OpenGL: Difference between revisions

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{{libheader|GLUT}}
{{libheader|GLUT}}


In this example, we use [http://en.wikipedia.org/wiki/OpenGL_Utility_Toolkit GLUT] to create a window and handle the main loop in a portable way. Windowing systems like MS Windows and X11 have their own platform-specific ways of handling these things.
In this example, we use [[wp:OpenGL_Utility_Toolkit|GLUT]] to create a window and handle the main loop in a portable way. Windowing systems like MS Windows and X11 have their own platform-specific ways of handling these things.


<lang c>#include<GL/gl.h>
<lang c>#include<GL/gl.h>

Revision as of 22:08, 11 August 2010

Task
OpenGL
You are encouraged to solve this task according to the task description, using any language you may know.
Task
OpenGL
You are encouraged to solve this task according to the task description, using any language you may know.

In this task, the goal is to display a smooth shaded triangle with OpenGL.

Triangle created using C example compiled with GCC 4.1.2 and freeglut3.

AutoHotkey

<lang AutoHotkey>hOpenGL32 := DllCall("LoadLibrary", "Str", "opengl32") Gui, +LastFound +Resize hDC := DllCall("GetDC", "uInt", WinExist())

VarSetCapacity(pfd, 40, 0) NumPut(40, pfd, 0, "uShort") NumPut(1, pfd, 2, "uShort") NumPut(37, pfd, 4, "uInt") NumPut(24, pfd, 9, "uChar") NumPut(16, pfd, 23, "uChar") DllCall("SetPixelFormat", "uInt", hDC, "uInt", DllCall("ChoosePixelFormat", "uInt", hDC, "uInt", &pfd), "uInt", &pfd)

hRC := DllCall("opengl32\wglCreateContext", "uInt", hDC) DllCall("opengl32\wglMakeCurrent", "uInt", hDC, "uInt", hRC) Gui, Show, w640 h480, Triangle OnExit, ExitSub SetTimer, Paint, 50 return


Paint: DllCall("opengl32\glClearColor", "Float", 0.3, "Float", 0.3, "Float", 0.3, "Float", 0) DllCall("opengl32\glClear", "uInt", 0x4100) ;GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT

DllCall("opengl32\glShadeModel", "uInt", 0x1D01) ;GL_SMOOTH

DllCall("opengl32\glLoadIdentity") DllCall("opengl32\glTranslatef", "Float", -15, "Float", -15, "Float", 0)

DllCall("opengl32\glBegin", "uInt", 0x0004) ;GL_TRIANGLES DllCall("opengl32\glColor3f", "Float", 1, "Float", 0, "Float", 0) DllCall("opengl32\glVertex2f", "Float", 0, "Float", 0) DllCall("opengl32\glColor3f", "Float", 0, "Float", 1, "Float", 0) DllCall("opengl32\glVertex2f", "Float", 30, "Float", 0) DllCall("opengl32\glColor3f", "Float", 0, "Float", 0, "Float", 1) DllCall("opengl32\glVertex2f", "Float", 0, "Float", 30) DllCall("opengl32\glEnd")

DllCall("SwapBuffers", "uInt", hDC) return


GuiSize: DllCall("opengl32\glViewport", "Int", 0, "Int", 0, "Int", A_GuiWidth, "Int", A_GuiHeight) DllCall("opengl32\glMatrixMode", "uInt", 0x1701) ;GL_PROJECTION DllCall("opengl32\glLoadIdentity") DllCall("opengl32\glOrtho", "Double", -30, "Double", 30, "Double", -30, "Double", 30, "Double", -30, "Double", 30) DllCall("opengl32\glMatrixMode", "uInt", 0x1700) ;GL_MODELVIEW return


GuiClose: ExitApp


ExitSub: DllCall("opengl32\wglMakeCurrent", "uInt", 0, "uInt", 0) DllCall("opengl32\wglDeleteContext", "uInt", hRC) DllCall("ReleaseDC", "uInt", hDC) DllCall("FreeLibrary", "uInt", hOpenGL32) ExitApp</lang>

C

Library: GLUT

In this example, we use GLUT to create a window and handle the main loop in a portable way. Windowing systems like MS Windows and X11 have their own platform-specific ways of handling these things.

