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juggler.html
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juggler.html
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<html>
<head>
<title>Ray-traced Juggler</title>
</head>
<script type="x-shader/x-vertex" id="passThruVS">
attribute vec2 coord;
varying vec2 pos;
void main(void) {
pos = coord;
gl_Position = vec4(coord, 0, 1.0);
gl_PointSize = 1.0;
}
</script>
<script type="x-shader/x-fragment" id="rayTracingFS">
precision highp float;
varying vec2 pos;
const float THRESHOLD = 1e-1;
struct PointLight {
vec3 location;
vec3 color;
float attenuation;
};
struct Object {
// For sphere, quat.xyz is center, quat.w is radius
// For plane, quat.xyz is normal, quat.w is D
vec4 quat;
vec4 color_type; // color_type.w == 0 <- sphere, 1.0 <- plane, 2.0 <- checkered sphere, 3.0 <- checkered plane
// Light coefficients
vec4 material; //.x is ambient, .y is diffuse, .z is specular and w is reflect
};
struct Camera {
vec3 location;
vec3 vx,vy,vz;
};
struct Ray {
vec3 origin, dir;
};
float sqr(float x) { return x*x; }
bool ObjectIntersect(in Object obj, in Ray ray, out float distance) {
if (obj.color_type.w == 1.0 || obj.color_type.w == 3.0) {
float cf = dot(obj.quat.xyz, ray.dir);
if (abs(cf) < THRESHOLD)
return false;
distance = -( dot(obj.quat.xyz, ray.origin ) + obj.quat.w ) / cf;
return distance >= THRESHOLD;
}
if (obj.color_type.w == 0.0 || obj.color_type.w == 2.0) {
// Intersection of ray with sphere is a quadratic equation
// len(ray.origin + distance*ray.direction - sphere.location) = sphere.radius
// which is identical to
// sqr(distance) + 2*distance*dot(ray.direction, OC) + dot(OC,OC) - sqr(radius)
// where OC is ray.origin - sphere.location
vec3 oc = obj.quat.xyz - ray.origin;
float ocd = dot(oc, ray.dir);
float d4 = sqr(obj.quat.w) + sqr(ocd) - dot(oc, oc);
if (d4 < 0.0)
return false;
d4 = sqrt(d4);
distance = ocd - d4;
if (distance <= THRESHOLD)
distance = ocd + d4;
return distance >= THRESHOLD;
}
return false;
}
// Scene defenition
const int numLights = 1;
const int numObjects = 71;
uniform Object objects[numObjects];
uniform PointLight lights[numLights];
uniform Camera camera;
struct SurfaceProps {
// Light coefficients
float ambient, diffuse, specular, reflect;
vec3 point;
vec3 color;
vec3 norm;
};
bool Scene_Intersects(in Ray ray) {
for(int idx = 0; idx < numObjects; ++idx) {
float d;
if (ObjectIntersect(objects[idx], ray, d)) {
return true;
}
}
return false;
}
int Scene_Intersect(in Ray ray, out SurfaceProps props) {
float bestDistance = 1e6;
int bestIdx = -1;
for(int idx = 0; idx < numObjects; ++idx) {
float d;
if (ObjectIntersect(objects[idx], ray, d)) {
if (d < bestDistance) {
bestDistance = d;
bestIdx = idx;
}
}
}
if (bestIdx < 0) return bestIdx;
props.point = ray.origin + bestDistance * ray.dir;
for(int idx = 0; idx < numObjects; ++idx) {
if (idx != bestIdx) continue;
if (objects[idx].color_type.w == 0.0 || objects[idx].color_type.w == 2.0) {
props.norm = normalize(props.point - objects[idx].quat.xyz);
} else {
props.norm = objects[idx].quat.xyz;
}
props.color = objects[idx].color_type.xyz;
props.ambient = objects[idx].material.x;
props.diffuse = objects[idx].material.y;
props.specular = objects[idx].material.z;
