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distancefield3.html
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<!DOCTYPE html>
<html>
<head>
<!--
Ray Marching demo by Kevin Roast
- Lots of code/ideas for this demo come from reading:
http://www.iquilezles.org/www/material/nvscene2008/rwwtt.pdf
http://www.pouet.net/topic.php?which=7931&page=1
http://www.pouet.net/topic.php?which=7920&page=1
http://iquilezles.org/www/articles/distfunctions/distfunctions.htm
https://www.shadertoy.com/
If you want to understand this stuff read through the PDF and pouet.net links above!
-->
<script src="scripts/dat.gui.min.js"></script>
<script src="scripts/stats.min.js"></script>
<script id="vertex" type="x-shader">
attribute vec2 aVertexPosition;
void main()
{
gl_Position = vec4(aVertexPosition, 0.0, 1.0);
}
</script>
<script id="fragment" type="x-shader">
#ifdef GL_ES
precision highp float;
#endif
uniform float time;
uniform vec2 resolution;
uniform vec3 cameraPos;
uniform vec3 cameraLookat;
uniform vec3 lightDir;
uniform vec3 lightColour;
uniform float specular;
uniform float specularHardness;
uniform vec3 diffuse;
uniform bool postEffects;
uniform bool moveCamera;
uniform bool reflections;
#define GAMMA 0.8
#define CONTRAST 1.1
#define SATURATION 1.3
#define BRIGHTNESS 1.3
#define RAY_DEPTH 128
#define MAX_DEPTH 100.0
#define DISTANCE_MIN 0.001
#define PI 3.14159265
const vec2 delta = vec2(DISTANCE_MIN, 0.);
float Hash(in float n)
{
return fract(sin(n)*43758.5453123);
}
float Noise(in vec2 x)
{
vec2 p = floor(x);
vec2 f = fract(x);
f = f*f*(3.0-2.0*f);
float n = p.x + p.y*57.0;
float res = mix(mix( Hash(n+ 0.0), Hash(n+ 1.0),f.x),
mix( Hash(n+ 57.0), Hash(n+ 58.0),f.x),f.y);
return res;
}
float FractalNoise(in vec2 xy)
{
float w = 0.7;
float f = 0.0;
for (int i = 0; i < 3; i++)
{
f += Noise(xy) * w;
w *= 0.5;
xy *= 2.333;
}
return f;
}
// This should return continuous positive values when outside and negative values inside,
// which roughly indicate the distance of the nearest surface.
float Dist(vec3 pos)
{
float height = Noise(pos.xz)*.1753 + Noise(pos.xy*(cos(time*.11)*.13))*.255 + Noise(pos.zx*(0.3+(sin(time*.1)*.1))) + FractalNoise(pos.xz)*.1753;
return dot(pos-vec3(0.,-height,0.), vec3(0.,1.,0.));
}
vec3 GetNormal(vec3 pos)
{
vec3 n;
n.x = Dist( pos + delta.xyy ) - Dist( pos - delta.xyy );
n.y = Dist( pos + delta.yxy ) - Dist( pos - delta.yxy );
n.z = Dist( pos + delta.yyx ) - Dist( pos - delta.yyx );
return normalize(n);
}
// Original method by David Hoskins
vec3 GetClouds(in vec3 sky, in vec3 rd)
{
if (rd.y < 0.01) return sky;
float v = (200.0-cameraPos.y)/rd.y;
rd.xz *= v;
rd.xz += cameraPos.xz;
rd.xz *= .010;
float f = (FractalNoise(rd.xz) - 0.35) * 5.0;
// Uses the ray's y component for horizon fade of fixed colour clouds...
return mix(sky, vec3(0.55, 0.55, 0.85), clamp(f*rd.y - 0.1, 0.0, 1.0));
}
// Original method by David Hoskins
vec3 Sky(in vec3 rd)
{
float sunAmount = max(dot(rd, lightDir), 0.0);
float v = pow(1.0 - max(rd.y,0.0),6.);
vec3 sky = mix(vec3(.1, .2, .3), vec3(.32, .32, .32), v);
sky += lightColour * sunAmount * sunAmount * .25 + lightColour * min(pow(sunAmount, 800.0)*1.5, .3);
sky = GetClouds(sky, rd);
return clamp(sky, 0.0, 1.0);
}
// Fog routine - original by IQ
vec3 Fog(vec3 rgb, vec3 rd, float distance) // camera to point distance
{
const float b = 0.04;
float fogAmount = 1.0 - exp(-distance*b);
vec3 fogColor = Sky(rd);
return mix(rgb, fogColor, fogAmount);
}
// Based on a shading method by Ben Weston.
