This document contains Ring code for creating and rendering a 3D cube using RingOpenGL and RingFreeGLUT. It defines functions for initializing GLUT and OpenGL, creating a window, registering callbacks for rendering and user input handling, and contains the main rendering logic. Key functions include initalizing GLUT with glutInit(), registering callbacks like glutDisplayFunc() and glutSpecialFunc(), and defining the display callback which contains the OpenGL code to render the multi-colored cube using GL_QUADS. User input callbacks allow rotating the cube with arrow keys.

1. Ring Documentation, Release 1.5.4
func main
// init GLUT and create window
glutInit()
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA)
glutInitWindowPosition(100,100)
glutInitWindowSize(320,320)
glutCreateWindow("RingFreeGLUT - Test - 9 SnowMan")
// register callbacks
glutDisplayFunc(:renderScene)
glutReshapeFunc(:changeSize)
glutIdleFunc(:renderScene)
glutIgnoreKeyRepeat(1)
glutKeyboardFunc(:processNormalKeys)
glutSpecialFunc(:pressKey)
glutSpecialUpFunc(:releaseKey)
// here are the two new functions
glutMouseFunc(:mouseButton)
glutMotionFunc(:mouseMove)
// OpenGL init
glEnable(GL_DEPTH_TEST)
glEnable(GL_CULL_FACE)
// init Menus
createPopupMenus()
// enter GLUT event processing cycle
glutMainLoop()
Screen Shots:
The First screen shot
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2. Ring Documentation, Release 1.5.4
The Second screen shot
54.15 Make a Cube using RingOpenGL and RingFreeGLUT
Example:
load "freeglut.ring"
load "opengl21lib.ring"
// ----------------------------------------------------------
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// Global Variables
// ----------------------------------------------------------
rotate_y=0
rotate_x=0
// ----------------------------------------------------------
// display() Callback function
// ----------------------------------------------------------
func display
// Clear screen and Z-buffer
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)
// Reset transformations
glLoadIdentity()
// Rotate when user changes rotate_x and rotate_y
glRotatef( rotate_x, 1.0, 0.0, 0.0 )
glRotatef( rotate_y, 0.0, 1.0, 0.0 )
//Multi-colored side - FRONT
glBegin(GL_POLYGON)
glColor3f( 1.0, 0.0, 0.0 ) glVertex3f( 0.5, -0.5, -0.5 ) # P1 is red
glColor3f( 0.0, 1.0, 0.0 ) glVertex3f( 0.5, 0.5, -0.5 ) # P2 is green
glColor3f( 0.0, 0.0, 1.0 ) glVertex3f( -0.5, 0.5, -0.5 ) # P3 is blue
glColor3f( 1.0, 0.0, 1.0 ) glVertex3f( -0.5, -0.5, -0.5 ) # P4 is purple
glEnd()
// White side - BACK
glBegin(GL_POLYGON)
glColor3f( 1.0, 1.0, 1.0 )
glVertex3f( 0.5, -0.5, 0.5 )
glVertex3f( 0.5, 0.5, 0.5 )
glVertex3f( -0.5, 0.5, 0.5 )
glVertex3f( -0.5, -0.5, 0.5 )
glEnd()
// Purple side - RIGHT
glBegin(GL_POLYGON)
glColor3f( 1.0, 0.0, 1.0 )
glVertex3f( 0.5, -0.5, -0.5 )
glVertex3f( 0.5, 0.5, -0.5 )
glVertex3f( 0.5, 0.5, 0.5 )
glVertex3f( 0.5, -0.5, 0.5 )
glEnd()
// Green side - LEFT
glBegin(GL_POLYGON)
glColor3f( 0.0, 1.0, 0.0 )
glVertex3f( -0.5, -0.5, 0.5 )
glVertex3f( -0.5, 0.5, 0.5 )
glVertex3f( -0.5, 0.5, -0.5 )
glVertex3f( -0.5, -0.5, -0.5 )
glEnd()
// Blue side - TOP
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glBegin(GL_POLYGON)
glColor3f( 0.0, 0.0, 1.0 )
glVertex3f( 0.5, 0.5, 0.5 )
glVertex3f( 0.5, 0.5, -0.5 )
glVertex3f( -0.5, 0.5, -0.5 )
glVertex3f( -0.5, 0.5, 0.5 )
glEnd()
// Red side - BOTTOM
glBegin(GL_POLYGON)
glColor3f( 1.0, 0.0, 0.0 )
glVertex3f( 0.5, -0.5, -0.5 )
glVertex3f( 0.5, -0.5, 0.5 )
glVertex3f( -0.5, -0.5, 0.5 )
glVertex3f( -0.5, -0.5, -0.5 )
