var BABYLON = BABYLON || {};

(function () {
    BABYLON.Mesh = function (name, vertexDeclaration, scene) {
        this.name = name;
        this.id = name;
        this._scene = scene;
        this._vertexDeclaration = vertexDeclaration;

        this._vertexStrideSize = 0;
        for (var index = 0; index < vertexDeclaration.length; index++) {
            this._vertexStrideSize += vertexDeclaration[index];
        }

        this._vertexStrideSize *= 4; // sizeof(float)

        this._totalVertices = 0;
        this._worldMatrix = BABYLON.Matrix.Identity();

        scene.meshes.push(this);

        this.position = new BABYLON.Vector3(0, 0, 0);
        this.rotation = new BABYLON.Vector3(0, 0, 0);
        this.scaling = new BABYLON.Vector3(1, 1, 1);

        this._vertices = [];
        this._indices = [];
        this.subMeshes = [];

        // Animations
        this.animations = [];

        // Cache
        this._positions = null;
        this._cache = {
            position: null,
            scaling: null,
            rotation: null
        };

        this._childrenFlag = false;
    };

    // Constants
    BABYLON.Mesh.BILLBOARDMODE_NONE = 0;
    BABYLON.Mesh.BILLBOARDMODE_X = 1;
    BABYLON.Mesh.BILLBOARDMODE_Y = 2;
    BABYLON.Mesh.BILLBOARDMODE_Z = 4;
    BABYLON.Mesh.BILLBOARDMODE_ALL = 7;

    // Members    
    BABYLON.Mesh.prototype.material = null;
    BABYLON.Mesh.prototype.parent = null;
    BABYLON.Mesh.prototype._isReady = true;
    BABYLON.Mesh.prototype._isEnabled = true;
    BABYLON.Mesh.prototype.isVisible = true;
    BABYLON.Mesh.prototype.isPickable = true;
    BABYLON.Mesh.prototype.visibility = 1.0;
    BABYLON.Mesh.prototype.billboardMode = BABYLON.Mesh.BILLBOARDMODE_NONE;
    BABYLON.Mesh.prototype.checkCollisions = false;

    BABYLON.Mesh.prototype.onDispose = false;

    // Properties

    BABYLON.Mesh.prototype.getBoundingInfo = function () {
        return this._boundingInfo;
    };

    BABYLON.Mesh.prototype.getScene = function () {
        return this._scene;
    };

    BABYLON.Mesh.prototype.getWorldMatrix = function () {
        return this._worldMatrix;
    };

    BABYLON.Mesh.prototype.getTotalVertices = function () {
        return this._totalVertices;
    };

    BABYLON.Mesh.prototype.getVertices = function () {
        return this._vertices;
    };

    BABYLON.Mesh.prototype.getTotalIndices = function () {
        return this._indices.length;
    };

    BABYLON.Mesh.prototype.getIndices = function () {
        return this._indices;
    };

    BABYLON.Mesh.prototype.getVertexStrideSize = function () {
        return this._vertexStrideSize;
    };

    BABYLON.Mesh.prototype.getFloatVertexStrideSize = function () {
        return this._vertexStrideSize / 4;
    };

    BABYLON.Mesh.prototype._needToSynchonizeChildren = function () {
        return this._childrenFlag;
    };

    BABYLON.Mesh.prototype.isSynchronized = function () {
        if (this.billboardMode !== BABYLON.Mesh.BILLBOARDMODE_NONE)
            return false;

        if (!this._cache.position || !this._cache.rotation || !this._cache.scaling) {
            return false;
        }

        if (!this._cache.position.equals(this.position))
            return false;

        if (!this._cache.rotation.equals(this.rotation))
            return false;

        if (!this._cache.scaling.equals(this.scaling))
            return false;

        if (this.parent)
            return !this.parent._needToSynchonizeChildren();

        return true;
    };

    BABYLON.Mesh.prototype.isReady = function () {
        return this._isReady;
    };

    BABYLON.Mesh.prototype.isEnabled = function () {
        if (!this.isReady() || !this._isEnabled) {
            return false;
        }

        if (this.parent) {
            return this.parent.isEnabled();
        }

        return true;
    };

    BABYLON.Mesh.prototype.setEnabled = function (value) {
        this._isEnabled = value;
    };

    BABYLON.Mesh.prototype.isAnimated = function () {
        return this._animationStarted;
    };

