Re: triangles & aspects
Clangray <[email protected]> Fri, 24 Mar 2017 17:03:33 -0400
| Newsgroups | gmane.comp.lib.sdl |
|---|---|
| Message-ID | <1490389413.1256237.922669192.700597CA@webmail.messagingengine.com> |
This is a multi-part message in MIME format. --===============1477408826352424832== Content-Transfer-Encoding: 7bit Content-Type: multipart/alternative; boundary="_----------=_149038941312562374" This is a multi-part message in MIME format. --_----------=_149038941312562374 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" I know the math, its just if I want to place an equilateral triangle in several different places on the screen I'd like to know what anybody has done before me in this situation: are there any automated functions in SDL2? *Most importantly they need to be filled triangles. How do I fill traingles?? : )* -- Gray Family [email protected] On Fri, Mar 24, 2017, at 02:58 AM, Sanette wrote: > Le 23/03/2017 =C3=A0 22:19, speartip a =C3=A9crit : > > 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 >=20 >=20 > Hi >=20 > 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 ?) >=20 > 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=C2=B0 to obtain the two other sides. >=20 > --=20 > sanette -- full_time_linux >=20 >=20 > _________________________________________________ > SDL mailing list > [email protected] > http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org --_----------=_149038941312562374 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8" <!DOCTYPE html> <html> <head> <title></title> </head> <body><div>I know the math, its just if I want to place an equilateral tria= ngle in several different places on the screen I'd like to know what anybod= y has done before me in this situation: are there any automated functions i= n SDL2?<br></div> <div><br></div> <div> <b>Most importantly they need to be filled triangles. How do I fill t= raingles?? : )</b><br></div> <div><br></div> <div id=3D"sig43414442"><div class=3D"signature">--<br></div> <div class=3D"signature"> Gray Family<br></div> <div class=3D"signature"> [email protected]<br></div> <div class=3D"signature"><br></div> </div> <div><br></div> <div><br></div> <div>On Fri, Mar 24, 2017, at 02:58 AM, Sanette wrote:<br></div> <blockquote type=3D"cite"><div>Le 23/03/2017 =C3=A0 22:19, speartip a =C3= =A9crit :<br></div> <div> <span style=3D"white-space:pre;">> Hi, > > I am endeavoring to put some simple triangles in my screen. The SDL wi= ki gives an example of - yes - connecting 3 drawlines. Am I overlooking som= ething 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 lab= or 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 kn= ow whether I was missing some piece of info. > > > _______________________________________________ > SDL mailing list > <a href=3D"mailto:[email protected]">[email protected]</a> > = <a href=3D"http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org">http://list= s.libsdl.org/listinfo.cgi/sdl-libsdl.org</a></span><br></div> <div> <br></div> <div> <br></div> <div> Hi<br></div> <div> <br></div> <div> your question is not terribly clear. Mathematically, a triangle is<br= ></div> <div> just given by 3 points, so there is no problem. (By the way do you want<br></div> <div> simple triangles or filled triangles ? Do you want anti-aliasing ?)<b= r></div> <div> <br></div> <div> Maybe what you mean in fact is an equilateral triangle: all sides have<br></div> <div> same length. Then, yes there is some math behind this. There are many<br></div> <div> possibilities. Either you compute the position of the third point<br>= </div> <div> given the first two. Or it might be easier to draw a horizontal= <br></div> <div> segment (the base of the triangle), and then use SDL_RenderCopyEx to<= br></div> <div> copy+rotate by 60=C2=B0 to obtain the two other sides.<br></div> <div> <br></div> <div> -- <br></div> <div> sanette -- full_time_linux<br></div> <div> <br></div> <div> <br></div> <div><u>_______________________________________________</u><br></div> <div>SDL mailing list<br></div> <div><a href=3D"mailto:[email protected]">[email protected]</a><br></= div> <div><a href=3D"http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org">http:/= /lists.libsdl.org/listinfo.cgi/sdl-libsdl.org</a><br></div> </blockquote><div><br></div> </body> </html> --_----------=_149038941312562374-- --===============1477408826352424832== 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 --===============1477408826352424832==--