glEnd()
glFlush()
glutSwapBuffers()
// ----------------------------------------------------------
// specialKeys() Callback Function
// ----------------------------------------------------------
func specialKeys
key = glutEventKey()
// Right arrow - increase rotation by 5 degree
switch Key
on GLUT_KEY_RIGHT
rotate_y += 5
// Left arrow - decrease rotation by 5 degree
on GLUT_KEY_LEFT
rotate_y -= 5
on GLUT_KEY_UP
rotate_x += 5
on GLUT_KEY_DOWN
rotate_x -= 5
off
// Request display update
glutPostRedisplay()
// ----------------------------------------------------------
// main() function
// ----------------------------------------------------------
func main
// Initialize GLUT and process user parameters
glutInit()
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// Request double buffered true color window with Z-buffer
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH)
// Create window
glutCreateWindow("Awesome Cube")
// Enable Z-buffer depth test
glEnable(GL_DEPTH_TEST)
// Callback functions
glutDisplayFunc(:display)
glutSpecialFunc(:specialKeys)
// Pass control to GLUT for events
glutMainLoop()
// Return to OS
Screen Shot:
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6. CHAPTER
FIFTYFIVE
USING RINGOPENGL AND RINGALLEGRO FOR 3D GRAPHICS
In this chapter we will learn about using RingOpenGL and RingAllegro
55.1 3D Cube and Texture
Source Code:
# Load Libraries
load "gamelib.ring" # RingAllegro Library
load "opengl21lib.ring" # RingOpenGL Library
#==============================================================
# To Support MacOS X
al_run_main()
func al_game_start # Called by al_run_main()
main() # Now we call our main function
#==============================================================
func main
new GraphicsApp {
start()
}
class GraphicsApp from GraphicsAppBase
TITLE = "Ring Cube"
bitmap texture
xrot = 0.0
yrot = 0.0
zrot = 0.0
func loadresources
bitmap = al_load_bitmap("ring.bmp")
texture = al_get_opengl_texture(bitmap)
func destroyResources
al_destroy_bitmap(bitmap)
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7. Ring Documentation, Release 1.5.4
func drawScene
w = 800 h = 600
ratio = w / h
glViewport(0, 0, w, h)
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
gluPerspective(45,ratio,1,100)
glMatrixMode(GL_MODELVIEW)
glLoadIdentity()
glEnable(GL_TEXTURE_2D)
glShadeModel(GL_SMOOTH)
glClearColor(0.0, 0.0, 0.0, 0.5)
glClearDepth(1.0)
glEnable(GL_DEPTH_TEST)
glEnable(GL_CULL_FACE)
glDepthFunc(GL_LEQUAL)
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST)
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
glLoadIdentity()
glTranslatef(0.0,0.0,-5.0)
glRotatef(xrot,1.0,0.0,0.0)
glRotatef(yrot,0.0,1.0,0.0)
glRotatef(zrot,0.0,0.0,1.0)
glBindTexture(GL_TEXTURE_2D, texture)
glBegin(GL_QUADS)
// Front Face
glTexCoord2f(0.0, 0.0) glVertex3f(-1.0, -1.0, 1.0)
glTexCoord2f(1.0, 0.0) glVertex3f( 1.0, -1.0, 1.0)
glTexCoord2f(1.0, 1.0) glVertex3f( 1.0, 1.0, 1.0)
glTexCoord2f(0.0, 1.0) glVertex3f(-1.0, 1.0, 1.0)
// Back Face
glTexCoord2f(1.0, 0.0) glVertex3f(-1.0, -1.0, -1.0)
glTexCoord2f(1.0, 1.0) glVertex3f(-1.0, 1.0, -1.0)
glTexCoord2f(0.0, 1.0) glVertex3f( 1.0, 1.0, -1.0)
glTexCoord2f(0.0, 0.0) glVertex3f( 1.0, -1.0, -1.0)
// Top Face
glTexCoord2f(0.0, 1.0) glVertex3f(-1.0, 1.0, -1.0)
glTexCoord2f(0.0, 0.0) glVertex3f(-1.0, 1.0, 1.0)
glTexCoord2f(1.0, 0.0) glVertex3f( 1.0, 1.0, 1.0)
glTexCoord2f(1.0, 1.0) glVertex3f( 1.0, 1.0, -1.0)
// Bottom Face
glTexCoord2f(1.0, 1.0) glVertex3f(-1.0, -1.0, -1.0)
glTexCoord2f(0.0, 1.0) glVertex3f( 1.0, -1.0, -1.0)