    // Methods
    BABYLON.Mesh.prototype.computeWorldMatrix = function () {
        if (this.isSynchronized()) {
            this._childrenFlag = false;
            return this._worldMatrix;
        }

        this._childrenFlag = true;
        this._cache.position = this.position.clone();
        this._cache.rotation = this.rotation.clone();
        this._cache.scaling = this.scaling.clone();

        var localWorld = BABYLON.Matrix.Scaling(this.scaling.x, this.scaling.y, this.scaling.z).multiply(
            BABYLON.Matrix.RotationYawPitchRoll(this.rotation.y, this.rotation.x, this.rotation.z));

        // Billboarding
        var matTranslation = BABYLON.Matrix.Translation(this.position.x, this.position.y, this.position.z);
        if (this.billboardMode !== BABYLON.Mesh.BILLBOARDMODE_NONE) {
            var localPosition = this.position.clone();
            var zero = this._scene.activeCamera.position.clone();

            if (this.parent) {
                localPosition = localPosition.add(this.parent.position);
                matTranslation = BABYLON.Matrix.Translation(localPosition.x, localPosition.y, localPosition.z);
            }

            if (this.billboardMode & BABYLON.Mesh.BILLBOARDMODE_ALL === BABYLON.Mesh.BILLBOARDMODE_ALL) {
                zero = this._scene.activeCamera.position;
            } else {
                if (this.billboardMode & BABYLON.Mesh.BILLBOARDMODE_X)
                    zero.x = localPosition.x + BABYLON.Engine.epsilon;
                if (this.billboardMode & BABYLON.Mesh.BILLBOARDMODE_Y)
                    zero.y = localPosition.y + BABYLON.Engine.epsilon;
                if (this.billboardMode & BABYLON.Mesh.BILLBOARDMODE_Z)
                    zero.z = localPosition.z + BABYLON.Engine.epsilon;
            }

            var matBillboard = BABYLON.Matrix.LookAtLH(localPosition, zero, BABYLON.Vector3.Up());
            matBillboard.m[12] = matBillboard.m[13] = matBillboard.m[14] = 0;

            matBillboard.invert();

            localWorld = BABYLON.Matrix.RotationY(Math.PI).multiply(localWorld.multiply(matBillboard));
        }

        localWorld = localWorld.multiply(matTranslation);

        // Parent
        if (this.parent && this.billboardMode === BABYLON.Mesh.BILLBOARDMODE_NONE) {
            var parentWorld = this.parent.getWorldMatrix();

            localWorld = localWorld.multiply(parentWorld);
        }

        this._worldMatrix = localWorld;

        // Bounding info
        if (this._boundingInfo) {
            this._scaleFactor = Math.max(this.scaling.x, this.scaling.y);
            this._scaleFactor = Math.max(this._scaleFactor, this.scaling.z);

            if (this.parent)
                this._scaleFactor = this._scaleFactor * this.parent._scaleFactor;

            this._boundingInfo._update(localWorld, this._scaleFactor);

            for (var subIndex = 0; subIndex < this.subMeshes.length; subIndex++) {
                var subMesh = this.subMeshes[subIndex];

                subMesh.updateBoundingInfo(localWorld, this._scaleFactor);
            }
        }

        return localWorld;
    };

    BABYLON.Mesh.prototype._createGlobalSubMesh = function () {
        if (!this._totalVertices || !this._indices) {
            return null;
        }

        this.subMeshes = [];
        return new BABYLON.SubMesh(0, 0, this._totalVertices, 0, this._indices.length, this);
    };


    BABYLON.Mesh.prototype.subdivide = function (count) {
        if (count < 1) {
            return;
        }

        var subdivisionSize = this._indices.length / count;
        var offset = 0;

        this.subMeshes = [];
        for (var index = 0; index < count; index++) {
            BABYLON.SubMesh.CreateFromIndices(0, offset, Math.min(subdivisionSize, this._indices.length - offset), this);

            offset += subdivisionSize;
        }
    };

    BABYLON.Mesh.prototype.setVertices = function (vertices, uvCount, updatable) {
        if (this._vertexBuffer) {
            this._scene.getEngine()._releaseBuffer(this._vertexBuffer);
        }

        this._uvCount = uvCount;

        if (updatable) {
            this._vertexBuffer = this._scene.getEngine().createDynamicVertexBuffer(vertices.length * 4);
            this._scene.getEngine().updateDynamicVertexBuffer(this._vertexBuffer, vertices);
        } else {
            this._vertexBuffer = this._scene.getEngine().createVertexBuffer(vertices);
        }

        this._vertices = vertices;

        this._totalVertices = vertices.length / this.getFloatVertexStrideSize();

        this._boundingInfo = new BABYLON.BoundingInfo(vertices, this.getFloatVertexStrideSize(), 0, vertices.length);

        this._createGlobalSubMesh();
        this._positions = null;
    };

