#!/usr/bin/env ruby

#/*
# * Copyright (c) 1993-1997, Silicon Graphics, Inc.
# * ALL RIGHTS RESERVED 
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# * or publicity pertaining to distribution of the software without specific,
# * written prior permission. 
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# * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
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# * 
# * US Government Users Restricted Rights #

# * Use, duplication, or disclosure by the Government is subject to
# * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
# * (c)(1)(ii) of the Rights in Technical Data and Computer Software
# * clause at DFARS 252.227-7013 and/or in similar or successor
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# * Unpublished-- rights reserved under the copyright laws of the
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# * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
# *
# * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
# */
#
#/*
# This code was created by Jeff Molofee '99
# (ported to SDL by Sam Lantinga '2000)
#
# If you've found this code useful, please let me know.
#
# Visit me at www.demonews.com/hosted/nehe 
#
##################################################################### 
# Port of NeHe's OpenGL tutorials to Ruby (http://www.ruby-lang.org)
# by Martin Stannard (martin@optushome.com.au)
# 
# Requires the following Ruby libraries:
#
# opengl : http://www2.giganet.net/~yoshi/
# RUDL : http://froukepc.dhs.org/rudl/index.html
# 
# lesson07.rbw :
#
# lit rotating textured cube with switchable texture mapping and lighting
# 
# */

require 'RUDL'
include RUDL
require "opengl"
require 'glut'
require "rational"

include Constant

$Textures = []

xspeed = 0.0
yspeed = 0.0
z = -5.0 # depth into the screen.

# white ambient light at half intensity (rgba) 
$LightAmbient = [0.5, 0.5, 0.5, 1.0]

# super bright, full intensity diffuse light.
$LightDiffuse = [1.0, 1.0, 1.0, 1.0]

# position of light (x, y, z, (position of light)) 
$LightPosition = [0.0, 0.0, 2.0]

# rotation angles
xrot, yrot = 0.0, 0.0

$Filter = 0

ScreenWidth, ScreenHeight = 640, 480

STDOUT.sync = TRUE # flush all output to screen immediately

$d = DisplaySurface.new([ScreenWidth, ScreenHeight], OPENGL|DOUBLEBUF) #|FULLSCREEN)

# Load Bitmaps And Convert To Textures
def loadGLTextures
	# Load Texture
	raw_image = Surface.load_new("Data07/crate.bmp")
	if (raw_image.nil?)
		SDL_Quit
		exit (1)
	end
	# convert bmp from RGB to RGB - no RGB mask on Windows
    image = Surface.new(raw_image.size, SWSURFACE, 24, [0x000000FF, 0x0000FF00, 0x00FF0000, 0])
    image.blit(raw_image, [0,0])

	# Create Texture   
	$Textures = GL.GenTextures(3);

	# texture 1 (poor quality scaling)
	GL.BindTexture(GL::TEXTURE_2D, $Textures[0]);
	GL.TexParameteri(GL::TEXTURE_2D, GL::TEXTURE_MAG_FILTER, GL::NEAREST);
	GL.TexParameteri(GL::TEXTURE_2D, GL::TEXTURE_MIN_FILTER, GL::NEAREST);
	GL.TexImage2D(GL::TEXTURE_2D, 0, 3, image.w, image.h, 0, GL::RGB, GL::UNSIGNED_BYTE, image.pixels)

	# texture 2 (linear scaling)
	GL.BindTexture(GL::TEXTURE_2D, $Textures[1]);
	GL.TexParameteri(GL::TEXTURE_2D, GL::TEXTURE_MAG_FILTER, GL::LINEAR);
	GL.TexParameteri(GL::TEXTURE_2D, GL::TEXTURE_MIN_FILTER, GL::LINEAR);
	GL.TexImage2D(GL::TEXTURE_2D, 0, 3, image.w, image.h, 0, GL::RGB, GL::UNSIGNED_BYTE, image.pixels)
	
	# texture 3 (mipmapped scaling)
	GL.BindTexture(GL::TEXTURE_2D, $Textures[2]);
	GL.TexParameteri(GL::TEXTURE_2D, GL::TEXTURE_MAG_FILTER, GL::LINEAR);
	GL.TexParameteri(GL::TEXTURE_2D, GL::TEXTURE_MIN_FILTER, GL::LINEAR_MIPMAP_NEAREST);
	GL.TexImage2D(GL::TEXTURE_2D, 0, 3, image.w, image.h, 0, GL::RGB, GL::UNSIGNED_BYTE, image.pixels)

