package require tcl3d
proc tclDisplayFunc { toglwin } {
#BEGIN OF MAIN LOOP
# Clear color and depth buffer
glClear [expr $::GL_COLOR_BUFFER_BIT | $::GL_DEPTH_BUFFER_BIT]
glLoadIdentity ; # Reset the current modelview matrix
glTranslatef 0.0 0.0 -5.0 ; # Transformations
glRotatef $::xrot 1.0 0.0 0.0
glRotatef $::yrot 0.0 1.0 0.0
glRotatef $::zrot 0.0 0.0 1.0
drawGeometry ; # Draw the actual geometry
$toglwin swapbuffers ; # Swap front and back buffer
#END OF MAIN LOOP
}

proc tclCreateFunc { toglwin } {

glShadeModel GL_SMOOTH ; # Enable smooth shading
glClearColor 0.0 0.0 0.0 0.5 ; # Black background
glClearDepth 1.0 ; # Depth buffer setup
glEnable GL_DEPTH_TEST ; # Enable depth testing

}


proc tclReshapeFunc { toglwin w h } {

glViewport 0 0 $w $h ; # Reset the current viewport
glMatrixMode GL_PROJECTION ; # Select the projection matrix
glLoadIdentity ; # Reset the projection matrix
# Calculate the aspect ratio of the window
gluPerspective 45.0 [expr double($w)/double($h)] 0.1 100.0
glMatrixMode GL_MODELVIEW ; # Select the modelview matrix
glLoadIdentity ; # Reset the modelview matrix

}