matrix - convert Point3D To Screen2D get wrong result in three.js -


i use function in three.js 69

  function point3dtoscreen2d(point3d,camera){     var p = point3d.clone();     var vector = p.project(camera);      vector.x = (vector.x + 1) / 2 * window.innerwidth;     vector.y = -(vector.y - 1) / 2 * window.innerheight;      return vector;    }

it works fine when keep scene still. when rotate scene made mistake , return wrong position in screen.it occurs when rotate how 180 degrees.it shoudn't have position in screen showed.

i set position var tmpv=point3dtoscreen2d(new three.vector3(-67,1033,-2500),camera); in update , show css3d.and when rotate 180 degrees less 360 , point shows in screen again.obviously it's wrong position can telled scene , haven't rotate 360 degrees.

i know little matrix,so don't know how project works.

here source of project in three.js:

project: function () {          var matrix;          return function ( camera ) {              if ( matrix === undefined ) matrix = new three.matrix4();              matrix.multiplymatrices( camera.projectionmatrix, matrix.getinverse( camera.matrixworld ) );             return this.applyprojection( matrix );          };      }()

is matrix.getinverse( camera.matrixworld ) redundant? tried delete , didn't work. can me?thanks.

you projecting 3d point world space screen space using pattern one:

var vector = new three.vector3(); var canvas = renderer.domelement;  vector.set( 1, 2, 3 );  // map normalized device coordinate (ndc) space vector.project( camera );  // map 2d screen space vector.x = math.round( (   vector.x + 1 ) * canvas.width  / 2 ), vector.y = math.round( ( - vector.y + 1 ) * canvas.height / 2 ); vector.z = 0;

however, using approach, points behind camera projected screen space, too.

you said want filter out points behind camera. that, can use pattern first:

var matrix = new three.matrix4(); // create once , reuse  ...  // matrix maps world space camera space matrix.getinverse( camera.matrixworld );  // transform point world space camera space p.applymatrix( matrix );

since camera located @ origin in camera space, , since camera looking down negative-z axis in camera space, points behind camera have z-coordinate greater zero.

// check if point behind camera if ( p.z > 0 ) ...

three.js r.71


-

Popular posts from this blog

c# - ODP.NET Oracle.ManagedDataAccess causes ORA-12537 network session end of file -

overview i want replace oracle.dataaccess orcale. managed dataaccess, opening connection latter throws ora-12537 network session end of file exception. exception message / stack trace {oracleinternal.network.networkexception (0x000030f9): ora-12537 : netzwerksession: dateiende @ oracleinternal.network.readerstream.read(orabuf ob) @ oracleinternal.ttc.orabufreader.getdatafromnetwork() @ oracleinternal.ttc.orabufreader.read(boolean bignoredata) @ oracleinternal.ttc.marshallingengine.unmarshalub1(boolean bignoredata) @ oracleinternal.ttc.ttcprotocolnegotiation.readresponse()} i trying connect oracle 11g database , not have client installed on local machine. working test application (unmanaged) using oracle.dataaccess works fine . using system; using oracle.dataaccess.client; namespace app.odp.unmanaged { internal class program { private static void main(string[] args) { //dummy connection string...
Read more

matlab - Compression and Decompression of ECG Signal using HUFFMAN ALGORITHM -

i want compress , decompress ecg signal stored text message text file , find out file size, cr,prd ratio,and qs. here code compression , decompression of ecg signal using huffman algorithm. i'm trying find out file size, compression ratio,prd ratio,qs. but error i'm getting the ecg file in text format. %clearing variables , screen enter code here clear all; close all; clc; [file1]=uigetfile('*.txt'); %fprintf('enter ecg file name :%s',file1); p=file1; t=sprintf('%s',p); b1=dlmread([file1]); len=length(b1); lead=input('enter lead number :'); %lead=str2double(lead); col2=b1(1:end,lead); e=fix(sqrt(len)); m=1; i=1:e j=1:e g2(i,j)=fix(col2(m)*1000); %amplifying 1000 m=m+1; end end g3=g2; i=1:e j=1:e ...
Read more

utf 8 - split utf-8 string into bytes in python -

i trying split utf-8 string bytes in python 3. problem is, when use bytearray, byte, encode etc functions array size of element 14 bytes, not 1 byte expected. need split text file sequence of bytes , send them byte after byte using sockets. tried this: infile = open (file, "r") str = infile.read() byte_str = bytes(str, 'utf-8') print("size of byte_str",sys.getsizeof(byte_str[0])) print gives me 14, need 1... suggestion? quoting official documentation : sys.getsizeof(object[, default]) return size of object in bytes. object can type of object. built-in objects return correct results, not have hold true third-party extensions implementation specific. only memory consumption directly attributed object accounted for, not memory consumption of objects refers to. if given, default returned if object not provide means retrieve size. otherwise typeerror raised. getsizeof() calls object’s __sizeof__ method , adds ...
Read more