	# 2d texture, 3 colors, width, height, RGB in that order, byte data, and the data.
    GLU.Build2DMipmaps(GL::TEXTURE_2D, 3, image.w, image.h, GL::RGB, GL::UNSIGNED_BYTE, image.pixels); 
end

def init(w,h)
  	loadGLTextures
	GL.ClearColor(0.0, 0.0, 0.0, 0.0)
	GL.ClearDepth(1.0)
	GL.DepthFunc(GL::LESS)
	GL.Enable(GL::DEPTH_TEST)
	GL.ShadeModel(GL::SMOOTH)
   
	GL.MatrixMode(GL::PROJECTION)
	GL.LoadIdentity()
   
	GLU.Perspective(45.0, w.to_f/h.to_f, 0.1, 100.0)
	GL.MatrixMode(GL::MODELVIEW)
	GL.LoadIdentity()
	GLU.LookAt(0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0)
	# set up light number 0.
    GL.Light(GL::LIGHT0, GL::AMBIENT, $LightAmbient)  # add lighting. (ambient)
    GL.Light(GL::LIGHT0, GL::DIFFUSE, $LightDiffuse)  # add lighting. (diffuse).
    GL.Light(GL::LIGHT0, GL::POSITION, $LightPosition) # set light position.
    GL.Enable(GL::LIGHT0)                             # turn light 1 on.
  	GL.Enable(GL::LIGHTING)
end

display = Proc.new {
	GL.Clear(GL::COLOR_BUFFER_BIT | GL::DEPTH_BUFFER_BIT) # Clear The Screen And The Depth Buffer

	GL.Enable(GL::TEXTURE_2D);
	GL.BindTexture(GL::TEXTURE_2D, $Textures[$Filter]);

	GL.LoadIdentity();				# make sure we're no longer rotated.
	GL.Translate(0.0, 0.0, z)		# Move Right 3 Units, and back into the screen 7
	
	GL.Rotate(xrot, 1.0, 0.0, 0.0)		# Rotate The Cube On X, Y, and Z
	GL.Rotate(yrot, 0.0, 1.0, 0.0)		# Rotate The Cube On X, Y, and Z
	
	# draw a cube (6 quadrilaterals)
	GL.Begin(GL::QUADS);				# start drawing the cube.

	# top of cube
    GL.Normal( 0.0, 1.0, 0.0);                              	# front face points out of the screen on z.
	GL.TexCoord(0.0, 1.0);	GL.Vertex3f( 1.0, 1.0, -1.0)		# Top Right Of The Quad (Top)
	GL.TexCoord(1.0, 1.0);	GL.Vertex3f(-1.0,  1.0, -1.0)		# Top Left Of The Quad (Top)
	GL.TexCoord(1.0, 0.0);	GL.Vertex3f(-1.0,  1.0,  1.0)		# Bottom Left Of The Quad (Top)
	GL.TexCoord(0.0, 0.0);	GL.Vertex3f( 1.0,  1.0,  1.0)		# Bottom Right Of The Quad (Top)

	# bottom of cube
    GL.Normal( 0.0, -1.0, 0.0);                              	# front face points out of the screen on z.
	GL.TexCoord(0.0, 1.0);	GL.Vertex3f( 1.0, -1.0,  1.0)		# Top Right Of The Quad (Bottom)
	GL.TexCoord(1.0, 1.0);	GL.Vertex3f(-1.0, -1.0,  1.0)		# Top Left Of The Quad (Bottom)
	GL.TexCoord(1.0, 0.0);	GL.Vertex3f(-1.0, -1.0, -1.0)		# Bottom Left Of The Quad (Bottom)
	GL.TexCoord(0.0, 0.0);	GL.Vertex3f( 1.0, -1.0, -1.0)		# Bottom Right Of The Quad (Bottom)
	# front of cube
    GL.Normal( 0.0, 0.0, 1.0);                              	# front face points out of the screen on z.
	GL.TexCoord(0.0, 1.0);	GL.Vertex3f( 1.0,  1.0,  1.0)		# Top Right Of The Quad (Front)
	GL.TexCoord(1.0, 1.0);	GL.Vertex3f(-1.0,  1.0,  1.0)		# Top Left Of The Quad (Front)
	GL.TexCoord(1.0, 0.0);	GL.Vertex3f(-1.0, -1.0,  1.0)		# Bottom Left Of The Quad (Front)
	GL.TexCoord(0.0, 0.0);	GL.Vertex3f( 1.0, -1.0,  1.0)		# Bottom Right Of The Quad (Front)