<lang c>#include<GL/gl.h>

  1. include<GL/glut.h>

void paint(void) { glClearColor(0.3,0.3,0.3,0.0); glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

glShadeModel(GL_SMOOTH);

glLoadIdentity(); glTranslatef(-15.0, -15.0, 0.0);

glBegin(GL_TRIANGLES); glColor3f(1.0, 0.0, 0.0); glVertex2f(0.0, 0.0); glColor3f(0.0, 1.0, 0.0); glVertex2f(30.0, 0.0); glColor3f(0.0, 0.0, 1.0); glVertex2f(0.0, 30.0); glEnd();

glFlush(); }

void reshape(int width, int height) { glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0); glMatrixMode(GL_MODELVIEW); }

int main(int argc, char *argv[]) { glutInit(&argc, argv); glutInitWindowSize(640, 480); glutCreateWindow("Triangle");

glutDisplayFunc(paint); glutReshapeFunc(reshape);

glutMainLoop();

return 0; }</lang>

C#

C# example using the OpenTK library, which is multiplatform and provides C# OpenGL bindings for .Net and Mono. This code creates it's own window and draws the triangle into it.

<lang csharp>using OpenTK; using OpenTK.Graphics; namespace OpenGLTest { 

   class Program
   {
       static void Main(string[] args)
       {
           //Create the OpenGL window
           GameWindow window = new GameWindow(640, 480, GraphicsMode.Default, "OpenGL Example");

           GL.MatrixMode(MatrixMode.Projection);
           GL.LoadIdentity();
           GL.Ortho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0);
           GL.MatrixMode(MatrixMode.Modelview);

           //Add event handler to render to the window when called
           window.RenderFrame += new RenderFrameEvent(a_RenderFrame);
           //Starts the window's updating/rendering events
           window.Run();
       }
       static void a_RenderFrame(GameWindow sender, RenderFrameEventArgs e)
       {
           GL.ClearColor(0.3f, 0.3f, 0.3f, 0f);
           GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);

           GL.ShadeModel(ShadingModel.Smooth);

           GL.LoadIdentity();
           GL.Translate(-15.0f, -15.0f, 0.0f);

           GL.Begin(BeginMode.Triangles);
           GL.Color3(1.0f, 0.0f, 0.0f);
           GL.Vertex2(0.0f, 0.0f);
           GL.Color3(0.0f, 1.0f, 0.0f);
           GL.Vertex2(30f, 0.0f);
           GL.Color3(0.0f, 0.0f, 1.0f);
           GL.Vertex2(0.0f, 30.0f);
           GL.End();
           //Swaps the buffers on the window so that what we draw becomes visible
           sender.SwapBuffers();
       }
   }

}</lang>

Clojure

Library: Penumbra

In this example, we use Penumbra, which is an idiomatic wrapper for OpenGL. <lang lisp>(use 'penumbra.opengl) (require '[penumbra.app :as app])

(defn init [state] 

 (app/title! "Triangle")
 (clear-color 0.3 0.3 0.3 0)
 (shade-model :smooth)
 state)

(defn reshape [[x y w h] state] 

 (ortho-view -30 30 -30 30 -30 30)
 (load-identity)
 (translate -15 -15)
 state)

(defn display [[dt time] state] 

 (draw-triangles
   (color 1 0 0) (vertex 0 0)
   (color 0 1 0) (vertex 30 0)
   (color 0 0 1) (vertex 0 30)))

(app/start {:display display, :reshape reshape, :init init} {})</lang>

D

Works with: GDC
Works with: DMD
Library: dglut

opengl_sample.d: <lang d>module opengl_sample; // file name + directory import dglut.core, dglut.window, dglut.opengl;

void main() { 

 with (new Canvas) {
   setName("Triangle");
   map;

   onResize = (Canvas self) { // A delegate literal that takes a parameter.
     with (self) glViewport(0, 0, width, height);
     MatrixMode.Projection.Identity; // For functions without parameters, the () can be omitted.
     glOrtho(-30, 30, -30, 30, -30, 30);
     MatrixMode.Modelview;
   };

   onDisplay=(Canvas self) {
     scope(exit) self.swap; // Scope guards ease exception-safe programming
     glClearColor(0.3f, 0.3f, 0.3f, 0f);
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
     glLoadIdentity;
     // A convenience wrapper around glTranslatef. Supports numbers, arrays and vectors.
     Translate(-15, -15, 0);
     // This is a delegate literal as well. Triangles is a wrapper around glBegin and glEnd.
     Triangles = {
       Color(1f, 0f, 0f); Vertex(0, 0);
       Color(0f, 1f, 0f); Vertex(30, 0);
       Color(0f, 0f, 1f); Vertex(0, 30);
     };
   };
 }
 loop;

