

Task

Display a smooth shaded triangle with OpenGL.

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


#include "fbgfx.bi"
#include once "GL/gl.bi"
#include once "GL/glu.bi"
 
screen 18, 16, , 2
 
glViewport 0, 0, 640, 480                      'Set the viewport
glMatrixMode GL_PROJECTION                     ' Select projection
glLoadIdentity                                 ' Set this to default
gluPerspective 45.0, 640./480., 0.1, 100.0   ' Set perspective view options
glMatrixMode GL_MODELVIEW                      ' Set to modelview mode
glLoadIdentity                                 ' ...and set it to default
glClearColor 0.5, 0.5, 0.5, 0.0               ' Set clearscreen color to middle grey
glShadeModel GL_SMOOTH                         ' set to smooth shading
glClearDepth 1.0                               ' Allow the deletion of the depth buffer
glEnable GL_DEPTH_TEST                         ' turn on depth testing
glDepthFunc GL_LEQUAL                          ' The Type Of Depth Test To Do
glHint GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST  ' niceness tweaks
 
do
 
glClear GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT  ' clear screen and depth
glLoadIdentity
 
glTranslatef 0.0f, 0.0f, -6.0f                ' move camera back so we can see the triangle
 
glBegin GL_TRIANGLES                          ' Drawing Using Triangles
    glColor3f 1.0f, 0.0f, 0.0f                  ' red
    glVertex3f  0.0f, 1.0f, 0.0f              ' Top
    glColor3f 0.0f, 1.0f, 0.0f                  ' green
    glVertex3f -1.0f,-1.0f, 0.0f              ' Bottom Left
    glColor3f 0.0f, 0.0f, 1.0f                  ' blue
    glVertex3f  1.0f,-1.0f, 0.0f              ' Bottom Right
glEnd                                         ' Finished Drawing The Triangle
 
flip
 
loop while inkey = ""