addons/OpenGL/docs/tutorial/lesson1/main.io

   1 // NeHe Tutorial #1
   2 // See original source and C based tutorial at:
   3 // http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=01
   4 //
   5 // Ported to Io by Steve Dekorte 2003
   6 // 2004-08-01 Updated by Doc O'Leary
   7
   8 /*
   9     This code shows how to get OpenGL going with Io.  Support is provided by
  10     the OpenGL object, which is in the ioDesktop binary.  Simply run it with
  11     this file as the argument, and you should get a boring and
  12     empty-yet-stylishly-black GLUT window.
  13
  14     For the most part, the lessons translate fairly directly from the given
  15     C code over to Io.  For the purposes of clarity, only changed code will
  16     be documented, and then only extensively if there is a significant
  17     difference between the site's code and the code ported to Io.
  18 */
  19
  20 // While we could technically clone OpenGL itself, it is really a singleton.
  21 // To avoid adding all these methods to it, we'll simply make it our parent.
  22 Demo := Object clone
  23 Demo appendProto(OpenGL)
  24
  25 // This method handles what ReSizeGLScene does in the original tutorial.
  26 Demo reshape := method(w, h,
  27     glViewport(0, 0, w, h)
  28     glMatrixMode(GL_PROJECTION)
  29     glLoadIdentity
  30     gluPerspective(45.0, w / h, 0.1, 100.0)
  31     glMatrixMode(GL_MODELVIEW)
  32     glLoadIdentity
  33 )
  34
  35 //  Same as the InitGL of the original.
  36 Demo InitGL := method(
  37     glShadeModel(GL_SMOOTH)       // Enables Smooth Shading
  38     glClearColor(0, 0, 0, 0)      // Black Background
  39     glClearDepth(1)               // Enables Clearing Of The Depth Buffer
  40     glEnable(GL_DEPTH_TEST)       // Enables Depth Testing
  41     glDepthFunc(GL_LEQUAL)        // The Type Of Depth Test To Do
  42
  43     glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST)   // Really Nice Perspective Calculations
  44 )
  45
  46 // This method handles what DrawGLScene does in the original tutorial.
  47 Demo display := method(
  48     // Clear The Screen And The Depth Buffer
  49     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
  50     glLoadIdentity
  51
  52     glutSwapBuffers     // Because GLUT double buffers.
  53 )
  54
  55 //  To avoid all the window consruction steps, we just use GLUT.
  56 //  This is same as is done in the main() for Mac OS X:
  57 //  http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=Mac_OS_X
  58 Demo main := method(
  59     glutInit
  60     glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH)
  61     glutInitWindowSize(640, 480)
  62     glutCreateWindow("Jeff Molofee's GL Code Tutorial ... NeHe '99")
  63     glutEventTarget(self)
  64
  65     self InitGL
  66
  67     // Call our display and reshape methods by default.
  68     glutDisplayFunc
  69     glutReshapeFunc
  70
  71     glutMainLoop // Start Event Processing Engine
  72 )
  73
  74 // And, of course, we have to call main to get everything going.
  75 Demo main