350行路径追踪渲染器online demo


function CreateFPSCounter() {
    var mFrame;
    var mTo;
    var mFPS;
    var mLastTime;
    var mDeltaTime;
    var iReset = function (time) {
        time = time || 0;
        mFrame = 0;
        mTo = time;
        mFPS = 60.0;
        mLastTime = time;
        mDeltaTime = 0;
    }
    var iCount = function (time) {
        mFrame++;
        mDeltaTime = time - mLastTime;
        mLastTime = time;
        if ((time - mTo) > 500.0) {
            mFPS = 1000.0 * mFrame / (time - mTo);
            mFrame = 0;
            mTo = time;
            return true;
        }
        return false;
    }
    var iGetFPS = function () {
        return mFPS;
    }
    var iGetDeltaTime = function () {
        return mDeltaTime;
    }
    return { Reset: iReset, Count: iCount, GetFPS: iGetFPS, GetDeltaTime: iGetDeltaTime };
}
function RequestFullScreen(ele) {
    if (ele == null) ele = document.documentElement;
    if (ele.requestFullscreen) ele.requestFullscreen();
    else if (ele.msRequestFullscreen) ele.msRequestFullscreen();
    else if (ele.mozRequestFullScreen) ele.mozRequestFullScreen();
    else if (ele.webkitRequestFullscreen) ele.webkitRequestFullscreen(Element.ALLOW_KEYBOARD_INPUT);
}
function Init() {
    if (window.init_flag === undefined) {
        console.log("init_flag");
        var iMouse = window.iMouse = { x: 0, y: 0, z: 0, w: 0 };
        var cv = document.getElementById("displayPort");
        var fpsConter = CreateFPSCounter();
        var context = cv.getContext('2d');
        var W = cv.clientWidth; H = cv.clientHeight;
        var imageData = context.getImageData(0, 0, W, H);
        var pixels = imageData.data;
        for (var i = 0; i < W * H; ++i)
            pixels[4 * i + 3] = 255;
        function MainLoop(deltaTime) {
            var tracer = window.rayTracer;
            if (tracer == null) return;
            if (iMouse.z > 0.) tracer.ResetFrames();
            var frames = tracer.CountFrames();
            var i = 0, color;
            for (var y = 0; y < H; ++y) {
                for (var x = 0; x < W; ++x, ++i) {
                    color = tracer.Render(x, y, W, H);
                    pixels[i++] = (color.r * 255) | 0;
                    pixels[i++] = (color.g * 255) | 0;
                    pixels[i++] = (color.b * 255) | 0;
                }
            }
            context.putImageData(imageData, 0, 0);
            // console.log(deltaTime, fpsConter.GetFPS())
        }
        function elementPos(element) {
            var x = 0, y = 0;
            while (element.offsetParent) {
                x += element.offsetLeft;
                y += element.offsetTop;
                element = element.offsetParent;
            }
            return { x: x, y: y };
        }
        function getMouseCoords(ev, canvasElement) {
            var pos = elementPos(canvasElement);
            var mcx = (ev.pageX - pos.x) * canvasElement.width / canvasElement.offsetWidth;
            var mcy = (ev.pageY - pos.y) * canvasElement.height / canvasElement.offsetHeight;
            return { x: mcx, y: mcy };
        }
        cv.onmousemove = function (ev) {
            var mouse = getMouseCoords(ev, cv);
            iMouse.x = mouse.x;
            iMouse.y = mouse.y;
        }
        cv.onmousedown = function (ev) {
            if (ev.button === 0) iMouse.z = 1;
            else if (ev.button === 2) { 
                iMouse.w = 1;
                RequestFullScreen(cv);
            }
        }
        document.onmouseup = function (ev) {
            if (ev.button === 0) iMouse.z = 0;
            else if (ev.button === 2) iMouse.w = 0;
        }
        ; (function (loopFunc) {
            var fisrt = true;
            function L(timestamp) {