}</lang>

Factor

Translated from C <lang factor>USING: kernel math math.rectangles opengl.gl sequences ui ui.gadgets ui.render ; IN: rosettacode.opengl

TUPLE: triangle-gadget < gadget ;

reshape ( width height -- )
   [ 0 0 ] 2dip glViewport
   GL_PROJECTION glMatrixMode
   glLoadIdentity
   -30.0 30.0 -30.0 30.0 -30.0 30.0 glOrtho
   GL_MODELVIEW glMatrixMode ;
paint ( -- )
   0.3 0.3 0.3 0.0 glClearColor
   GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT bitor glClear
   GL_SMOOTH glShadeModel
   glLoadIdentity
   -15.0 -15.0 0.0 glTranslatef
   GL_TRIANGLES glBegin
   1.0 0.0 0.0 glColor3f 0.0 0.0 glVertex2f
   0.0 1.0 0.0 glColor3f 30.0 0.0 glVertex2f
   0.0 0.0 1.0 glColor3f 0.0 30.0 glVertex2f 
   glEnd
   glFlush ;

M: triangle-gadget pref-dim* drop { 640 480 } ; M: triangle-gadget draw-gadget* 

   rect-bounds nip first2 reshape paint ;
triangle-window ( -- )
  [ triangle-gadget new "Triangle" open-window ] with-ui ;

MAIN: triangle-window </lang>

Forth

Works with: bigFORTH
Library: MINOS
Library: Theseus

triangle.fs: <lang forth>import glconst import float glconst also float also opengl also</lang>

triangle.m: <lang forth>#! xbigforth \ automatic generated code \ do not edit

also editor also minos also forth

include triangle.fs component class triangle public: 

 early widget
 early open
 early dialog
 early open-app
( [varstart] )  ( [varend] )

how: 

 : open     new DF[ 0 ]DF s" Triangle" open-component ;
 : dialog   new DF[ 0 ]DF s" Triangle" open-dialog ;
 : open-app new DF[ 0 ]DF s" Triangle" open-application ;

class;

triangle implements 

( [methodstart] )  ( [methodend] )
 : widget  ( [dumpstart] )
       GL[ ^ glcanvas with

0 0 w @ h @ glViewport GL_PROJECTION glMatrixMode glLoadIdentity -30e 30e -30e 30e -30e 30e glOrtho GL_MODELVIEW glMatrixMode 0.3e 0.3e 0.3e 0.0e glClearColor GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT or glClear GL_SMOOTH glShadeModel glLoadIdentity -15e -15e 0e glTranslatef GL_TRIANGLES glBegin 1e 0e 0e glColor3f 0e 0e glVertex2f 0e 1e 0e glColor3f 30e 0e glVertex2f 0e 0e 1e glColor3f 0e 30e glVertex2f glEnd glFlush endwith ]GL ( MINOS ) ^^ CK[ ( x y b n -- ) 2drop 2drop ]CK ( MINOS ) $280 $1 *hfil $1E0 $1 *vfil glcanvas new 

     &1 vabox new
   ( [dumpend] ) ;
 : init  ^>^^  assign  widget 1 :: init ;

class;

main
 triangle open-app
 $1 0 ?DO  stop  LOOP bye ;

script? [IF] main [THEN] previous previous previous</lang>

Haskell

<lang haskell>import Graphics.Rendering.OpenGL import Graphics.UI.GLUT

main = do 

 getArgsAndInitialize
  createWindow "Triangle"
 displayCallback $= display
     
 matrixMode $= Projection
 loadIdentity
 ortho2D 0 30 0 30
 matrixMode $= Modelview 0
 
 mainLoop

display = do 

 clear [ColorBuffer]
 renderPrimitive Triangles $ do
   corner 1 0 0 5 5
   corner 0 1 0 25 5
   corner 0 0 1 5 25
 swapBuffers

corner r g b x y = do color (Color3 r g b :: Color3 GLfloat) 

                     vertex (Vertex2 x y   :: Vertex2 GLfloat)</lang>

J

<lang J>coclass 'example' (coinsert[require) 'jzopengl'

create=:3 :0 

 ogl=: conew'jzopengl'
 wd 'pc p;cc c isigraph opengl rightmove bottommove;pas 0 0;pshow;'

)

p_close=: destroy=:3 :0 

 destroy__ogl
 wd'pclose'
 codestroy

)

corner=:4 :0 

 glColor3d x
 glVertex2d y

)

p_c_paint=:3 :0 

 rc__ogl
 glClear GL_COLOR_BUFFER_BIT
 glBegin GL_TRIANGLES
   1 0 0 corner 0 0-0.5
   0 1 0 corner 1 0-0.5
   0 0 1 corner 0 1-0.5
 glEnd
 show__ogl

)

conew~'example'</lang>

Note: OpenGL's initial state is well defined by the OpenGL standard.

