Hi i am trying to draw a spiral galaxy without usage of point sprites, so far i was able to draw billboards, but in order to display galaxy properly i need to change their size in realtime, with glpointsprites i could just define where i want to put a sprite and set its maximum and minimum size (the whole sizing thing was automatic), like in this video.
Main problem is that i set point sprite size with pixels, and with billboards i use numbers.
So far i set a fixed size:
But it only looks good from this distance.
Anyway, i am now trying to write a sizing function for these billboards, where minimum size is 1 pixel (less than 100.0f dist from a billboard) and maximum is 35 pixels. (more than 3500.0f dist from a billboard)
BUT the problem is how do i calculate size of a billboard to a coressponding size in pixels?
I tried to do some perspective calculations but i am far from getting it done, any help?
and pls dont ask why i dont want to use point sprites, cuz i won't run my program on a different computer after every build, and mine (that i work on) does not support such thing. Oh and i cant use shaders aswell.
But maybe my GL_POINT_SPRITE implementation lacks of something since my cards supports them but i cant make these point textured.
Edited by WiredCat, 22 May 2014 - 08:46 AM.