Re: triangles & aspects
Sanette <[email protected]> Fri, 24 Mar 2017 07:58:11 +0100
| Newsgroups | gmane.comp.lib.sdl |
|---|---|
| Message-ID | <[email protected]> |
This is a multi-part message in MIME format. --===============8183634492896865277== Content-Type: multipart/alternative; boundary="------------0548F7EFCD319A035FB5C3FE" This is a multi-part message in MIME format. --------------0548F7EFCD319A035FB5C3FE Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 8bit Le 23/03/2017 à 22:19, speartip a écrit : > Hi, > > I am endeavoring to put some simple triangles in my screen. The SDL wiki gives an example of - yes - connecting 3 drawlines. Am I overlooking something or do these lines have to be arrived at mathematically or hardcoded to know what anchoring coordinates they must belong to form the triangle. I don't see a function to make the triangle for you. This becomes rather labor intensive to create your triangle. Also once made, if your aspect ratio changes the lines of the triangle will have to be recalculated to maintain the equality of the angles. I can make a function to correct, no prob. > > Before venturing out on some crazy triangle project, just wanted to know whether I was missing some piece of info. > > > _______________________________________________ > SDL mailing list > [email protected] > http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org Hi your question is not terribly clear. Mathematically, a triangle is just given by 3 points, so there is no problem. (By the way do you want simple triangles or filled triangles ? Do you want anti-aliasing ?) Maybe what you mean in fact is an equilateral triangle: all sides have same length. Then, yes there is some math behind this. There are many possibilities. Either you compute the position of the third point given the first two. Or it might be easier to draw a horizontal segment (the base of the triangle), and then use SDL_RenderCopyEx to copy+rotate by 60° to obtain the two other sides. -- sanette -- full_time_linux --------------0548F7EFCD319A035FB5C3FE Content-Type: text/html; charset=iso-8859-15 Content-Transfer-Encoding: 8bit <html> <head> <meta content="text/html; charset=iso-8859-15" http-equiv="Content-Type"> </head> <body bgcolor="#FFFFFF" text="#000000"> Le 23/03/2017 à 22:19, speartip a écrit :<br> <span style="white-space: pre;">> Hi, > > I am endeavoring to put some simple triangles in my screen. The SDL wiki gives an example of - yes - connecting 3 drawlines. Am I overlooking something or do these lines have to be arrived at mathematically or hardcoded to know what anchoring coordinates they must belong to form the triangle. I don't see a function to make the triangle for you. This becomes rather labor intensive to create your triangle. Also once made, if your aspect ratio changes the lines of the triangle will have to be recalculated to maintain the equality of the angles. I can make a function to correct, no prob. > > Before venturing out on some crazy triangle project, just wanted to know whether I was missing some piece of info. > > > _______________________________________________ > SDL mailing list > <a class="moz-txt-link-abbreviated" href="mailto:[email protected]">[email protected]</a> > <a class="moz-txt-link-freetext" href="http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org">http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org</a></span><br> <br> <br> Hi<br> <br> your question is not terribly clear. Mathematically, a triangle is<br> just given by 3 points, so there is no problem. (By the way do you want<br> simple triangles or filled triangles ? Do you want anti-aliasing ?)<br> <br> Maybe what you mean in fact is an equilateral triangle: all sides have<br> same length. Then, yes there is some math behind this. There are many<br> possibilities. Either you compute the position of the third point<br> given the first two. Or it might be easier to draw a horizontal<br> segment (the base of the triangle), and then use SDL_RenderCopyEx to<br> copy+rotate by 60° to obtain the two other sides.<br> <br> -- <br> sanette -- full_time_linux<br> <br> </body> </html> --------------0548F7EFCD319A035FB5C3FE-- --===============8183634492896865277== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ SDL mailing list [email protected] http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org --===============8183634492896865277==--