The Ring programming language version 1.6 book - Part 60 of 189

1. Ring Documentation, Release 1.6
// -----------------------------------
// MENUS
// -----------------------------------
func processMenuStatus
status = glutEventStatus()
if status = GLUT_MENU_IN_USE
menuFlag = 1
else
menuFlag = 0
ok
func processMainMenu
// nothing to do in here
// all actions are for submenus
func processFillMenu
option = glutEventValue()
switch option
on C_FILL
glPolygonMode(GL_FRONT, GL_FILL)
on C_LINE
glPolygonMode(GL_FRONT, GL_LINE)
off
func processFontMenu
option = glutEventValue()
switch (option) {
on C_INT_GLUT_BITMAP_8_BY_13
font = GLUT_BITMAP_8_BY_13
on C_INT_GLUT_BITMAP_9_BY_15
font = GLUT_BITMAP_9_BY_15
on C_INT_GLUT_BITMAP_TIMES_ROMAN_10
font = GLUT_BITMAP_TIMES_ROMAN_10
on C_INT_GLUT_BITMAP_TIMES_ROMAN_24
font = GLUT_BITMAP_TIMES_ROMAN_24
on C_INT_GLUT_BITMAP_HELVETICA_10
font = GLUT_BITMAP_HELVETICA_10
on C_INT_GLUT_BITMAP_HELVETICA_12
font = GLUT_BITMAP_HELVETICA_12
on C_INT_GLUT_BITMAP_HELVETICA_18
font = GLUT_BITMAP_HELVETICA_18
off
func processColorMenu
option = glutEventValue()
55.14. Frames Per Second 563

2. Ring Documentation, Release 1.6
switch option
on C_RED
red = 1.0
green = 0.0
blue = 0.0
on C_GREEN
red = 0.0
green = 1.0
blue = 0.0
on C_BLUE
red = 0.0
green = 0.0
blue = 1.0
on C_ORANGE
red = 1.0
green = 0.5
blue = 0.5
off
func createPopupMenus
fontMenu = glutCreateMenu(:processFontMenu)
glutAddMenuEntry("BITMAP_8_BY_13 ",C_INT_GLUT_BITMAP_8_BY_13 )
glutAddMenuEntry("BITMAP_9_BY_15",C_INT_GLUT_BITMAP_9_BY_15 )
glutAddMenuEntry("BITMAP_TIMES_ROMAN_10 ",C_INT_GLUT_BITMAP_TIMES_ROMAN_10 )
glutAddMenuEntry("BITMAP_TIMES_ROMAN_24",C_INT_GLUT_BITMAP_TIMES_ROMAN_24 )
glutAddMenuEntry("BITMAP_HELVETICA_10 ",C_INT_GLUT_BITMAP_HELVETICA_10 )
glutAddMenuEntry("BITMAP_HELVETICA_12",C_INT_GLUT_BITMAP_HELVETICA_12 )
glutAddMenuEntry("BITMAP_HELVETICA_18",C_INT_GLUT_BITMAP_HELVETICA_18 )
fillMenu = glutCreateMenu(:processFillMenu)
glutAddMenuEntry("Fill",C_FILL)
glutAddMenuEntry("Line",C_LINE)
colorMenu = glutCreateMenu(:processColorMenu)
glutAddMenuEntry("Red",C_RED);
glutAddMenuEntry("Blue",C_BLUE);
glutAddMenuEntry("Green",C_GREEN);
glutAddMenuEntry("Orange",C_ORANGE);
mainMenu = glutCreateMenu(:processMainMenu)
glutAddSubMenu("Polygon Mode", fillMenu)
glutAddSubMenu("Color", colorMenu)
glutAddSubMenu("Font",fontMenu)
// attach the menu to the right button
glutAttachMenu(GLUT_RIGHT_BUTTON)
// this will allow us to know if the menu is active
glutMenuStatusFunc(:processMenuStatus)
// -----------------------------------
// MAIN
// -----------------------------------
55.14. Frames Per Second 564

3. Ring Documentation, Release 1.6
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
55.14. Frames Per Second 565

4. Ring Documentation, Release 1.6
The Second screen shot
55.15 Make a Cube using RingOpenGL and RingFreeGLUT
Example:
load "freeglut.ring"
load "opengl21lib.ring"
// ----------------------------------------------------------
55.15. Make a Cube using RingOpenGL and RingFreeGLUT 566

5. Ring Documentation, Release 1.6
// 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
55.15. Make a Cube using RingOpenGL and RingFreeGLUT 567

6. Ring Documentation, Release 1.6
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()
55.15. Make a Cube using RingOpenGL and RingFreeGLUT 568

7. Ring Documentation, Release 1.6
// 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:
55.15. Make a Cube using RingOpenGL and RingFreeGLUT 569

8. CHAPTER
FIFTYSIX
USING RINGOPENGL AND RINGALLEGRO FOR 3D GRAPHICS
In this chapter we will learn about using RingOpenGL and RingAllegro
56.1 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)
570

9. Ring Documentation, Release 1.6
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)
56.1. 3D Cube and Texture 571

10. Ring Documentation, Release 1.6
// 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,
56.1. 3D Cube and Texture 572