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178 lines
5.1 KiB
178 lines
5.1 KiB
var Point3d = require('./Point3d');
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/**
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* @class Camera
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* The camera is mounted on a (virtual) camera arm. The camera arm can rotate
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* The camera is always looking in the direction of the origin of the arm.
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* This way, the camera always rotates around one fixed point, the location
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* of the camera arm.
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*
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* Documentation:
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* http://en.wikipedia.org/wiki/3D_projection
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*/
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function Camera() {
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this.armLocation = new Point3d();
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this.armRotation = {};
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this.armRotation.horizontal = 0;
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this.armRotation.vertical = 0;
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this.armLength = 1.7;
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this.cameraOffset = new Point3d();
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this.offsetMultiplier = 0.6;
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this.cameraLocation = new Point3d();
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this.cameraRotation = new Point3d(0.5*Math.PI, 0, 0);
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this.calculateCameraOrientation();
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}
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/**
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* Set offset camera in camera coordinates
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* @param {Number} x offset by camera horisontal
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* @param {Number} y offset by camera vertical
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*/
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Camera.prototype.setOffset = function(x, y) {
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var abs = Math.abs,
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sign = Math.sign,
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mul = this.offsetMultiplier,
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border = this.armLength * mul;
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if (abs(x) > border) {
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x = sign(x) * border;
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}
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if (abs(y) > border) {
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y = sign(y) * border;
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}
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this.cameraOffset.x = x;
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this.cameraOffset.y = y;
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this.calculateCameraOrientation();
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};
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/**
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* Get camera offset by horizontal and vertical
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*/
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Camera.prototype.getOffset = function() {
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return this.cameraOffset;
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};
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/**
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* Set the location (origin) of the arm
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* @param {Number} x Normalized value of x
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* @param {Number} y Normalized value of y
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* @param {Number} z Normalized value of z
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*/
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Camera.prototype.setArmLocation = function(x, y, z) {
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this.armLocation.x = x;
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this.armLocation.y = y;
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this.armLocation.z = z;
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this.calculateCameraOrientation();
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};
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/**
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* Set the rotation of the camera arm
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* @param {Number} horizontal The horizontal rotation, between 0 and 2*PI.
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* Optional, can be left undefined.
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* @param {Number} vertical The vertical rotation, between 0 and 0.5*PI
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* if vertical=0.5*PI, the graph is shown from the
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* top. Optional, can be left undefined.
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*/
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Camera.prototype.setArmRotation = function(horizontal, vertical) {
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if (horizontal !== undefined) {
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this.armRotation.horizontal = horizontal;
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}
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if (vertical !== undefined) {
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this.armRotation.vertical = vertical;
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if (this.armRotation.vertical < 0) this.armRotation.vertical = 0;
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if (this.armRotation.vertical > 0.5*Math.PI) this.armRotation.vertical = 0.5*Math.PI;
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}
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if (horizontal !== undefined || vertical !== undefined) {
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this.calculateCameraOrientation();
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}
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};
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/**
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* Retrieve the current arm rotation
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* @return {object} An object with parameters horizontal and vertical
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*/
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Camera.prototype.getArmRotation = function() {
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var rot = {};
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rot.horizontal = this.armRotation.horizontal;
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rot.vertical = this.armRotation.vertical;
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return rot;
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};
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/**
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* Set the (normalized) length of the camera arm.
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* @param {Number} length A length between 0.71 and 5.0
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*/
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Camera.prototype.setArmLength = function(length) {
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if (length === undefined)
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return;
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this.armLength = length;
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// Radius must be larger than the corner of the graph,
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// which has a distance of sqrt(0.5^2+0.5^2) = 0.71 from the center of the
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// graph
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if (this.armLength < 0.71) this.armLength = 0.71;
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if (this.armLength > 5.0) this.armLength = 5.0;
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this.setOffset(this.cameraOffset.x, this.cameraOffset.y);
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this.calculateCameraOrientation();
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};
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/**
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* Retrieve the arm length
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* @return {Number} length
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*/
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Camera.prototype.getArmLength = function() {
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return this.armLength;
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};
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/**
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* Retrieve the camera location
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* @return {Point3d} cameraLocation
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*/
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Camera.prototype.getCameraLocation = function() {
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return this.cameraLocation;
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};
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/**
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* Retrieve the camera rotation
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* @return {Point3d} cameraRotation
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*/
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Camera.prototype.getCameraRotation = function() {
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return this.cameraRotation;
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};
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/**
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* Calculate the location and rotation of the camera based on the
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* position and orientation of the camera arm
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*/
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Camera.prototype.calculateCameraOrientation = function() {
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// calculate location of the camera
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this.cameraLocation.x = this.armLocation.x - this.armLength * Math.sin(this.armRotation.horizontal) * Math.cos(this.armRotation.vertical);
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this.cameraLocation.y = this.armLocation.y - this.armLength * Math.cos(this.armRotation.horizontal) * Math.cos(this.armRotation.vertical);
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this.cameraLocation.z = this.armLocation.z + this.armLength * Math.sin(this.armRotation.vertical);
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// calculate rotation of the camera
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this.cameraRotation.x = Math.PI/2 - this.armRotation.vertical;
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this.cameraRotation.y = 0;
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this.cameraRotation.z = -this.armRotation.horizontal;
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var xa = this.cameraRotation.x;
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var za = this.cameraRotation.z;
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var dx = this.cameraOffset.x;
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var dy = this.cameraOffset.y;
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var sin = Math.sin, cos = Math.cos;
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this.cameraLocation.x = this.cameraLocation.x + dx * cos(za) + dy * - sin(za) * cos(xa);
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this.cameraLocation.y = this.cameraLocation.y + dx * sin(za) + dy * cos(za) * cos(xa);
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this.cameraLocation.z = this.cameraLocation.z + dy * sin(xa);
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};
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module.exports = Camera;
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