The Ring programming language version 1.9 book - Part 67 of 210

1. Ring Documentation, Release 1.9
61.14 Frames Per Second
Example
load "freeglut.ring"
load "opengl21lib.ring"
// angle of rotation for the camera direction
angle = 0.0
// actual vector representing the camera's direction
lx=0.0 lz=-1.0
// XZ position of the camera
x=0.0 z=5.0
// the key states. These variables will be zero
//when no key is being presses
deltaAngle = 0.0
deltaMove = 0
xOrigin = -1
// Constant definitions for Menus
C_RED = 1
C_GREEN = 2
C_BLUE = 3
C_ORANGE = 4
C_FILL = 5
C_LINE = 6
// Pop up menu identifiers
fillMenu=NULL
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2. Ring Documentation, Release 1.9
fontMenu=NULL
mainMenu=NULL
colorMenu=NULL
// color for the nose
red = 1.0
blue=0.5
green=0.5
// scale of snowman
scale = 1.0
// menu status
menuFlag = 0
// default font
font = GLUT_BITMAP_TIMES_ROMAN_24
C_INT_GLUT_BITMAP_8_BY_13 = 7
C_INT_GLUT_BITMAP_9_BY_15 = 8
C_INT_GLUT_BITMAP_TIMES_ROMAN_10 = 9
C_INT_GLUT_BITMAP_TIMES_ROMAN_24 = 10
C_INT_GLUT_BITMAP_HELVETICA_10 = 11
C_INT_GLUT_BITMAP_HELVETICA_12 = 12
C_INT_GLUT_BITMAP_HELVETICA_18 = 13
// width and height of the window
h = 0
w = 0
// variables to compute frames per second
frame=0
time=0
timebase=0
s = ""
func changeSize
w = glutEventWidth()
h = glutEventHeight()
// Prevent a divide by zero, when window is too short
// (you cant make a window of zero width).
if h = 0
h = 1
ok
ratio = w * 1.0 / h
// Use the Projection Matrix
glMatrixMode(GL_PROJECTION)
// Reset Matrix
glLoadIdentity()
// Set the viewport to be the entire window
glViewport(0, 0, w, h)
// Set the correct perspective.
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3. Ring Documentation, Release 1.9
gluPerspective(45.0, ratio, 0.1, 100.0)
// Get Back to the Modelview
glMatrixMode(GL_MODELVIEW)
func drawSnowMan
glScalef(scale, scale, scale)
glColor3f(1.0, 1.0, 1.0)
// Draw Body
glTranslatef(0.0 ,0.75, 0.0)
glutSolidSphere(0.75,20,20)
// Draw Head
glTranslatef(0.0, 1.0, 0.0)
glutSolidSphere(0.25,20,20)
// Draw Eyes
glPushMatrix()
glColor3f(0.0,0.0,0.0)
glTranslatef(0.05, 0.10, 0.18)
glutSolidSphere(0.05,10,10)
glTranslatef(-0.1, 0.0, 0.0)
glutSolidSphere(0.05,10,10)
glPopMatrix()
// Draw Nose
glColor3f(red, green, blue)
glRotatef(0.0,1.0, 0.0, 0.0)
glutSolidCone(0.08,0.5,10,2)
glColor3f(1.0, 1.0, 1.0)
func renderBitmapString x,y,z,font,string
glRasterPos3f(x, y,z)
for c in string
glutBitmapCharacter(font,ascii(c))
next
func renderStrokeFontString x,y,z,font,string
glPushMatrix()
glTranslatef(x, y,z)
glScalef(0.002, 0.002, 0.002)
for c in string
glutStrokeCharacter(font, Ascii(c));
next
glPopMatrix()
func restorePerspectiveProjection
glMatrixMode(GL_PROJECTION)
// restore previous projection matrix
glPopMatrix()
// get back to modelview mode
glMatrixMode(GL_MODELVIEW)
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4. Ring Documentation, Release 1.9
func setOrthographicProjection
// switch to projection mode
glMatrixMode(GL_PROJECTION)
// save previous matrix which contains the
//settings for the perspective projection
glPushMatrix()
// reset matrix
glLoadIdentity()
// set a 2D orthographic projection
gluOrtho2D(0, w, h, 0)
// switch back to modelview mode
glMatrixMode(GL_MODELVIEW)
func computePos deltaMove
x += deltaMove * lx * 0.1
z += deltaMove * lz * 0.1
