The Ring programming language version 1.6 book - Part 59 of 189
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The document describes code for rendering a 3D snowman scene and calculating frames per second using OpenGL and GLUT. It defines functions for drawing a snowman, handling keyboard/mouse input to rotate the camera, and displaying the FPS count using bitmap fonts. Popup menus are created to change rendering options like fill mode, font, and color. The main function initializes GLUT, registers callbacks, and enters the event loop.
The Ring programming language version 1.6 book - Part 59 of 189
- 1. Ring Documentation, Release 1.6 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 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 55.13. Using Fonts 553
- 2. Ring Documentation, Release 1.6 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 // ----------------------------------- // 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() 55.13. Using Fonts 554
- 3. Ring Documentation, Release 1.6 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() 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) 55.13. Using Fonts 555
- 4. Ring Documentation, Release 1.6 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 // ----------------------------------- func main // init GLUT and create window glutInit() glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA) glutInitWindowPosition(100,100) glutInitWindowSize(320,320) glutCreateWindow("RingFreeGLUT - Test 11") // 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 Shot 55.13. Using Fonts 556
- 5. Ring Documentation, Release 1.6 55.14 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 55.14. Frames Per Second 557
- 6. Ring Documentation, Release 1.6 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. 55.14. Frames Per Second 558
- 7. Ring Documentation, Release 1.6 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) 55.14. Frames Per Second 559
- 8. Ring Documentation, Release 1.6 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() 55.14. Frames Per Second 560
- 9. Ring Documentation, Release 1.6 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 55.14. Frames Per Second 561
- 10. Ring Documentation, Release 1.6 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 55.14. Frames Per Second 562