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.
C
Compiler: gcc 3.3.3
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.
#include<GL/gl.h>
#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;
}
D
Libraries: dglut, an OpenGL toolkit in the spirit of GLUT. Currently only runs on X11, though MacOS and Win32 support is in progress.
opengl_sample.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; // For functions without parameters, the () can be omitted.
glLoadIdentity;
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;
Translate(-15, -15, 0); // A convenience wrapper around glTranslatef. Supports numbers, arrays and vectors.
Triangles = { // This is a delegate literal as well. Triangles is a wrapper around glBegin and glEnd.
Color(1f, 0f, 0f); Vertex(0, 0);
Color(0f, 1f, 0f); Vertex(30, 0);
Color(0f, 0f, 1f); Vertex(0, 30);
};
};
}
loop;
}
Forth
Compiler: bigFORTH
Libraries: MINOS, Theseus:
triangle.fs:
import glconst import float glconst also float also opengl also
triangle.m:
#! 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]
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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)
MAXScript
The choice of OpenGL or D3D in MAX is a user configuration setting. All MAXScript code is platform independent.
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
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;
Library
This is an example of a library. You may see a list of other libraries used on Rosetta Code at Category:Solutions by Library.
This is an example of a library. You may see a list of other libraries used on Rosetta Code at Category:Solutions by Library.
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; },
});
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()