The description you mention states that the projection by a pin-hole camera (one that does not introduce lens distortion) is modeled by R_u = f*tan(theta) and the projection by common fisheye lens cameras (that is, distorted) is modeled by R_d = 2*f*sin(theta/2) You already know R_d and theta and if you knew the camera’s focal … Read more
You do not need to have any objects in your scene to do this. You already know the camera position. Using vector.unproject( camera ) you can get a ray pointing in the direction you want. You just need to extend that ray, from the camera position, until the z-coordinate of the tip of the ray … Read more
From the MongoDB docs: A projection can explicitly include several fields. In the following operation, find() method returns all documents that match the query. In the result set, only the item and qty fields and, by default, the _id field return in the matching documents. db.inventory.find( { type: ‘food’ }, { item: 1, qty: 1 … Read more
MongoDB 2.2’s new $elemMatch projection operator provides another way to alter the returned document to contain only the first matched shapes element: db.test.find( {“shapes.color”: “red”}, {_id: 0, shapes: {$elemMatch: {color: “red”}}}); Returns: {“shapes” : [{“shape”: “circle”, “color”: “red”}]} In 2.2 you can also do this using the $ projection operator, where the $ in a … Read more