props.reflect = objects[idx].material.w;
// Checked sphere pattern
if (objects[idx].color_type.w == 2.0) {
if (mod(floor(atan(props.norm.x/props.norm.z)*4.0),2.0) == 0.0
^^ mod(floor(acos(props.norm.y)*4.0),2.0) == 0.0) {
props.color = vec3(1.0)-props.color;
}
}
// Checked plane pattern
if (objects[idx].color_type.w == 3.0) {
vec3 px = props.norm.z == 0.0 ? vec3(-props.norm.y, props.norm.x, 0.0) : normalize(cross(props.norm, vec3(1.0,0,0)));
vec3 py = cross(px,props.norm);
vec3 origin = -objects[idx].quat.w*objects[idx].quat.xyz;
vec3 offs = props.point - origin;
if (mod(floor(dot(offs,px)),2.0) == 0.0 ^^ mod(floor(dot(offs,py)),2.0) == 0.0) {
props.color = vec3(1.0)-props.color;
}
}
}
return bestIdx;
}
void main(void) {
Ray ray = Ray(camera.location, normalize(camera.vz+.6*pos.x*camera.vx + .6*pos.y*camera.vy));
vec3 color = vec3(0.0);
float weight = 1.0;
SurfaceProps props;
for(int depth = 0; depth < 5; ++depth) {
int objIdx = Scene_Intersect(ray, props);
if (objIdx < 0) {
color += weight * vec3(0.2, 0.2, 0.8);
break;
}
color += weight * props.ambient * props.color;
for(int idx = 0; idx < numLights; ++idx) {
vec3 lightDir = lights[idx].location - props.point;
Ray lightRay = Ray(props.point, normalize(lightDir));
// Check if light is occluded
if (Scene_Intersects(lightRay)) continue;
float attenuation = sqr(lights[idx].attenuation)/dot(lightDir, lightDir);
float angle = abs(dot(lightRay.dir, props.norm));
if (angle < THRESHOLD) continue;
// Add diffuse light component
if (props.diffuse >= THRESHOLD)
color += weight*props.diffuse*angle*attenuation*lights[idx].color*props.color;
// Add specular light component using Blinn–Phong reflection mode
if (props.specular >= THRESHOLD) {
vec3 halfway = normalize(lightRay.dir - ray.dir);
color += weight*props.specular*attenuation*pow(dot(halfway, props.norm), 30.0)*lights[idx].color;
}
}
if (weight * props.reflect < THRESHOLD) {
break;
}
float viewAngle = dot(ray.dir, props.norm);
weight *= props.reflect;
ray.dir -= props.norm * 2.0 * viewAngle;
ray.origin = props.point;
}
gl_FragColor = vec4(color, 1.0);
}
</script>
<script type="text/javascript">
function rotateX(angle) {
const cos = Math.cos(angle);
const sin = Math.sin(angle);
return [
1, 0, 0,
0, cos, -sin,
0, sin, cos,
];
}
function rotateY(angle) {
const cos = Math.cos(angle);
const sin = Math.sin(angle);
return [
cos, 0, sin,
0, 1, 0,
-sin, 0, cos,
];
}
function rotateZ(angle) {
const cos = Math.cos(angle);
const sin = Math.sin(angle);
return [
cos, -sin, 0,
sin, cos, 0,
0, 0, 1,
];
}
function mulMatVec(mat, vec) {
return [
vec[0]*mat[0] + vec[1]*mat[1] + vec[2]*mat[2],
vec[0]*mat[3] + vec[1]*mat[4] + vec[2]*mat[5],
vec[0]*mat[6] + vec[1]*mat[7] + vec[2]*mat[8],
];
}
function mulMatMat(mata, matb) {
const c1 = mulMatVec(mata, [matb[0], matb[3], matb[6]])
const c2 = mulMatVec(mata, [matb[1], matb[4], matb[7]])
const c3 = mulMatVec(mata, [matb[2], matb[5], matb[8]])
return [
c1[0], c2[0], c3[0],
c1[1], c2[1], c3[1],
c1[2], c2[2], c3[2],
];
}
class GLContext {
constructor(canvas) {
if (canvas == null)
throw 'Can not find canvas';
const ctx = canvas.getContext('webgl');
if (ctx == null)
throw 'Can not get WebGL context...';
ctx.viewport(0, 0, canvas.clientWidth, canvas.clientHeight);