                if (fisrt) {
                    fisrt = false, fpsConter.Reset(timestamp)
                } else {
                    fpsConter.Count(timestamp);
                }
                loopFunc(fpsConter.GetDeltaTime());
                requestAnimationFrame(L)
            };
            requestAnimationFrame(L);
        })(MainLoop);
        window.init_flag = true;
    }
}
function CreateTracer() {
    try {
        (new Function(document.getElementById("codeEditor").value))();
        window.rayTracer = new window.pt();
        window.iMouse.x = window.iMouse.y = 0;
        var cv = document.getElementById("displayPort");
        var W = cv.clientWidth; H = cv.clientHeight;
        window.rayTracer.CreateBackBuffer(W, H);
    } catch(e) {
        alert(e)
    }
}
Init();
CreateTracer();


window.pt = (function () {
    // 3维向量
    function Vec3(x, y, z) {
        x = x === undefined ? 0 : x;
        this.x = x;
        this.y = y === undefined ? x : y;
        this.z = z === undefined ? x : z;
    } Vec3.prototype = {
        Set: function (x, y, z) { this.x = x, this.y = y, this.z = z; return this; },
        Copy: function (other) { this.x = other.x, this.y = other.y, this.z = other.z; return this; },
        Add: function (other) { return new Vec3(this.x + other.x, this.y + other.y, this.z + other.z); },
        AddSelf: function (other) { this.x += other.x, this.y += other.y, this.z += other.z; return this; },
        Sub: function (other) { return new Vec3(this.x - other.x, this.y - other.y, this.z - other.z); },
        SubSelf: function (other) { this.x -= other.x, this.y -= other.y, this.z -= other.z; return this; },
        Scale: function (factor) { return new Vec3(this.x * factor, this.y * factor, this.z * factor); },
        ScaleSelf: function (factor) { this.x *= factor, this.y *= factor, this.z *= factor; return this; },
        Length: function () { return Math.sqrt(this.x * this.x + this.y * this.y + this.z * this.z); },
        Normalize: function () { return this.Scale(1. / this.Length()); },
        NormalizeSelf: function () { var l = 1. / Math.sqrt(this.x * this.x + this.y * this.y + this.z * this.z); this.x *= l; this.y *= l; this.z *= l; return this; },
        Dot: function (other) { return this.x * other.x + this.y * other.y + this.z * other.z; },
        Cross: function (other) { return new Vec3(this.y * other.z - this.z * other.y, this.z * other.x - this.x * other.z, this.x * other.y - this.y * other.x); }
    }
    var eye = new Vec3(0, 0, -2.41);
    var up = new Vec3(0, 1, 0);
    var zero = new Vec3(0, 0, 0);
    var one = new Vec3(1, 1, 1);
    var sqrt2 = Math.sqrt(2);
    // 颜色
    function Color(r, g, b) { this.r = r; this.g = g; this.b = b; }
    Color.prototype = {
        Set: function (r, g, b) { this.r = r; this.g = g; this.b = b; return this; },
        Copy: function (other) { this.r = other.r, this.g = other.g, this.b = other.b; return this; },
        Scale: function (factor) { return new Color(this.r * factor, this.g * factor, this.b * factor); },
        ScaleSelf: function (factor) { this.r *= factor, this.g *= factor, this.b *= factor; return this; },
        Multiply: function (other) { return new Color(this.r * other.r, this.g * other.g, this.b * other.b); },
        MultiplySelf: function (other) { this.r *= other.r, this.g *= other.g, this.b *= other.b; return this; },
        Lerp: function (other, t) { return new Color((1 - t) * this.r + t * other.r, (1 - t) * this.g + t * other.g, (1 - t) * this.b + t * other.b); },
        Gamma: function (s) { var inv = 1/s; return new Color(Math.pow(this.r, inv), Math.pow(this.g, inv), Math.pow(this.b, inv)); },
        GammaSelf: function (s) { var inv = 1/s; return this.Set(Math.pow(this.r, inv), Math.pow(this.g, inv), Math.pow(this.b, inv)); return this; }
