Re: [racket-users] Re: How to draw a 3D ball?
Le 20/07/2015 11:03, Mianlai Zhou a écrit : Hi, Thanks for your answer. I meant the former, i.e., a 2D pict of a ball with some shading to make it look 3D. Is there any quick way to do it or I have to implement the algorithm by myself? The answer is more general than just in the context of Racket... Do you want something of this kind (sorry for the quality, it was just a 30 second test, it could be better). The algorithm is just a radial gradient, and a clipping circle. Its 'softness' translates visually into the amount of specularity, or the roughness, if you prefer. Some exquisite parametrization may be found anywhere, e. g. here (a page on SVG): http://doc.qt.io/qt-5/qtsvg-svgviewer-files-spheres-svg.html which gives: See also the book Flash 3D Cheats Most Wanted by Yard, Balkan, et al. Now, the Racket solution ... You will find the information about radial gradients (with examples) here, in your local doc: ... /doc/draw/radial-gradient_.html?q=gradient#%28tech._radial._gradient%29 On line: http://docs.racket-lang.org/draw/radial-gradient_.html#%28tech._radial._gradient%29 To have something more realistic, you should combine (at least) the diffuse and specular lighting, which is non-linear. Quite easy, and implemented in the 3D simulation in SVG, and several drawing packages, but all depends on your ambitions. For simple drawings, a quite trivial CSS suffices, there is a radial gradient in the standard, and multiple colour stops are possible. http://www.w3schools.com/css/css3_gradients.asp Best regards Jerzy Karczmarczuk /Caen, France/ -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Re: How to draw a 3D ball?
Hi, Thanks for your answer. I meant the former, i.e., a 2D pict of a ball with some shading to make it look 3D. Is there any quick way to do it or I have to implement the algorithm by myself? Thanks again. On Mon, Jul 20, 2015 at 8:38 AM, Jack Firth jackhfi...@gmail.com wrote: On Saturday, July 18, 2015 at 7:30:42 PM UTC-7, Mianlai Zhou wrote: Hi all, I am wondering how to change the following code of a 2D circle into a 3D ball: (require slideshow) (colorize (filled-ellipse (* size 15) (* size 15)) red) My intention is to make the picture look like a real ball in 3-dimension. Is there such a function existing already in Racket? Thank you in advance. By 3D ball do you want a 2D pict of a ball with some shading to make it look 3D, or a 3D model of a ball? If it's the latter you can use the pict3d package (raco pkg install pict3d): (require pict3d) (sphere origin 1) If you do this in DrRacket, the repl will show a window with a 3D ball model in it. You can click it and use the arrow keys to change the angle and position you view the ball from. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[racket-users] Re: How to draw a 3D ball?
On Saturday, July 18, 2015 at 7:30:42 PM UTC-7, Mianlai Zhou wrote: Hi all, I am wondering how to change the following code of a 2D circle into a 3D ball: (require slideshow) (colorize (filled-ellipse (* size 15) (* size 15)) red) My intention is to make the picture look like a real ball in 3-dimension. Is there such a function existing already in Racket? Thank you in advance. By 3D ball do you want a 2D pict of a ball with some shading to make it look 3D, or a 3D model of a ball? If it's the latter you can use the pict3d package (raco pkg install pict3d): (require pict3d) (sphere origin 1) If you do this in DrRacket, the repl will show a window with a 3D ball model in it. You can click it and use the arrow keys to change the angle and position you view the ball from. -- You received this message because you are subscribed to the Google Groups Racket Users group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
