projection-matrix

问题 Does anybody know what are the correct values to setup the projection and view matrix for a XNA rendering in order to match with the Kinect RGB camera? For example, if the skeleton head joint coordinates are (X,Y,Z) then if I draw a sphere at these coordinates in my 3D space, the rendering should overlap the head in the RGB image. 回答1: In the end I took a trial and error approach and determined the parameters. You can find more details here: http://www.mindtreatstudios.com/our-projects/kinect

问题 I need to draw parts of a texture on trapezoids polygons. (old school fake-3D race game, the road is made of these trapezoids and I want to apply a texture on them.) But the texture appears wrong, like if each of the two triangles forming a trapezoid are half of a parrallelogram instead, they have each a different horizontal skewing, not a global perspective transformation. Searching for a solution I see that this problem is common and the reason why is that the two triangles are not equal

问题 Currently, I'm attempting to create a Camera class in LWJGL, but I've been running into a problem with the projection matrix. For some reason, when I try to multiply the vertices by the projection matrix, nothing at all appears on screen. Camera class public class Camera { private Vector3f position, rotation; private Matrix4f view; private final Vector3f xAxis, yAxis, zAxis; private float fov, aspect, zNear, zFar; private Matrix4f projection; public Camera(float fov, float aspect, float zNear

问题 Ptoject Tango provides a point cloud, how can you get the position in pixels of a 3D point in the point cloud in meters? I tried using the projection matrix but I get very small values (0.5,1.3 etc) instead of say 1234,324 (in pixels). I include the code I have tried //Get the current rotation matrix Matrix4 projMatrix = mRenderer.getCurrentCamera().getProjectionMatrix(); //Get all the points in the pointcloud and store them as 3D points FloatBuffer pointsBuffer = mPointCloudManager

问题 Over the past few weeks I've been attempting to learn the libGDX library. I'm finding it hard, especially for my first endeavor toward game development, to comprehend the system of Camera/viewport relationships. One line of code that I've been told to use, and the API mentions, is: batch.setProjectionMatrix(camera.combined); Despite a good 4 hours of research, I'm still lacking a complete understanding of the functionality of this code. It is to my basic understanding that it "tells" the

问题 How to determinate the 4x4 S matrix so that the P gets projected into Q, on the XZ (Y=0) plane? Q = S P 回答1: I will give the general solution for central projection from a point C to a plane E (assuming that L is not contained in E ). I will use Octave/MATLAB notation for convenience. Let L be given in homogeneous coordinates L=[lx ly lz 1]' And E be given in Hessian normal form (also homogeneous coordinates) E=[nx, ny, ,nz, d]' where [nx, ny, nz] is the normal to the plane and d is its

问题 I use two projection matrices P1 and P2 (for example I'm using dinosaur dataset) and I need to compute the fundamental matrix F. So I use two Matlab functions: Peter Kovesi's function: www.csse.uwa.edu.au/~pk/Research/MatlabFns/Projective/fundfromcameras.m Zisserman: www.robots.ox.ac.uk/~vgg/hzbook/code/vgg_multiview/vgg_F_from_P.m These functions should do the same thing, but I have a different F value ! How it's possible? Which is the right functions? If two points X1 and X2 are "the same"

问题 I am trying to render a small region of the screen to an off-screen texture. This is part of a screenshot function in my app where the user selects a region on the screen and saves this to an image. While the region on the screen might be 250x250px, the saved image can be a lot larger like 1000x1000px. I understand the process of rendering to a texture using an FBO. I'm mostly stuck when it comes to defining the projection matrix that clips the scene so that only the screenshot region is

问题 I have developed a simple three.js application that renders a cube. I have created three files: index.html , viewer_style.css and viewer.js . The content of index.html is the following: <!DOCTYPE html> <html> <head> <meta charset=utf-8> <title>My first three.js app</title> <link rel='stylesheet' type='text/css' href='viewer_style.css'> <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script> <script src="js/three.js"></script> <script src="js/controls

问题 I'm using the python OpenGL bindings, and trying to only use modern opengl calls. I have a VBO with verticies, and I am trying to render with an orthographic projection matrix passed to the vertex shader. At present I am calculating my projection matrix with the following values: from numpy import array w = float(width) h = float(height) n = 0.5 f = 3.0 matrix = array([ [2/w, 0, 0, 0], [ 0, 2/h, 0, 0], [ 0, 0, 1/(f-n), -n/(f-n)], [ 0, 0, 0, 1], ], 'f') #later projectionUniform =