    }
    function MakeColor255(r, g, b) { return new Color(r / 255, g / 255, b / 255); }
    var colorWhite = new Color(1, 1, 1);
    var colorBlack = new Color(0, 0, 0);
    var colorRed = new Color(1, 0, 0);
    var colorGreen = new Color(0, 1, 0);
    var colorBlue = new Color(0, 0, 1);
    var colorSky = new Color(0.5, 0.7, 1.0);
    // 光线
    function Ray(o, d, t) {
        this.origin = o;
        this.direction = d;
        this.t = t || 1;
    } Ray.prototype = {
        GetOrigin: function () { return this.origin; },
        GetDirection: function () { return this.direction; },
        GetT: function () { return this.t; },
        GetPoint: function (t) { return this.origin.Add(this.direction.Scale(typeof t === 'number' ? t : this.t)); },
    }
    function Material(type, parameters) {
        this.type = type;
        this.parameters = parameters == null ? {} : parameters;
    }
    // 球体
    function Sphere(center, radius, material) {
        this.center = center;
        this.radius = radius;
        this.material = material;
    } Sphere.prototype = {
        Intersection(ray) {
            var oc = ray.GetOrigin().Sub(this.center);
            var b = oc.Dot(ray.GetDirection());
            var c = oc.Dot(oc) - this.radius * this.radius;
            var h = b * b - c;
            if (h < 0) return -1;
            return -b - Math.sqrt(h);
        },
        HitNormal(hit) {
            return hit.Sub(this.center).ScaleSelf(1. / this.radius);
        }
    }
    // 相机
    function Camera(eye, target, up) {
        this.eye = new Vec3().Copy(eye);
        this.target = new Vec3().Copy(target);
        this.up = new Vec3().Copy(up);
        this.CalcUVW(eye);
        this.an = 0;
        this.ro = new Vec3().Copy(this.eye);
    } Camera.prototype = {
        CalcUVW(eye) {
            this.w = this.target.Sub(eye).NormalizeSelf();
            this.u = this.w.Cross(this.up).NormalizeSelf();
            this.v = this.u.Cross(this.w);
        },
        GetRay(u, v, width, height) {
            if (iMouse.z > 0.) {
                var an = 2 * Math.PI * (iMouse.x / width);
                this.ro = new Vec3().Set(this.eye.z * Math.sin(an), 0.0, this.eye.z * Math.cos(an));
                this.CalcUVW(this.ro);
                this.an = an;
            }
            var ro = this.ro;
            var rd = this.target.Sub(this.eye).AddSelf(new Vec3(u * sqrt2, v * sqrt2, 0.)).NormalizeSelf();
            var x = rd.x, y = rd.y, z = rd.z;
            rd.x = x * this.u.x + y * this.v.x + z * this.w.x;
            rd.y = x * this.u.y + y * this.v.y + z * this.w.y;
            rd.z = x * this.u.z + y * this.v.z + z * this.w.z;
            return new Ray(ro, rd, 0);
        }
    }
    // 后缓冲区
    function BackBuffer(width, height, frames) {
        this.width = width;
        this.height = height;
        this.data = new Array(width * height * 4);
    } BackBuffer.prototype = {
        Clear: function (r, g, b) {
            r = r === undefined ? 0 : r;
            g = g === undefined ? r : g;
            b = b === undefined ? r : b;
            var size = this.width * this.height;
            for (var i = 0; i < size; ++i) {
                this.data[4 * i + 0] = r;
                this.data[4 * i + 1] = g;
                this.data[4 * i + 2] = b;
                this.data[4 * i + 3] = 1;
            }
        },
        Read: function (x, y) {
            var offset = (y * this.width + x) * 4;
            var r = this.data[offset + 0];
            var g = this.data[offset + 1];
            var b = this.data[offset + 2];
            return [r, g, b];
        },
        Write: function (x, y, r, g, b) {
            var offset = (y * this.width + x) * 4;