    BABYLON.Mesh.prototype.updateVertices = function (vertices) {
        var engine = this._scene.getEngine();
        engine.updateDynamicVertexBuffer(this._vertexBuffer, vertices);
        this._vertices = vertices;
        this._positions = null;
    };

    BABYLON.Mesh.prototype.setIndices = function (indices) {
        if (this._indexBuffer) {
            this._scene.getEngine()._releaseBuffer(this._indexBuffer);
        }

        this._indexBuffer = this._scene.getEngine().createIndexBuffer(indices);
        this._indices = indices;

        this._createGlobalSubMesh();
    };

    BABYLON.Mesh.prototype.render = function (subMesh) {
        if (!this._vertexBuffer || !this._indexBuffer) {
            return;
        }

        var engine = this._scene.getEngine();

        // World
        var world = this.getWorldMatrix();

        // Material
        var effectiveMaterial = subMesh.getMaterial();

        if (!effectiveMaterial || !effectiveMaterial.isReady(this)) {
            return;
        }

        effectiveMaterial._preBind();
        effectiveMaterial.bind(world, this);

        // Wireframe
        var indexToBind = this._indexBuffer;
        var useTriangles = true;

        if (engine.forceWireframe || effectiveMaterial.wireframe) {
            indexToBind = subMesh.getLinesIndexBuffer(this._indices, engine);
            useTriangles = false;
        }

        // VBOs
        engine.bindBuffers(this._vertexBuffer, indexToBind, this._vertexDeclaration, this._vertexStrideSize, effectiveMaterial.getEffect());

        // Draw order
        engine.draw(useTriangles, useTriangles ? subMesh.indexStart : 0, useTriangles ? subMesh.indexCount : subMesh.linesIndexCount);

        // Unbind
        effectiveMaterial.unbind();
    };

    BABYLON.Mesh.prototype.isDescendantOf = function (ancestor) {
        if (this.parent) {
            if (this.parent === ancestor) {
                return true;
            }

            return this.parent.isDescendantOf(ancestor);
        }
        return false;
    };

    BABYLON.Mesh.prototype.getDescendants = function () {
        var results = [];
        for (var index = 0; index < this._scene.meshes.length; index++) {
            var mesh = this._scene.meshes[index];
            if (mesh.isDescendantOf(this)) {
                results.push(mesh);
            }
        }

        return results;
    };

    BABYLON.Mesh.prototype.getEmittedParticleSystems = function () {
        var results = [];
        for (var index = 0; index < this._scene.particleSystems.length; index++) {
            var particleSystem = this._scene.particleSystems[index];
            if (particleSystem.emitter === this) {
                results.push(particleSystem);
            }
        }

        return results;
    };

    BABYLON.Mesh.prototype.getHierarchyEmittedParticleSystems = function () {
        var results = [];
        var descendants = this.getDescendants();
        descendants.push(this);

        for (var index = 0; index < this._scene.particleSystems.length; index++) {
            var particleSystem = this._scene.particleSystems[index];
            if (descendants.indexOf(particleSystem.emitter) !== -1) {
                results.push(particleSystem);
            }
        }

        return results;
    };

    BABYLON.Mesh.prototype.getChildren = function () {
        var results = [];
        for (var index = 0; index < this._scene.meshes.length; index++) {
            var mesh = this._scene.meshes[index];
            if (mesh.parent == this) {
                results.push(mesh);
            }
        }

        return results;
    };

    BABYLON.Mesh.prototype.isInFrustrum = function (frustumPlanes) {
        return this._boundingInfo.isInFrustrum(frustumPlanes);
    };

    BABYLON.Mesh.prototype.setMaterialByID = function (id) {
        var materials = this._scene.materials;
        for (var index = 0; index < materials.length; index++) {
            if (materials[index].id == id) {
                this.material = materials[index];
                return;
            }
        }

        // Multi
        var multiMaterials = this._scene.multiMaterials;
        for (var index = 0; index < multiMaterials.length; index++) {
            if (multiMaterials[index].id == id) {
                this.material = multiMaterials[index];
                return;
            }
        }
    };

    BABYLON.Mesh.prototype.getAnimatables = function () {
        var results = [];

        if (this.material) {
            results.push(this.material);
        }

        return results;
    };

