl</title>
<meta charset="utf-8" />
<style>
#stage {
position: absolute;
top: 0;
left: 0;
}
#debug {
position: absolute;
bottom: 0;
right: 0;
}
</style>
</head>
<body>
<canvas id="stage">
sorry. your browser is from the dark ages. please initiate
temporal leap to a minimally brighter future where browsers can
investigate the third dimension.
</canvas>
<span id="debug"></span>
<script type="gl/vertex-shader">
attribute vec3 pos;
varying vec3 world_pos;
uniform mat4 transform;
void main() {
world_pos = pos;
gl_Position = vec4(transform * vec4(pos, 1));
}
</script>
<script type="gl/fragment-shader">
precision mediump float;
varying vec3 world_pos;
void main() {
gl_FragColor = vec4(world_pos.x, world_pos.y, world_pos.z, 1);
}
</script>
<script>
var createShader = function(src, type) {
var shader = gl.createShader(type);
gl.shaderSource(shader, src);
gl.compileShader(shader);
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
throw gl.getShaderInfoLog(shader);
}
return shader;
}
var createProgram = function(vs, fs) {
var program = gl.createProgram();
var vs = createShader(vs, gl.VERTEX_SHADER);
var fs = createShader(fs, gl.FRAGMENT_SHADER);
gl.attachShader(program, vs);
gl.attachShader(program, fs);
gl.linkProgram(program);
if (!gl.getProgramParameter(program, gl.LINK_STATUS)) {
throw gl.getProgramInfoLog(program);
}
return program;
}
var geometry = {};
geometry.cube = function() {
return [
// front
0, 0, 0,
1, 0, 0,
0, 1, 0,
0, 1, 0,
1, 0, 0,
1, 1, 0,
// back
1, 0, 1,
0, 0, 1,
1, 1, 1,
1, 1, 1,
0, 0, 1,
0, 1, 1,
// left
0, 0, 1,
0, 0, 0,
0, 1, 1,
0, 1, 1,
0, 0, 0,
0, 1, 0,
// right
1, 0, 0,
1, 0, 1,
1, 1, 0,
1, 1, 0,
1, 0, 1,
1, 1, 1,
// top
0, 1, 0,
1, 1, 0,
0, 1, 1,
0, 1, 1,
1, 1, 0,
1, 1, 1,
// bottom
0, 0, 1,
1, 0, 1,
0, 0, 0,
0, 0, 0,
1, 0, 1,
1, 0, 0
];
};
var matrix = {};
matrix.multiply = function(a, dim_a, b, dim_b) {
if (dim_a[1] != dim_b[0]) {
throw new Error("cols a != rows b");
} else {
var c = [];
var s = dim_a[1];
var n = dim_a[0],
m = dim_b[1];
for (var i = 0; i < n; i++) {
for (var j = 0; j < m; j++) {
var sum = 0;
for (var k = 0; k < s; k++) {
sum += a[i * s + k] * b[k * m + j];
}
c[i * m + j] = sum;
}
}
return c;
}
};
matrix.multiplyMany4x4 = function() {
var m = arguments[0];
for(var i = 1; i < arguments.length; i++) {
m = matrix.multiply(m, [4, 4], arguments[i], [4, 4]);
}
return m;
}
matrix.identity = function(dim) {
var m = [];
for(var i = 0; i < dim; i++) {
for(var j = 0; j < dim; j++) {
m[i * dim + j] = i == j ? 1.0 : 0.0;
}
}
return m;
}
matrix.transpose = function(m, dim) {
var t = [];
for(var i = 0; i < dim[0]; i++) {
for(var j = 0; j < dim[1]; j++) {
t[j * dim[0] + i] = m[i * dim[1] + j];
}
}
return t;
}
matrix.translate = function(tx, ty, tz) {
var tx = tx || 0.0, ty = ty || 0.0, tz = tz || 0.0;
return [
1, 0, 0, 0,
0, 1, 0, 0,
0, 0, 1, 0,
tx, ty, tz, 1
];
}
matrix.scale = function(sx, sy, sz) {
var sx = sx || 1.0, sy = sy || 1.0, sz = sz || 1.0;
return [
sx, 0, 0, 0,
0, sy, 0, 0,
0, 0, sz, 0,
0, 0, 0, 1
];
}
matrix.rotateX = function(angle) {
var s = Math.sin(angle);