ctx.clearColor(0, 0, 0, 1.0);
ctx.clear(ctx.COLOR_BUFFER_BIT);
this._ctx = ctx;
this.PRIMITIVES = {
POINTS: ctx.POINTS,
LINE_STRIP: ctx.LINE_STRIP,
LINES: ctx.LINES,
TRIANGLE_STRIP: ctx.TRIANGLE_STRIP,
TRIANGLES: ctx.TRIANGLES,
};
this.VERTEX_SHADER = ctx.VERTEX_SHADER;
this.FRAGMENT_SHADER = ctx.FRAGMENT_SHADER;
}
getGLContext() {
if (!this._ctx) throw 'Missing context';
return this._ctx;
}
compileShader(type, source) {
const glCtx = this.getGLContext();
var rc = glCtx.createShader(type);
glCtx.shaderSource(rc, source);
glCtx.compileShader(rc);
if (!glCtx.getShaderParameter(rc, glCtx.COMPILE_STATUS)) {
throw glCtx.getShaderInfoLog(rc) + ' in ' + source;
}
return rc;
}
getElementById(id) {
const element = document.getElementById(id);
if (element == null) {
throw 'Can not find shader by element id ' + id;
}
return element;
}
compileShaderById(id) {
const glCtx = this.getGLContext();
const element = this.getElementById(id);
const source = element.innerHTML;
if (element.type === 'x-shader/x-vertex') {
return this.compileShader(glCtx.VERTEX_SHADER, source);
}
if (element.type === 'x-shader/x-fragment') {
return this.compileShader(glCtx.FRAGMENT_SHADER, source);
}
throw 'Unknown shader type ' + element.type;
}
linkProgram(shaders) {
const glCtx = this.getGLContext();
const rc = glCtx.createProgram();
for(var cnt = 0; cnt < shaders.length; cnt++) {
if (!shaders[cnt]) {
throw 'Can not link program with null shaders';
}
glCtx.attachShader(rc, shaders[cnt]);
}
glCtx.linkProgram(rc);
if (!glCtx.getProgramParameter(rc, glCtx.LINK_STATUS)) {
throw glCtx.getProgramInfoLog(rc);
}
return rc;
}
setUniformf(name) {
const glCtx = this.getGLContext();
const prog = glCtx.getParameter(glCtx.CURRENT_PROGRAM);
const idx = glCtx.getUniformLocation(prog, name);
if (arguments.length == 2)
glCtx.uniform1f(idx, arguments[1]);
else if (arguments.length == 3)
glCtx.uniform2f(idx, arguments[1], arguments[2]);
else if (arguments.length == 4)
glCtx.uniform3f(idx, arguments[1], arguments[2], arguments[3]);
else if (arguments.length == 5)
glCtx.uniform4f(idx, arguments[1], arguments[2], arguments[3], arguments[4]);
else
throw "Unsupported number of uniform arguments";
}
setUniformi(name) {
const glCtx = this.getGLContext();
const prog = glCtx.getParameter(glCtx.CURRENT_PROGRAM);
const idx = glCtx.getUniformLocation(prog, name);
if (arguments.length == 2)
glCtx.uniform1i(idx, arguments[1]);
else if (arguments.length == 3)
glCtx.uniform2i(idx, arguments[1], arguments[2]);
else if (arguments.length == 4)
glCtx.uniform3i(idx, arguments[1], arguments[2], arguments[3]);
else if (arguments.length == 5)
glCtx.uniform4i(idx, arguments[1], arguments[2], arguments[3], arguments[4]);
else
throw "Unsupported number of uniform arguments";
}
draw2DArray(type, name, arr) {
const glCtx = this.getGLContext();
const prog = glCtx.getParameter(glCtx.CURRENT_PROGRAM);
const idx = glCtx.getAttribLocation(prog, name);
var buf = glCtx.createBuffer();
glCtx.bindBuffer(glCtx.ARRAY_BUFFER, buf);
glCtx.bufferData(glCtx.ARRAY_BUFFER, new Float32Array(arr), glCtx.STATIC_DRAW);
glCtx.enableVertexAttribArray(idx);
glCtx.vertexAttribPointer(idx, 2, glCtx.FLOAT, false, 0, 0);
glCtx.drawArrays(type, 0, arr.length/2);
glCtx.deleteBuffer(buf);
}