            this.data[offset + 0] = r;
            this.data[offset + 1] = g;
            this.data[offset + 2] = b;
        }
    }
    // 追踪器
    function Tracer() {
        this.camera = new Camera(eye, zero, up);
        this.spheres = new Array(
            new Sphere(new Vec3(-0.5, 0.0, 0.), 1.0, new Material(1, { refractRate: 1.5, color: MakeColor255(196, 32, 128) })),
            new Sphere(new Vec3(0.825, -0.5, -0.5), 0.5, new Material(2, { color: new Color(0.1, 1., 0.125) })),
            new Sphere(new Vec3(-0.75, -0.65, -1.), 0.2, new Material(2, { fuzz: 0.3, color: colorBlue })),
            new Sphere(new Vec3(0.25, 0.15, -1.), 0.25, new Material(3, { refractRate: 1.2, glass : true, fuzz: 0.3, color: colorWhite })),
            new Sphere(new Vec3(-1.05, -0.25, -1.), 0.25, new Material(3, { refractRate: 1.2, fuzz: 0.3, color: colorWhite })),
            new Sphere(new Vec3(0.0, -10000.85, -1.0), 10000.0, new Material(1, null))
        );
        this.frames = 0;
    } Tracer.prototype = {
        RandomPointInUnitSphere: function () {
            return new Vec3(
                Math.random() * 2. - 1.,
                Math.random() * 2. - 1.,
                Math.random() * 2. - 1.
            );
        },
        // 基向量
        Frisvad: function (n, f, r) {
            if (n.z < -0.999999) {
                f.Set(0., -1, 0);
                r.Set(-1, 0, 0);
            } else {
                var a = 1. / (1. + n.z);
                var b = -n.x * n.y * a;
                f.Set(1. - n.x * n.x * a, b, -n.x);
                r.Set(b, 1. - n.y * n.y * a, -n.y);
            }
        },
        // cos权重随机半球采样
        CosWeightedRandomHemisphereDirection(normal) {
            var x = Math.random(), y = Math.random();
            var u = new Vec3(), v = new Vec3(), w = normal;
            this.Frisvad(w, u, v);
            var ra = Math.sqrt(y);
            var rx = ra * Math.cos(2 * Math.PI * x);
            var ry = ra * Math.sin(2 * Math.PI * x);
            var rz = Math.sqrt(1.0 - y);
            u.x = rx * u.x + ry * v.x + rz * w.x;
            u.y = rx * u.y + ry * v.y + rz * w.y;
            u.z = rx * u.z + ry * v.z + rz * w.z;
            return u.NormalizeSelf();
        },
        Scatered: function (color, ray, sphere) {
            var material = sphere.material;
            var hit = ray.GetPoint();
            if (material.type === 1) {
                return this.Diffused(color, hit, sphere.HitNormal(hit), ray.GetDirection())
            } else if (material.type === 2) {
                return this.Reflected(color, hit, sphere.HitNormal(hit), ray.GetDirection(), material.parameters.fuzz);
            } else if (material.type === 3) {
                return this.Refracted(color, hit, sphere.HitNormal(hit), ray.GetDirection(), material.parameters.refractRate, material.parameters.glass);
            }
        },
        Diffused: function (color, hit, normal, direction) {
            color.ScaleSelf(0.5);
            var target = hit.Add(normal).AddSelf(this.RandomPointInUnitSphere());
            return new Ray(hit, target.SubSelf(hit).NormalizeSelf());
            //return new Ray(hit, this.CosWeightedRandomHemisphereDirection(normal));
        },
        Reflected: function (color, hit, normal, direction, fuzz) {
            function reflect(direction, normal) {
                var l = -2 * direction.Dot(normal);
                return normal.Scale(l).AddSelf(direction);
            }
            color.ScaleSelf(0.5);
            var n = this.RandomPointInUnitSphere().ScaleSelf(fuzz || 0);
            var r = reflect(direction, normal);
            return new Ray(hit, r.AddSelf(n).NormalizeSelf());
        },