func renderScene
if deltaMove
computePos(deltaMove)
ok
// Clear Color and Depth Buffers
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
// Reset transformations
glLoadIdentity()
// Set the camera
gluLookAt( x, 1.0, z,
x+lx, 1.0, z+lz,
0.0, 1.0, 0.0)
// Draw ground
glColor3f(0.9, 0.9, 0.9)
glBegin(GL_QUADS)
glVertex3f(-100.0, 0.0, -100.0)
glVertex3f(-100.0, 0.0, 100.0)
glVertex3f( 100.0, 0.0, 100.0)
glVertex3f( 100.0, 0.0, -100.0)
glEnd()
// Draw 9 SnowMen
for i = -3 to -1
for j = -3 to -1
glPushMatrix()
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5. Ring Documentation, Release 1.9
glTranslatef(i*10.0, 0.0, j * 10.0)
drawSnowMan()
number = (i+3)*3+(j+3)
renderBitmapString(0.0, 0.5, 0.0,font ,""+number)
glPopMatrix()
next
next
// Code to compute frames per second
frame++
time=glutGet(GLUT_ELAPSED_TIME)
if time - timebase > 1000
s = "RingFreeGLUT - FPS: " + (frame*1000.0/(time-timebase))
timebase = time
frame = 0
ok
// Code to display a string (fps) with bitmap fonts
setOrthographicProjection()
glPushMatrix()
glLoadIdentity()
renderBitmapString(5,30,0,GLUT_BITMAP_HELVETICA_18,s)
glPopMatrix()
restorePerspectiveProjection()
glutSwapBuffers()
// -----------------------------------
// KEYBOARD
// -----------------------------------
func processNormalKeys
key = glutEventKey()
xx = glutEventX()
yy = glutEventY()
switch key
on 27
glutDestroyMenu(mainMenu)
glutDestroyMenu(fillMenu)
glutDestroyMenu(colorMenu)
glutDestroyMenu(fontMenu)
Shutdown()
off
func pressKey
key = glutEventKey()
xx = glutEventX()
yy = glutEventY()
switch key
on GLUT_KEY_UP
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6. Ring Documentation, Release 1.9
deltaMove = 0.5
on GLUT_KEY_DOWN
deltaMove = -0.5
off
func releaseKey
key = glutEventKey()
switch key
on GLUT_KEY_UP
deltaMove = 0
on GLUT_KEY_DOWN
deltaMove = 0
off
// -----------------------------------
// MOUSE
// -----------------------------------
func mouseMove
xx = glutEventX()
yy = glutEventY()
// this will only be true when the left button is down
if xOrigin >= 0
// update deltaAngle
deltaAngle = (xx - xOrigin) * 0.001
// update camera's direction
lx = sin(angle + deltaAngle)
lz = -cos(angle + deltaAngle)
ok
func mouseButton
button = glutEventButton()
state = glutEventState()
xx = glutEventX()
yy = glutEventY()
// only start motion if the left button is pressed
if button = GLUT_LEFT_BUTTON
// when the button is released
if state = GLUT_UP
angle += deltaAngle
xOrigin = -1
else
// state = GLUT_DOWN
xOrigin = xx
ok
ok
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7. Ring Documentation, Release 1.9
// -----------------------------------
// 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()
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8. Ring Documentation, Release 1.9
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
// -----------------------------------
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9. Ring Documentation, Release 1.9
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
61.14. Frames Per Second 637

10. Ring Documentation, Release 1.9
The Second screen shot
61.15 Make a Cube using RingOpenGL and RingFreeGLUT
Example:
load "freeglut.ring"
load "opengl21lib.ring"
// ----------------------------------------------------------
61.15. Make a Cube using RingOpenGL and RingFreeGLUT 638