c++ - Transformation hierarchy causes object to jump in space? -


i have 2 objects want parent tri child of torus. when , multiply matricies adding parents modelview childs, child jumps in space initially, on right , few units. insert offset this, , how calculate it?

obj = make_shared<object>(*this); obj->rename("tri"); obj->type->val_s = "tri"; obj->t->val_3 = glm::vec3(-4.f, 1.5f, 0.f); allobj.push_back(obj);   obj = make_shared<object>(*this); obj->rename("torus"); obj->type->val_s = "obj"; obj->t->val_3 = glm::vec3(3.f, 2.f, 0.f); allobj.push_back(obj);  //matrix scalem = glm::scale(glm::mat4(), s->val_3); rotationm = glm::tomat4(r_quat); glm::vec3 usablepivot = t->val_3 - pivot->val_3; glm::mat4 localaxis1m = glm::translate(glm::mat4(), usablepivot); glm::mat4 localaxis2m = glm::translate(glm::mat4(), -usablepivot);  translationm = glm::translate(glm::mat4(), t->val_3);  modelm = translationm * localaxis2m * rotationm * scalem * localaxis1m;  //view usableview = mygl->viewm;  //projection usableprojection = mygl->projectionm;  //mvp if (parent == "world") { mvp = usableprojection * usableview * modelm; } else { mvp = usableprojection * usableview * parentto->modelm * modelm; }

matrix order in mine opengl apps:

  1. sub-object matrices

    • the lowest in ownership hierarchy first
    • they local parents
    • their have offset point (0,0,0) of parent space
    • if not , local world jump reason
    • in case sub-objects not sub objects
    • and handle them normal object without parent

  2. object world

    • is transform matrix of objects without parent
    • they local scene world

  3. then goes camera view

    • it inverse of camera space
    • where z-axis view direction

  4. last projection

    • like gluperspective(...)
    • this 1 stored in gl_projection matrix on fixed pipeline
    • instead of gl_modelview

  5. clipping done opengl separately via glviewport

    • (your usable view think)

look more info here

  • you can check content of matrices
  • look @ positions 12,13,14 offset vector stored
  • do not forget vector local parent coordinate system!!!
  • so more rotated ...
  • also idea draw axis lines each tested matrix in parent space
  • to see if correct
  • i use red,gree,blue lines x,y,z - axis
  • just extract origin of coordinate system [12,13,14]
  • and draw line same point + a*axis vector
  • a line length (big enough see line not point)
  • axis vectors @ positions x=[0,1,2], y=[4,5,6], z=[8,9,10]
  • do not forget set matrices parent coordinate system !!!
  • if handle matrices self via glsl not forget that
  • direction vectors normals transformed without offset
  • so whole transform matrix (all multilicated without projection , camera)
  • set offset 0 [12,13,14]=(0.0,0.0,0.0)
  • and multiply matrix

Comments

Post a Comment

Popular posts from this blog

javascript - RequestAnimationFrame not working when exiting fullscreen switching space on Safari -

request animation frame stops working when exiting fullscreen clicking on original space's safari window. fine if fullscreen mode canceled escape key or calling cancelfullscreen(). steps reproduce: open https://dl.dropboxusercontent.com/u/769042/prezi/safari-fullscreen.html click "draw raf", kittie appears click "fullscreen", go fullscreen click "draw raf", kittie appears go space original safari was, showing "click exit fullscreen mode", click anywhere, out fullscreen click "draw raf", nothing happens what handling click calling: window.requestanimationframe(draw); which draws on canvas context: function draw() { ctx.drawimage(img, math.random()*500|0, math.random()*400|0, 100, 100); } i checked .hidden , .visibilitystate, updated correctly. tested on osx 10.9.3, safari 7.0.4 (9537.76.4). has workaround/solution other switching old settimeout? this sounds webkit bug 88940 : using reque...
Read more

jsf - How to ajax update an item in the footer of a PrimeFaces dataTable? -

this visual of table have: +---------+------------+-------------------+ | header1 | header2 | header3 | +---------+------------+-------------------+ | row | input | calc'ed output | | row b | input b | calc'ed output b | | etc.. | etc.. | etc.. | +---------+------------+-------------------+ | total: total calc'ed output | +------------------------------------------+ and stripped-down code: <p:datatable id="mytable" value="#{mybean.somelist}" var="currentitem"> <p:column headertext="header1"> <h:outputtext value="#{currentitem.name}" /> </p:column> <p:column headertext="header2"> <pe:inputnumber value="#{currentitem.inputval}"> <p:ajax event="change" listener="#{mybean.changelistener}" update="outputval outputtotal...
Read more

django - CSRF verification failed. Request aborted. CSRF cookie not set -

error: reason given failure: csrf cookie not set. in general, can occur when there genuine cross site request forgery, or when django's csrf mechanism has not been used correctly. post forms, need ensure: browser accepting cookies. view function uses requestcontext template, instead of context. in template, there {% csrf_token %} template tag inside each post form targets internal url. if not using csrfviewmiddleware, must use csrf_protect on views use csrf_token template tag, accept post data. you're seeing section of page because have debug = true in django settings file. change false, , initial error message displayed. can customize page using csrf_failure_view setting. did find, nothing helped, must foolish(( my template <form method="post">{% csrf_token %} {% field in form %} <div class="control-group"> {{ field }} </div> {% endfor %} <input type=...
Read more