        Refracted: function (color, hit, normal, direction, refractRate, glass) {
            var glass = glass === undefined ? false : glass;
            var outwardNormal, realRate;
            var cosWi = direction.Dot(normal);
            if (cosWi > 0) {
                outwardNormal = normal.Scale(-1);
                realRate = glass ? 1.0 / refractRate : refractRate;
                //realRate = 1.0 / refractRate;
                //realRate = refractRate;
                cosWi = direction.Dot(outwardNormal);
            } else {
                outwardNormal = normal;
                realRate = glass ? refractRate : 1.0 / refractRate;
                //realRate = refractRate;
                //realRate = 1.0 / refractRate;
            }
            var cos2Wo = 1.0 - realRate * realRate * (1.0 - cosWi * cosWi);
            if (cos2Wo > 0) {
                var y = outwardNormal.Scale(-Math.sqrt(cos2Wo));
                var x = outwardNormal.Scale(-cosWi).AddSelf(direction).ScaleSelf(realRate);
                var refractRay = x.AddSelf(y);
                return new Ray(hit, refractRay);
            } else {
                return this.Reflected(color, hit, normal, direction);
            }
        },
        Trace: function (ray, deep) {
            var color = new Color().Copy(colorWhite);
            if (deep > 5) {
                color.Copy(colorBlack);
                return color;
            }
            var hitSomething = false, min = 999, t, sphere;
            this.spheres.forEach(function (sp) {
                t = sp.Intersection(ray);
                if (t > 0. && t < min) {
                    hitSomething = true;
                    min = t;
                    sphere = sp;
                }
            });
            if (hitSomething) {
                ray.t = min;
                var material = sphere.material;
                if (material.parameters.color) color.Copy(material.parameters.color);
                var newRay = this.Scatered(color, ray, sphere, color);
                color.MultiplySelf(this.Trace(newRay, deep + 1));
            } else {
                var t = 0.5 * (ray.direction.y + 1.0);
                return colorWhite.Lerp(colorSky, t);
            }
            return color;
        },
        Render: function (x, y, width, height) {
            // antialiasing
            var u = (x + Math.random()) / width, v = (y + Math.random()) / height;
            u = (u * 2 - 1.) * (width / height);
            v = 1. - v * 2;
            var ray = this.camera.GetRay(u, v, width, height);
            var color = this.Trace(ray, 0);
            // backbuffer
            var buffer = this.buffer;
            if (buffer) {
                var frames = this.frames;
                var c = buffer.Read(x, y);
                var f = (frames - 1) / frames;
                var r = c[0], g = c[1], b = c[2];
                r = r * f + color.r / frames;
                g = g * f + color.g / frames;
                b = b * f + color.b / frames;
                buffer.Write(x, y, r, g, b);
                color.Set(r, g, b)
            }
            // gamma corrected
            color.GammaSelf(2.2);
            return color;
        },
        CreateBackBuffer: function (width, height) {
            var buffer = new BackBuffer(width, height);
            buffer.Clear();
            this.buffer = buffer;
        },
        CountFrames: function () {
            return ++this.frames;
        },
        ResetFrames: function () {
            this.frames = 0;
            return this.frames;
        },
    }
    return Tracer;
})()

这是一个简单的路径追踪demo

移动视角:左键按下+鼠标移动

全屏查看:右键按下

posted on 2019-12-07 15:21 LSH 阅读(566) 评论(0) 编辑收藏引用

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350行路径追踪渲染器online demo