    // Cache
    BABYLON.Mesh.prototype._generatePointsArray = function () {
        if (this._positions)
            return;

        this._positions = [];

        var stride = this.getFloatVertexStrideSize();

        for (var index = 0; index < this._vertices.length; index += stride) {
            this._positions.push(BABYLON.Vector3.FromArray(this._vertices, index));
        }
    };

    // Collisions
    BABYLON.Mesh.prototype._collideForSubMesh = function (subMesh, transformMatrix, collider) {
        this._generatePointsArray();
        // Transformation
        if (!subMesh._lastColliderWorldVertices || !subMesh._lastColliderTransformMatrix.equals(transformMatrix)) {
            subMesh._lastColliderTransformMatrix = transformMatrix;
            subMesh._lastColliderWorldVertices = [];
            var start = subMesh.verticesStart;
            var end = (subMesh.verticesStart + subMesh.verticesCount);
            for (var i = start; i < end; i++) {
                subMesh._lastColliderWorldVertices.push(BABYLON.Vector3.TransformCoordinates(this._positions[i], transformMatrix));
            }
        }
        // Collide
        collider._collide(subMesh, subMesh._lastColliderWorldVertices, this._indices, subMesh.indexStart, subMesh.indexStart + subMesh.indexCount, subMesh.verticesStart);
    };

    BABYLON.Mesh.prototype._processCollisionsForSubModels = function (collider, transformMatrix) {
        for (var index = 0; index < this.subMeshes.length; index++) {
            var subMesh = this.subMeshes[index];

            // Bounding test
            if (this.subMeshes.length > 1 && !subMesh._checkCollision(collider))
                continue;

            this._collideForSubMesh(subMesh, transformMatrix, collider);
        }
    };

    BABYLON.Mesh.prototype._checkCollision = function (collider) {
        // Bounding box test
        if (!this._boundingInfo._checkCollision(collider))
            return;

        // Transformation matrix
        var transformMatrix = this._worldMatrix.multiply(BABYLON.Matrix.Scaling(1.0 / collider.radius.x, 1.0 / collider.radius.y, 1.0 / collider.radius.z));

        this._processCollisionsForSubModels(collider, transformMatrix);
    };

    BABYLON.Mesh.prototype.intersectsMesh = function (mesh, precise) {
        if (!this._boundingInfo || !mesh._boundingInfo) {
            return false;
        }

        return this._boundingInfo.intersects(mesh._boundingInfo, precise);
    };

    BABYLON.Mesh.prototype.intersectsPoint = function (point) {
        if (!this._boundingInfo) {
            return false;
        }

        return this._boundingInfo.intersectsPoint(point);
    };

    // Picking
    BABYLON.Mesh.prototype.intersects = function (ray) {
        if (!this._boundingInfo || !ray.intersectsSphere(this._boundingInfo.boundingSphere)) {
            return { hit: false, distance: 0 };
        }

        this._generatePointsArray();

        var distance = Number.MAX_VALUE;

        for (var index = 0; index < this.subMeshes.length; index++) {
            var subMesh = this.subMeshes[index];

            // Bounding test
            if (this.subMeshes.length > 1 && !subMesh.canIntersects(ray))
                continue;

            var result = subMesh.intersects(ray, this._positions, this._indices);

            if (result.hit) {
                if (result.distance < distance && result.distance >= 0) {
                    distance = result.distance;
                }
            }
        }

        if (distance >= 0)
            return { hit: true, distance: distance };

        return { hit: false, distance: 0 };
    };

    // Clone
    BABYLON.Mesh.prototype.clone = function (name, newParent) {
        var result = new BABYLON.Mesh(name, this._vertexDeclaration, this._scene);

        BABYLON.Tools.DeepCopy(this, result, ["name", "material"], ["_uvCount", "_vertices", "_indices", "_totalVertices"]);

        // Bounding info
        result._boundingInfo = new BABYLON.BoundingInfo(result._vertices, result.getFloatVertexStrideSize(), 0, result._vertices.length);

        // Material
        result.material = this.material;

        // Buffers
        result._vertexBuffer = this._vertexBuffer;
        this._vertexBuffer.references++;

        result._indexBuffer = this._indexBuffer;
        this._indexBuffer.references++;

        // Parent
        if (newParent) {
            result.parent = newParent;
        }