vec3 Shading(vec3 pos, vec3 rd, vec3 norm, vec3 ro)
{
vec3 light = lightColour * max(0.0, dot(norm, lightDir));
vec3 view = normalize(-rd);
vec3 heading = normalize(view + lightDir);
float spec = pow(max(0.0, dot(heading, norm)), specularHardness);
float fresnel = 0.0;
if (reflections)
{
fresnel = pow(1.0 - dot(view, norm), 8.0);
fresnel = mix(.01, 1.0, min(1.0, fresnel));
}
light = clamp((diffuse * light) + (spec * specular * lightColour), 0.0, 1.0) * (1.0-fresnel);
if (fresnel > 0.01)
{
vec3 refrd = reflect(rd, norm);
light += Sky(refrd) * fresnel;
}
light = Fog(light, rd, length(ro-pos));
return light;
}
// Original method by David Hoskins
vec3 PostEffects(vec3 rgb, vec2 xy)
{
rgb = pow(rgb, vec3(GAMMA));
rgb = mix(vec3(.5), mix(vec3(dot(vec3(.2125, .7154, .0721), rgb*BRIGHTNESS)), rgb*BRIGHTNESS, SATURATION), CONTRAST);
rgb *= .4+0.5*pow(40.0*xy.x*xy.y*(1.0-xy.x)*(1.0-xy.y), 0.2 );
return rgb;
}
// Camera function by TekF
// Compute ray from camera parameters
vec3 GetRay(vec3 dir, vec2 pos)
{
pos = pos - 0.5;
pos.x *= resolution.x/resolution.y;
dir = normalize(dir);
vec3 right = normalize(cross(vec3(0.,1.,0.),dir));
vec3 up = normalize(cross(dir,right));
return dir + right*pos.x + up*pos.y;
}
vec4 March(vec3 ro, vec3 rd)
{
float t = 0.0;
float d = 1.0;
for (int i=0; i<RAY_DEPTH; i++)
{
vec3 p = ro + rd * t;
d = Dist(p);
if (abs(d) < DISTANCE_MIN)
{
return vec4(p, 1.0);
}
t += d;
if (t >= MAX_DEPTH) break;
}
return vec4(0.0);
}
void main()
{
vec3 off = vec3(0.0);
if (moveCamera) off.z -= time*5.0;
vec2 p = gl_FragCoord.xy / resolution.xy;
vec3 ro = cameraPos + off;
vec3 rd = normalize(GetRay((cameraLookat-off)-cameraPos+off, p));
vec4 res = March(ro, rd);
if (res.a == 1.0) res.rgb = clamp(Shading(res.rgb, rd, GetNormal(res.rgb), ro).rgb, 0.0, 1.0);
else res.rgb = Sky(rd);
if (postEffects) res.rgb = PostEffects(res.rgb, p);
gl_FragColor = vec4(res.rgb, 1.0);
}
</script>
<script type="text/javascript">
var requestAnimationFrame = window.requestAnimationFrame || window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame || window.msRequestAnimationFrame ||
function(c) {window.setTimeout(c, 15)};
var config = {
camera: {
x: 0.0, y: 5.0, z: 0.0
},
lookat: {
x: -125.0, y: -20.0, z: -95.0
},
lightDir: {
x: -1.0, y: 0.25, z: -1.0
},
lightColour: {
r: 0.6, g: 0.8, b: 1.4
},
surface: {
specular: 64.0,
specularHardness: 512.0,
diffuse: 0.2
},
global: {
reflections: true,
postEffects: true,
moveCamera: true
}
};
function init()
{
var pause = false;
document.addEventListener('keydown', function(e) {
switch (e.keyCode)
{
case 27: // ESC
pause = !pause;
break;
}
}, false);
// add GUI controls
var mobile = (navigator.userAgent.indexOf("Android") !== -1);
var gui = new dat.GUI();
var panel = gui.addFolder('Camera Position');
panel.add(config.camera, "x").min(-256).max(256).step(0.1);
panel.add(config.camera, "y").min(-100).max(100).step(0.1);
panel.add(config.camera, "z").min(-100).max(100).step(0.1);
//panel.open();
panel = gui.addFolder('Camera LookAt');
panel.add(config.lookat, "x").min(-256).max(256).step(0.1);
panel.add(config.lookat, "y").min(-100).max(100).step(0.1);
panel.add(config.lookat, "z").min(-100).max(100).step(0.1);
if (!mobile) panel.open();
panel = gui.addFolder('Light Direction');
panel.add(config.lightDir, "x").min(-10).max(10).step(0.1);
panel.add(config.lightDir, "y").min(-10).max(10).step(0.1);
panel.add(config.lightDir, "z").min(-10).max(10).step(0.1);
if (!mobile) panel.open();
panel = gui.addFolder('Light Colour');
panel.add(config.lightColour, "r").min(0).max(3).step(0.1);
panel.add(config.lightColour, "g").min(0).max(3).step(0.1);
panel.add(config.lightColour, "b").min(0).max(3).step(0.1);
if (!mobile) panel.open();
panel = gui.addFolder('Surface');
panel.add(config.surface, "specular").min(0).max(64);
panel.add(config.surface, "specularHardness").min(16).max(1024).step(16);
panel.add(config.surface, "diffuse").min(0).max(1).step(0.05);
//panel.open();
panel = gui.addFolder('Global');
panel.add(config.global, "reflections").name("Reflections");
panel.add(config.global, "postEffects").name("Post Effects");
panel.add(config.global, "moveCamera").name("Move Camera");
if (!mobile) panel.open();