}
class RayTracerScene {
constructor(canvas) {
const ctx = new GLContext(canvas);
const prog = ctx.linkProgram(['passThruVS', 'rayTracingFS'].map(_ => ctx.compileShaderById(_)));
ctx.getGLContext().useProgram(prog);
this.ctx = ctx;
this.aspect = canvas.clientWidth/canvas.clientHeight;
this.objIdx = 0;
//this.setCamera(0, 2.5, -10);
this.setCamera(-4, 5.5, -10);
//plane
this.addObject(0.0, 1.0, 0.0, 0.0,
0.0, 0.0, 1.0, 3.0,
0.1, 0.5, 0.4, 0.4);
// Juggler spheres from http://www.etwright.org/cghist/rt2.js
var spheres = [
{color: [0.9,0.9,0.9], pos: [-0.9,-2.1,5.3], radius: 0.6, type: 2},
{color: [0.9,0.9,0.9], pos: [-1.1,1.9,5.9], radius: 0.6, type: 2},
{color: [0.9,0.9,0.9], pos: [-0.4,-1.2,6.8], radius: 0.6, type: 2},
{color: [1,0.7,0.7], pos: [0.0, 0.0, 6.1], radius: 0.5, type: 1},
{color: [0.2,0.1,0.1], pos: [0.02, 0.0, 6.12], radius: 0.5, type: 1},
{color: [0.1,0.1,1], pos: [-0.4, 0.2, 6.1], radius: 0.15, type: 1},
{color: [0.1,0.1,1], pos: [-0.4, -0.2, 6.1], radius: 0.15, type: 1},
{color: [1,0.7,0.7], pos: [0.0, 0.0, 5.5], radius: 0.2, type: 1},
{color: [1,0.1,0.1], type: 1, pos: [0,0,4.6], radius: 0.8, strips: [
{pos: [0,0,3.3], radius: 0.6, count: 5},
]},
// Left leg
{color: [1,0.7,0.7], type: 1, pos: [0,0.6,2.9], radius: 0.2, strips: [
{pos: [-0.6,0.6,1.6], radius: 0.2, count: 6},
{pos: [-0.4,0.6,0], radius: 0.1, count: 7},
]},
// Right leg
{color: [1,0.7,0.7], type: 1, pos: [0,-0.6,2.9], radius: 0.2, strips: [
{pos: [0.2,-0.6,1.6], radius: 0.2, count: 6},
{pos: [0.4,-0.6,0], radius: 0.1, count: 7},
]},
// Right arm
{color: [1,0.7,0.7], type: 1, pos: [0,-0.7,5.1], radius: 0.2, strips: [
{pos: [-0.2,-1.2,4.2], radius: 0.2, count: 6},
{pos: [-1.1,-2,4.1], radius: 0.1, count: 7},
]},
// Left arm
{color: [1,0.7,0.7], type: 1, pos: [0,0.7,5.1], radius: 0.2, strips: [
{pos: [-0.2,1.2,4.2], radius: 0.2, count: 6},
{pos: [-1.0,1.9,4.8], radius: 0.1, count: 7},
]},
];
spheres.forEach(function(sphere) {
let color = sphere['color'];
var pos = sphere['pos'];
var radius = sphere['radius'];
let matType = sphere['type'];
let mat = matType === 2 ? [ .1, .4, .8, .9] : [ .4, .6, .4, .0];
this.addObject(pos[1], pos[2], pos[0], radius,
color[0], color[1], color[2], 0.0,
mat[0], mat[1], mat[2], mat[3]);
if (!('strips' in sphere)) {
return;
}
sphere['strips'].forEach(function(target) {
let count = target['count'];
let tgt_radius = target['radius'];
let tgt_pos = target['pos'];
let rad_step = (tgt_radius - radius)/count;
let pos_step = [(tgt_pos[0]-pos[0])/count, (tgt_pos[1]-pos[1])/count, (tgt_pos[2]-pos[2])/count];
for(var i = 1; i <= count; ++i) {
let x = pos[1] + i * pos_step[1];
let y = pos[2] + i * pos_step[2];
let z = pos[0] + i * pos_step[0];
let r = radius + i * rad_step;
this.addObject(x, y, z, r,
color[0], color[1], color[2], 0.0,
mat[0], mat[1], mat[2], mat[3]);
}
pos = tgt_pos;
radius = tgt_radius;
}, this);
}, this);
// Lights
ctx.setUniformf('lights[0].location', 50, 150, -100);
ctx.setUniformf('lights[0].color', 1, 1, 1);
ctx.setUniformf('lights[0].attenuation', 190);
}
render(x0 = -1.0, y0 = -1.0, x1 = 1.0, y1 = 1.0) {
this.ctx.draw2DArray(this.ctx.PRIMITIVES.TRIANGLE_STRIP, 'coord', [x0, y0, x1, y0, x0, y1, x1, y1]);
}
setColor(i,r,g,b,w=0.0) {
this.ctx.setUniformf('objects['+i+'].color_type',r,g,b,w);