        // Children
        for (var index = 0; index < this._scene.meshes.length; index++) {
            var mesh = this._scene.meshes[index];

            if (mesh.parent == this) {
                mesh.clone(mesh.name, result);
            }
        }

        // Particles
        for (var index = 0; index < this._scene.particleSystems.length; index++) {
            var system = this._scene.particleSystems[index];

            if (system.emitter == this) {
                system.clone(system.name, result);
            }
        }

        return result;
    };

    // Dispose
    BABYLON.Mesh.prototype.dispose = function (doNotRecurse) {
        if (this._vertexBuffer) {
            //this._scene.getEngine()._releaseBuffer(this._vertexBuffer);
            this._vertexBuffer = null;
        }

        if (this._indexBuffer) {
            this._scene.getEngine()._releaseBuffer(this._indexBuffer);
            this._indexBuffer = null;
        }

        // Remove from scene
        var index = this._scene.meshes.indexOf(this);
        this._scene.meshes.splice(index, 1);

        if (doNotRecurse) {
            return;
        }

        // Particles
        for (var index = 0; index < this._scene.particleSystems.length; index++) {
            if (this._scene.particleSystems[index].emitter == this) {
                this._scene.particleSystems[index].dispose();
                index--;
            }
        }

        // Children
        var objects = this._scene.meshes.slice(0);
        for (var index = 0; index < objects.length; index++) {
            if (objects[index].parent == this) {
                objects[index].dispose();
            }
        }

        // Callback
        if (this.onDispose) {
            this.onDispose();
        }
    };

    // Statics
    BABYLON.Mesh.CreateBox = function (name, size, scene, updatable) {
        var box = new BABYLON.Mesh(name, [3, 3, 2], scene);

        var normals = [
            new BABYLON.Vector3(0, 0, 1),
            new BABYLON.Vector3(0, 0, -1),
            new BABYLON.Vector3(1, 0, 0),
            new BABYLON.Vector3(-1, 0, 0),
            new BABYLON.Vector3(0, 1, 0),
            new BABYLON.Vector3(0, -1, 0)
        ];

        var indices = [];
        var vertices = [];

        // Create each face in turn.
        for (var index = 0; index < normals.length; index++) {
            var normal = normals[index];

            // Get two vectors perpendicular to the face normal and to each other.
            var side1 = new BABYLON.Vector3(normal.y, normal.z, normal.x);
            var side2 = BABYLON.Vector3.Cross(normal, side1);

            // Six indices (two triangles) per face.
            var verticesLength = vertices.length / 8;
            indices.push(verticesLength);
            indices.push(verticesLength + 1);
            indices.push(verticesLength + 2);

            indices.push(verticesLength);
            indices.push(verticesLength + 2);
            indices.push(verticesLength + 3);

            // Four vertices per face.
            var vertex = normal.subtract(side1).subtract(side2).scale(size / 2);
            vertices.push(vertex.x, vertex.y, vertex.z, normal.x, normal.y, normal.z, 1.0, 1.0);

            vertex = normal.subtract(side1).add(side2).scale(size / 2);
            vertices.push(vertex.x, vertex.y, vertex.z, normal.x, normal.y, normal.z, 0.0, 1.0);

            vertex = normal.add(side1).add(side2).scale(size / 2);
            vertices.push(vertex.x, vertex.y, vertex.z, normal.x, normal.y, normal.z, 0.0, 0.0);

            vertex = normal.add(side1).subtract(side2).scale(size / 2);
            vertices.push(vertex.x, vertex.y, vertex.z, normal.x, normal.y, normal.z, 1.0, 0.0);
        }

        box.setVertices(vertices, 1, updatable);
        box.setIndices(indices);

        return box;
    };

    BABYLON.Mesh.CreateSphere = function (name, segments, diameter, scene, updatable) {
        var sphere = new BABYLON.Mesh(name, [3, 3, 2], scene);

        var radius = diameter / 2;

        var totalZRotationSteps = 2 + segments;
        var totalYRotationSteps = 2 * totalZRotationSteps;

        var indices = [];
        var vertices = [];

        for (var zRotationStep = 0; zRotationStep <= totalZRotationSteps; zRotationStep++) {
            var normalizedZ = zRotationStep / totalZRotationSteps;
            var angleZ = (normalizedZ * Math.PI);

            for (var yRotationStep = 0; yRotationStep <= totalYRotationSteps; yRotationStep++) {
                var normalizedY = yRotationStep / totalYRotationSteps;

                var angleY = normalizedY * Math.PI * 2;