	# back of cube.
    GL.Normal( 0.0, 0.0, -1.0);                              	# front face points out of the screen on z.
	GL.TexCoord(0.0, 1.0);  GL.Vertex3f( 1.0, -1.0, -1.0)		# Top Right Of The Quad (Back)
	GL.TexCoord(1.0, 1.0); 	GL.Vertex3f(-1.0, -1.0, -1.0)		# Top Left Of The Quad (Back)
	GL.TexCoord(1.0, 0.0); 	GL.Vertex3f(-1.0,  1.0, -1.0)		# Bottom Left Of The Quad (Back)
	GL.TexCoord(0.0, 0.0); 	GL.Vertex3f( 1.0,  1.0, -1.0)		# Bottom Right Of The Quad (Back)

	# left of cube
    GL.Normal( -1.0, 0.0, 0.0);                              	# front face points out of the screen on z.
	GL.TexCoord(0.0, 1.0);	GL.Vertex3f(-1.0,  1.0,  1.0)		# Top Right Of The Quad (Left)
	GL.TexCoord(1.0, 1.0);	GL.Vertex3f(-1.0,  1.0, -1.0)		# Top Left Of The Quad (Left)
	GL.TexCoord(1.0, 0.0);	GL.Vertex3f(-1.0, -1.0, -1.0)		# Bottom Left Of The Quad (Left)
	GL.TexCoord(0.0, 0.0);	GL.Vertex3f(-1.0, -1.0,  1.0)		# Bottom Right Of The Quad (Left)

	# Right of cube
    GL.Normal( 1.0, 0.0, 0.0);                              	# front face points out of the screen on z.
	GL.TexCoord(0.0, 1.0);	GL.Vertex3f( 1.0,  1.0, -1.0)	      	# Top Right Of The Quad (Right)
	GL.TexCoord(1.0, 1.0);	GL.Vertex3f( 1.0,  1.0,  1.0)		# Top Left Of The Quad (Right)
	GL.TexCoord(1.0, 0.0);	GL.Vertex3f( 1.0, -1.0,  1.0)		# Bottom Left Of The Quad (Right)
	GL.TexCoord(0.0, 0.0);	GL.Vertex3f( 1.0, -1.0, -1.0)		# Bottom Right Of The Quad (Right)
	GL.End();

	GL.Disable(GL::TEXTURE_2D);
	xrot += xspeed
	yrot += yspeed
}

reshape = Proc.new { |w, h|
	GL.Viewport(0, 0,  w,  h) 
	GL.MatrixMode(GL::PROJECTION)
	GL.LoadIdentity()
	GLU.Perspective(60.0, w.to_f/h.to_f, 1.0, 20.0)
	GL.MatrixMode(GL::MODELVIEW)
	GL.LoadIdentity()
	GLU.LookAt(0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0)
}

init(ScreenWidth, ScreenHeight)

Key.set_repeat(0,0)

$Light = true

keydown = false
done=false

while !done
	event=EventQueue.poll
	case event
	  #	when MouseButtonDownEvent
	  #	restart
		when QuitEvent
			done = true
		when KeyDownEvent 
		  #keydown = true
			if event.key == K_ESCAPE
				done = false
			end
			if event.key == K_l
	    		$Light = !$Light # switch the current value of light, between 0 and 1.
	        	puts "Light is now #{$Light}"
				if $Light == false
	        		GL.Disable(GL::LIGHTING)
				else
				  	GL.Enable(GL::LIGHTING)
				end
			end
			if event.key == K_f
	        	$Filter += 1 
				$Filter = 0 if $Filter > 2
	        	puts "Filter is now #{$Filter}"
			end
			exit if event.key == K_ESCAPE
	end
	if Key.pressed?.size > 1 # [300][true] ???? 
		z -= 0.005 if Key.pressed?[K_PAGEUP]
		z += 0.005 if Key.pressed?[K_PAGEDOWN]
		xspeed -= 0.004 if Key.pressed?[K_UP]
		xspeed += 0.004 if Key.pressed?[K_DOWN]
		yspeed -= 0.004 if Key.pressed?[K_LEFT]
		yspeed += 0.004 if Key.pressed?[K_RIGHT]
	end
	reshape.call(ScreenWidth, ScreenHeight)
	display.call
	$d.flip
end