2D OpenGL library

1. GLOBAL functions
---------------------------
Graphics(w,h,FullScreen=False,FPS=30)  -- create main display
Cls                                                            --- Clear screen
Flip                                                   -- flip screen (note FPS set by Graphics command)
SetColor() , SetClsColor()             --- global for all 2D drawing/images
SetAlpha() , SetBlend()                      --- global for all 2D drawing/images


2. DISPLAY functions  (under GL Type)
---------------------------
SetOrigin() , SetScale() , SetRotation()  ---  global display transformations
StoreColor() / RestoreColor() -- quick way to snapshot/restore color
ResetDisplay()  -- resets scaling, rotation, origin, color, alpha, blend

3. 2D Drawing (currently global procedural functions)
-------------------------
Plot , DrawLine
DrawOval , DrawPoly , DrawRect --- All having filled / unfilled options
DrawText (default OpenGL version. No fancy stuff. Ideal for degugging)
SetLineWidth()

4. IMAGES (TImage)
-------------------------
:Load(url$,filtered=False) -- Unfiltered or filtered (bilinear)
.Copy() --- copies existing image but sharing same texture
.Grab(x,y) -- grabs screen at x,y into image (fast)
.Draw(x#,y#,frame=0) -- draw an image at x,y
.SetRotation(angle#=0) -- set images rotation
.SetScale(sx#=0,sy#=0) -- set imges scale
.SetSize(w,h) --- set images actual pixel size
.SetFrames(col,row) -- determine animation frames
.SetFrameRect(x#,y#,w#,h#) -- set a rectangular area for rendering
.MidHandle()  -- sets the images handle to central postion
.SetHandle(x#=0,y#=0)  -- Sets images handle to specific location

5. PACKED IMAGES  - Single-Surface type (TPack)
-------------------------
:LoadPack(filename$)   -- loads an image pack (one large image+ini file)
.GetImage(name$)    -- Returns a new TImage (although sharing same texture as stored in the pack)
.CountImages()    -- returns the number of images in the pack

6. FONTS  (TFont)
-------------------------
The font set is generated by a separate tool, which simply renders the
characters into an image, saving this image alongside a *.ini file which 
determines where each character is within the image

:Load(url$,filtered=False) -- Unfiltered or filtered (bilinear)
.DrawText(t$,x,y) --- draws the custom text
.SetScale(sx#=0,sy#=0)   --- scaling for the text
.SetRotation(ang#)  -- rotate the text (from top/left anchor point)

' standard
For n=1 to 1000
   Plot x,y
Next

' speed up
glBegin GL_POINTS
For n=1 To 1000
  glVertex2f x,y
Next
glEnd

Global spriteset:TImage=TImage.Load("pack1.png")

Local fish:TImage=spriteset.Copy()
fish.SetFrameRect 5,5,64,40

Local cat:TImage=spriteset.Copy()
cat.SetFrameRect 74,50,32,26

Global spriteset:TImage=TImage.LoadPack("pack1.png")

Local fish:TImage=TImage.FromPack("fish")

Local cat:TImage=TImage.FromPack("cat")

SuperStrict
Graphics 800,600
SetBlend alphablend
AutoMidHandle True
Local angle:Float = 0
Local scalex:Float = 2.0
Local scaley:Float = 2.0
Local text:String = "center spin text"
Local mX:Float = Float(TextWidth(text))/2.0 'center text x
Local mY:Float = Float(TextHeight(text))/2.0 ' center text y

SetScale scalex,scaley

Repeat
	Cls()

	Local  s:Float = Sin(angle)
	Local  c:Float = Cos(angle)
	' transform variables for scale and rotation
	Local ix:Float = c * scalex
	Local iy:Float =-s * scaley
	Local jx:Float = s * scalex
	Local jy:Float = c * scaley
	' actual reposition of the x and y for rotating in center of text.
	Local x:Float = 300.0 - (mX * ix + mY * iy)
	Local y:Float = 300.0 - (mX * jx + mY * jy)

	SetRotation angle

	For Local n:Int = 0 Until text.length
		Local s:String = Chr(text[n])
		DrawText s,x,y
		Local w:Float = TextWidth(s)
		x :+ w * ix
		y :+ w * jx
	Next
	angle :+ .1
	Flip()
Until KeyDown(key_escape)

msg$="Example of rotated text/nusing font.SetRotation()/nAngle="+String(ang)

fnt.SetRotation ang
fnt.DrawText msg,240,120