                var rotationZ = BABYLON.Matrix.RotationZ(-angleZ);
                var rotationY = BABYLON.Matrix.RotationY(angleY);
                var afterRotZ = BABYLON.Vector3.TransformCoordinates(BABYLON.Vector3.Up(), rotationZ);
                var complete = BABYLON.Vector3.TransformCoordinates(afterRotZ, rotationY);

                var vertex = complete.scale(radius);
                var normal = BABYLON.Vector3.Normalize(vertex);

                vertices.push(vertex.x, vertex.y, vertex.z, normal.x, normal.y, normal.z, normalizedZ, normalizedY);
            }

            if (zRotationStep > 0) {
                var verticesCount = vertices.length / 8;
                for (var firstIndex = verticesCount - 2 * (totalYRotationSteps + 1) ; (firstIndex + totalYRotationSteps + 2) < verticesCount; firstIndex++) {
                    indices.push((firstIndex));
                    indices.push((firstIndex + 1));
                    indices.push(firstIndex + totalYRotationSteps + 1);

                    indices.push((firstIndex + totalYRotationSteps + 1));
                    indices.push((firstIndex + 1));
                    indices.push((firstIndex + totalYRotationSteps + 2));
                }
            }
        }

        sphere.setVertices(vertices, 1, updatable);
        sphere.setIndices(indices);

        return sphere;
    };

    // Cylinder (Code from SharpDX.org)
    BABYLON.Mesh.CreateCylinder = function (name, height, diameter, tessellation, scene, updatable) {
        var radius = diameter / 2;
        var indices = [];
        var vertices = [];
        var cylinder = new BABYLON.Mesh(name, [3, 3, 2], scene);


        var getCircleVector = function (i) {
            var angle = (i * 2.0 * Math.PI / tessellation);
            var dx = Math.sin(angle);
            var dz = Math.cos(angle);

            return new BABYLON.Vector3(dx, 0, dz);
        };

        var createCylinderCap = function (isTop) {
            // Create cap indices.
            for (var i = 0; i < tessellation - 2; i++) {
                var i1 = (i + 1) % tessellation;
                var i2 = (i + 2) % tessellation;

                if (isTop) {
                    var tmp = i1;
                    var i1 = i2;
                    i2 = tmp;
                }

                var vbase = vertices.length / cylinder.getFloatVertexStrideSize();
                indices.push(vbase);
                indices.push(vbase + i1);
                indices.push(vbase + i2);
            }


            // Which end of the cylinder is this?
            var normal = new BABYLON.Vector3(0, 1, 0);
            var textureScale = new BABYLON.Vector2(-0.5, -0.5);

            if (!isTop) {
                normal = normal.scale(-1);
                textureScale.x = -textureScale.x;
            }

            // Create cap vertices.
            for (var i = 0; i < tessellation; i++) {
                var circleVector = getCircleVector(i);
                var position = circleVector.scale(radius).add(normal.scale(height));
                var textureCoordinate = new BABYLON.Vector2(circleVector.x * textureScale.x + 0.5, circleVector.z * textureScale.y + 0.5);

                vertices.push(
                    position.x, position.y, position.z,
                    normal.x, normal.y, normal.z,
                    textureCoordinate.x, textureCoordinate.y
                );
            }
        };

        height /= 2;

        var topOffset = new BABYLON.Vector3(0, 1, 0).scale(height);

        var stride = tessellation + 1;

        // Create a ring of triangles around the outside of the cylinder.
        for (var i = 0; i <= tessellation; i++)
        {
            var normal = getCircleVector(i);
            var sideOffset = normal.scale(radius);
            var textureCoordinate = new BABYLON.Vector2(i / tessellation, 0);

            var position = sideOffset.add(topOffset);
            vertices.push(
                            position.x, position.y, position.z,
                            normal.x, normal.y, normal.z,
                            textureCoordinate.x, textureCoordinate.y
                        );

            position = sideOffset.subtract(topOffset);
            textureCoordinate.y += 1;
            vertices.push(
                            position.x, position.y, position.z,
                            normal.x, normal.y, normal.z,
                            textureCoordinate.x, textureCoordinate.y
                        );

            indices.push(i * 2);
            indices.push((i * 2 + 2) % (stride * 2));
            indices.push(i * 2 + 1);

            indices.push(i * 2 + 1);
            indices.push((i * 2 + 2) % (stride * 2));
            indices.push((i * 2 + 3) % (stride * 2));
        }

