Babylon.js/src/Cameras/targetCamera.ts

import { serialize, serializeAsVector3, serializeAsMeshReference } from "../Misc/decorators";
import { Nullable } from "../types";
import { Camera } from "./camera";
import { Scene } from "../scene";
import { Quaternion, Matrix, Vector3, Vector2, TmpVectors } from "../Maths/math.vector";
import { Epsilon } from '../Maths/math.constants';
import { Axis } from '../Maths/math.axis';
/**
 * A target camera takes a mesh or position as a target and continues to look at it while it moves.
 * This is the base of the follow, arc rotate cameras and Free camera
 * @see https://doc.babylonjs.com/features/cameras
 */
export class TargetCamera extends Camera {
    private static _RigCamTransformMatrix = new Matrix();
    private static _TargetTransformMatrix = new Matrix();
    private static _TargetFocalPoint = new Vector3();

    private _tmpUpVector = Vector3.Zero();
    private _tmpTargetVector = Vector3.Zero();

    /**
     * Define the current direction the camera is moving to
     */
    public cameraDirection = new Vector3(0, 0, 0);
    /**
     * Define the current rotation the camera is rotating to
     */
    public cameraRotation = new Vector2(0, 0);

    /** Gets or sets a boolean indicating that the scaling of the parent hierarchy will not be taken in account by the camera */
    public ignoreParentScaling = false;

    /**
     * When set, the up vector of the camera will be updated by the rotation of the camera
     */
    public updateUpVectorFromRotation = false;
    private _tmpQuaternion = new Quaternion();

    /**
     * Define the current rotation of the camera
     */
    @serializeAsVector3()
    public rotation = new Vector3(0, 0, 0);

    /**
     * Define the current rotation of the camera as a quaternion to prevent Gimbal lock
     */
    public rotationQuaternion: Quaternion;

    /**
     * Define the current speed of the camera
     */
    @serialize()
    public speed = 2.0;

    /**
     * Add constraint to the camera to prevent it to move freely in all directions and
     * around all axis.
     */
    public noRotationConstraint = false;

    /**
     * Reverses mouselook direction to 'natural' panning as opposed to traditional direct
     * panning
     */
    public invertRotation = false;

    /**
     * Speed multiplier for inverse camera panning
     */
    public inverseRotationSpeed = 0.2;

    /**
     * Define the current target of the camera as an object or a position.
     */
    @serializeAsMeshReference("lockedTargetId")
    public lockedTarget: any = null;

    /** @hidden */
    public _currentTarget = Vector3.Zero();
    /** @hidden */
    public _initialFocalDistance = 1;
    /** @hidden */
    public _viewMatrix = Matrix.Zero();
    /** @hidden */
    public _camMatrix = Matrix.Zero();
    /** @hidden */
    public _cameraTransformMatrix = Matrix.Zero();
    /** @hidden */
    public _cameraRotationMatrix = Matrix.Zero();

    /** @hidden */
    public _referencePoint = new Vector3(0, 0, 1);
    /** @hidden */
    public _transformedReferencePoint = Vector3.Zero();

    /** @hidden */
    public _reset: () => void;

    private _defaultUp = Vector3.Up();

    /**
     * Instantiates a target camera that takes a mesh or position as a target and continues to look at it while it moves.
     * This is the base of the follow, arc rotate cameras and Free camera
     * @see https://doc.babylonjs.com/features/cameras
     * @param name Defines the name of the camera in the scene
     * @param position Defines the start position of the camera in the scene
     * @param scene Defines the scene the camera belongs to
     * @param setActiveOnSceneIfNoneActive Defines wheter the camera should be marked as active if not other active cameras have been defined
     */
    constructor(name: string, position: Vector3, scene: Scene, setActiveOnSceneIfNoneActive = true) {
        super(name, position, scene, setActiveOnSceneIfNoneActive);
    }

    /**
     * Gets the position in front of the camera at a given distance.
     * @param distance The distance from the camera we want the position to be
     * @returns the position
     */
    public getFrontPosition(distance: number): Vector3 {
        this.getWorldMatrix();
        var direction = this.getTarget().subtract(this.position);
        direction.normalize();
        direction.scaleInPlace(distance);
        return this.globalPosition.add(direction);
    }

