update method

Implementation

void update() {
	final camera = data.camera;
	final frustums = this.frustums;

	// for each frustum we need to find its min-max box aligned with the light orientation
	// the position in _lightOrientationMatrix does not matter, as we transform there and back
	_lightOrientationMatrix.lookAt( Vector3(), data.lightDirection, _up );
	_lightOrientationMatrixInverse.setFrom( _lightOrientationMatrix ).invert();

	for (int i = 0; i < frustums.length; i ++ ) {

		final light = lights[ i ];
		final shadowCam = light.shadow?.camera;
		final texelWidth = ( shadowCam!.right - shadowCam.left ) / data.shadowMapSize;
		final texelHeight = ( shadowCam.top - shadowCam.bottom ) / data.shadowMapSize;
		_cameraToLightMatrix.multiply2( _lightOrientationMatrixInverse, camera.matrixWorld );
		frustums[ i ].toSpace( _cameraToLightMatrix, _lightSpaceFrustum );

		final nearVerts = _lightSpaceFrustum.vertices.near;
		final farVerts = _lightSpaceFrustum.vertices.far;
		_bbox.empty();
		for (int j = 0; j < 4; j ++ ) {

			_bbox.expandByPoint( nearVerts[ j ] );
			_bbox.expandByPoint( farVerts[ j ] );

		}

		_bbox.getCenter( _center );
		_center.z = _bbox.max.z + data.lightMargin;
		_center.x = ( _center.x / texelWidth ).floor() * texelWidth;
		_center.y = ( _center.y / texelHeight ).floor() * texelHeight;
		_center.applyMatrix4( _lightOrientationMatrix );

		light.position.setFrom( _center );
		light.target?.position.setFrom( _center );

		light.target?.position.x += data.lightDirection.x;
		light.target?.position.y += data.lightDirection.y;
		light.target?.position.z += data.lightDirection.z;
	}
}