glTexCoord2f(0.0, 0.0) glVertex3f( 1.0, -1.0, 1.0)
glTexCoord2f(1.0, 0.0) glVertex3f(-1.0, -1.0, 1.0)
// Right face
glTexCoord2f(1.0, 0.0) glVertex3f( 1.0, -1.0, -1.0)
glTexCoord2f(1.0, 1.0) glVertex3f( 1.0, 1.0, -1.0)
glTexCoord2f(0.0, 1.0) glVertex3f( 1.0, 1.0, 1.0)
glTexCoord2f(0.0, 0.0) glVertex3f( 1.0, -1.0, 1.0)
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// Left Face
glTexCoord2f(0.0, 0.0) glVertex3f(-1.0, -1.0, -1.0)
glTexCoord2f(1.0, 0.0) glVertex3f(-1.0, -1.0, 1.0)
glTexCoord2f(1.0, 1.0) glVertex3f(-1.0, 1.0, 1.0)
glTexCoord2f(0.0, 1.0) glVertex3f(-1.0, 1.0, -1.0)
glEnd()
xrot += 0.3
yrot += 0.2
zrot += 0.4
class GraphicsAppBase
display event_queue ev timeout
timer redraw = true
FPS = 60
SCREEN_W = 800
SCREEN_H = 600
KEY_UP = 1
KEY_DOWN = 2
KEY_LEFT = 3
KEY_RIGHT = 4
Key = [false,false,false,false]
TITLE = "Graphics Application"
func start
SetUp()
loadResources()
eventsLoop()
destroy()
func setup
al_init()
al_init_image_addon()
al_set_new_display_flags(ALLEGRO_OPENGL)
display = al_create_display(SCREEN_W,SCREEN_H)
al_set_Window_title(display,TITLE)
al_clear_to_color(al_map_rgb(0,0,0))
event_queue = al_create_event_queue()
al_register_event_source(event_queue,
al_get_display_event_source(display))
ev = al_new_allegro_event()
timeout = al_new_allegro_timeout()
al_init_timeout(timeout, 0.06)
timer = al_create_timer(1.0 / FPS)
al_register_event_source(event_queue,
al_get_timer_event_source(timer))
al_start_timer(timer)
al_install_mouse()
al_register_event_source(event_queue,
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al_get_mouse_event_source())
al_install_keyboard()
al_register_event_source(event_queue,
al_get_keyboard_event_source())
func eventsLoop
while true
al_wait_for_event_until(event_queue, ev, timeout)
switch al_get_allegro_event_type(ev)
on ALLEGRO_EVENT_DISPLAY_CLOSE
exit
on ALLEGRO_EVENT_TIMER
redraw = true
on ALLEGRO_EVENT_MOUSE_AXES
mouse_x = al_get_allegro_event_mouse_x(ev)
mouse_y = al_get_allegro_event_mouse_y(ev)
on ALLEGRO_EVENT_MOUSE_ENTER_DISPLAY
mouse_x = al_get_allegro_event_mouse_x(ev)
mouse_y = al_get_allegro_event_mouse_y(ev)
on ALLEGRO_EVENT_MOUSE_BUTTON_UP
exit
on ALLEGRO_EVENT_KEY_DOWN
switch al_get_allegro_event_keyboard_keycode(ev)
on ALLEGRO_KEY_UP
key[KEY_UP] = true
on ALLEGRO_KEY_DOWN
key[KEY_DOWN] = true
on ALLEGRO_KEY_LEFT
key[KEY_LEFT] = true
on ALLEGRO_KEY_RIGHT
key[KEY_RIGHT] = true
off
on ALLEGRO_EVENT_KEY_UP
switch al_get_allegro_event_keyboard_keycode(ev)
on ALLEGRO_KEY_UP
key[KEY_UP] = false
on ALLEGRO_KEY_DOWN
key[KEY_DOWN] = false
on ALLEGRO_KEY_LEFT
key[KEY_LEFT] = false
on ALLEGRO_KEY_RIGHT
key[KEY_RIGHT] = false
on ALLEGRO_KEY_ESCAPE
exit
off
off
if redraw and al_is_event_queue_empty(event_queue)
redraw = false
drawScene()
al_flip_display()
ok
callgc()
end
func destroy
destroyResources()
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al_destroy_timer(timer)
al_destroy_allegro_event(ev)
al_destroy_allegro_timeout(timeout)
al_destroy_event_queue(event_queue)
al_destroy_display(display)
al_exit()
func loadresources
func drawScene
func destroyResources
Screen Shot:
55.2 Many Cubes
Source Code:
# Load Libraries
load "gamelib.ring" # RingAllegro Library
load "opengl21lib.ring" # RingOpenGL Library
#==============================================================
# To Support MacOS X
al_run_main()
func al_game_start # Called by al_run_main()
main() # Now we call our main function
#==============================================================
func main
55.2. Many Cubes 554