        // Create flat triangle fan caps to seal the top and bottom.
        createCylinderCap(true);
        createCylinderCap(false);
        
        cylinder.setVertices(vertices, 1, updatable);
        cylinder.setIndices(indices);

        return cylinder;
    };

    // Torus  (Code from SharpDX.org)
    BABYLON.Mesh.CreateTorus = function (name, diameter, thickness, tessellation, scene, updatable) {
        var torus = new BABYLON.Mesh(name, [3, 3, 2], scene);

        var indices = [];
        var vertices = [];

        var stride = tessellation + 1;

        for (var i = 0; i <= tessellation; i++) {
            var u = i / tessellation;

            var outerAngle = i * Math.PI * 2.0 / tessellation - Math.PI / 2.0;

            var transform = BABYLON.Matrix.Translation(diameter / 2.0, 0, 0).multiply(BABYLON.Matrix.RotationY(outerAngle));

            for (var j = 0; j <= tessellation; j++) {
                var v = 1 - j / tessellation;

                var innerAngle = j * Math.PI * 2.0 / tessellation + Math.PI;
                var dx = Math.cos(innerAngle);
                var dy = Math.sin(innerAngle);

                // Create a vertex.
                var normal = new BABYLON.Vector3(dx, dy, 0);
                var position = normal.scale(thickness / 2);
                var textureCoordinate = new BABYLON.Vector2(u, v);

                position = BABYLON.Vector3.TransformCoordinates(position, transform);
                normal = BABYLON.Vector3.TransformNormal(normal, transform);

                vertices.push(
                    position.x, position.y, position.z,
                    normal.x, normal.y, normal.z,
                    textureCoordinate.x, textureCoordinate.y
                );

                // And create indices for two triangles.
                var nextI = (i + 1) % stride;
                var nextJ = (j + 1) % stride;

                indices.push(i * stride + j);
                indices.push(i * stride + nextJ);
                indices.push(nextI * stride + j);


                indices.push(i * stride + nextJ);
                indices.push(nextI * stride + nextJ);
                indices.push(nextI * stride + j);
            }
        }

        torus.setVertices(vertices, 1, updatable);
        torus.setIndices(indices);

        return torus;
    };


    // Plane
    BABYLON.Mesh.CreatePlane = function (name, size, scene, updatable) {
        var plane = new BABYLON.Mesh(name, [3, 3, 2], scene);

        var indices = [];
        var vertices = [];

        // Vertices
        var halfSize = size / 2.0;
        vertices.push(-halfSize, -halfSize, 0, 0, 0, -1.0, 0.0, 0.0);
        vertices.push(halfSize, -halfSize, 0, 0, 0, -1.0, 1.0, 0.0);
        vertices.push(halfSize, halfSize, 0, 0, 0, -1.0, 1.0, 1.0);
        vertices.push(-halfSize, halfSize, 0, 0, 0, -1.0, 0.0, 1.0);

        // Indices
        indices.push(0);
        indices.push(1);
        indices.push(2);

        indices.push(0);
        indices.push(2);
        indices.push(3);

        plane.setVertices(vertices, 1, updatable);
        plane.setIndices(indices);

        return plane;
    };

    BABYLON.Mesh.CreateGround = function (name, width, height, subdivisions, scene, updatable) {
        var ground = new BABYLON.Mesh(name, [3, 3, 2], scene);

        var indices = [];
        var vertices = [];
        var row, col;

        for (row = 0; row <= subdivisions; row++) {
            for (col = 0; col <= subdivisions; col++) {
                var position = new BABYLON.Vector3((col * width) / subdivisions - (width / 2.0), 0, ((subdivisions - row) * height) / subdivisions - (height / 2.0));
                var normal = new BABYLON.Vector3(0, 1.0, 0);

                vertices.push(position.x, position.y, position.z,
                    normal.x, normal.y, normal.z,
                    col / subdivisions, row / subdivisions);
            }
        }

        for (row = 0; row < subdivisions; row++) {
            for (col = 0; col < subdivisions; col++) {
                indices.push(col + 1 + (row + 1) * (subdivisions + 1));
                indices.push(col + 1 + row * (subdivisions + 1));
                indices.push(col + row * (subdivisions + 1));

                indices.push(col + (row + 1) * (subdivisions + 1));
                indices.push(col + 1 + (row + 1) * (subdivisions + 1));
                indices.push(col + row * (subdivisions + 1));
            }
        }

        ground.setVertices(vertices, 1, updatable);
        ground.setIndices(indices);

        return ground;
    };