    /** @hidden */
    public _getLockedTargetPosition(): Nullable<Vector3> {
        if (!this.lockedTarget) {
            return null;
        }

        if (this.lockedTarget.absolutePosition) {
            this.lockedTarget.computeWorldMatrix();
        }

        return this.lockedTarget.absolutePosition || this.lockedTarget;
    }

    private _storedPosition: Vector3;
    private _storedRotation: Vector3;
    private _storedRotationQuaternion: Quaternion;

    /**
     * Store current camera state of the camera (fov, position, rotation, etc..)
     * @returns the camera
     */
    public storeState(): Camera {
        this._storedPosition = this.position.clone();
        this._storedRotation = this.rotation.clone();
        if (this.rotationQuaternion) {
            this._storedRotationQuaternion = this.rotationQuaternion.clone();
        }

        return super.storeState();
    }

    /**
     * Restored camera state. You must call storeState() first
     * @returns whether it was successful or not
     * @hidden
     */
    public _restoreStateValues(): boolean {
        if (!super._restoreStateValues()) {
            return false;
        }

        this.position = this._storedPosition.clone();
        this.rotation = this._storedRotation.clone();

        if (this.rotationQuaternion) {
            this.rotationQuaternion = this._storedRotationQuaternion.clone();
        }

        this.cameraDirection.copyFromFloats(0, 0, 0);
        this.cameraRotation.copyFromFloats(0, 0);

        return true;
    }

    /** @hidden */
    public _initCache() {
        super._initCache();
        this._cache.lockedTarget = new Vector3(Number.MAX_VALUE, Number.MAX_VALUE, Number.MAX_VALUE);
        this._cache.rotation = new Vector3(Number.MAX_VALUE, Number.MAX_VALUE, Number.MAX_VALUE);
        this._cache.rotationQuaternion = new Quaternion(Number.MAX_VALUE, Number.MAX_VALUE, Number.MAX_VALUE, Number.MAX_VALUE);
    }

    /** @hidden */
    public _updateCache(ignoreParentClass?: boolean): void {
        if (!ignoreParentClass) {
            super._updateCache();
        }

        var lockedTargetPosition = this._getLockedTargetPosition();
        if (!lockedTargetPosition) {
            this._cache.lockedTarget = null;
        }
        else {
            if (!this._cache.lockedTarget) {
                this._cache.lockedTarget = lockedTargetPosition.clone();
            }
            else {
                this._cache.lockedTarget.copyFrom(lockedTargetPosition);
            }
        }

        this._cache.rotation.copyFrom(this.rotation);
        if (this.rotationQuaternion) {
            this._cache.rotationQuaternion.copyFrom(this.rotationQuaternion);
        }
    }

    // Synchronized
    /** @hidden */
    public _isSynchronizedViewMatrix(): boolean {
        if (!super._isSynchronizedViewMatrix()) {
            return false;
        }

        var lockedTargetPosition = this._getLockedTargetPosition();

        return (this._cache.lockedTarget ? this._cache.lockedTarget.equals(lockedTargetPosition) : !lockedTargetPosition)
            && (this.rotationQuaternion ? this.rotationQuaternion.equals(this._cache.rotationQuaternion) : this._cache.rotation.equals(this.rotation));
    }

    // Methods
    /** @hidden */
    public _computeLocalCameraSpeed(): number {
        var engine = this.getEngine();
        return this.speed * Math.sqrt((engine.getDeltaTime() / (engine.getFps() * 100.0)));
    }

    // Target

    /**
     * Defines the target the camera should look at.
     * @param target Defines the new target as a Vector or a mesh
     */
    public setTarget(target: Vector3): void {
        this.upVector.normalize();

        this._initialFocalDistance = target.subtract(this.position).length();

        if (this.position.z === target.z) {
            this.position.z += Epsilon;
        }

        this._referencePoint.normalize().scaleInPlace(this._initialFocalDistance);

