glMatrixMode GL_PROJECTION
glLoadIdentity
glFrustum -1 1 -1 1 1 100
glMatrixMode GL_MODELVIEW
glLoadIdentity
glBegin GL_TRIANGLES
glColor 1 0 0
glVertex3 1 -1 -1.1
glColor 0 1 0
glVertex3 1 1 -1.1
glColor 0 0 1
glVertex3 -4 1 -5
glEnd