    BABYLON.Mesh.CreateGroundFromHeightMap = function (name, url, width, height, subdivisions, minHeight, maxHeight, scene, updatable) {
        var ground = new BABYLON.Mesh(name, [3, 3, 2], scene);

        var img = new Image();
        img.onload = function () {
            var indices = [];
            var vertices = [];
            var row, col;

            // Getting height map data
            var canvas = document.createElement("canvas");
            var context = canvas.getContext("2d");
            var heightMapWidth = img.width;
            var heightMapHeight = img.height;
            canvas.width = heightMapWidth;
            canvas.height = heightMapHeight;

            context.drawImage(img, 0, 0);

            var buffer = context.getImageData(0, 0, heightMapWidth, heightMapHeight).data;

            // Vertices
            for (row = 0; row <= subdivisions; row++) {
                for (col = 0; col <= subdivisions; col++) {
                    var position = new BABYLON.Vector3((col * width) / subdivisions - (width / 2.0), 0, ((subdivisions - row) * height) / subdivisions - (height / 2.0));

                    // Compute height
                    var heightMapX = (((position.x + width / 2) / width) * (heightMapWidth - 1)) | 0;
                    var heightMapY = (((position.z + height / 2) / height) * (heightMapHeight - 1)) | 0;

                    var pos = (heightMapX + heightMapY * heightMapWidth) * 4;
                    var r = buffer[pos] / 255.0;
                    var g = buffer[pos + 1] / 255.0;
                    var b = buffer[pos + 2] / 255.0;

                    var gradient = r * 0.3 + g * 0.59 + b * 0.11;

                    position.y = minHeight + (maxHeight - minHeight) * gradient;

                    // Add  vertex
                    vertices.push(position.x, position.y, position.z,
                        0, 0, 0,
                        col / subdivisions, row / subdivisions);
                }
            }

            // Indices
            for (row = 0; row < subdivisions; row++) {
                for (col = 0; col < subdivisions; col++) {
                    indices.push(col + 1 + (row + 1) * (subdivisions + 1));
                    indices.push(col + 1 + row * (subdivisions + 1));
                    indices.push(col + row * (subdivisions + 1));

                    indices.push(col + (row + 1) * (subdivisions + 1));
                    indices.push(col + 1 + (row + 1) * (subdivisions + 1));
                    indices.push(col + row * (subdivisions + 1));
                }
            }

            // Normals
            BABYLON.Mesh.ComputeNormal(vertices, indices, ground.getFloatVertexStrideSize());

            // Transfer
            ground.setVertices(vertices, 1, updatable);
            ground.setIndices(indices);

            ground._isReady = true;
        };

        img.src = url;

        ground._isReady = false;

        return ground;
    };

    // Tools
    BABYLON.Mesh.ComputeNormal = function (vertices, indices, stride, normalOffset) {
        var positions = [];
        var facesOfVertices = [];
        var index;

        if (normalOffset === undefined) {
            normalOffset = 3;
        }

        for (index = 0; index < vertices.length; index += stride) {
            var position = new BABYLON.Vector3(vertices[index], vertices[index + 1], vertices[index + 2]);
            positions.push(position);
            facesOfVertices.push([]);
        }
        // Compute normals
        var facesNormals = [];
        for (index = 0; index < indices.length / 3; index++) {
            var i1 = indices[index * 3];
            var i2 = indices[index * 3 + 1];
            var i3 = indices[index * 3 + 2];

            var p1 = positions[i1];
            var p2 = positions[i2];
            var p3 = positions[i3];

            var p1p2 = p1.subtract(p2);
            var p3p2 = p3.subtract(p2);

            facesNormals[index] = BABYLON.Vector3.Normalize(BABYLON.Vector3.Cross(p1p2, p3p2));
            facesOfVertices[i1].push(index);
            facesOfVertices[i2].push(index);
            facesOfVertices[i3].push(index);
        }

        for (index = 0; index < positions.length; index++) {
            var faces = facesOfVertices[index];

            var normal = BABYLON.Vector3.Zero();
            for (var faceIndex = 0; faceIndex < faces.length; faceIndex++) {
                normal = normal.add(facesNormals[faces[faceIndex]]);
            }

            normal = BABYLON.Vector3.Normalize(normal.scale(1.0 / faces.length));

            vertices[index * stride + normalOffset] = normal.x;
            vertices[index * stride + normalOffset + 1] = normal.y;
            vertices[index * stride + normalOffset + 2] = normal.z;
        }
    };
})();