var c = Math.cos(angle);
return [
1, 0, 0, 0,
0, c, s, 0,
0, -s, c, 0,
0, 0, 0, 1
];
}
matrix.rotateY = function(angle) {
var s = Math.sin(angle);
var c = Math.cos(angle);
return [
c, 0, -s, 0,
0, 1, 0, 0,
s, 0, c, 0,
0, 0, 0, 1
];
}
matrix.rotateZ = function(angle) {
var s = Math.sin(angle);
var c = Math.cos(angle);
return [
c, s, 0, 0,
-s, c, 0, 0,
0, 0, 1, 0,
0, 0, 0, 1
];
}
</script>
<script>
window.trixl = {};
trixl.stage = document.querySelector("#stage");
trixl.window = {w: window.innerWidth, h: window.innerHeight};
trixl.stage.width = trixl.window.w;
trixl.stage.height = trixl.window.h;
trixl.debug = document.querySelector("#debug");
trixl.debug_pos = function(pos) {
var coord_html = function(coord) {
var s = (coord.toString() + " ").slice(0, 6);
if (coord < -1.0 || coord > 1.0) {
return '<span style="color: red">' + s + '</span>';
} else {
return '<span>' + s + '</span>';
}
return s;
}
trixl.debug.innerHTML = coord_html(pos[0]) + ", " + coord_html(pos[1]) + ", " + coord_html(pos[2]);
}
var gl = trixl.gl = trixl.stage.getContext("webgl");
//gl.enable(gl.CULL_FACE);
gl.enable(gl.DEPTH_TEST);
var vertexPosBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, vertexPosBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(geometry.cube()), gl.STATIC_DRAW);
var vs = document.querySelector("script[type='gl/vertex-shader']").textContent;
var fs = document.querySelector("script[type='gl/fragment-shader']").textContent;
var program = createProgram(vs, fs);
gl.useProgram(program);
program.vertexPosAttrib = gl.getAttribLocation(program, 'pos');
gl.enableVertexAttribArray(program.vertexPosAttrib);
gl.vertexAttribPointer(program.vertexPosBuffer, 3, gl.FLOAT, false, 0, 0);
var angle = {x: 0, y: 0, z: 0};
program.transform = gl.getUniformLocation(program, 'transform');
trixl.redraw = function() {
var transform = matrix.multiplyMany4x4(
//matrix.identity(4), matrix.identity(4) /*
matrix.translate(-0.5, -0.5, -0.0),
matrix.scale(0.5, 0.5, 0.5),
matrix.rotateZ(angle.z / 4),
//matrix.rotateY(angle.y / 10),
matrix.rotateX(angle.x / 4),
//matrix.translate(-0.5, -0.5, 0),
//matrix.translate(-0.5, -0.5, -0.5),
matrix.translate(-0.0, -0.0, -0.1)
//matrix.perspective(Math.PI / 3, trixl.window.w / trixl.window.h, 0, 2000) //*/
);
trixl.debug_pos(matrix.multiply([1,1,1,1], [1, 4], transform, [4, 4]));
gl.uniformMatrix4fv(program.transform, false, transform);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
gl.drawArrays(gl.TRIANGLES, 0, 6 * 6);
angle.x += Math.PI / 10;
angle.y += Math.PI / 10;
angle.z += Math.PI / 10;
}
trixl.step = function() {
trixl.redraw();
trixl.step.reqId = requestAnimationFrame(trixl.step);
}
trixl.start = function() {
trixl.step.reqId = requestAnimationFrame(trixl.step);
}
trixl.stop = function() {
cancelAnimationFrame(trixl.step.reqId);
trixl.step.reqId = null;
}
trixl.start();
document.addEventListener("keydown", function(ev) {
if (ev.keyCode == 32) {
if (trixl.step.reqId == null) {
trixl.start();
} else {
trixl.stop();
}
}
});
</script>
</body>
</html>
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