Response time will vary greatly on scene complexity, so if I ever start working So for the most part I'm not worried about speed, as theĪlgorithms described here all seem to give me an instant response so far.
3d rectangle code#
Times a second as possible, so the code is called far less than the renderingĪnd animation code. Selection isn't speed critical, since a user won't click to select as many Or in writing the descriptions I've made some mistakes.
Kingdoms Creator, but it's possible when editing code for this tutorial I use all of these selection algorithms (and more) in the 3D The algorithms explained here though can beįairly advanced, and I'm sure I could have gone into more depth in many places. I'm assuming a reader will have knowledge of the basic 3D math, suchĪs the Dot product and its uses. I find knowing as much as possible about 3D math in general (time-permitting) 3D collision detection in particular is closely related to selection. In general, there might be times when you find you can apply some of the ideasĬovered here. For more informationĪbout OpenGL go to If you want to know more about programming a 3D Editor this tutorial shouldīe useful to you, but even if you're more interested in just 3D programming Reads), so it will help to be familiar with OpenGL, but of course the conceptsĪnd descriptions should be useful whatever you use for rendering. In the source code it uses OpenGL for any rendering (or buffer In this tutorial any source code is given in C++, and uses a 3d Select everything within a rectangle using
Render the scene into the back buffer for pixel exact selection.Ĭalculate the world space ray from the point on the screen clicked,Ĭalculate the point a ray intersects with a plane. | 3D Vector Class | Line Mesh Intersection (sample program), Triangle Selection Program You might also want to read my Weekly Articles related to this topic: Line Box Intersection | I may also try to clarify some parts of the text later. I plan to add images and diagrams to this tutorial sometime in the future. ( Visual example of one of the types of selection discussed. Selection Tutorial (3d programming) by Jonathan Kreuzer