MAXScript

The choice of OpenGL or D3D in MAX is a user configuration setting. All MAXScript code is platform independent. <lang maxscript>newMesh = mesh numVerts:3 numFaces:1 setMesh newMesh vertices:#([-100, -100, 0], [100, -100, 0], [-100, 100, 0]) faces:#([1, 2, 3]) defaultVCFaces newMesh setVertColor newMesh 1 red setVertColor newMesh 2 green setVertColor newMesh 3 blue setCVertMode newMesh true update newMesh viewport.setType #view_top max tool maximize viewport.SetRenderLevel #smoothhighlights</lang>

OCaml

Library: glMLite

<lang ocaml>open GL open Glut

let display() = 

 glClearColor 0.3 0.3 0.3 0.0;
 glClear[GL_COLOR_BUFFER_BIT; GL_DEPTH_BUFFER_BIT];

 glShadeModel GL_SMOOTH;

 glLoadIdentity();
 glTranslate (-15.0) (-15.0) (0.0);

 glBegin GL_TRIANGLES;
 glColor3 1.0 0.0 0.0;
 glVertex2 0.0 0.0;
 glColor3 0.0 1.0 0.0;
 glVertex2 30.0 0.0;
 glColor3 0.0 0.0 1.0;
 glVertex2 0.0 30.0;
 glEnd();

 glFlush();

let reshape ~width ~height = 

 glViewport 0 0 width height;
 glMatrixMode GL_PROJECTION;
 glLoadIdentity();
 glOrtho(-30.0) 30.0 (-30.0) 30.0 (-30.0) 30.0;
 glMatrixMode GL_MODELVIEW;

let () = 

 ignore(glutInit Sys.argv);
 glutInitWindowSize 640 480;
 ignore(glutCreateWindow "Triangle");

 glutDisplayFunc ~display;
 glutReshapeFunc ~reshape;

 glutMainLoop();
</lang>

Perl

<lang perl>use OpenGL;

sub triangle { 

   glBegin GL_TRIANGLES;
   glColor3f 1.0, 0.0, 0.0;
   glVertex2f 5.0, 5.0;
   glColor3f 0.0, 1.0, 0.0;
   glVertex2f 25.0, 5.0;
   glColor3f 0.0, 0.0, 1.0;
   glVertex2f 5.0, 25.0;
   glEnd;

};

glpOpenWindow; glMatrixMode GL_PROJECTION; glLoadIdentity; gluOrtho2D 0.0, 30.0, 0.0, 30.0; glMatrixMode GL_MODELVIEW;

glClear GL_COLOR_BUFFER_BIT; triangle; glpFlush;

glpMainLoop;</lang>

Library: SDL

<lang perl>use SDL::App; use SDL::Event; use SDL::OpenGL;

$app = SDL::App->new( 

 -gl => 1,

);

sub triangle { 

 glBegin(GL_TRIANGLES);
 glColor(1.0, 0.0, 0.0);
 glVertex(5.0, 5.0);
 glColor(0.0, 1.0, 0.0);
 glVertex(25.0, 5.0);
 glColor(0.0, 0.0, 1.0);
 glVertex(5.0, 25.0);
 glEnd();

}

glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(0.0, 30.0, 0.0, 30.0); glMatrixMode(GL_MODELVIEW); glClear(GL_COLOR_BUFFER_BIT); triangle(); $app->sync; $app->loop ({ 

 SDL_QUIT() => sub { exit; },

});</lang>

PicoLisp

This is for the 64-bit version. <lang PicoLisp>(load "@lib/openGl.l")

(glutInit) (glutInitWindowSize 400 300) (glutCreateWindow "Triangle")

(displayPrg 

  (glClearColor 0.3 0.3 0.3 0.0)
  (glClear (| GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT))
  (glShadeModel GL_SMOOTH)
  (glLoadIdentity)
  (glTranslatef -15.0 -15.0 0.0)
  (glBegin GL_TRIANGLES)
  (glColor3f 1.0 0.0 0.0)
  (glVertex2f 0.0 0.0)
  (glColor3f 0.0 1.0 0.0)
  (glVertex2f 30.0 0.0)
  (glColor3f 0.0 0.0 1.0)
  (glVertex2f 0.0 30.0)
  (glEnd)
  (glFlush) )