        Matrix.LookAtLHToRef(this.position, target, this._defaultUp, this._camMatrix);
        this._camMatrix.invert();

        this.rotation.x = Math.atan(this._camMatrix.m[6] / this._camMatrix.m[10]);

        var vDir = target.subtract(this.position);

        if (vDir.x >= 0.0) {
            this.rotation.y = (-Math.atan(vDir.z / vDir.x) + Math.PI / 2.0);
        } else {
            this.rotation.y = (-Math.atan(vDir.z / vDir.x) - Math.PI / 2.0);
        }

        this.rotation.z = 0;

        if (isNaN(this.rotation.x)) {
            this.rotation.x = 0;
        }

        if (isNaN(this.rotation.y)) {
            this.rotation.y = 0;
        }

        if (isNaN(this.rotation.z)) {
            this.rotation.z = 0;
        }

        if (this.rotationQuaternion) {
            Quaternion.RotationYawPitchRollToRef(this.rotation.y, this.rotation.x, this.rotation.z, this.rotationQuaternion);
        }
    }

    /**
     * Defines the target point of the camera.
     * The camera looks towards it form the radius distance.
     */
    public get target(): Vector3 {
        return this.getTarget();
    }
    public set target(value: Vector3) {
        this.setTarget(value);
    }

    /**
     * Return the current target position of the camera. This value is expressed in local space.
     * @returns the target position
     */
    public getTarget(): Vector3 {
        return this._currentTarget;
    }

    /** @hidden */
    public _decideIfNeedsToMove(): boolean {
        return Math.abs(this.cameraDirection.x) > 0 || Math.abs(this.cameraDirection.y) > 0 || Math.abs(this.cameraDirection.z) > 0;
    }

    /** @hidden */
    public _updatePosition(): void {
        if (this.parent) {
            this.parent.getWorldMatrix().invertToRef(TmpVectors.Matrix[0]);
            Vector3.TransformNormalToRef(this.cameraDirection, TmpVectors.Matrix[0], TmpVectors.Vector3[0]);
            this.position.addInPlace(TmpVectors.Vector3[0]);
            return;
        }
        this.position.addInPlace(this.cameraDirection);
    }

    /** @hidden */
    public _checkInputs(): void {
        var directionMultiplier = this.invertRotation ? -this.inverseRotationSpeed : 1.0;
        var needToMove = this._decideIfNeedsToMove();
        var needToRotate = Math.abs(this.cameraRotation.x) > 0 || Math.abs(this.cameraRotation.y) > 0;

        // Move
        if (needToMove) {
            this._updatePosition();
        }

        // Rotate
        if (needToRotate) {
            //rotate, if quaternion is set and rotation was used
            if (this.rotationQuaternion) {
                this.rotationQuaternion.toEulerAnglesToRef(this.rotation);
            }

            this.rotation.x += this.cameraRotation.x * directionMultiplier;
            this.rotation.y += this.cameraRotation.y * directionMultiplier;

            // Apply constraints
            if (!this.noRotationConstraint) {
                var limit = 1.570796;

                if (this.rotation.x > limit) {
                    this.rotation.x = limit;
                }
                if (this.rotation.x < -limit) {
                    this.rotation.x = -limit;
                }
            }

            //rotate, if quaternion is set and rotation was used
            if (this.rotationQuaternion) {
                var len = this.rotation.lengthSquared();
                if (len) {
                    Quaternion.RotationYawPitchRollToRef(this.rotation.y, this.rotation.x, this.rotation.z, this.rotationQuaternion);
                }
            }
        }

        // Inertia
        if (needToMove) {
            if (Math.abs(this.cameraDirection.x) < this.speed * Epsilon) {
                this.cameraDirection.x = 0;
            }

            if (Math.abs(this.cameraDirection.y) < this.speed * Epsilon) {
                this.cameraDirection.y = 0;
            }

            if (Math.abs(this.cameraDirection.z) < this.speed * Epsilon) {
                this.cameraDirection.z = 0;
            }

            this.cameraDirection.scaleInPlace(this.inertia);
        }
        if (needToRotate) {
            if (Math.abs(this.cameraRotation.x) < this.speed * Epsilon) {
                this.cameraRotation.x = 0;
            }

            if (Math.abs(this.cameraRotation.y) < this.speed * Epsilon) {
                this.cameraRotation.y = 0;
            }
            this.cameraRotation.scaleInPlace(this.inertia);
        }

        super._checkInputs();
    }

    protected _updateCameraRotationMatrix() {
        if (this.rotationQuaternion) {
            this.rotationQuaternion.toRotationMatrix(this._cameraRotationMatrix);
        } else {
            Matrix.RotationYawPitchRollToRef(this.rotation.y, this.rotation.x, this.rotation.z, this._cameraRotationMatrix);
        }
    }

