rotation

问题 I need help in math in general for euler angles and specifically in ARKit. I looked at many references for calculation of euler angles but I wondered why apple in its tutorial calculated yaw from atan2(r11, r12) as follow: let yaw = atan2f(camera.transform.columns.0.x, camera.transform.columns.1.x) If I need to calculate pitch or roll, for example how? I need to understand yaw and why they not always depends on yaw = camera.eularAngle.y Please check this code and questions in comments, I'm

问题 How would you change the direction of a rotating image/rect in Pygame? Applying positive and negative degree values works but it seems to only be able to rotate one direction throughout my window. Is there a way to ensure a change in direction of rotation? Perhaps change up rotation of a spinning image every 5 seconds, or if able to change the direction of the spin when hitting a X or Y axis. I've added some code below. It seems like switching movement directions is easy with rect.move_ip as

问题 I'm making a top-down shooter and the player's gun is offset from the coordinates of the object. I'm using GameMaker:Studio, so the x and y coords are the center of the object. The offset of the image is set here: bullet_offset_x = 30; bullet_offset_y = 28; And here is the code for shooting the gun: var xpos = x + (bullet_offset_x * cos(degtorad(direction))) - (bullet_offset_y * sin(degtorad(direction))); var ypos = y + (bullet_offset_x * sin(degtorad(direction))) + (bullet_offset_y * cos

问题 I want to create a function that receives an angle, two vectors, one of them being an unit vector that defines the direction of the axis of rotation and the other is the vector to be rotated and a point P that defines the anchoring position of the rotation. To implement this in Eigen I guess I would have to use the geometry module, unfortunately, I think the documentation of this module is not great and I am failing to understand it. My idea is to combine the rotation transformation AngleAxis

问题 So I'm reading in files from a directory, figuring out which way they need to be rotated. Rotating and then saving. That part works... The issue is, after it saves the file it gets recompressed and I go from 1.5meg images to 250k images. I need to keep the file size around the original. I tried using jhead.exe and calling it from a command line but couldn't get any of my arguments to pass in correctly. Here's my code snipit to detect, rotate, and save. foreach (FileInfo f in dir.GetFiles("*

问题 I have 2 mesh objects. Anchor and Rod. The Anchor rotates around z-axis, as illustrated by the image. The rod is supposed to move only backward and forwards. Here is the image: http://imageshack.us/photo/my-images/841/7a83.png/. But i am stuck with trying to figure out the matrix calculation. For example if the anchor rotates 45degrees, so its facing the x-axis, how can i make the rod still move backwards and forwards? 回答1: For the rotation around z axis : var rotation = new THREE.Matrix4()

问题 I'm am working on a project at the moment where I am trying to create a Hilbert curve using the Python Imaging Library. I have created a function which will generate new coordinates for the curve through each iteration and place them into various lists which then I want to be able to move, rotate and scale. I was wondering if anyone could give me some tips or a way to do this as I am completely clueless. Still working on the a lot of the code. #! usr/bin/python import Image, ImageDraw import

问题 I'm detecting markers on images captured by my iPad. Because of that I want to calculate translations and rotations between them, I want to change change perspective on images these image, so it would look like I'm capturing them directly above markers. Right now I'm using points2D.push_back(cv::Point2f(0, 0)); points2D.push_back(cv::Point2f(50, 0)); points2D.push_back(cv::Point2f(50, 50)); points2D.push_back(cv::Point2f(0, 50)); Mat perspectiveMat = cv::getPerspectiveTransform(points2D,

问题 I would like to calculate an (nxn) rotation matrix in the n-dimensional space given the following: The point to rotate. An angle of rotation. An axis of rotation (an (n-2) subspace that passes through the origin given by (n-2) unit vectors that span the subspace). the final rotated point. I think that number 4 (the final rotated point) is redundant and it is possible to calculate the rotation matrix without it. But I have them all. Is there a matlab function that already implements it? I know

问题 I'm detecting markers on images captured by my iPad. Because of that I want to calculate translations and rotations between them, I want to change change perspective on images these image, so it would look like I'm capturing them directly above markers. Right now I'm using points2D.push_back(cv::Point2f(0, 0)); points2D.push_back(cv::Point2f(50, 0)); points2D.push_back(cv::Point2f(50, 50)); points2D.push_back(cv::Point2f(0, 50)); Mat perspectiveMat = cv::getPerspectiveTransform(points2D,