(reshapeFunc 

  '((Width Height)
     (glViewport 0 0 Width Height)
     (glMatrixMode GL_PROJECTION)
     (glLoadIdentity)
     (glOrtho -30.0 30.0 -30.0 30.0 -30.0 30.0)
     (glMatrixMode GL_MODELVIEW) ) )
  1. Exit upon mouse click

(mouseFunc '((Btn State X Y) (bye)))

(glutMainLoop)</lang>

Python

<lang python>#-*- coding: utf8 -*-

from OpenGL.GL import * from OpenGL.GLUT import *

def paint(): 

   glClearColor(0.3,0.3,0.3,0.0)
   glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)

   glShadeModel(GL_SMOOTH)

   glLoadIdentity()
   glTranslatef(-15.0, -15.0, 0.0)

   glBegin(GL_TRIANGLES)
   glColor3f(1.0, 0.0, 0.0)
   glVertex2f(0.0, 0.0)
   glColor3f(0.0, 1.0, 0.0)
   glVertex2f(30.0, 0.0)
   glColor3f(0.0, 0.0, 1.0)
   glVertex2f(0.0, 30.0)
   glEnd()

   glFlush()

def reshape(width, height): 

   glViewport(0, 0, width, height)
   glMatrixMode(GL_PROJECTION)
   glLoadIdentity()
   glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0)
   glMatrixMode(GL_MODELVIEW)

if __name__ == '__main__': 

   glutInit(1, 1)
   glutInitWindowSize(640, 480)
   glutCreateWindow("Triangle")

   glutDisplayFunc(paint)
   glutReshapeFunc(reshape)

   glutMainLoop()</lang>

R

Library: rgl

<lang R>library(rgl) x <- c(-1, -1, 1) y <- c(0, -1, -1) z <- c(0, 0, 0) M <- cbind(x,y,z) rgl.bg(color="gray15") triangles3d(M, col=rainbow(8))</lang>

Ruby

Library: ruby-opengl

<lang ruby>require 'rubygems' require 'gl' require 'glut'

include Gl include Glut

paint = lambda do 

 glClearColor(0.3,0.3,0.3,0.0)
 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

 glShadeModel(GL_SMOOTH)

 glLoadIdentity
 glTranslatef(-15.0, -15.0, 0.0)

 glBegin(GL_TRIANGLES)
   glColor3f(1.0, 0.0, 0.0)
   glVertex2f(0.0, 0.0)
   glColor3f(0.0, 1.0, 0.0)
   glVertex2f(30.0, 0.0)
   glColor3f(0.0, 0.0, 1.0)
   glVertex2f(0.0, 30.0)
 glEnd

 glFlush

end

reshape = lambda do |width, height| 

 glViewport(0, 0, width, height)
 glMatrixMode(GL_PROJECTION)
 glLoadIdentity
 glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0)
 glMatrixMode(GL_MODELVIEW)

end

glutInit glutInitWindowSize(640, 480) glutCreateWindow("Triangle")

glutDisplayFunc(paint) glutReshapeFunc(reshape)

glutMainLoop</lang>

Tcl

Library: Tk


Library: tcl3d

<lang Tcl>package require Tk package require tcl3d

proc resizedWin {win w h} { 

   glViewport 0 0 $w $h
   glMatrixMode GL_PROJECTION
   glLoadIdentity
   glOrtho -30.0 30.0 -30.0 30.0 -30.0 30.0
   glMatrixMode GL_MODELVIEW

} proc paintShape {win} { 

   glClearColor 0.0 0.0 0.0 0.5
   glClear [expr {$::GL_COLOR_BUFFER_BIT+$::GL_DEPTH_BUFFER_BIT}]
   glShadeModel GL_SMOOTH
   glLoadIdentity
   glTranslatef -15.0 -15.0 0.0
   glBegin GL_TRIANGLES
   glColor3f 1.0 0.0 0.0
   glVertex2f 5.0 5.0
   glColor3f 0.0 1.0 0.0
   glVertex2f 25.0 5.0
   glColor3f 0.0 0.0 1.0
   glVertex2f 5.0 25.0
   glEnd
   $win swapbuffers

}

togl .surface -width 640 -height 480 -double true -depth true \ 

   -displayproc paintShape -reshapeproc resizedWin

pack .surface -fill both -expand 1</lang>Most of this code should be very familiar to anyone looking at the C version above, or with normal Tk applications.

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