var stats = new Stats();
document.body.appendChild(stats.domElement);
// create webgl context on the canvas element
var canvas = document.getElementById("canvas"),
aspect = canvas.width / canvas.height;
try
{
var gl = canvas.getContext("experimental-webgl");
}
catch (e)
{
document.write("Whoops! No useful WEB-GL impl available. Shame on you and your browser vendor.<br>" + e.message);
return;
}
gl.viewport(0, 0, canvas.width, canvas.height);
gl.clearColor(0, 0, 0, 1);
gl.clear(gl.COLOR_BUFFER_BIT);
// get the vertex and fragment shader source
var v = document.getElementById("vertex").firstChild.nodeValue;
var f = document.getElementById("fragment").firstChild.nodeValue;
// compile and link the shaders
var vs = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(vs, v);
gl.compileShader(vs);
var fs = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(fs, f);
gl.compileShader(fs);
var program = gl.createProgram();
gl.attachShader(program, vs);
gl.attachShader(program, fs);
gl.linkProgram(program);
// debug shader compile status
var error = false;
if (!gl.getShaderParameter(vs, gl.COMPILE_STATUS))
{
error = true;
console.log(gl.getShaderInfoLog(vs));
}
if (!gl.getShaderParameter(fs, gl.COMPILE_STATUS))
{
error = true;
console.log(gl.getShaderInfoLog(fs));
}
if (!gl.getProgramParameter(program, gl.LINK_STATUS))
{
error = true;
console.log(gl.getProgramInfoLog(program));
}
if (error) return;
var firstTime = Date.now();
(f = function() {
if (!pause)
{
stats.begin();
// create vertices to fill the canvas with a single quad
var vertices = new Float32Array(
[
-1, 1*aspect, 1, 1*aspect, 1, -1*aspect,
-1, 1*aspect, 1, -1*aspect, -1, -1*aspect
]);
var vbuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, vbuffer);
gl.bufferData(gl.ARRAY_BUFFER, vertices, gl.STATIC_DRAW);
var triCount = 2,
numItems = vertices.length / triCount;
gl.useProgram(program);
var time = (Date.now() - firstTime) / 1000.0;
program.time = gl.getUniformLocation(program, "time");
gl.uniform1f(program.time, time);
program.resolution = gl.getUniformLocation(program, "resolution");
gl.uniform2f(program.resolution, canvas.width, canvas.height);
program.cameraPos = gl.getUniformLocation(program, "cameraPos");
gl.uniform3f(program.cameraPos, config.camera.x, config.camera.y, config.camera.z);
program.cameraLookat = gl.getUniformLocation(program, "cameraLookat");
gl.uniform3f(program.cameraLookat, config.lookat.x, config.lookat.y, config.lookat.z);
program.lightDir = gl.getUniformLocation(program, "lightDir");
// pre normalise light dir
var x = config.lightDir.x, y = config.lightDir.y, z = config.lightDir.z;
var len = x*x + y*y + z*z;
len = 1.0 / Math.sqrt(len);
gl.uniform3f(program.lightDir, config.lightDir.x*len, config.lightDir.y*len, config.lightDir.z*len);
program.lightColour = gl.getUniformLocation(program, "lightColour");
gl.uniform3f(program.lightColour, config.lightColour.r, config.lightColour.g, config.lightColour.b);
program.specular = gl.getUniformLocation(program, "specular");
gl.uniform1f(program.specular, config.surface.specular);
program.specularHardness = gl.getUniformLocation(program, "specularHardness");
gl.uniform1f(program.specularHardness, config.surface.specularHardness);
program.diffuse = gl.getUniformLocation(program, "diffuse");
gl.uniform3f(program.diffuse, config.surface.diffuse,config.surface.diffuse,config.surface.diffuse);
program.moveCamera = gl.getUniformLocation(program, "moveCamera");
gl.uniform1f(program.moveCamera, config.global.moveCamera);
program.postEffects = gl.getUniformLocation(program, "postEffects");
gl.uniform1f(program.postEffects, config.global.postEffects);
program.reflections = gl.getUniformLocation(program, "reflections");
gl.uniform1f(program.reflections, config.global.reflections);
program.aVertexPosition = gl.getAttribLocation(program, "aVertexPosition");
gl.enableVertexAttribArray(program.aVertexPosition);
gl.vertexAttribPointer(program.aVertexPosition, triCount, gl.FLOAT, false, 0, 0);
gl.drawArrays(gl.TRIANGLES, 0, numItems);
stats.end();
}
requestAnimationFrame(f);
})();
}
</script>
</head>
<body onload="init()">
<canvas id="canvas" width="768" height="512">
</body>
</html>