    /**
     * Update the up vector to apply the rotation of the camera (So if you changed the camera rotation.z this will let you update the up vector as well)
     * @returns the current camera
     */
    private _rotateUpVectorWithCameraRotationMatrix(): TargetCamera {
        Vector3.TransformNormalToRef(this._defaultUp, this._cameraRotationMatrix, this.upVector);
        return this;
    }

    private _cachedRotationZ = 0;
    private _cachedQuaternionRotationZ = 0;
    /** @hidden */
    public _getViewMatrix(): Matrix {
        if (this.lockedTarget) {
            this.setTarget(this._getLockedTargetPosition()!);
        }

        // Compute
        this._updateCameraRotationMatrix();

        // Apply the changed rotation to the upVector
        if (this.rotationQuaternion && this._cachedQuaternionRotationZ != this.rotationQuaternion.z) {
            this._rotateUpVectorWithCameraRotationMatrix();
            this._cachedQuaternionRotationZ = this.rotationQuaternion.z;
        } else if (this._cachedRotationZ != this.rotation.z) {
            this._rotateUpVectorWithCameraRotationMatrix();
            this._cachedRotationZ = this.rotation.z;
        }

        Vector3.TransformCoordinatesToRef(this._referencePoint, this._cameraRotationMatrix, this._transformedReferencePoint);

        // Computing target and final matrix
        this.position.addToRef(this._transformedReferencePoint, this._currentTarget);
        if (this.updateUpVectorFromRotation) {
            if (this.rotationQuaternion) {
                Axis.Y.rotateByQuaternionToRef(this.rotationQuaternion, this.upVector);
            } else {
                Quaternion.FromEulerVectorToRef(this.rotation, this._tmpQuaternion);
                Axis.Y.rotateByQuaternionToRef(this._tmpQuaternion, this.upVector);
            }
        }
        this._computeViewMatrix(this.position, this._currentTarget, this.upVector);
        return this._viewMatrix;
    }

    protected _computeViewMatrix(position: Vector3, target: Vector3, up: Vector3): void {
        if (this.ignoreParentScaling) {
            if (this.parent) {
                const parentWorldMatrix = this.parent.getWorldMatrix();
                Vector3.TransformCoordinatesToRef(position, parentWorldMatrix, this._globalPosition);
                Vector3.TransformCoordinatesToRef(target, parentWorldMatrix, this._tmpTargetVector);
                Vector3.TransformNormalToRef(up, parentWorldMatrix, this._tmpUpVector);
                this._markSyncedWithParent();
            } else {
                this._globalPosition.copyFrom(position);
                this._tmpTargetVector.copyFrom(target);
                this._tmpUpVector.copyFrom(up);
            }

            if (this.getScene().useRightHandedSystem) {
                Matrix.LookAtRHToRef(this._globalPosition, this._tmpTargetVector, this._tmpUpVector, this._viewMatrix);
            } else {
                Matrix.LookAtLHToRef(this._globalPosition, this._tmpTargetVector, this._tmpUpVector, this._viewMatrix);
            }
            return;
        }

        if (this.getScene().useRightHandedSystem) {
            Matrix.LookAtRHToRef(position, target, up, this._viewMatrix);
        } else {
            Matrix.LookAtLHToRef(position, target, up, this._viewMatrix);
        }

        if (this.parent) {
            const parentWorldMatrix = this.parent.getWorldMatrix();
            this._viewMatrix.invert();
            this._viewMatrix.multiplyToRef(parentWorldMatrix, this._viewMatrix);
            this._viewMatrix.getTranslationToRef(this._globalPosition);
            this._viewMatrix.invert();
            this._markSyncedWithParent();
        } else {
            this._globalPosition.copyFrom(position);
        }
    }