}
setMaterialProps(i, a=0, d=0, s=0, r=0) {
this.ctx.setUniformf('objects['+i+'].material',a, d, s, r);
}
setCamera(x=0, y=0, z=-1) {
this.ctx.setUniformf('camera.location', x, y, z);
this.ctx.setUniformf('camera.vx', this.aspect, 0, 0);
this.ctx.setUniformf('camera.vy', 0, 1, 0);
this.ctx.setUniformf('camera.vz', 0, 0, 1);
}
setCameraRotation(longitude, latitude, spin) {
var mat = mulMatMat(rotateY(-latitude), rotateX(longitude));
this.ctx.setUniformf('camera.vx', this.aspect*mat[0], this.aspect*mat[3], this.aspect*mat[6]);
this.ctx.setUniformf('camera.vy', mat[1], mat[4], mat[7]);
this.ctx.setUniformf('camera.vz', mat[2], mat[5], mat[8]);
}
addObject(x,y,z,w,r,g,b,t,amb,diff,spec,refl) {
let ctx = this.ctx;
let idx = this.objIdx++;
ctx.setUniformf('objects['+idx+'].quat', x, y, z, w);
this.setColor(idx, r, g, b, t);
this.setMaterialProps(idx, amb, diff, spec, refl);
}
}
var orientationEventReceived = false;
function registerMotionEventListener() {
var compOrientation = {alpha: 0, beta: 0, gamma: 0};
window.addEventListener('devicemotion', function(event) {
orientationEventReceived = true;
compOrientation.alpha += event.rotationRate.alpha*event.interval;
compOrientation.beta += event.rotationRate.beta*event.interval;
compOrientation.gamma += event.rotationRate.gamma*event.interval;
const alpha = Math.PI* compOrientation.alpha / 180;
const beta = Math.PI* compOrientation.beta / 180;
const gamma = Math.PI* compOrientation.gamma / 180;
if (window.orientation == 0.0) {
scene.setCameraRotation(alpha, beta, gamma);
} else if (window.orientation == 90.0) {
scene.setCameraRotation(beta, alpha, alpha);
} else if (window.orientation == -90.0) {
scene.setCameraRotation(-beta, -alpha, alpha);
} else {
scene.setCameraRotation(0, 0, 0);
}
scene.render();
});
}
function requestPermissions() {
if (typeof DeviceMotionEvent === 'undefined') {
return;
}
if (typeof DeviceMotionEvent.requestPermission !== 'function') {
return;
}
DeviceMotionEvent.requestPermission(function(state) {
if (state == 'granted') {
registerMotionEventListener();
}
}).catch(console.error);
}
function displayClickToEnable() {
document.getElementById('click-to-enable').style.visibility='visible';
}
function configureTracer() {
const canvas = document.getElementById('canvas');
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
try {
scene = new RayTracerScene(canvas);
scene.render();
canvas.addEventListener('mousemove', function(event) {
var xn = scene.aspect*(event.x/canvas.clientWidth - .5);
var yn = (event.y/canvas.clientHeight - .5);
scene.setCamera(-4.0 + xn, 5.5 + yn, -10);
//scene.setCameraRotation(xn, yn,0);
scene.render();
});
registerMotionEventListener();
setTimeout(function() {
if (orientationEventReceived) {
return;
}
displayClickToEnable();
}, 1500);
} catch (e) {
alert('Inialization failed: ' + e);
return;
}
}
</script>
</script>
<body onLoad="configureTracer();">
<DIV>
<H1 style="display:inline">RayTracer as fragment shader</H1>
<DIV style="display:inline;visibility:hidden" id="click-to-enable">
<INPUT TYPE="submit" onClick="requestPermissions();" value="Click here to enable orientation events" />
</DIV>
<canvas id="canvas" width="1024px" height="1024px"></canvas>
</body>
</html>