three.js/src/cameras/Camera.js

/**
 * @author mr.doob / http://mrdoob.com/
 * @author mikael emtinger / http://gomo.se/
 */

THREE.Camera = function( FOV, aspect, zNear, zFar, renderer, target ) {

	THREE.Object3D.call( this );

	this.FOV              = FOV      || 50;
	this.aspect           = aspect   || 1.0;
	this.zNear            = zNear    || 0.1;
	this.zFar             = zFar     || 2000;
	this.screenCenterX    = 0;
	this.screenCenterY    = 0;
	this.target           = target   || new THREE.Object3D();
	this.useTarget        = true;
	this.up               = new THREE.Vector3( 0, 1, 0 );

	this.inverseMatrix     = new THREE.Matrix4();
	this.projectionMatrix = null;

	// movement

	this.tmpVec = new THREE.Vector3();

	this.translateX = function ( amount ) {

		this.tmpVec.sub( this.target.position, this.position ).normalize().multiplyScalar( amount );
		this.tmpVec.crossSelf( this.up );

		this.position.addSelf( this.tmpVec );
		this.target.position.addSelf( this.tmpVec );

	};

	/* TODO
	this.translateY = function ( amount ) {

	};
	*/

	this.translateZ = function ( amount ) {

		this.tmpVec.sub( this.target.position, this.position ).normalize().multiplyScalar( amount );

		this.position.subSelf( this.tmpVec );
		this.target.position.subSelf( this.tmpVec );

	};

	this.updateProjectionMatrix();

}

THREE.Camera.prototype             = new THREE.Object3D();
THREE.Camera.prototype.constructor = THREE.Camera;
THREE.Camera.prototype.supr        = THREE.Object3D.prototype;


/*
 * Update projection matrix
 *
 * TODO: make it work also for ortho camera
*/

THREE.Camera.prototype.updateProjectionMatrix = function() {

	this.projectionMatrix = THREE.Matrix4.makePerspective( this.FOV, this.aspect, this.zNear, this.zFar );

}


/*
 * Update
 */

THREE.Camera.prototype.update = function( parentGlobalMatrix, forceUpdate, camera ) {

	if( this.useTarget ) {

		// local

		this.localMatrix.lookAt( this.position, this.target.position, this.up );


		// global

		if( parentGlobalMatrix )
			this.globalMatrix.multiply( parentGlobalMatrix, this.localMatrix );
		else
			this.globalMatrix.copy( this.localMatrix );

		THREE.Matrix4.makeInvert( this.globalMatrix, this.inverseMatrix );
		//THREE.Matrix4.makeInvertTo( this.globalMatrix, this.inverseMatrix );

		forceUpdate = true;

	} else {

		if( this.matrixAutoUpdate )
			forceUpdate |= this.updateMatrix();

		if( forceUpdate || this.matrixNeedsUpdate ) {

			if( parentGlobalMatrix )
				this.globalMatrix.multiply( parentGlobalMatrix, this.localMatrix );
			else
				this.globalMatrix.copy( this.localMatrix );

			this.matrixNeedsUpdate = false;
			forceUpdate              = true;

			THREE.Matrix4.makeInvert( this.globalMatrix, this.inverseMatrix );
			//THREE.Matrix4.makeInvertTo( this.globalMatrix, this.inverseMatrix );

		}

	}

	// update children

	for( var i = 0; i < this.children.length; i++ )
		this.children[ i ].update( this.globalMatrix, forceUpdate, camera );

};


/*
 * FrustumContains
 * Checks object against projected image (as opposed to ordinary frustum check)
 *
 * TODO: make it work also for ortho camera
 */

THREE.Camera.prototype.frustumContains = function( object3D ) {

	// object pos

	var vx0 = object3D.globalMatrix.n14,
	    vy0 = object3D.globalMatrix.n24,
		vz0 = object3D.globalMatrix.n34;


	// check z

	var inverse = this.inverseMatrix;
	var radius  = object3D.boundRadius * object3D.boundRadiusScale;
	var vz1     = ( inverse.n31 * vx0 + inverse.n32 * vy0 + inverse.n33 * vz0 + inverse.n34 );

	if( vz1 - radius > -this.zNear )
		return false;

	if( vz1 + radius < -this.zFar )
		return false;


	// check x

	vz1 -= radius;

	var perspective      = this.projectionMatrix;
	var ooZ              = 1 / ( perspective.n43 * vz1 );
	var ooZscreenCenterX = ooZ * this.screenCenterX;
	var vx1              = ( inverse.n11 * vx0 + inverse.n12 * vy0 + inverse.n13 * vz0 + inverse.n14 ) * perspective.n11 * ooZscreenCenterX;
	radius               = perspective.n11 * radius * ooZscreenCenterX;

	if( vx1 + radius < -this.screenCenterX )
		return false;

	if( vx1 - radius > this.screenCenterX )
		return false;


	// check y

	var vy1 = ( inverse.n21 * vx0 + inverse.n22 * vy0 + inverse.n23 * vz0 + inverse.n24 ) * perspective.n22 * ooZ * this.screenCenterY;

	if( vy1 + radius < -this.screenCenterY )
		return false;

	if( vy1 - radius > this.screenCenterY )
		return false;


	// inside

	object3D.screenPosition.set( vx1, vy1, vz1, radius );

	return true;

};