    /**
     * @hidden
     */
    public createRigCamera(name: string, cameraIndex: number): Nullable<Camera> {
        if (this.cameraRigMode !== Camera.RIG_MODE_NONE) {
            var rigCamera = new TargetCamera(name, this.position.clone(), this.getScene());
            rigCamera.isRigCamera = true;
            rigCamera.rigParent = this;
            if (this.cameraRigMode === Camera.RIG_MODE_VR || this.cameraRigMode === Camera.RIG_MODE_WEBVR) {
                if (!this.rotationQuaternion) {
                    this.rotationQuaternion = new Quaternion();
                }
                rigCamera._cameraRigParams = {};
                rigCamera.rotationQuaternion = new Quaternion();
            }
            return rigCamera;
        }
        return null;
    }

    /**
     * @hidden
     */
    public _updateRigCameras() {
        var camLeft = <TargetCamera>this._rigCameras[0];
        var camRight = <TargetCamera>this._rigCameras[1];

        this.computeWorldMatrix();

        switch (this.cameraRigMode) {
            case Camera.RIG_MODE_STEREOSCOPIC_ANAGLYPH:
            case Camera.RIG_MODE_STEREOSCOPIC_SIDEBYSIDE_PARALLEL:
            case Camera.RIG_MODE_STEREOSCOPIC_SIDEBYSIDE_CROSSEYED:
            case Camera.RIG_MODE_STEREOSCOPIC_OVERUNDER:
            case Camera.RIG_MODE_STEREOSCOPIC_INTERLACED:
                //provisionnaly using _cameraRigParams.stereoHalfAngle instead of calculations based on _cameraRigParams.interaxialDistance:
                var leftSign = (this.cameraRigMode === Camera.RIG_MODE_STEREOSCOPIC_SIDEBYSIDE_CROSSEYED) ? 1 : -1;
                var rightSign = (this.cameraRigMode === Camera.RIG_MODE_STEREOSCOPIC_SIDEBYSIDE_CROSSEYED) ? -1 : 1;
                this._getRigCamPositionAndTarget(this._cameraRigParams.stereoHalfAngle * leftSign, camLeft);
                this._getRigCamPositionAndTarget(this._cameraRigParams.stereoHalfAngle * rightSign, camRight);
                break;

            case Camera.RIG_MODE_VR:
                if (camLeft.rotationQuaternion) {
                    camLeft.rotationQuaternion.copyFrom(this.rotationQuaternion);
                    camRight.rotationQuaternion.copyFrom(this.rotationQuaternion);
                } else {
                    camLeft.rotation.copyFrom(this.rotation);
                    camRight.rotation.copyFrom(this.rotation);
                }
                camLeft.position.copyFrom(this.position);
                camRight.position.copyFrom(this.position);

                break;
        }
        super._updateRigCameras();
    }

    private _getRigCamPositionAndTarget(halfSpace: number, rigCamera: TargetCamera) {
        var target = this.getTarget();
        target.subtractToRef(this.position, TargetCamera._TargetFocalPoint);

        TargetCamera._TargetFocalPoint.normalize().scaleInPlace(this._initialFocalDistance);
        var newFocalTarget = TargetCamera._TargetFocalPoint.addInPlace(this.position);

        Matrix.TranslationToRef(-newFocalTarget.x, -newFocalTarget.y, -newFocalTarget.z, TargetCamera._TargetTransformMatrix);
        TargetCamera._TargetTransformMatrix.multiplyToRef(Matrix.RotationAxis(rigCamera.upVector, halfSpace), TargetCamera._RigCamTransformMatrix);
        Matrix.TranslationToRef(newFocalTarget.x, newFocalTarget.y, newFocalTarget.z, TargetCamera._TargetTransformMatrix);

        TargetCamera._RigCamTransformMatrix.multiplyToRef(TargetCamera._TargetTransformMatrix, TargetCamera._RigCamTransformMatrix);

        Vector3.TransformCoordinatesToRef(this.position, TargetCamera._RigCamTransformMatrix, rigCamera.position);
        rigCamera.setTarget(newFocalTarget);
    }

    /**
     * Gets the current object class name.
     * @return the class name
     */
    public getClassName(): string {
        return "TargetCamera";
    }
}