projection

问题 Reading the documentation on Cloud Datastore, it's pretty clear that a Get retrieves the entire entity, and that a query is always done against the index. Here's where it gets confusing, because according to the documentation: Projection queries allow you to query Cloud Datastore for just those specific properties of an entity that you actually need, at lower latency and cost than retrieving the entire entity But if all queries are done against an index, a query would never retrieve the

问题 I have a triangle with points A, B, C and Point in space (P). How can I get distance from point to plane? I need to calc distance from P to plane, even when my triangle lie far away(or not above to the point, like on picture). Point and triangle: 回答1: If the point is P(x1,y1,z1) and the plane is ax+by+cz+d = 0 Distance dist = Abs(a*x1+b*y1+c*z1+d) / Sqrt(a^2+b^2+c^2) 回答2: I assume you want to compute perpendicular distance between point and plane given 3 points on it forming a triangle. Here

问题 I have a triangle with points A, B, C and Point in space (P). How can I get distance from point to plane? I need to calc distance from P to plane, even when my triangle lie far away(or not above to the point, like on picture). Point and triangle: 回答1: If the point is P(x1,y1,z1) and the plane is ax+by+cz+d = 0 Distance dist = Abs(a*x1+b*y1+c*z1+d) / Sqrt(a^2+b^2+c^2) 回答2: I assume you want to compute perpendicular distance between point and plane given 3 points on it forming a triangle. Here

问题 I am using mongodb java driver 3.4. In the mongodb database documents are saved according to the following structure: { "_id" : ObjectId("595a9fc4fe3f36402b7edf0e"), "id" : "123", "priceInfo" : [ {object1: value1}, {object2: value2}, {object3: value3} ] } In order to retrieve the "priceInfo"-Array of a Document with a specific id, I wrote the following code: collection.find(eq("id", id)).first().projection(fields(include("priceInfo"), excludeId())); I wrote this code according too the

问题 I'm trying to properly configure my Camera and Sprite s in libGDX to show up in a 2D coordinate system properly with the origin at the bottom left hand corner. I set up my Camera like this: cameraWidth = Gdx.graphics.getWidth(); cameraHeight = Gdx.graphics.getHeight(); camera = new OrthographicCamera(1, cameraHeight/cameraWidth); And I set up my Sprite s like this: sprite.setOrigin(sprite.getWidth()/2, sprite.getHeight()/2); sprite.setScale(scale); sprite.setPosition(startX,startY); My

问题 Here is my code to project Velodyne points into the images: cam = 2; frame = 20; % compute projection matrix velodyne->image plane R_cam_to_rect = eye(4); [P, Tr_velo_to_cam, R] = readCalibration('D:/Shared/training/calib/',frame,cam) R_cam_to_rect(1:3,1:3) = R; P_velo_to_img = P*R_cam_to_rect*Tr_velo_to_cam; % load and display image img = imread(sprintf('D:/Shared/training/image_2/%06d.png',frame)); fig = figure('Position',[20 100 size(img,2) size(img,1)]); axes('Position',[0 0 1 1]); imshow

问题 I'm currently experiencing the issue mentioned here (and several other places): Subsonic 3 Linq Projection Issue This is occurring using the 3.0.0.4 release package, and it also occurs when I grab the latest from GitHub and build it. I am using the LINQ Templates. I have this code: var newModel = new ViewModels.HomeIndexViewModel() { PulseListViewModel = new ViewModels.PulseListViewModel { Pulses = from p in _pulseQuery join a in _accountQuery on p.AccountId equals a.AccountId orderby p

问题 I've been wondering which kind of projections should I use, so I did a little test, which covered 5 types of projections (based on docs: https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#projections): 1. Entity projection This is just a standard findAll() provided by Spring Data repository. Nothing fancy here. Service: List<SampleEntity> projections = sampleRepository.findAll(); Entity: @Entity @Table(name = "SAMPLE_ENTITIES") public class SampleEntity { @Id private Long id;

问题 I've been wondering which kind of projections should I use, so I did a little test, which covered 5 types of projections (based on docs: https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#projections): 1. Entity projection This is just a standard findAll() provided by Spring Data repository. Nothing fancy here. Service: List<SampleEntity> projections = sampleRepository.findAll(); Entity: @Entity @Table(name = "SAMPLE_ENTITIES") public class SampleEntity { @Id private Long id;

问题 I have 3 points in a 3D space of which I know the exact locations. Suppose they are: (x0,y0,z0) , (x1,y1,z1) and (x2,y2,z2) . Also I have a camera that is looking at these 3 points and I know the 2D locations of those three points on camera view plane. So for example (x0,y0,z0) will be (x0',y0') , and (x1,y1,z1) will be (x1',y1') and (x2,y2,z2) will be (x2',y2') from the camera's point of view. What is the easiest way to find the projection matrix that will project those 3D points into 2D